CA2438700A1 - Membrane separation for sulfur reduction - Google Patents
Membrane separation for sulfur reduction Download PDFInfo
- Publication number
- CA2438700A1 CA2438700A1 CA002438700A CA2438700A CA2438700A1 CA 2438700 A1 CA2438700 A1 CA 2438700A1 CA 002438700 A CA002438700 A CA 002438700A CA 2438700 A CA2438700 A CA 2438700A CA 2438700 A1 CA2438700 A1 CA 2438700A1
- Authority
- CA
- Canada
- Prior art keywords
- sulfur
- naphtha
- membrane
- feed
- fraction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G53/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes
- C10G53/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only
- C10G53/08—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only including at least one sorption step
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
- C10G67/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
- C10G31/11—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by dialysis
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G53/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes
- C10G53/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only
Abstract
A membrane process for the removal of sulfur species from a naphtha feed, in particular, a FCC light cat naphtha, without a substantial loss of olefin yield is disclosed. The process involves contacting a naphtha feed stream wi th a membrane having sufficient flux and selectivity to separate a sulfur deficient retentate fraction from a sulfur enriched permeate fraction, preferably, under pervaporation conditions. Sulfur deficient retentate fractions are useful directly into the gasoline pool. Sulfur-enriched permea te fractions are rich in sulfur containing aromatic and nonaromatic hydrocarbon s and are further treated with conventional sulfur removal technologies, e.g. hydrotreating, to reduce sulfur content. The process of the invention provid es high quality naphtha products having a reduced sulfur content and a high content of olefin compounds.
Description
MEMBRANE SEPARATION FOR SULFUR REDUCTION
FIELD OF THE INVENTION
The present invention relates to a process of reducing sulfur content in a hydrocarbon stream. More specifically, the present invention relates to a membrane separation process for reducing the sulfur content of a naphtha feed stream, in particular, a FCC cat naphtha, while substantially maintaining the initial olefin content of the feed.
BACKGROUND OF THE INVENTION
1o Environmental concerns have resulted in legislation which places limits on the sulfur content of gasoline. In the European Union, for instance, a maximum sulfur level of 150 ppm by the year 2000 has been stipulated, with a further reduction to a maximum of 50 ppm by the year 2005. Sulfur in the gasoline is a direct contributor of SOx emissions, and it also poisons the low temperature activity of automotive catalytic 15 converters. When considering the effects of changes in fuel composition on emissions, . lowering the level of sulfur has the largest potential for combined reduction in hydrocarbon, CO and NOx emissions.
Gasoline comprises a mixture of products from several process units, but the major source of sulfur in the gasoline pool is fluid catalytic cracking (FCC) naphtha 2o which usually contributes between a third and a half of the total amount of the gasoline pool. Thus, effective sulfur reduction is most efficient when focusing attention on FCC
naphtha.
A number of solutions have been suggested to reduce sulfur in gasoline, but none of them have proven to be ideal. Since sulfur in the FCC feed is the prime 25 contributor of sulfur level in FCC naphtha, an obvious approach is hydrotreating the feed.
While hydrotreating allows the sulfur content in gasoline to be reduced to any desired level, installing or adding the necessary hydrotreating capacity requires a substantial capital expenditure and increased operating costs. Further, olefin and naphthene compounds are susceptible to hydrogenation during hydrotreating. This leads to a significant loss in octane number. Hydrotreating the FCC naphtha is also problematic since the high olefin content is again prone to hydrogenation.
Little has been reported on the selective permeation of sulfur containing compounds using a membrane separation process. For example, U.S. Patent 5,396,019 (Sartori et al.) teaches the use of crosslinked fluorinated polyolefin membranes for aromatics/saturates separation. Example 7 of this patent reports thiophene at a level of 500 ppm.
U.5. Patent 5,643,442 (Sweet et al.) teaches the lowering of sulfur content from a hydrotreated distillate effluent feed using a membrane separation process. The preferred to membrane is a polyester-imide membrane operated under pervaporation conditions.
U.5. Patent 4,962,271 (Black et al.) teaches the selective separation of mufti-ring aromatic hydrocarbons from lube oil distillates by perstraction using a polyurea/urethane membrane. The Examples discuss benzothiophenes analysis for separated fractions.
U.5. Patent 5,635,055 (Sweet et al.) discloses a method for increasing the yields of gasoline and light olefins from a liquid hydrocarbonaceous feed stream boiling in the ranges of 650°F to about 1050°F. The method involves thermal or catalytic cracking the feed, passing the cracked feed through an aromatic separation zone containing a polyester-imide membrane to separate aromatic/non-aromatic rich fractions, and thereafter, treating the non-aromatic rich fraction to further cracking processing. A sulfur enrichment factor of less than 1.4 was achieved in the permeate.
U.5. Patent 5,005,632 (Schucker) discloses a method of separating mixtures of aromatics and non-aromatics into aromatic enriched streams and non-aromatics-enriched streams using one side of a poly-urea/urethane membrane.
It would be highly desirable to use a selective membrane separation technique for the reduction of sulfur in hydrocarbon streams, in particular, naphtha streams.
Membrane processing offers a number of potential advantages over conventional sulfur removal processes, including greater selectivity, lower operating costs, easily scaled operations, adaptability to changes in process streams and simple control schemes.
FIELD OF THE INVENTION
The present invention relates to a process of reducing sulfur content in a hydrocarbon stream. More specifically, the present invention relates to a membrane separation process for reducing the sulfur content of a naphtha feed stream, in particular, a FCC cat naphtha, while substantially maintaining the initial olefin content of the feed.
BACKGROUND OF THE INVENTION
1o Environmental concerns have resulted in legislation which places limits on the sulfur content of gasoline. In the European Union, for instance, a maximum sulfur level of 150 ppm by the year 2000 has been stipulated, with a further reduction to a maximum of 50 ppm by the year 2005. Sulfur in the gasoline is a direct contributor of SOx emissions, and it also poisons the low temperature activity of automotive catalytic 15 converters. When considering the effects of changes in fuel composition on emissions, . lowering the level of sulfur has the largest potential for combined reduction in hydrocarbon, CO and NOx emissions.
Gasoline comprises a mixture of products from several process units, but the major source of sulfur in the gasoline pool is fluid catalytic cracking (FCC) naphtha 2o which usually contributes between a third and a half of the total amount of the gasoline pool. Thus, effective sulfur reduction is most efficient when focusing attention on FCC
naphtha.
A number of solutions have been suggested to reduce sulfur in gasoline, but none of them have proven to be ideal. Since sulfur in the FCC feed is the prime 25 contributor of sulfur level in FCC naphtha, an obvious approach is hydrotreating the feed.
While hydrotreating allows the sulfur content in gasoline to be reduced to any desired level, installing or adding the necessary hydrotreating capacity requires a substantial capital expenditure and increased operating costs. Further, olefin and naphthene compounds are susceptible to hydrogenation during hydrotreating. This leads to a significant loss in octane number. Hydrotreating the FCC naphtha is also problematic since the high olefin content is again prone to hydrogenation.
Little has been reported on the selective permeation of sulfur containing compounds using a membrane separation process. For example, U.S. Patent 5,396,019 (Sartori et al.) teaches the use of crosslinked fluorinated polyolefin membranes for aromatics/saturates separation. Example 7 of this patent reports thiophene at a level of 500 ppm.
U.5. Patent 5,643,442 (Sweet et al.) teaches the lowering of sulfur content from a hydrotreated distillate effluent feed using a membrane separation process. The preferred to membrane is a polyester-imide membrane operated under pervaporation conditions.
U.5. Patent 4,962,271 (Black et al.) teaches the selective separation of mufti-ring aromatic hydrocarbons from lube oil distillates by perstraction using a polyurea/urethane membrane. The Examples discuss benzothiophenes analysis for separated fractions.
U.5. Patent 5,635,055 (Sweet et al.) discloses a method for increasing the yields of gasoline and light olefins from a liquid hydrocarbonaceous feed stream boiling in the ranges of 650°F to about 1050°F. The method involves thermal or catalytic cracking the feed, passing the cracked feed through an aromatic separation zone containing a polyester-imide membrane to separate aromatic/non-aromatic rich fractions, and thereafter, treating the non-aromatic rich fraction to further cracking processing. A sulfur enrichment factor of less than 1.4 was achieved in the permeate.
U.5. Patent 5,005,632 (Schucker) discloses a method of separating mixtures of aromatics and non-aromatics into aromatic enriched streams and non-aromatics-enriched streams using one side of a poly-urea/urethane membrane.
It would be highly desirable to use a selective membrane separation technique for the reduction of sulfur in hydrocarbon streams, in particular, naphtha streams.
Membrane processing offers a number of potential advantages over conventional sulfur removal processes, including greater selectivity, lower operating costs, easily scaled operations, adaptability to changes in process streams and simple control schemes.
SUMMARY OF THE INVENTION
We have now developed a selective membrane separation process which preferentially reduces the sulfur content of a hydrocarbon containing naphtha feed while substantially maintaining the content of olefins presence in the feed. The term "substantially maintaining the content of olefins presence in the feed" is used herein to indicate maintaining at least 50 wt % of olefins initially present in the untreated feed. In accordance with the process of the invention, the naphtha feed stream is contacted with a membrane separation zone containing a membrane having a sufficient flux and selectivity to separate a permeate fraction enriched in aromatic and nonaxomatic hydrocarbon 1 o containing sulfur species and a sulfur deficient retentate fraction. The retentate fraction produced by the membrane process can be employed directly or blended into a gasoline pool without further processing. The sulfur enriched fraction is treated to reduce sulfur content using conventional sulfur removal technologies, e.g. hydrotreating.
The sulfur reduced permeate product may thereafter be blended into a gasoline pool.
In accordance with the process of the invention, the sulfur deficient retentate comprises no less than 50 wt % of the feed and retains greater than 50 wt % of the initial olefin content of the feed. Consequently, the process of the invention offers the advantage of improved economics by minimizing the volume of the feed to be treated by conventional high cost sulfur reduction technologies, e.g. hydrotreating.
Additionally, the 2o process of the invention provides for an increase in the olefin content of the overall naphtha product without the need for additional processing to restore octane values.
The membrane process of the invention offers further advantages over conventional sulfur removal processes such as lower capital and operating expenses, greater selectivity, easily scaled operations, and greater adaptability to changes in process streams and simple control schemes.
DETAILED DESCRIPTION OF THE DRAWING
The Figure outlines the membrane process of the invention for the reduction of the sulfur content of a naphtha feed stream.
DETAILED DESCRIPTION OF THE INVENTION
The membrane process of the invention is useful to produce high quality naphtha products having a reduced sulfur content and a high olefin content. In accordance with the process of the invention, a naphtha feed containing olefins and sulfur containing-io aromatic hydrocarbon compounds and sulfur containing-nonaromatic hydrocarbon compounds, is conveyed over a membrane separation zone to reduce sulfur content. The membrane separation zone comprises a membrane having a sufficient flux and selectivity to separate the feed into a sulfur deficient retentate fraction and a permeate fraction enriched in both aromatic and non-aromatic sulfur containing hydrocarbon compounds as 15 compared to the intial naphtha feed. The naphtha feed is in a liquid or substantially liquid form.
For purposes of this invention, the term "naphtha" is used herein to indicate hydrocarbon streams found in refinery operations that have a boiling range between about 50°C to about 220°C. Preferably, the naphtha is not hydrotreated prior to use in the 2o invention process. Typically, the hydrocarbon streams will contain greater than 150 ppm, preferably from about 150 ppm to about 3000 ppm, most preferably from about 300 to about 1000 ppm, sulfur.
The term "aromatic hydrocarbon compounds" is used herein to designate a hydrocarbon-based organic compound containing one or more aromatic rings, e.g.
fused 25 and/or bridged. An aromatic ring is typified by benzene having a single aromatic nucleus.
Aromatic compounds having more than one aromatic ring include, for example, naphthalene, anthracene, etc. Preferred aromatic hydrocarbons useful in the present invention include those having 1 to 2 aromatic rings.
The term "non-aromatic hydrocarbon" is used herein to designate a hydrocaxbon-based organic compound having no aromatic nucleus.
For the purposes of this invention, the term "hydrocarbon" is used to mean an organic compound having a predominately hydrocarbon character. It is contemplated within the scope of this def nition that a hydrocarbon compound may contain at least one non-hydrocarbon radical (e.g. sulfur or oxygen) provided that said non-hydrocarbon radical does not alter the predominant hydrocarbon nature of the organic compound and/or does not react to alter the chemical nature of the membrane within the context of the present invention.
1o For purposes of this invention, the term "sulfur enrichment factor" is used herein to indicate the ratio of the sulfur content in the permeate divided by the sulfur content in the feed.
The sulfur deficient retentate fraction obtained using the membrane process of the invention typically contains less than 100 ppm, preferably less than 50 ppm , and most preferably, less than 30 ppm sulfur. In a preferred embodiment, the sulfur content of the recovered retentate stream is from less than 30 wt %, preferably less than 20 wt %, and most preferably less than 10 wt % of the initial sulfur content of the feed.
The Figure outlines a preferred membrane process in accordance with the present invention. A naphtha feed stream 1 containing sulfur and olefin compounds is contacted 2o with the membrane 2. The feed stream 1 is split into a permeate stream 3 and a retentate stream 4. The retentate stream 4 is reduced in sulfur content but substantially retains the olefin content of the feed stream 1. The retentate stream 4 may be sent to the gasoline pool without further processing. The permeate stream 3 contains a high sulfur content and is treated with conventional sulfur reduction technology to produce a reduced sulfur permeate stream 5 which is also blended into the gasoline pool.
Advantageously, the total naphtha product resulting from the retentate stream and reduced sulfur permeate stream 5 will have a higher olefin content when compared to the olefin content of a product stream resulting from 100% treatment with conventional sulfur reduction technology, e.g., hydrotreating. Typically, the olefin content of the total naphtha product will be at least 50 wt %, preferably at least 70 wt %, most preferably at least 80 wt %, of the total feed passed over the membrane. For purposes of the invention, the term "total naphtha product" is used herein to indicate the total amount of sulfur deficient retentate product and reduced sulfur permeate product.
The retentate stream 4 and the permeate stream 5 may be used combined into a gasoline pool or in the alternative, may be used for different purposes. For example, retentate stream 4 may be blended into the gasoline pool, while permeate stream 5 is used, for example, as a feed stream to a reformer.
1 o The quantity of retentate 4 produced by the system determines the %
recovery, which is the fraction of retentate 4 compared to the initial naphtha feed stream.
Preferably, the membrane process is conducted at high % recovery in order to decrease costs. Costs per cubic meter of naphtha treated depends upon such factors as capital equipment, membrane, energy, and operating costs. As the amount of % recovery increases, the required membrane selectivity for a one-stage system increases, while the relative system cost decreases. For a membrane operating at 50% recovery, an overall 1.90 sulfur enrichment factor is typical. At 80% recovery, an overall sulfur enrichment factor of 4.60 is typical. As will be understood by one skilled in the arts, system costs will go down with increased % recovery, since less feed is vaporized through the 2o membrane, requiring lower energy and less membrane area.
Generally, the sulfur deficient retentate fraction contains at least 50 wt %, preferably at least 70 wt %, most preferably at least 80 wt %, of the total feed passed over the membrane. Such a high recovery of sulfur deficient product provides increased economics by minimizing the volume of the feed which is typically treated by high cost sulfur reduction technologies, such as hydrotreating. Typically, the membrane process reduces the amount of naphtha feed sent for further sulfur reduction by 50%, preferably by about 70%, most preferably, by about 80%.
Hydrocarbon feeds useful in the membrane process of the invention comprise naphtha containing feeds that boil in the gasoline boiling range, 50°C
to about 220°C
which fraction contains sulfur and olefin unsaturation. Feeds of this type include light naphthas typically having a boiling range of about 50°C to about 105°C , intermediate naphtha typically having a boiling range of about l OS°C to about 160°C and heavy naphthas having a boiling range of about 160°C to about 220°C.
The process can be applied to thermally cracked naphthas such as pyrolysis gasoline and coker naphtha. In a preferred embodiment of the invention, the feed is a catalytically cracked naphtha produced in such processes as Thermofor Catalytic Cracking (TCC) and FCC since both 1o processes typically produce naphthas characterized by the presence of olefin unsaturation and sulfur. In the more preferred embodiment of the invention, the hydrocarbon feed is an FCC naphtha, with the most preferred feed being a FCC light cat naphtha having a boiling range of about SO°C to about 105°C. It is also contemplated within the scope of the invention that the feed may be a straight run naphtha having a boiling range between about 50°C to about 220°C.
Membranes useful in the present invention are those membranes having a sufficient flux and selectivity to permeate sulfur containing compounds in the presence of naphtha containing sulfur and olefin unsaturation. The membrane will typically have a sulfur enrichment factor of greater than 1.5, preferably greater than 2, even more 2o preferably from about 2 to about 20, most preferably from about 2.5 to 15.
Preferably, the membranes have an asymmetric structure which may be defined as an entity composed of a dense ultra-thin top "skin" layer over a thicker porous substructure of a same or different material. Typically, the asymmetric membrane is supported on a suitable porous backing or support material.
In a preferred embodiment of the invention, the membrane is a polyimide membrane prepared from a Matrimid~ 5218 or a Lenzing polyimide polymer as described in U.S. Patent Application Serial No. 091126,261, herein incorporated by reference.
In another embodiment of the invention, the membrane is one having a siloxane based polymer as part of the active separation layer. Typically, this separation layer is coated onto a microporous or ultrafiltration support. Examples of membrane structure incorporating polysiloxane functionality are found in U.S. Patent No.
4,781,733, U.S.
Patent 4,243,701, U.S. Patent No. 4,230,463, U.S. Patent No. 4,493,714, U.S.
Patent No.
5,265,734, U.S. Patent No. 5,286,280 and U.S. Patent No. 5,733,663, said references being herein incorporated by reference.
In still another embodiment of the invention, the membrane is an aromatic polyurea/urethane membrane as disclosed in U.S. Patent 4,962,271, herein incorporated l0 by reference, which polyurea/urethane membranes are characterized as possessing a urea index of at least 20 % but less than 100%, an aromatic carbon content of at least 1 S mole %, a functional group density of at least about 10 per 1000 grams of polymer, and a C=O/NH ratio of less than about 8.
I5 The membranes can be used in any convenient form such as sheets, tubes or hollow fibers. Sheets can be used to fabricate spiral wound modules familiar to those skilled in the art. Alternatively, sheets can be used to fabricate a flat stack permeator comprising a multitude of membrane layers alternately separated by feed-retentate spacers and permeate spacers. This device is described in U.S. Patent No. 5,104,532, herein 2o incorporated by reference.
Tubes can be used in the form of mufti-leaf modules wherein each tube is flattened and placed in parallel with other flattened tubes. Internally each tube contains a spacer. Adjacent pairs of flattened tubes are separated by layers of spacer material. The flattened tubes with positioned spacer material is fitted into a pressure resistant housing 25 equipped with fluid entrance and exit means. The ends of the tubes are clamped to create separate interior and exterior zones relative to the tubes in the housing.
Apparatus of this type is described and claimed in U.S. Patent No. 4,761,229, herein incorporated by 'reference.
Hollow fibers can be employed in bundled arrays potted at either end to form tube sheets and fitted into a pressure vessel thereby isolating the insides of the tubes from the outsides of the tubes. Apparatus of this type are known in the art. A
modification of the standard design involves dividing the hollow fiber bundle into separate zones by use of baffles which redirect fluid flow on the tube side of the bundle and prevent fluid channeling and polarization on the tube side. This modification is disclosed and claimed in U.S. Patent No. 5,169,530, herein incorporated by reference.
Multiple separation elements, be they spirally wound, plate and frame, or hollow fiber elements can be employed either in series or in parallel. U.S. Patent No. 5,238,563, l0 herein incorporated by reference, discloses a multiple-element housing wherein the elements are grouped in parallel with a feed/retentate zone defined by a space enclosed by two tube sheets arranged at the same end of the element.
The process of the invention employs selective membrane separation conducted under pervaporation or perstxaction conditions. Preferably, the process is conducted 15 under pervaporation conditions.
The pervaporation process relies on vacuum or sweep gas on the permeate side to evaporate or otherwise remove the permeate from the surface to the membrane.
The feed is in the liquid andlor gas state. When in the gas state the process can be described as vapor permeation. Pervaporation can be performed at a temperature of from about 25°C
2o to 200°C and higher, the maximum temperature being that temperature at which the membrane is physically damaged. It is preferred that the pervaporation process be operated as a single stage operation to reduce capital costs.
The pervaporation process also generally relies on vacuum on the permeate side to evaporate the permeate from the surface of the membrane and maintain the concentration 25 gradient driving force which drives the separation process. The maximum temperature employed in pervaporation will be that necessary to vaporize the components in the feed which one desires to selectively permeate through the membrane while still being below the temperature at which the membrane is physically damaged. Alternatively to a vacuum, a sweep gas can be used on the permeate side to remove the product. In this mode the permeate side would be at atmospheric pressure.
In a perstraction process, the permeate molecules in the feed diffuse into the membrane f lm, migrate through the film and reemerge on the permeate side under the influence of a concentration gradient. A sweep flow of liquid is used on the permeate side of the membrane to maintain the concentration gradient driving force. The perstraction process is described in U.S. Patent No. 4,962,271, herein incorporated by reference.
In accordance with the process of the invention, the sulfur-enriched permeate is 1 o treated to reduce sulfur content using conventional sulfur reduction technologies including, but not limited to, hydrotreating, adsorption and catalytic distillation. ~ Specific sulfur reduction processes which may be used in process of the invention include, but are not limited to, Exxon Scanfining, IFP Prime G, CDTECH and Phillips S-Zorb, which processes are described in Tier 2/Sulfur Regulatory Impact Analysis, Environmental Protection Agency, Dec. 1999, Chapter IV 49-53, herein incorporated by reference.
Very significant reductions in naphtha sulfur content are achievable by the process of the invention, in some cases, sulfur reduction of 90% is readily achievable using the process of the invention, while substantially or significantly maintaining the level of olefins initially present in the feed. Typically, the total amount of olefin compounds 2o present in the total naphtha product will be greater than 50 wt %, preferably from about 60 to about 95 wt %, most preferably, from about 80 to about 95 wt %, of the olefin content of the initial feed.
Sulfur deficient naphthas produced by the process of the invention are useful in a gasoline pool feedstock to provide high quality gasoline and light olefin products. As will be recognized by one skilled in the art, increased economics and higher octane valves are achievable as a whole using the process of the invention since the portion of the total naphtha feed requiring blending and further hydropxocessing is greatly reduced by the process of the invention. Further, since the portion of the feed requiring treatment with conventional olefin-destroying sulfur reduction technologies, such as hydrotreating, is greatly reduced, the overall naphtha product will have a significant increase in olefin content as compared to products treated 100% by conventional sulfur reduction technologies.
To further illustrate the present invention and the advantages thereof, the following specific examples are given. The examples are given as specific illustrations of the claim invention. It should be understood, however, that the invention is not limited to the specific details set forth in the examples.
All parts and percentages in the examples as well as the remainder of the l0 specification are by weight unless otherwise specified.
Further, any range of numbers recited in the specification or claims, such as that representing a particular set of properties, units of measure, conditions, physical states or percentages, is intended to literally incorporate expressly herein by reference or otherwise, any number falling within such range, including any subset of numbers within any range so recited.
EXAMPLES
Membrane coupons are mounted in a sample holder for pervaporation tests. A
feed solution of naphtha obtained from a refinery or a model solution mixed in the laboratory is pumped across the membrane surface. The equipment is designed so that the feed solution can be heated and placed under pressure, up to about 5 bar.
A vacuum pump is connected to a cold trap, and then to the permeate side of the membrane. The pump generates a vacuum on the permeate side of less than 20 mm Hg. The permeate is condensed in the cold trap and subsequently analyzed by gas chromatography.
These experiments were performed at low stage cut so that Less than 1 % of the feed is collected as permeate. An enrichment factor (EF) is calculated on the basis of sulfur content in the permeate divided by sulfur content in the feed.
Example 1 A commercial pervaporation membrane (PERVAP~ 1060) from Sulzer ChemTech, Switzerland, with a polysiloxane separation layer, was tested with a component model feed (Table 1 ). The membrane shows a substantial permeation rate and an enrichment factor of 2.35 for thiophene. At the higher temperature with naphtha feedstock the mercaptans (alkyl S) had a 2.37 enrichment factor.
The same membrane was also tested with a refinery naphtha stream (Table 2).
The compounds at the heavier end of this naphtha sample have higher boiling points than the operating temperature leading to lower permeation rates through the membrane for to those components. Increase in temperature gives higher permeation rates.
The comparison of feed solutions between Tables l and 2 showed that solutions with both relatively high and low thiophene content can be enriched in the membrane permeate.
Table 1 Pervaporation experiments with model feed Membrane from Example 1 Feed Permeate Permeate Feed tem erature (C) 24 71 Feed ressure (bar) 4.0 4.3 Permeate pressure (mm Hg) 9.9 10.1 1-Pentene (wei ht %) 11.9 26.2 23.1 2,2,4-Trimeth 1 entane wei 32.8 23.0 22.4 ht %) Meth lcyclohexane (wei ht 13.1 12.1 12.1 %) Toluene (wei ht %) 42.2 38.6 42.5 Thiophene (ppm sulfur) 248 S81 S40 Permeate flux (k /ma/hr) 1.3 6.2 Sulfur enrichment factor 2.3 S 2.18 Table 2 Pervaporation experiments with refinery naphtha Membrane from Example 1 Feed Permeate Permeate Feed tem erature (C) 24 74 Feed ressure (bar) 4.S 4.S
Permeate pressure (mm Hg) 8.4 9.S
Merca tans (all m sulfur) 39 84 93 Thio hene 43 I24 107 Meth 1 thin henes 78 122 111 Tetrah dro thio henes 10 13 14 C2-Thio henes lOS 68 81 Thio henol S 1 2 C3-Thiophenes 90 24 3 S
Methyl thio henol 1 S 0 0 C4-Thio henes S6 0 8 Unidentified S in Gasoline 2 S 5 Ran a Benzothio hene 1 S 1 16 27 Alkyl benzothiophenes 326 28 39 Permeate flux (k /m~/hr) 1.1 S.0 Sulfur enrichment factor (thio 2.91 2.S 1 hene) Example 2 A polyimide membrane was fashioned according to the methods of U.S. Patent 5,264,166 and tested for pervaporation. A dope solution containing 26%
Matrimid 5218 polyimide, 5% malefic acid, 20% acetone, and 49% N-methyl pyrrolidone was cast at 4 ft/min onto a non-woven polyester fabric with a blade gap set at 7 mil. After about 30 seconds the coated fabric was quenched in water at 22 °C to form the membrane structure. The membrane was washed with water to remove residual solvents, then 1 o solvent exchanged by immersion in 2-propanone, followed by immersion in a bath of equal mixtures of lube oil/2-propanone/toluene bath. . The membrane was air dried to yield an asymmetric membrane filled with a conditioning agent.
For pervaporation testing, the membrane was rinsed with the feed solution, and then mounted solvent wet in the cell holder. Results for a 5- component model feed are shown in Table 3. Curiously, the pervaporation performance improved at the higher temperature in both flux and selectivity, indicating that process conditions can favorably impact membrane performance. The membrane showed an enrichment factor of 1.68 for thiophene.
Table 3 Pervaporation experiments with model feed Membrane from Example 2 Feed Permeate Permeate Feed tem erature (C) 24 67 Feed ressure (bar) 4.3 4.5 Permeate pressure (mm Hg) 9.5 7.0 1-Pentene (wei ht %) 10.6 8.7 12.2 2,2,4-Trimeth 1 entane (wei 34.5 32.3 31.6 ht %) Meth lcyclohexane (weight 13.6 13.6 13.2 %) Toluene (weight %) 41.3 45.5 43.0 Thiophene (ppm sulfur) 249 350 423 Permeate flux (kg/ma/hr) 1.5 5.8 Sulfur enrichment factor ~ ~ 1.39 1.68 Example 3 Another polyimide membrane was fashioned according to the methods of US
Patent Application Serial No. 09/126,261 and tested for pervaporation. A dope solution containing 20% Lenzing P84, 69 % p-dioxane, and 11 % dimethylformamide was cast at 4 ft/min onto a non-woven polyester fabric with a blade gap set at 7 mil.
After about 3 seconds the coated fabric was quenched in water at 20 °C to form the membrane structure. The membrane was washed with water to remove residual solvents, solvent exchanged by immersion in 2-butanone, followed by immersion in a bath of equal 1 o mixtures Tube oil/2-butanone/toluene. The membrane was then air dried to yield an asymmetric membrane filled with a conditioning agent.
For pervaporation testing, the membrane was rinsed with the feed solution, and then mounted solvent wet in the cell holder. Results with naphtha are shown in Table 4.
The membrane showed an enrichment factor of 4.69 for thiophene. Mercaptans (alkyl S) had a 3.45 enrichment factor. At a rate of 99% recovery of retentate, there is 98.6%
recovery of olefins in the retentate.
Table 4 Pervaporation Experiments with Refinery Naphtha Membrane from Example 3 Feed Permeate Feed tem erature (C) 77 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 5.1 Merca tans (all m sulfur) 40 13 8 Thio hene 55 257 Meth 1 thin henes 105 339 Tetrahydro thio henes 11 34 C2-Thiophenes 142 220 Thio henol 5 4 C3-Thio henes 77 62 Methyl thio henol 12 8 C4-Thio henes 49 15 Unidentified S in Gasoline Range3 15 Benzothio hene 62 26 Alkyl benzothiophenes 246 45 Paraffins (all wei ht %) 4.32 4.15 Iso araffins 30.99 18.58 Aromatics 20.79 25.44 Na hthenes 11.49 7.89 Olefins 32.41 43.93 Permeate flux (kg/m /hr) 3.25 Sulfur enrichment factor (thio 4.69 hene Since a large fraction of the olefins are not permeated through the membrane, but retained in the retentate, the octane value of naphtha that can be sent to the gasoline pool is improved.
to Example 4 A polyimide composite membrane was formed by spin coating Matrimid 5218 upon a microporous support. A 20% Matrimid solution in dimethylformamide was spin coated at 2000 rpm for 10 sec, then at 4000 rpm for 10 seconds, upon a 0.45 micron pore size nylon membrane disk (Millipore Corporation, Bedford, MA; Cat. #
HNWP04700).
The membrane was then air dried. The membrane was directly tested with naphtha feed (Table 5) and showed an enrichment factor of 2.68 for thiophene. Mercaptans (alkyl S) had a 1.41 enrichment factor. At a rate of 99% recovery of retentate, there was 99.1 recovery of olefins in the retentate.
1 o Table 5 Pervaporation Experiments with Refinery Nabhtha Membrane from Example 4 Feed Permeate Feed tem erature (C) 78 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 4.3 Merca tans all m sulfur) 23 32 Thio hene 66 176 Meth 1 thio henes 134 351 Tetrahydro thio henes 16 34 C2-Thio henes 198 356 Thio henol 6 9 C3-Thio henes 110 166 Meth 1 thio henol 13 14 C4-Thio henes 75 66 Unidentified S in Gasoline 4 8 Ran a Benzothio hene 73 95 Alkyl benzothiophenes 108 110 Paraffins (all wei ht %) 4.42 3.69 Iso araffins 28.02 21.70 Aromatics 23.09 3 3 .00 Na hthenes 11.14 ~ 11.61 Olefins 33.33 30.00 Permeate flux (k /m2/hr) 0.90 Sulfur enrichment factor (thio 2.68 hene) Example 5 A polyurealurethane (PUU) composite membrane was formed through coating of a porous substrate following the methods of US Patent 4,921,611. To a solution of 0.7866 g of toluene diisocyanate terminated polyethylene adipate (Aldrich Chemical Company, Milwaukee, WI; Cat. # 43,351-9) in 9.09 g of p-dioxane was added 0.1183 g of 4-4'-methylene dianiline (Aldrich; # 13,245-4) dissolved in 3.00 g p-dioxane. When the solution began to gel it was coated with a blade gap set 3.6 mil above a 0.2 micron pore size microporous polytetrafluoroethylene (PTFE) membrane (W.L. Gore, Elkton, MD). The solvent evaporates to give a continuous film. The composite membrane was to then heated in an oven 100 °C for one hour. The final composite membrane structure had a PUU coating 3 microns thick measured by scanning electron microscopy. The membrane was directly tested with naphtha (Table 6). The membrane showed an enrichment factor of 7.53 for thiophene and 3.15 for mercaptans.
Table 6 Pervaporation Expeximents with Refinery Naphtha Membrane from Example 5 Feed Permeate Feed tem erature (C 78 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 2.6 Merca tans all m sulfur 8 25 Thio hene 49 370 Methyl thiophenes 142 857 Tetrah dro thio henes 14 38 C2-Thio henes 186 604 Thio henol 6 12 C3-Thio henes 103 224 Meth 1 thio henol 20 26 C4-Thio henes 62 99 Unidentified S in Gasoline 1 11 Ran a Benzothio hene 101 320 Alkyl benzothiophenes 381 490 Permeate flux (k /m /hr) 0.038_ Sulfur enrichment factor (thio' 7.53 hene Example 6 A polyurea/urethane (PUU) composite membrane was formed as in Example 5, but by replacing p-dioxane with N,N-dimethylformamide (DMF). To 0.4846 g of toluene diisocyanate terminated polyethylene adipate (Aldrich Chemical Company, Milwaukee, 1o WI; Cat. # 43,351-9) in 3.29 g of DMF was added 0.0749 g of 4-4'-methylene dianiline (Aldrich; # 13,245-4) dissolved in 0.66 g DMF. When the solution began to gel it was coated with a blade gap set 3.6 mil above a 0.2 micron pore size microporous polytetrafluoroethylene (PTFE) membrane (W.L. Gore, Elkton, MD). The solvent evaporates to give a continuous film. The composite membrane was then heated in an oven at 94 °C for two hours. The final composite membrane structure had a PUU coating weight of 6.1 g/m~'. The membrane was directly tested with naphtha (Table 7).
The membrane shows an enrichment factor of 9.58 for thiophene and 4.15 for mercaptans (alkyl S). At a rate of 99% recovery of retentate, there is 99.2% recovery of olefins in the retentate.
Table 7 Pervaporation experiments with ref nery naphtha Membrane from Example 6 Feed Permeate Feed tem erature (C) 75 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 2.8 Merca tans (aIl m sulfur) 20 84 Thio hene 33 321 Methyl thiophenes 83 588 Tetrahydro thio henes 10 45 C2-Thio henes 105 413 Thio henol 4 8 C3-Thio henes 60 156 Meth 1 thio henol 12 19 C4-Thio henes 24 116 Unidentified S in Gasoline 0 5 Ran a Benzothio hene 44 247 Alkyl benzothiophenes 44 245 Paraffins (all wei ht %) 4.00 1.91 Iso araffins 29.48 10.33 Aromatics 26.18 57.91 Na hthenes 10.46 4.98 Olefins 29.88 24.87 Permeate flux (kg/m /hr) 0.085 Sulfur enrichment factor (thiophene) ~ 9.58 to Example 7 An FCC light cat naphtha with a boiling range of 50 to 98°C contains 300 ppm of S
compounds. It is pumped at rate of 100 m3/hr into a membrane pervaporation system operated at 98 °C.
A sulfur enrichment membrane having a permeation rate of 3 kg/m2/hr is incorporated into a spiral-wound module containing I 5 ma of membrane. The module contains feed spacers, membrane, and permeate spacers wound around a central perforated metal collection tube. Adhesives are used to separate the feed and permeate channels, bind 1 o the materials to the collection tube, and seal the outer casing. The modules are 48 inches in length and 8 inches in diameter. 480 of these modules are mounted in pressure housings as a single stage system. Vacuum is maintained on the permeate side. The condensed permeate is collected at a rate of 30 m3/hr and contains greater than 930 ppm S compounds.
Overall enrichment factor is 3.1 for S compounds. This permeate is sent to conventional hydrotreating to reduce S content to 30 ppm, and then sent to the gasoline pool.
Retentate generated from the pervaporation system at 70 m3/hr contains less than 30 ppm of sulfur compounds. This naphtha is sent to the gasoline pool. The process reduced the amount of naphtha sent to conventional hydrotreating by 70%.
We have now developed a selective membrane separation process which preferentially reduces the sulfur content of a hydrocarbon containing naphtha feed while substantially maintaining the content of olefins presence in the feed. The term "substantially maintaining the content of olefins presence in the feed" is used herein to indicate maintaining at least 50 wt % of olefins initially present in the untreated feed. In accordance with the process of the invention, the naphtha feed stream is contacted with a membrane separation zone containing a membrane having a sufficient flux and selectivity to separate a permeate fraction enriched in aromatic and nonaxomatic hydrocarbon 1 o containing sulfur species and a sulfur deficient retentate fraction. The retentate fraction produced by the membrane process can be employed directly or blended into a gasoline pool without further processing. The sulfur enriched fraction is treated to reduce sulfur content using conventional sulfur removal technologies, e.g. hydrotreating.
The sulfur reduced permeate product may thereafter be blended into a gasoline pool.
In accordance with the process of the invention, the sulfur deficient retentate comprises no less than 50 wt % of the feed and retains greater than 50 wt % of the initial olefin content of the feed. Consequently, the process of the invention offers the advantage of improved economics by minimizing the volume of the feed to be treated by conventional high cost sulfur reduction technologies, e.g. hydrotreating.
Additionally, the 2o process of the invention provides for an increase in the olefin content of the overall naphtha product without the need for additional processing to restore octane values.
The membrane process of the invention offers further advantages over conventional sulfur removal processes such as lower capital and operating expenses, greater selectivity, easily scaled operations, and greater adaptability to changes in process streams and simple control schemes.
DETAILED DESCRIPTION OF THE DRAWING
The Figure outlines the membrane process of the invention for the reduction of the sulfur content of a naphtha feed stream.
DETAILED DESCRIPTION OF THE INVENTION
The membrane process of the invention is useful to produce high quality naphtha products having a reduced sulfur content and a high olefin content. In accordance with the process of the invention, a naphtha feed containing olefins and sulfur containing-io aromatic hydrocarbon compounds and sulfur containing-nonaromatic hydrocarbon compounds, is conveyed over a membrane separation zone to reduce sulfur content. The membrane separation zone comprises a membrane having a sufficient flux and selectivity to separate the feed into a sulfur deficient retentate fraction and a permeate fraction enriched in both aromatic and non-aromatic sulfur containing hydrocarbon compounds as 15 compared to the intial naphtha feed. The naphtha feed is in a liquid or substantially liquid form.
For purposes of this invention, the term "naphtha" is used herein to indicate hydrocarbon streams found in refinery operations that have a boiling range between about 50°C to about 220°C. Preferably, the naphtha is not hydrotreated prior to use in the 2o invention process. Typically, the hydrocarbon streams will contain greater than 150 ppm, preferably from about 150 ppm to about 3000 ppm, most preferably from about 300 to about 1000 ppm, sulfur.
The term "aromatic hydrocarbon compounds" is used herein to designate a hydrocarbon-based organic compound containing one or more aromatic rings, e.g.
fused 25 and/or bridged. An aromatic ring is typified by benzene having a single aromatic nucleus.
Aromatic compounds having more than one aromatic ring include, for example, naphthalene, anthracene, etc. Preferred aromatic hydrocarbons useful in the present invention include those having 1 to 2 aromatic rings.
The term "non-aromatic hydrocarbon" is used herein to designate a hydrocaxbon-based organic compound having no aromatic nucleus.
For the purposes of this invention, the term "hydrocarbon" is used to mean an organic compound having a predominately hydrocarbon character. It is contemplated within the scope of this def nition that a hydrocarbon compound may contain at least one non-hydrocarbon radical (e.g. sulfur or oxygen) provided that said non-hydrocarbon radical does not alter the predominant hydrocarbon nature of the organic compound and/or does not react to alter the chemical nature of the membrane within the context of the present invention.
1o For purposes of this invention, the term "sulfur enrichment factor" is used herein to indicate the ratio of the sulfur content in the permeate divided by the sulfur content in the feed.
The sulfur deficient retentate fraction obtained using the membrane process of the invention typically contains less than 100 ppm, preferably less than 50 ppm , and most preferably, less than 30 ppm sulfur. In a preferred embodiment, the sulfur content of the recovered retentate stream is from less than 30 wt %, preferably less than 20 wt %, and most preferably less than 10 wt % of the initial sulfur content of the feed.
The Figure outlines a preferred membrane process in accordance with the present invention. A naphtha feed stream 1 containing sulfur and olefin compounds is contacted 2o with the membrane 2. The feed stream 1 is split into a permeate stream 3 and a retentate stream 4. The retentate stream 4 is reduced in sulfur content but substantially retains the olefin content of the feed stream 1. The retentate stream 4 may be sent to the gasoline pool without further processing. The permeate stream 3 contains a high sulfur content and is treated with conventional sulfur reduction technology to produce a reduced sulfur permeate stream 5 which is also blended into the gasoline pool.
Advantageously, the total naphtha product resulting from the retentate stream and reduced sulfur permeate stream 5 will have a higher olefin content when compared to the olefin content of a product stream resulting from 100% treatment with conventional sulfur reduction technology, e.g., hydrotreating. Typically, the olefin content of the total naphtha product will be at least 50 wt %, preferably at least 70 wt %, most preferably at least 80 wt %, of the total feed passed over the membrane. For purposes of the invention, the term "total naphtha product" is used herein to indicate the total amount of sulfur deficient retentate product and reduced sulfur permeate product.
The retentate stream 4 and the permeate stream 5 may be used combined into a gasoline pool or in the alternative, may be used for different purposes. For example, retentate stream 4 may be blended into the gasoline pool, while permeate stream 5 is used, for example, as a feed stream to a reformer.
1 o The quantity of retentate 4 produced by the system determines the %
recovery, which is the fraction of retentate 4 compared to the initial naphtha feed stream.
Preferably, the membrane process is conducted at high % recovery in order to decrease costs. Costs per cubic meter of naphtha treated depends upon such factors as capital equipment, membrane, energy, and operating costs. As the amount of % recovery increases, the required membrane selectivity for a one-stage system increases, while the relative system cost decreases. For a membrane operating at 50% recovery, an overall 1.90 sulfur enrichment factor is typical. At 80% recovery, an overall sulfur enrichment factor of 4.60 is typical. As will be understood by one skilled in the arts, system costs will go down with increased % recovery, since less feed is vaporized through the 2o membrane, requiring lower energy and less membrane area.
Generally, the sulfur deficient retentate fraction contains at least 50 wt %, preferably at least 70 wt %, most preferably at least 80 wt %, of the total feed passed over the membrane. Such a high recovery of sulfur deficient product provides increased economics by minimizing the volume of the feed which is typically treated by high cost sulfur reduction technologies, such as hydrotreating. Typically, the membrane process reduces the amount of naphtha feed sent for further sulfur reduction by 50%, preferably by about 70%, most preferably, by about 80%.
Hydrocarbon feeds useful in the membrane process of the invention comprise naphtha containing feeds that boil in the gasoline boiling range, 50°C
to about 220°C
which fraction contains sulfur and olefin unsaturation. Feeds of this type include light naphthas typically having a boiling range of about 50°C to about 105°C , intermediate naphtha typically having a boiling range of about l OS°C to about 160°C and heavy naphthas having a boiling range of about 160°C to about 220°C.
The process can be applied to thermally cracked naphthas such as pyrolysis gasoline and coker naphtha. In a preferred embodiment of the invention, the feed is a catalytically cracked naphtha produced in such processes as Thermofor Catalytic Cracking (TCC) and FCC since both 1o processes typically produce naphthas characterized by the presence of olefin unsaturation and sulfur. In the more preferred embodiment of the invention, the hydrocarbon feed is an FCC naphtha, with the most preferred feed being a FCC light cat naphtha having a boiling range of about SO°C to about 105°C. It is also contemplated within the scope of the invention that the feed may be a straight run naphtha having a boiling range between about 50°C to about 220°C.
Membranes useful in the present invention are those membranes having a sufficient flux and selectivity to permeate sulfur containing compounds in the presence of naphtha containing sulfur and olefin unsaturation. The membrane will typically have a sulfur enrichment factor of greater than 1.5, preferably greater than 2, even more 2o preferably from about 2 to about 20, most preferably from about 2.5 to 15.
Preferably, the membranes have an asymmetric structure which may be defined as an entity composed of a dense ultra-thin top "skin" layer over a thicker porous substructure of a same or different material. Typically, the asymmetric membrane is supported on a suitable porous backing or support material.
In a preferred embodiment of the invention, the membrane is a polyimide membrane prepared from a Matrimid~ 5218 or a Lenzing polyimide polymer as described in U.S. Patent Application Serial No. 091126,261, herein incorporated by reference.
In another embodiment of the invention, the membrane is one having a siloxane based polymer as part of the active separation layer. Typically, this separation layer is coated onto a microporous or ultrafiltration support. Examples of membrane structure incorporating polysiloxane functionality are found in U.S. Patent No.
4,781,733, U.S.
Patent 4,243,701, U.S. Patent No. 4,230,463, U.S. Patent No. 4,493,714, U.S.
Patent No.
5,265,734, U.S. Patent No. 5,286,280 and U.S. Patent No. 5,733,663, said references being herein incorporated by reference.
In still another embodiment of the invention, the membrane is an aromatic polyurea/urethane membrane as disclosed in U.S. Patent 4,962,271, herein incorporated l0 by reference, which polyurea/urethane membranes are characterized as possessing a urea index of at least 20 % but less than 100%, an aromatic carbon content of at least 1 S mole %, a functional group density of at least about 10 per 1000 grams of polymer, and a C=O/NH ratio of less than about 8.
I5 The membranes can be used in any convenient form such as sheets, tubes or hollow fibers. Sheets can be used to fabricate spiral wound modules familiar to those skilled in the art. Alternatively, sheets can be used to fabricate a flat stack permeator comprising a multitude of membrane layers alternately separated by feed-retentate spacers and permeate spacers. This device is described in U.S. Patent No. 5,104,532, herein 2o incorporated by reference.
Tubes can be used in the form of mufti-leaf modules wherein each tube is flattened and placed in parallel with other flattened tubes. Internally each tube contains a spacer. Adjacent pairs of flattened tubes are separated by layers of spacer material. The flattened tubes with positioned spacer material is fitted into a pressure resistant housing 25 equipped with fluid entrance and exit means. The ends of the tubes are clamped to create separate interior and exterior zones relative to the tubes in the housing.
Apparatus of this type is described and claimed in U.S. Patent No. 4,761,229, herein incorporated by 'reference.
Hollow fibers can be employed in bundled arrays potted at either end to form tube sheets and fitted into a pressure vessel thereby isolating the insides of the tubes from the outsides of the tubes. Apparatus of this type are known in the art. A
modification of the standard design involves dividing the hollow fiber bundle into separate zones by use of baffles which redirect fluid flow on the tube side of the bundle and prevent fluid channeling and polarization on the tube side. This modification is disclosed and claimed in U.S. Patent No. 5,169,530, herein incorporated by reference.
Multiple separation elements, be they spirally wound, plate and frame, or hollow fiber elements can be employed either in series or in parallel. U.S. Patent No. 5,238,563, l0 herein incorporated by reference, discloses a multiple-element housing wherein the elements are grouped in parallel with a feed/retentate zone defined by a space enclosed by two tube sheets arranged at the same end of the element.
The process of the invention employs selective membrane separation conducted under pervaporation or perstxaction conditions. Preferably, the process is conducted 15 under pervaporation conditions.
The pervaporation process relies on vacuum or sweep gas on the permeate side to evaporate or otherwise remove the permeate from the surface to the membrane.
The feed is in the liquid andlor gas state. When in the gas state the process can be described as vapor permeation. Pervaporation can be performed at a temperature of from about 25°C
2o to 200°C and higher, the maximum temperature being that temperature at which the membrane is physically damaged. It is preferred that the pervaporation process be operated as a single stage operation to reduce capital costs.
The pervaporation process also generally relies on vacuum on the permeate side to evaporate the permeate from the surface of the membrane and maintain the concentration 25 gradient driving force which drives the separation process. The maximum temperature employed in pervaporation will be that necessary to vaporize the components in the feed which one desires to selectively permeate through the membrane while still being below the temperature at which the membrane is physically damaged. Alternatively to a vacuum, a sweep gas can be used on the permeate side to remove the product. In this mode the permeate side would be at atmospheric pressure.
In a perstraction process, the permeate molecules in the feed diffuse into the membrane f lm, migrate through the film and reemerge on the permeate side under the influence of a concentration gradient. A sweep flow of liquid is used on the permeate side of the membrane to maintain the concentration gradient driving force. The perstraction process is described in U.S. Patent No. 4,962,271, herein incorporated by reference.
In accordance with the process of the invention, the sulfur-enriched permeate is 1 o treated to reduce sulfur content using conventional sulfur reduction technologies including, but not limited to, hydrotreating, adsorption and catalytic distillation. ~ Specific sulfur reduction processes which may be used in process of the invention include, but are not limited to, Exxon Scanfining, IFP Prime G, CDTECH and Phillips S-Zorb, which processes are described in Tier 2/Sulfur Regulatory Impact Analysis, Environmental Protection Agency, Dec. 1999, Chapter IV 49-53, herein incorporated by reference.
Very significant reductions in naphtha sulfur content are achievable by the process of the invention, in some cases, sulfur reduction of 90% is readily achievable using the process of the invention, while substantially or significantly maintaining the level of olefins initially present in the feed. Typically, the total amount of olefin compounds 2o present in the total naphtha product will be greater than 50 wt %, preferably from about 60 to about 95 wt %, most preferably, from about 80 to about 95 wt %, of the olefin content of the initial feed.
Sulfur deficient naphthas produced by the process of the invention are useful in a gasoline pool feedstock to provide high quality gasoline and light olefin products. As will be recognized by one skilled in the art, increased economics and higher octane valves are achievable as a whole using the process of the invention since the portion of the total naphtha feed requiring blending and further hydropxocessing is greatly reduced by the process of the invention. Further, since the portion of the feed requiring treatment with conventional olefin-destroying sulfur reduction technologies, such as hydrotreating, is greatly reduced, the overall naphtha product will have a significant increase in olefin content as compared to products treated 100% by conventional sulfur reduction technologies.
To further illustrate the present invention and the advantages thereof, the following specific examples are given. The examples are given as specific illustrations of the claim invention. It should be understood, however, that the invention is not limited to the specific details set forth in the examples.
All parts and percentages in the examples as well as the remainder of the l0 specification are by weight unless otherwise specified.
Further, any range of numbers recited in the specification or claims, such as that representing a particular set of properties, units of measure, conditions, physical states or percentages, is intended to literally incorporate expressly herein by reference or otherwise, any number falling within such range, including any subset of numbers within any range so recited.
EXAMPLES
Membrane coupons are mounted in a sample holder for pervaporation tests. A
feed solution of naphtha obtained from a refinery or a model solution mixed in the laboratory is pumped across the membrane surface. The equipment is designed so that the feed solution can be heated and placed under pressure, up to about 5 bar.
A vacuum pump is connected to a cold trap, and then to the permeate side of the membrane. The pump generates a vacuum on the permeate side of less than 20 mm Hg. The permeate is condensed in the cold trap and subsequently analyzed by gas chromatography.
These experiments were performed at low stage cut so that Less than 1 % of the feed is collected as permeate. An enrichment factor (EF) is calculated on the basis of sulfur content in the permeate divided by sulfur content in the feed.
Example 1 A commercial pervaporation membrane (PERVAP~ 1060) from Sulzer ChemTech, Switzerland, with a polysiloxane separation layer, was tested with a component model feed (Table 1 ). The membrane shows a substantial permeation rate and an enrichment factor of 2.35 for thiophene. At the higher temperature with naphtha feedstock the mercaptans (alkyl S) had a 2.37 enrichment factor.
The same membrane was also tested with a refinery naphtha stream (Table 2).
The compounds at the heavier end of this naphtha sample have higher boiling points than the operating temperature leading to lower permeation rates through the membrane for to those components. Increase in temperature gives higher permeation rates.
The comparison of feed solutions between Tables l and 2 showed that solutions with both relatively high and low thiophene content can be enriched in the membrane permeate.
Table 1 Pervaporation experiments with model feed Membrane from Example 1 Feed Permeate Permeate Feed tem erature (C) 24 71 Feed ressure (bar) 4.0 4.3 Permeate pressure (mm Hg) 9.9 10.1 1-Pentene (wei ht %) 11.9 26.2 23.1 2,2,4-Trimeth 1 entane wei 32.8 23.0 22.4 ht %) Meth lcyclohexane (wei ht 13.1 12.1 12.1 %) Toluene (wei ht %) 42.2 38.6 42.5 Thiophene (ppm sulfur) 248 S81 S40 Permeate flux (k /ma/hr) 1.3 6.2 Sulfur enrichment factor 2.3 S 2.18 Table 2 Pervaporation experiments with refinery naphtha Membrane from Example 1 Feed Permeate Permeate Feed tem erature (C) 24 74 Feed ressure (bar) 4.S 4.S
Permeate pressure (mm Hg) 8.4 9.S
Merca tans (all m sulfur) 39 84 93 Thio hene 43 I24 107 Meth 1 thin henes 78 122 111 Tetrah dro thio henes 10 13 14 C2-Thio henes lOS 68 81 Thio henol S 1 2 C3-Thiophenes 90 24 3 S
Methyl thio henol 1 S 0 0 C4-Thio henes S6 0 8 Unidentified S in Gasoline 2 S 5 Ran a Benzothio hene 1 S 1 16 27 Alkyl benzothiophenes 326 28 39 Permeate flux (k /m~/hr) 1.1 S.0 Sulfur enrichment factor (thio 2.91 2.S 1 hene) Example 2 A polyimide membrane was fashioned according to the methods of U.S. Patent 5,264,166 and tested for pervaporation. A dope solution containing 26%
Matrimid 5218 polyimide, 5% malefic acid, 20% acetone, and 49% N-methyl pyrrolidone was cast at 4 ft/min onto a non-woven polyester fabric with a blade gap set at 7 mil. After about 30 seconds the coated fabric was quenched in water at 22 °C to form the membrane structure. The membrane was washed with water to remove residual solvents, then 1 o solvent exchanged by immersion in 2-propanone, followed by immersion in a bath of equal mixtures of lube oil/2-propanone/toluene bath. . The membrane was air dried to yield an asymmetric membrane filled with a conditioning agent.
For pervaporation testing, the membrane was rinsed with the feed solution, and then mounted solvent wet in the cell holder. Results for a 5- component model feed are shown in Table 3. Curiously, the pervaporation performance improved at the higher temperature in both flux and selectivity, indicating that process conditions can favorably impact membrane performance. The membrane showed an enrichment factor of 1.68 for thiophene.
Table 3 Pervaporation experiments with model feed Membrane from Example 2 Feed Permeate Permeate Feed tem erature (C) 24 67 Feed ressure (bar) 4.3 4.5 Permeate pressure (mm Hg) 9.5 7.0 1-Pentene (wei ht %) 10.6 8.7 12.2 2,2,4-Trimeth 1 entane (wei 34.5 32.3 31.6 ht %) Meth lcyclohexane (weight 13.6 13.6 13.2 %) Toluene (weight %) 41.3 45.5 43.0 Thiophene (ppm sulfur) 249 350 423 Permeate flux (kg/ma/hr) 1.5 5.8 Sulfur enrichment factor ~ ~ 1.39 1.68 Example 3 Another polyimide membrane was fashioned according to the methods of US
Patent Application Serial No. 09/126,261 and tested for pervaporation. A dope solution containing 20% Lenzing P84, 69 % p-dioxane, and 11 % dimethylformamide was cast at 4 ft/min onto a non-woven polyester fabric with a blade gap set at 7 mil.
After about 3 seconds the coated fabric was quenched in water at 20 °C to form the membrane structure. The membrane was washed with water to remove residual solvents, solvent exchanged by immersion in 2-butanone, followed by immersion in a bath of equal 1 o mixtures Tube oil/2-butanone/toluene. The membrane was then air dried to yield an asymmetric membrane filled with a conditioning agent.
For pervaporation testing, the membrane was rinsed with the feed solution, and then mounted solvent wet in the cell holder. Results with naphtha are shown in Table 4.
The membrane showed an enrichment factor of 4.69 for thiophene. Mercaptans (alkyl S) had a 3.45 enrichment factor. At a rate of 99% recovery of retentate, there is 98.6%
recovery of olefins in the retentate.
Table 4 Pervaporation Experiments with Refinery Naphtha Membrane from Example 3 Feed Permeate Feed tem erature (C) 77 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 5.1 Merca tans (all m sulfur) 40 13 8 Thio hene 55 257 Meth 1 thin henes 105 339 Tetrahydro thio henes 11 34 C2-Thiophenes 142 220 Thio henol 5 4 C3-Thio henes 77 62 Methyl thio henol 12 8 C4-Thio henes 49 15 Unidentified S in Gasoline Range3 15 Benzothio hene 62 26 Alkyl benzothiophenes 246 45 Paraffins (all wei ht %) 4.32 4.15 Iso araffins 30.99 18.58 Aromatics 20.79 25.44 Na hthenes 11.49 7.89 Olefins 32.41 43.93 Permeate flux (kg/m /hr) 3.25 Sulfur enrichment factor (thio 4.69 hene Since a large fraction of the olefins are not permeated through the membrane, but retained in the retentate, the octane value of naphtha that can be sent to the gasoline pool is improved.
to Example 4 A polyimide composite membrane was formed by spin coating Matrimid 5218 upon a microporous support. A 20% Matrimid solution in dimethylformamide was spin coated at 2000 rpm for 10 sec, then at 4000 rpm for 10 seconds, upon a 0.45 micron pore size nylon membrane disk (Millipore Corporation, Bedford, MA; Cat. #
HNWP04700).
The membrane was then air dried. The membrane was directly tested with naphtha feed (Table 5) and showed an enrichment factor of 2.68 for thiophene. Mercaptans (alkyl S) had a 1.41 enrichment factor. At a rate of 99% recovery of retentate, there was 99.1 recovery of olefins in the retentate.
1 o Table 5 Pervaporation Experiments with Refinery Nabhtha Membrane from Example 4 Feed Permeate Feed tem erature (C) 78 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 4.3 Merca tans all m sulfur) 23 32 Thio hene 66 176 Meth 1 thio henes 134 351 Tetrahydro thio henes 16 34 C2-Thio henes 198 356 Thio henol 6 9 C3-Thio henes 110 166 Meth 1 thio henol 13 14 C4-Thio henes 75 66 Unidentified S in Gasoline 4 8 Ran a Benzothio hene 73 95 Alkyl benzothiophenes 108 110 Paraffins (all wei ht %) 4.42 3.69 Iso araffins 28.02 21.70 Aromatics 23.09 3 3 .00 Na hthenes 11.14 ~ 11.61 Olefins 33.33 30.00 Permeate flux (k /m2/hr) 0.90 Sulfur enrichment factor (thio 2.68 hene) Example 5 A polyurealurethane (PUU) composite membrane was formed through coating of a porous substrate following the methods of US Patent 4,921,611. To a solution of 0.7866 g of toluene diisocyanate terminated polyethylene adipate (Aldrich Chemical Company, Milwaukee, WI; Cat. # 43,351-9) in 9.09 g of p-dioxane was added 0.1183 g of 4-4'-methylene dianiline (Aldrich; # 13,245-4) dissolved in 3.00 g p-dioxane. When the solution began to gel it was coated with a blade gap set 3.6 mil above a 0.2 micron pore size microporous polytetrafluoroethylene (PTFE) membrane (W.L. Gore, Elkton, MD). The solvent evaporates to give a continuous film. The composite membrane was to then heated in an oven 100 °C for one hour. The final composite membrane structure had a PUU coating 3 microns thick measured by scanning electron microscopy. The membrane was directly tested with naphtha (Table 6). The membrane showed an enrichment factor of 7.53 for thiophene and 3.15 for mercaptans.
Table 6 Pervaporation Expeximents with Refinery Naphtha Membrane from Example 5 Feed Permeate Feed tem erature (C 78 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 2.6 Merca tans all m sulfur 8 25 Thio hene 49 370 Methyl thiophenes 142 857 Tetrah dro thio henes 14 38 C2-Thio henes 186 604 Thio henol 6 12 C3-Thio henes 103 224 Meth 1 thio henol 20 26 C4-Thio henes 62 99 Unidentified S in Gasoline 1 11 Ran a Benzothio hene 101 320 Alkyl benzothiophenes 381 490 Permeate flux (k /m /hr) 0.038_ Sulfur enrichment factor (thio' 7.53 hene Example 6 A polyurea/urethane (PUU) composite membrane was formed as in Example 5, but by replacing p-dioxane with N,N-dimethylformamide (DMF). To 0.4846 g of toluene diisocyanate terminated polyethylene adipate (Aldrich Chemical Company, Milwaukee, 1o WI; Cat. # 43,351-9) in 3.29 g of DMF was added 0.0749 g of 4-4'-methylene dianiline (Aldrich; # 13,245-4) dissolved in 0.66 g DMF. When the solution began to gel it was coated with a blade gap set 3.6 mil above a 0.2 micron pore size microporous polytetrafluoroethylene (PTFE) membrane (W.L. Gore, Elkton, MD). The solvent evaporates to give a continuous film. The composite membrane was then heated in an oven at 94 °C for two hours. The final composite membrane structure had a PUU coating weight of 6.1 g/m~'. The membrane was directly tested with naphtha (Table 7).
The membrane shows an enrichment factor of 9.58 for thiophene and 4.15 for mercaptans (alkyl S). At a rate of 99% recovery of retentate, there is 99.2% recovery of olefins in the retentate.
Table 7 Pervaporation experiments with ref nery naphtha Membrane from Example 6 Feed Permeate Feed tem erature (C) 75 Feed ressure (bar) 4.5 Permeate pressure (mm Hg) 2.8 Merca tans (aIl m sulfur) 20 84 Thio hene 33 321 Methyl thiophenes 83 588 Tetrahydro thio henes 10 45 C2-Thio henes 105 413 Thio henol 4 8 C3-Thio henes 60 156 Meth 1 thio henol 12 19 C4-Thio henes 24 116 Unidentified S in Gasoline 0 5 Ran a Benzothio hene 44 247 Alkyl benzothiophenes 44 245 Paraffins (all wei ht %) 4.00 1.91 Iso araffins 29.48 10.33 Aromatics 26.18 57.91 Na hthenes 10.46 4.98 Olefins 29.88 24.87 Permeate flux (kg/m /hr) 0.085 Sulfur enrichment factor (thiophene) ~ 9.58 to Example 7 An FCC light cat naphtha with a boiling range of 50 to 98°C contains 300 ppm of S
compounds. It is pumped at rate of 100 m3/hr into a membrane pervaporation system operated at 98 °C.
A sulfur enrichment membrane having a permeation rate of 3 kg/m2/hr is incorporated into a spiral-wound module containing I 5 ma of membrane. The module contains feed spacers, membrane, and permeate spacers wound around a central perforated metal collection tube. Adhesives are used to separate the feed and permeate channels, bind 1 o the materials to the collection tube, and seal the outer casing. The modules are 48 inches in length and 8 inches in diameter. 480 of these modules are mounted in pressure housings as a single stage system. Vacuum is maintained on the permeate side. The condensed permeate is collected at a rate of 30 m3/hr and contains greater than 930 ppm S compounds.
Overall enrichment factor is 3.1 for S compounds. This permeate is sent to conventional hydrotreating to reduce S content to 30 ppm, and then sent to the gasoline pool.
Retentate generated from the pervaporation system at 70 m3/hr contains less than 30 ppm of sulfur compounds. This naphtha is sent to the gasoline pool. The process reduced the amount of naphtha sent to conventional hydrotreating by 70%.
Claims (82)
1. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction, said membrane having a sulfur enrichment factor of greater than 1.5, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbon and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compared to the naphtha feed;
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compound present in the feed.
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compound present in the feed.
2. The method of claim 1 wherein the membrane is an asymmetric membrane selected from the group consisting of a polyimide membrane, a polyurea-urethane membrane and a polysiloxane membrane.
3. The method of claim 1 wherein the membrane is a polyimide membrane.
4. The method of claim 1 wherein the membrane is a polyurea urethane membrane.
5. The method of claim 1 wherein the membrane is a polysiloxane membrane.
6. The method of claim 1 wherein the sulfur content of the sulfur deficient retentate fraction is less than 100 ppm.
7. The method of claim 6 wherein the sulfur content of the sulfur deficient fraction is less than 50 ppm.
8. The method of claim 6 wherein the sulfur content of the sulfur deficient retentate fraction is less than 30 ppm.
9. The method of claim 1 wherein the naphtha feed stream is a cracked naphtha.
10. The method of claim 9 wherein the naphtha is a FCC naphtha.
11. The method of claim 10 wherein the naphtha is a FCC light cat naphtha having a boiling range from about 50°C to about 105°C.
12. The method of claim 1 wherein the naphtha is a coker naphtha.
13. The method of claim 1 wherein the naphtha is a straight run.
14. The method of claim 1 wherein the sulfur deficient retentate fraction comprises at least 50 wt % of the total feed.
15. The method of claim 14 wherein the sulfur deficient retentate fraction comprises at least 70 wt % of the total feed.
16. The method of claim 1 wherein the membrane separation zone operates under pervaporation conditions.
17. The method of claim 1 wherein the membrane separation zone operates under perstraction conditions.
18. The method of claim 1 wherein the sulfur-enriched permeate fraction is subjected to a hydrotreating process to reduce sulfur content.
19. The method of claim 1 wherein the sulfur-enriched permeate fraction is subjected to an adsorption process to reduce sulfur content.
20. The method of claim 1 wherein the sulfur-enriched permeate fraction is subjected to a catalytic distillation process to reduce sulfur content.
21. The method of claim 1 wherein the membrane has a sulfur enrichment factor of greater than 2.
22. The method of claim 1 wherein the membrane has a sulfur enrichment factor ranging from about 2 to about 20.
23. The method of claim 1 wherein the total amount of olefin compounds in the retentate product stream and the permeate product stream is from about 50 to about 90 wt % of olefin compounds present in the feed.
24. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a polyimide membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction under pervaporation conditions, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbons and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compare to the naphtha feed;
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
25. The method of claim 24 wherein the membrane is one having a sulfur enrichment factor of greater than 1.5.
26. The method of claim 24 wherein the sulfur content of the sulfur deficient retentate fraction is less than 100 ppm.
27. The method of claim 26 wherein the sulfur content of the sulfur deficient fraction is less than 50 ppm.
28. The method of claim 26 wherein the sulfur content of the sulfur deficient retentate fraction is less than 30 ppm.
29. The method of claim 24 wherein the naphtha feed stream is a cracked naphtha.
30. The method of claim 29 wherein the naphtha is a FCC naphtha.
31. The method of claim 30 wherein the naphtha is a FCC light cat naphtha having a boiling range from about 50°C to about 105°C.
32. The method of claim 24 wherein the naphtha is a coker naphtha.
33. The method of claim 24 wherein the naphtha is a straight run.
34. The method of claim 24 wherein the sulfur deficient retentate fraction comprises at least 50 wt % of the total feed.
35. The method of claim 34 wherein the sulfur deficient retentate fraction comprises at least 70 wt % of the total feed.
36. The method of claim 24 wherein the sulfur-enriched permeate fraction is subjected to a hydrotreating process to reduce sulfur content.
37. The method of claim 24 wherein the sulfur-enriched permeate fraction is subjected to an adsorption process to reduce sulfur content.
38. The method of claim 24 wherein the sulfur-enriched permeate fraction is subjected to a catalytic distillation process to reduce sulfur content.
39. The method of claim 25 wherein the membrane has a sulfur enrichment factor of greater than 2.
40. The method of claim 25 wherein the membrane has a sulfur enrichment factor ranging from about 2 to about 20.
41. The method of claim 24 wherein the sulfur deficient retentate fraction contains from about 50 to about 90 wt % of olefin compounds present in the initial feed.
42. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a polysiloxane membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction under pervaporation conditions, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbons and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compared to the naphtha feed;
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
43. The method of claim 42 wherein the membrane is one having a sulfur enrichment factor of greater than 1.5.
44. The method of claim 42 wherein the sulfur content of the sulfur deficient retentate fraction is less than 100 ppm.
45. The method of claim 44 wherein the sulfur content of the sulfur deficient fraction is less than 50 ppm.
46. The method of claim 45 wherein the sulfur content of the sulfur deficient retentate fraction is less than 30 ppm.
47. The method of claim 42 wherein the naphtha feed stream is a cracked naphtha.
48. The method of claim 47 wherein the naphtha is a FCC naphtha.
49. The method of claim 48 wherein the naphtha is a FCC light cat naphtha having a boiling range from about 50°C to about 105°C.
50. The method of claim 42 wherein the naphtha is a coker naphtha.
51. The method of claim 42 wherein the naphtha is a straight run.
52. The method of claim 42 wherein the sulfur deficient retentate fraction comprises at least 50 wt % of the total feed.
53. The method of claim 52 wherein the sulfur deficient retentate fraction comprises at least 70 wt % of the total feed.
54. The method of claim 42 wherein the sulfur-enriched permeate fraction is subjected to a hydrotreating process to reduce sulfur content.
55. The method of claim 42 wherein the sulfur-enriched permeate fraction is subjected to an adsorption process to reduce sulfur content.
56. The method of claim 42 wherein the sulfur-enriched permeate fraction is subjected to a catalytic distillation process to reduce sulfur content.
57. The method of claim 42 wherein the membrane has a sulfur enrichment factor of greater than 2.
58. The method of claim 43 wherein the membrane has a sulfur enrichment factor ranging from about 2 to about 20.
59. The method of claim 42 wherein the sulfur deficient retentate fraction contains from about 50 to about 90 wt % of olefin compounds present in the initial feed.
60. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a polyurea urethane membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction under pervaporation conditions, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbons and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compared to the naphtha feed;
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.
61. The method of claim 60 wherein the membrane is one having a sulfur enrichment factor of greater than 1.5.
62. The method of claim 60 wherein the sulfur content of the sulfur deficient retentate fraction is less than 100 ppm.
63. The method of claim 62 wherein the sulfur content of the sulfur deficient fraction is less than 50 ppm.
64. The method of claim 63 wherein the sulfur content of the sulfur deficient retentate fraction is less than 30 ppm.
65. The method of claim 60 wherein the naphtha feed stream is a cracked naphtha.
66. The method of claim 65 wherein the naphtha is a FCC naphtha.
67. The method of claim 66 wherein the naphtha is a FCC light cat naphtha having a boiling range from about 50°C to about 105°C.
68. The method of claim 60 wherein the naphtha is a coker naphtha.
69. The method of claim 60 wherein the naphtha is a straight run.
70. The method of claim 60 wherein the sulfur deficient retentate fraction comprises at least 50 wt % of the total feed.
71. The method of claim 70 wherein the sulfur deficient retentate fraction comprises at least 70 wt % of the total feed.
72. The method of claim 60 wherein the sulfur-enriched permeate fraction is subjected to a hydrotreating process to reduce sulfur content.
73. The method of claim 60 wherein the sulfur-enriched permeate fraction is subjected to an adsorption process to reduce sulfur content.
74. The method of claim 60 wherein the sulfur-enriched permeate fraction is subjected to a catalytic distillation process to reduce sulfur content.
75. The method of claim 60 wherein the membrane has a sulfur enrichment factor of greater than 2.
76. The method of claim 75 wherein the membrane has a sulfur enrichment factor ranging from about 2 to about 20.
77. The method of claim 60 wherein the sulfur deficient retentate fraction contains from about 50 to about 90 wt % of olefin compounds present in the initial feed.
78. The method of claim 1 further comprising combining the sulfur deficient retentate product stream and the reduced sulfur permeate product stream.
79. The method of claim 24 further comprising combining the sulfur deficient retentate product stream and the reduced sulfur permeate product stream.
80. The method of claim 42 further comprising combining the sulfur deficient retentate product stream and the reduced sulfur permeate product stream.
81. The method of claim 60 further comprising combining the sulfur deficient retentate product stream and the reduced sulfur permeate product stream.
82. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction, said sulfur deficient retentate fraction comprising at least 50 wt % of the naphtha feed, said membrane having a sulfur enrichment factor of greater than 1.5, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbons and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compared to the naphtha feed;
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compound present in the feed.
ii) recovering the sulfur deficient retentate fraction as a product stream;
iii) subjecting the sulfur enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compound present in the feed.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/784,898 US6896796B2 (en) | 2001-02-16 | 2001-02-16 | Membrane separation for sulfur reduction |
US09/784,898 | 2001-02-16 | ||
PCT/US2002/005347 WO2002068568A2 (en) | 2001-02-16 | 2002-02-13 | Membrane separation for sulfur reduction |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2438700A1 true CA2438700A1 (en) | 2002-09-06 |
Family
ID=25133871
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002438700A Abandoned CA2438700A1 (en) | 2001-02-16 | 2002-02-13 | Membrane separation for sulfur reduction |
Country Status (13)
Country | Link |
---|---|
US (4) | US6896796B2 (en) |
EP (1) | EP1373439B1 (en) |
JP (1) | JP4218751B2 (en) |
KR (1) | KR100843791B1 (en) |
CN (3) | CN100564488C (en) |
AT (1) | ATE368094T1 (en) |
AU (1) | AU2002255584B2 (en) |
BR (1) | BR0207174A (en) |
CA (1) | CA2438700A1 (en) |
DE (1) | DE60221370T2 (en) |
ES (1) | ES2290288T3 (en) |
MX (1) | MXPA03007011A (en) |
WO (1) | WO2002068568A2 (en) |
Families Citing this family (86)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6702945B2 (en) * | 2000-12-28 | 2004-03-09 | Exxonmobil Research And Engineering Company | Ionic membranes for organic sulfur separation from liquid hydrocarbon solutions |
US20020139719A1 (en) * | 2000-12-28 | 2002-10-03 | Minhas Bhupender S. | Removal of thiophenic sulfur from gasoline by membrane separation process |
US6649061B2 (en) | 2000-12-28 | 2003-11-18 | Exxonmobil Research And Engineering Company | Membrane process for separating sulfur compounds from FCC light naphtha |
US6736961B2 (en) * | 2001-01-30 | 2004-05-18 | Marathon Oil Company | Removal of sulfur from a hydrocarbon through a selective membrane |
JP3759435B2 (en) * | 2001-07-11 | 2006-03-22 | ソニー株式会社 | XY address type solid-state imaging device |
US7267761B2 (en) * | 2003-09-26 | 2007-09-11 | W.R. Grace & Co.-Conn. | Method of reducing sulfur in hydrocarbon feedstock using a membrane separation zone |
CN1886486A (en) * | 2003-11-04 | 2006-12-27 | 国际壳牌研究有限公司 | Process for upgrading a liquid hydrocarbon stream with a non-porous or nano-filtration membrane |
US7303681B2 (en) * | 2003-11-18 | 2007-12-04 | Exxonmobil Research And Engineering Company | Dynamic membrane wafer assembly and method |
AU2004291500A1 (en) * | 2003-11-18 | 2005-06-02 | Exxonmobil Research And Engineering Company | Method and apparatus for separating aromatic hydrocarbons in a non-adiabatic membrane system |
US7318898B2 (en) * | 2003-11-18 | 2008-01-15 | Exxonmobil Research And Engineering Company | Polymeric membrane wafer assembly and method |
WO2005049181A1 (en) * | 2003-11-18 | 2005-06-02 | Exxonmobil Research And Engineering Company | Process and system for separating components for blending |
EP1802729A1 (en) * | 2004-10-11 | 2007-07-04 | Shell Internationale Research Maatschappij B.V. | Process for separating colour bodies and/or asphalthenic contaminants from a hydrocarbon mixture |
US7452404B2 (en) | 2005-02-02 | 2008-11-18 | Intelligent Energy, Inc. | Multi-stage sulfur removal system and process for an auxiliary fuel system |
US7452405B2 (en) * | 2005-02-02 | 2008-11-18 | Intelligent Energy, Inc. | Multi stage sulfur removal system and process for an auxiliary fuel system |
KR101443739B1 (en) * | 2006-02-01 | 2014-09-26 | 인텔리전트 에너지, 인크. | Multi-stage sulfur removal system and process for an auxiliary fuel system |
WO2008027381A2 (en) * | 2006-08-31 | 2008-03-06 | Fluor Technologies Corporation | Hydrocarbon based sulfur solvent systems and methods |
US8246814B2 (en) * | 2006-10-20 | 2012-08-21 | Saudi Arabian Oil Company | Process for upgrading hydrocarbon feedstocks using solid adsorbent and membrane separation of treated product stream |
CN1974729B (en) * | 2006-11-23 | 2010-12-08 | 中国石油化工股份有限公司 | Prepn process of membrane material for desulfurizing FCC gasoline |
US7758751B1 (en) | 2006-11-29 | 2010-07-20 | Uop Llc | UV-cross-linked membranes from polymers of intrinsic microporosity for liquid separations |
US7797356B2 (en) * | 2007-02-02 | 2010-09-14 | Microsoft Corporation | Dynamically detecting exceptions based on data changes |
US20080295691A1 (en) * | 2007-06-01 | 2008-12-04 | Chunqing Liu | Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes |
US20080296527A1 (en) * | 2007-06-01 | 2008-12-04 | Chunqing Liu | Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes |
US20080300336A1 (en) * | 2007-06-01 | 2008-12-04 | Chunqing Liu | Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes |
US7837827B2 (en) * | 2007-06-28 | 2010-11-23 | Lam Research Corporation | Edge ring arrangements for substrate processing |
US8864996B2 (en) * | 2007-08-28 | 2014-10-21 | Exxonmobil Research And Engineering Company | Reduction of conradson carbon residue and average boiling points utilizing high pressure ultrafiltration |
US8177965B2 (en) * | 2007-08-28 | 2012-05-15 | Exxonmobil Research And Engineering Company | Enhancement of saturates content in heavy hydrocarbons utilizing ultrafiltration |
US7897828B2 (en) * | 2007-08-28 | 2011-03-01 | Exxonmobile Research And Engineering Company | Process for separating a heavy oil feedstream into improved products |
US7815790B2 (en) | 2007-08-28 | 2010-10-19 | Exxonmobil Research And Engineering Company | Upgrade of visbroken residua products by ultrafiltration |
US7871510B2 (en) * | 2007-08-28 | 2011-01-18 | Exxonmobil Research & Engineering Co. | Production of an enhanced resid coker feed using ultrafiltration |
US7867379B2 (en) * | 2007-08-28 | 2011-01-11 | Exxonmobil Research And Engineering Company | Production of an upgraded stream from steam cracker tar by ultrafiltration |
US7736493B2 (en) * | 2007-08-28 | 2010-06-15 | Exxonmobil Research And Engineering Company | Deasphalter unit throughput increase via resid membrane feed preparation |
US20090131242A1 (en) * | 2007-11-15 | 2009-05-21 | Chunqing Liu | Method of Making Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes |
US20090127197A1 (en) * | 2007-11-15 | 2009-05-21 | Chunqing Liu | Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes |
US20090126566A1 (en) * | 2007-11-15 | 2009-05-21 | Chunqing Liu | Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes |
US20090126567A1 (en) * | 2007-11-16 | 2009-05-21 | Chunqing Liu | Mixed Matrix Membranes Containing Molecular Sieves With Thin Plate Morphology |
US20090149313A1 (en) * | 2007-12-11 | 2009-06-11 | Chunqing Liu | Mixed Matrix Membranes Containing Low Acidity Nano-Sized SAPO-34 Molecular Sieves |
US20090149565A1 (en) * | 2007-12-11 | 2009-06-11 | Chunqing Liu | Method for Making High Performance Mixed Matrix Membranes |
US8226862B2 (en) * | 2007-12-12 | 2012-07-24 | Uop Llc | Molecular sieve/polymer asymmetric flat sheet mixed matrix membranes |
US20090152755A1 (en) * | 2007-12-12 | 2009-06-18 | Chunqing Liu | Molecular Sieve/Polymer Hollow Fiber Mixed Matrix Membranes |
US20090155464A1 (en) * | 2007-12-12 | 2009-06-18 | Chunqing Liu | Molecular Sieve/Polymer Mixed Matrix Membranes |
WO2009082493A1 (en) * | 2007-12-24 | 2009-07-02 | Saudi Arabian Oil Company | Membrane desulfurization of liquid hydrocarbon feedstreams |
US7943037B2 (en) * | 2008-03-11 | 2011-05-17 | Exxonmobil Research & Engineering Company | Hydroconversion process for petroleum resids using selective membrane separation followed by hydroconversion over carbon supported metal catalyst |
US7931798B2 (en) * | 2008-03-11 | 2011-04-26 | Exxonmobil Research And Engineering Company | Hydroconversion process for petroleum resids by hydroconversion over carbon supported metal catalyst followed by selective membrane separation |
US20090277837A1 (en) * | 2008-05-06 | 2009-11-12 | Chunqing Liu | Fluoropolymer Coated Membranes |
CN101591580B (en) * | 2008-05-29 | 2013-06-26 | 北京三聚环保新材料股份有限公司 | Desulfuration method of environmental-friendly liquefied petroleum gas |
JP2012503038A (en) * | 2008-09-15 | 2012-02-02 | ユーオーピー エルエルシー | Method to increase propylene yield and reduce benzene in the resulting naphtha fraction from cracked hydrocarbon feed |
US8127937B2 (en) * | 2009-03-27 | 2012-03-06 | Uop Llc | High performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes |
US8132677B2 (en) | 2009-03-27 | 2012-03-13 | Uop Llc | Polymer membranes prepared from aromatic polyimide membranes by thermal treating and UV crosslinking |
US8613362B2 (en) * | 2009-03-27 | 2013-12-24 | Uop Llc | Polymer membranes derived from aromatic polyimide membranes |
US8132678B2 (en) * | 2009-03-27 | 2012-03-13 | Uop Llc | Polybenzoxazole polymer-based mixed matrix membranes |
US8127936B2 (en) * | 2009-03-27 | 2012-03-06 | Uop Llc | High performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes |
US8561812B2 (en) * | 2009-03-27 | 2013-10-22 | Uop Llc | Blend polymer membranes comprising thermally rearranged polymers derived from aromatic polyimides containing ortho-positioned functional groups |
US20100133171A1 (en) * | 2009-03-27 | 2010-06-03 | Chunqing Liu | Polybenzoxazole Polymer-Based Mixed Matrix Membranes |
CN101927132B (en) * | 2009-04-16 | 2013-06-12 | 济南联星石油化工有限公司 | Chitosan/ synthetic hydrotalcite composite permeable membrane, preparation method and application thereof |
CN101927130B (en) * | 2009-04-16 | 2012-11-28 | 济南开发区星火科学技术研究院 | Method for removing sulfur-containing compounds from oil by utilizing membrane process |
US20100326913A1 (en) * | 2009-06-25 | 2010-12-30 | Uop Llc | Polybenzoxazole membranes prepared from aromatic polyamide membranes |
US8459469B2 (en) * | 2009-06-25 | 2013-06-11 | Uop Llc | Polybenzoxazole membranes prepared from aromatic polyamide membranes |
US20100133188A1 (en) * | 2009-06-25 | 2010-06-03 | Chunqing Liu | Polybenzoxazole Membranes Prepared From Aromatic Polyamide Membranes |
US20110000823A1 (en) * | 2009-07-01 | 2011-01-06 | Feras Hamad | Membrane desulfurization of liquid hydrocarbons using an extractive liquid membrane contactor system and method |
US7810652B2 (en) | 2009-09-25 | 2010-10-12 | Uop Llc | Method to improve the selectivity of polybenzoxazole membranes |
CN101724462B (en) * | 2009-12-05 | 2012-11-14 | 中国石油大学(华东) | Membrane separation-hydrogenation coupling process for desulfurizing FCC gasoline |
CN101817926B (en) * | 2010-04-07 | 2012-03-07 | 中科院广州化学有限公司 | Phosphate side chain-containing polyimide for gasoline desulphurization and preparation method thereof |
US8366804B2 (en) | 2010-05-28 | 2013-02-05 | Uop Llc | High permeance polyimide membranes for air separation |
KR101007600B1 (en) * | 2010-09-10 | 2011-01-12 | 쓰리웨이테크놀러지(주) | Device of controlling a load in an exercise equipment |
US8454832B2 (en) | 2010-11-29 | 2013-06-04 | Saudi Arabian Oil Company | Supported ionic liquid membrane system and process for aromatic separation from hydrocarbon feeds |
US20130319231A1 (en) * | 2010-12-09 | 2013-12-05 | Research Triangle Institute | Integrated system for acid gas removal |
US9333454B2 (en) | 2011-01-21 | 2016-05-10 | International Business Machines Corporation | Silicone-based chemical filter and silicone-based chemical bath for removing sulfur contaminants |
US8900491B2 (en) | 2011-05-06 | 2014-12-02 | International Business Machines Corporation | Flame retardant filler |
US8614288B2 (en) * | 2011-06-17 | 2013-12-24 | Uop Llc | Polyimide gas separation membranes |
US9186641B2 (en) | 2011-08-05 | 2015-11-17 | International Business Machines Corporation | Microcapsules adapted to rupture in a magnetic field to enable easy removal of one substrate from another for enhanced reworkability |
US8741804B2 (en) | 2011-10-28 | 2014-06-03 | International Business Machines Corporation | Microcapsules adapted to rupture in a magnetic field |
CN104395427B (en) | 2012-06-04 | 2016-05-11 | 沙特阿拉伯石油公司 | The manufacture of the polymer of thiophene, benzothiophene and their alkyl derivative |
US9716055B2 (en) | 2012-06-13 | 2017-07-25 | International Business Machines Corporation | Thermal interface material (TIM) with thermally conductive integrated release layer |
CN102911711B (en) * | 2012-10-25 | 2014-10-22 | 宁夏宝塔石化集团有限公司 | Membrane device for desulfurizing and refining catalytic gasoline |
JP6203393B2 (en) | 2013-12-16 | 2017-09-27 | サビック グローバル テクノロジーズ ビー.ブイ. | Treated mixed matrix polymer membrane |
WO2015095034A1 (en) | 2013-12-16 | 2015-06-25 | Sabic Global Technologies B.V. | Uv and thermally treated polymeric membranes |
US9669363B2 (en) | 2015-04-16 | 2017-06-06 | Uop Llc | High permeance membranes for gas separations |
WO2016209690A1 (en) | 2015-06-25 | 2016-12-29 | Uop Llc | Chemically and uv cross-linked high selectivity polyimide membranes for gas separations |
JP6644140B2 (en) | 2015-10-22 | 2020-02-12 | ユーオーピー エルエルシー | Double-layer coated membrane for gas separation |
WO2017087180A1 (en) | 2015-11-20 | 2017-05-26 | Uop Llc | High selectivity copolyimide membranes for separations |
US10471381B2 (en) | 2016-06-09 | 2019-11-12 | Uop Llc | High selectivity facilitated transport membranes and their use for olefin/paraffin separations |
US10328386B2 (en) | 2017-05-18 | 2019-06-25 | Uop Llc | Co-cast thin film composite flat sheet membranes for gas separations and olefin/paraffin separations |
US10569233B2 (en) | 2017-06-06 | 2020-02-25 | Uop Llc | High permeance and high selectivity facilitated transport membranes for olefin/paraffin separations |
US10751670B2 (en) | 2017-08-24 | 2020-08-25 | Uop Llc | High selectivity facilitated transport membrane comprising polyethersulfone/polyethylene oxide-polysilsesquioxane blend membrane for olefin/paraffin separations |
US10427997B2 (en) | 2017-12-27 | 2019-10-01 | Uop Llc | Modular membrane system and method for olefin separation |
JP7219440B2 (en) * | 2018-09-07 | 2023-02-08 | 学校法人 関西大学 | filtration membrane |
Family Cites Families (85)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US494775A (en) * | 1893-04-04 | Face-protector | ||
US573663A (en) * | 1896-12-22 | Half to marshall l | ||
US2002A (en) * | 1841-03-12 | Tor and planter for plowing | ||
US2779712A (en) | 1953-10-23 | 1957-01-29 | Standard Oil Co | Continuous process for the removal of mercaptans from hydrocarbons and apparatus therefor |
US2958656A (en) | 1954-07-16 | 1960-11-01 | American Oil Co | Method of separating hydrocarbons using ethyl cellulose permselective membrane |
US2923749A (en) | 1955-05-27 | 1960-02-02 | American Oil Co | Prevention of membrane rupture in a separatory process for oil soluble organic compounds using a non-porous plastic permeation membrane |
US2960462A (en) * | 1957-09-30 | 1960-11-15 | American Oil Co | Dual film combinations for membrane permeation |
US3179633A (en) | 1962-01-26 | 1965-04-20 | Du Pont | Aromatic polyimides from meta-phenylene diamine and para-phenylene diamine |
US3179632A (en) | 1962-01-26 | 1965-04-20 | Du Pont | Process for preparing polyimides by treating polyamide-acids with aromatic monocarboxylic acid anhydrides |
US3244763A (en) * | 1960-12-29 | 1966-04-05 | Exxon Research Engineering Co | Semi-permeable membrane extraction |
US3299157A (en) | 1961-03-07 | 1967-01-17 | Amicon Corp | Permeable membrane and method of making same for use in a paraxylene separation |
US3370102A (en) * | 1967-05-05 | 1968-02-20 | Abcor Inc | Isothermal-liquid-liquid permeation separation systems |
US3556990A (en) * | 1967-12-05 | 1971-01-19 | Arnold G Gulko | Reverse osmosis purification of hydrocarbon fuels |
US3546175A (en) | 1969-06-09 | 1970-12-08 | Du Pont | Soluble polyimides prepared from 2,4-diaminoisopropylbenzene and pyromellitic dianhydride and 3,4,3',4'-benzophenonetetracarboxylic dianhydride |
US3708458A (en) | 1971-03-16 | 1973-01-02 | Upjohn Co | Copolyimides of benzophenone tetracarboxylic acid dianhydride and mixture of diisocyanates |
US3822202A (en) | 1972-07-20 | 1974-07-02 | Du Pont | Heat treatment of membranes of selected polyimides,polyesters and polyamides |
US3853754A (en) | 1972-07-20 | 1974-12-10 | Du Pont | Membrane separation of homogeneous catalysts from nitrile solutions |
US3789079A (en) | 1972-09-22 | 1974-01-29 | Monsanto Co | Process for the separation of diene from organic mixtures |
US3816303A (en) | 1972-12-20 | 1974-06-11 | Us Interior | Poly(n-amido)imides as semipermeable membranes |
US3956112A (en) | 1973-01-02 | 1976-05-11 | Allied Chemical Corporation | Membrane solvent extraction |
DK143986C (en) | 1973-04-12 | 1982-04-26 | Berghof Forschungsinst | PROCEDURE FOR THE PREPARATION OF INSOLUTIBLE ASYMMETRIC POLYIMIDE MEMBRANES |
GB1434629A (en) | 1973-09-21 | 1976-05-05 | Noguera J M | Yarn spinning apparatus |
US4113628A (en) | 1974-06-05 | 1978-09-12 | E. I. Du Pont De Nemours And Company | Asymmetric polyimide membranes |
DE2627629C3 (en) | 1976-06-19 | 1979-12-20 | Bayer Ag, 5090 Leverkusen | Process for the separation of aromatic * hydrocarbons from mixtures with other organic compounds with the help of plastic membranes |
US4230463A (en) | 1977-09-13 | 1980-10-28 | Monsanto Company | Multicomponent membranes for gas separations |
JPS5471785A (en) | 1977-11-18 | 1979-06-08 | Nitto Electric Ind Co Ltd | Selectively permeable membrane and production thereof |
US4256567A (en) * | 1979-05-14 | 1981-03-17 | Engelhard Minerals & Chemicals Corporation | Treatment of petroleum stocks containing metals |
US4243701A (en) | 1979-11-08 | 1981-01-06 | Uop Inc. | Preparation of gas separation membranes |
US4307135A (en) | 1980-04-08 | 1981-12-22 | The United States Of America As Represented By The Secretary Of The Interior | Process for preparing an asymmetric permselective membrane |
US4493714A (en) | 1982-05-06 | 1985-01-15 | Teijin Limited | Ultrathin film, process for production thereof, and use thereof for concentrating a specified gas in a gaseous mixture |
US4468502A (en) | 1983-06-30 | 1984-08-28 | Monsanto Company | Cross-linked polyphenylene oxide |
EP0201614B1 (en) * | 1985-05-14 | 1989-12-27 | GebràDer Sulzer Aktiengesellschaft | Reactor for carrying out heterogeneous catalytic chemical reactions |
GB8531837D0 (en) | 1985-12-30 | 1986-02-05 | British Steel Corp | Cooling flow of molten material |
US4781733A (en) | 1986-07-23 | 1988-11-01 | Bend Research, Inc. | Semipermeable thin-film membranes comprising siloxane, alkoxysilyl and aryloxysilyl oligomers and copolymers |
US4761229A (en) | 1987-06-22 | 1988-08-02 | Thompson John A | Multi-leaf membrane module |
US4879044A (en) | 1987-10-14 | 1989-11-07 | Exxon Research And Engineering Company | Highly aromatic anisotropic polyurea/urethane membranes and their use for the separation of aromatics from non aromatics |
EP0312376A3 (en) | 1987-10-14 | 1990-01-31 | Exxon Research And Engineering Company | Polyurea membrane and its use for aromatics/non-aromatics separations |
GB8803767D0 (en) * | 1988-02-18 | 1988-03-16 | Ici Plc | Desulphurisation |
US4790941A (en) * | 1988-03-18 | 1988-12-13 | Separation Dynamics, Inc. | Fluid decontamination system |
US5019666A (en) | 1988-08-04 | 1991-05-28 | Exxon Research And Engineering Company | Non-porous polycarbonate membranes for separation of aromatics from saturates |
EP0361377B1 (en) | 1988-09-27 | 1995-06-28 | Ube Industries, Ltd. | Pervaporation method of separating liquid organic compound mixture through aromatic imide polymer asymmetric membrane |
DE3906464A1 (en) * | 1989-03-01 | 1990-09-06 | Bayer Ag | METHOD FOR PRODUCING UNSYMMETRIC SPIROORTHOCARBONATES |
US4944775A (en) | 1989-07-11 | 1990-07-31 | E. I. Du Pont De Nemours And Company | Preparation of poly(phenylene oxide) asymmetric gas separation membranes |
US4929358A (en) | 1989-08-09 | 1990-05-29 | Exxon Research And Engineering Company | Polyurethane-imide membranes and their use for the separation of aromatics from non-aromatics |
US5104532A (en) | 1989-09-15 | 1992-04-14 | Exxon Research And Engineering Company | Flat stack permeator |
US4990275A (en) | 1989-10-16 | 1991-02-05 | Exxon Research And Engineering Company | Polyimide aliphatic polyester copolymers (C-2356) |
EP0519132A1 (en) | 1989-10-18 | 1992-12-23 | Exxon Research And Engineering Company | Hollow fiber module |
US4962271A (en) | 1989-12-19 | 1990-10-09 | Exxon Research And Engineering Company | Selective separation of multi-ring aromatic hydrocarbons from distillates by perstraction |
US5159130A (en) | 1990-07-11 | 1992-10-27 | Exxon Research And Engineering Company | Polysulfone membranes for aromatics/saturates separation |
US5082987A (en) | 1990-10-15 | 1992-01-21 | Phillips Petroleum Company | Treatment of hydrocarbons |
US5045206A (en) * | 1990-12-05 | 1991-09-03 | Exxon Research & Engineering Company | Selective multi-ring aromatics extraction using a porous, non-selective partition membrane barrier |
US5232854A (en) * | 1991-03-15 | 1993-08-03 | Energy Biosystems Corporation | Multistage system for deep desulfurization of fossil fuels |
US5510265A (en) | 1991-03-15 | 1996-04-23 | Energy Biosystems Corporation | Multistage process for deep desulfurization of a fossil fuel |
US5265734A (en) | 1991-08-30 | 1993-11-30 | Membrane Products Kiryat Weitzman Ltd. | Silicon-derived solvent stable membranes |
US5290452A (en) | 1991-12-05 | 1994-03-01 | Exxon Research & Engineering Co. | Crosslinked polyester amide membranes and their use for organic separations |
US5198002A (en) | 1992-03-12 | 1993-03-30 | The United States Of America As Represented By The United States Department Of Energy | Gas stream clean-up filter and method for forming same |
US5306476A (en) | 1992-06-02 | 1994-04-26 | Electrochem, Inc. | Continuous sulfur removal process |
CA2097633A1 (en) | 1992-06-29 | 1993-12-30 | James R. Sweet | Integrated membrane/hydrocracking process for improved feedstock utilization in the production of reduced emissions gasoline |
US5238563A (en) | 1992-07-29 | 1993-08-24 | Exxon Research & Engineering Company | Multi-element housing |
US5241039A (en) | 1992-08-14 | 1993-08-31 | Exxon Research & Engineering Company | Polyimide/aliphatic polyester copolymers without pendent carboxylic acid groups (C-2662) |
CA2100643A1 (en) | 1992-08-14 | 1994-02-15 | Guido Sartori | Fluorinated polyolefin membranes for aromatics/saturates separation |
US5409599A (en) | 1992-11-09 | 1995-04-25 | Mobil Oil Corporation | Production of low sulfur distillate fuel |
US5286280A (en) | 1992-12-31 | 1994-02-15 | Hoechst Celanese Corporation | Composite gas separation membrane having a gutter layer comprising a crosslinked polar phenyl-containing - organopolysiloxane, and method for making the same - |
CA2111176A1 (en) | 1993-01-04 | 1994-07-05 | Joseph L. Feimer | Membrane process to remove elemental sulfur from gasoline |
US5264166A (en) | 1993-04-23 | 1993-11-23 | W. R. Grace & Co.-Conn. | Polyimide membrane for separation of solvents from lube oil |
NL9301535A (en) | 1993-09-06 | 1995-04-03 | Tno | A method for removing acidic components, such as mercaptans, from liquid hydrocarbons, such as a light oil fraction. |
US5556449A (en) | 1993-10-25 | 1996-09-17 | Membrane Technology And Research, Inc. | Acid gas fractionation process for fossil fuel gasifiers |
GB2277028B (en) * | 1993-12-24 | 1996-01-03 | Gw Chemicals Ltd | Cleaning beer dispense lines using peracetic acid |
DE4416330A1 (en) | 1994-05-09 | 1995-11-16 | Hoechst Ag | Composite membrane and process for its manufacture |
US5525235A (en) | 1994-05-17 | 1996-06-11 | Energy Biosystems Corporation | Method for separating a petroleum containing emulsion |
US5635055A (en) | 1994-07-19 | 1997-06-03 | Exxon Research & Engineering Company | Membrane process for increasing conversion of catalytic cracking or thermal cracking units (law011) |
US5643442A (en) | 1994-07-19 | 1997-07-01 | Exxon Research And Engineering Company | Membrane process for enhanced distillate or hydrotreated distillate aromatics reduction |
US5550199A (en) | 1994-12-02 | 1996-08-27 | Exxon Research And Engineering Company | Diepoxide crosslinked/esterified polyimide-aliphatic polyester copolymers |
US6024880A (en) | 1996-02-26 | 2000-02-15 | Ciora, Jr.; Richard J. | Refining of used oils using membrane- and adsorption-based processes |
US5863419A (en) | 1997-01-14 | 1999-01-26 | Amoco Corporation | Sulfur removal by catalytic distillation |
JPH10211732A (en) * | 1997-01-30 | 1998-08-11 | Canon Inc | Head and method for mounting the same |
US6187987B1 (en) | 1998-07-30 | 2001-02-13 | Exxon Mobil Corporation | Recovery of aromatic hydrocarbons using lubricating oil conditioned membranes |
US6180008B1 (en) | 1998-07-30 | 2001-01-30 | W. R. Grace & Co.-Conn. | Polyimide membranes for hyperfiltration recovery of aromatic solvents |
US6184176B1 (en) | 1999-08-25 | 2001-02-06 | Phillips Petroleum Company | Process for the production of a sulfur sorbent |
US6274533B1 (en) * | 1999-12-14 | 2001-08-14 | Phillips Petroleum Company | Desulfurization process and novel bimetallic sorbent systems for same |
US6303020B1 (en) * | 2000-01-07 | 2001-10-16 | Catalytic Distillation Technologies | Process for the desulfurization of petroleum feeds |
US6702945B2 (en) | 2000-12-28 | 2004-03-09 | Exxonmobil Research And Engineering Company | Ionic membranes for organic sulfur separation from liquid hydrocarbon solutions |
US6649061B2 (en) | 2000-12-28 | 2003-11-18 | Exxonmobil Research And Engineering Company | Membrane process for separating sulfur compounds from FCC light naphtha |
US20020139719A1 (en) * | 2000-12-28 | 2002-10-03 | Minhas Bhupender S. | Removal of thiophenic sulfur from gasoline by membrane separation process |
US6736961B2 (en) | 2001-01-30 | 2004-05-18 | Marathon Oil Company | Removal of sulfur from a hydrocarbon through a selective membrane |
-
2001
- 2001-02-16 US US09/784,898 patent/US6896796B2/en not_active Expired - Fee Related
-
2002
- 2002-02-13 BR BR0207174-6A patent/BR0207174A/en not_active Application Discontinuation
- 2002-02-13 CN CNB2005100882703A patent/CN100564488C/en not_active Expired - Fee Related
- 2002-02-13 JP JP2002568665A patent/JP4218751B2/en not_active Expired - Fee Related
- 2002-02-13 MX MXPA03007011A patent/MXPA03007011A/en active IP Right Grant
- 2002-02-13 KR KR1020037010695A patent/KR100843791B1/en not_active IP Right Cessation
- 2002-02-13 WO PCT/US2002/005347 patent/WO2002068568A2/en active IP Right Grant
- 2002-02-13 AU AU2002255584A patent/AU2002255584B2/en not_active Ceased
- 2002-02-13 AT AT02724988T patent/ATE368094T1/en not_active IP Right Cessation
- 2002-02-13 CA CA002438700A patent/CA2438700A1/en not_active Abandoned
- 2002-02-13 CN CNB028051084A patent/CN1320080C/en not_active Expired - Fee Related
- 2002-02-13 EP EP02724988A patent/EP1373439B1/en not_active Expired - Lifetime
- 2002-02-13 CN CNA2007101544578A patent/CN101186841A/en active Pending
- 2002-02-13 ES ES02724988T patent/ES2290288T3/en not_active Expired - Lifetime
- 2002-02-13 DE DE60221370T patent/DE60221370T2/en not_active Expired - Lifetime
-
2003
- 2003-03-06 US US10/382,409 patent/US7048846B2/en not_active Expired - Lifetime
-
2004
- 2004-05-14 US US10/846,818 patent/US7041212B2/en not_active Expired - Lifetime
- 2004-05-14 US US10/846,816 patent/US7018527B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
US20020153284A1 (en) | 2002-10-24 |
US7048846B2 (en) | 2006-05-23 |
JP4218751B2 (en) | 2009-02-04 |
CN1743424A (en) | 2006-03-08 |
JP2004528417A (en) | 2004-09-16 |
WO2002068568A2 (en) | 2002-09-06 |
WO2002068568A3 (en) | 2003-04-10 |
DE60221370T2 (en) | 2008-04-17 |
US20040211706A1 (en) | 2004-10-28 |
KR20030090641A (en) | 2003-11-28 |
US20040211705A1 (en) | 2004-10-28 |
CN1513049A (en) | 2004-07-14 |
EP1373439B1 (en) | 2007-07-25 |
US7041212B2 (en) | 2006-05-09 |
EP1373439A2 (en) | 2004-01-02 |
ES2290288T3 (en) | 2008-02-16 |
US7018527B2 (en) | 2006-03-28 |
DE60221370D1 (en) | 2007-09-06 |
CN101186841A (en) | 2008-05-28 |
US6896796B2 (en) | 2005-05-24 |
KR100843791B1 (en) | 2008-07-03 |
BR0207174A (en) | 2004-06-15 |
AU2002255584B2 (en) | 2007-06-28 |
US20030173255A1 (en) | 2003-09-18 |
CN100564488C (en) | 2009-12-02 |
MXPA03007011A (en) | 2003-11-18 |
ATE368094T1 (en) | 2007-08-15 |
CN1320080C (en) | 2007-06-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6896796B2 (en) | Membrane separation for sulfur reduction | |
AU2002255584A1 (en) | Membrane separation for sulfur reduction | |
US6187987B1 (en) | Recovery of aromatic hydrocarbons using lubricating oil conditioned membranes | |
US5396019A (en) | Fluorinated polyolefin membranes for aromatics/saturates separation | |
US6180008B1 (en) | Polyimide membranes for hyperfiltration recovery of aromatic solvents | |
US8821717B2 (en) | Process for upgrading hydrocarbon feedstocks using solid adsorbent and membrane separation of treated product stream | |
US7267761B2 (en) | Method of reducing sulfur in hydrocarbon feedstock using a membrane separation zone | |
US20100155300A1 (en) | Process for producing gasoline of increased octane and hydrogen-containing co-produced stream | |
GB2268186A (en) | Membrane/hydrocracking process for improved feedstock utilization in the production of reduced emissions gasoline | |
WO2009082493A1 (en) | Membrane desulfurization of liquid hydrocarbon feedstreams | |
EP1345873A1 (en) | Removal of thiophenic sulfur from gasoline by membrane separation process | |
US7951224B2 (en) | Process for improving the cetane rating of distillate and diesel boiling range fractions |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
FZDE | Discontinued |