US2882216A

US2882216A - Circulatory process for treatment of hydrocarbons with in situ production of hydrogen

Info

Publication number: US2882216A
Application number: US587699A
Authority: US
Inventors: Prentiss S Viles
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1956-05-28
Filing date: 1956-05-28
Publication date: 1959-04-14
Anticipated expiration: 1976-04-14

Description

Uni d SW68. aI TQ CIRCULATORY PROCESS FOR TREATMENT OF HYDROCARBONS WITH IN SITU PRODUCTION a or HYDROGEN l'rentiss S. Viles, Baytown, Tex., assignor, by mesne assignments, to Esso Research and Engineerin Company, Ehzabeth, N.J., a corporation of Delaware :Application May 28, 1956, Serial No. 587,699 9 Claims. 01. 208-60) of'hydrocarbons with hydrogen in which only hydrocarbon is added to the system in which the hydrocarbon is treated. i i i I The present invention may be briefly described as a method for treating hydrocarbons in a circulatory system in which a stream of feed hydrocarbon is formed.

The stream is contacted with a hydrocarbon conversion catalyst in a first reaction zone at a temperature within therange of 500 to 1200 F. and at a pressure in the range of 15 to 900 pounds per square inch gauge. By

contact with the hydrocarbon conversion catalyst a liquid hydrocarbon product is formed and a first gaseous product containing hydrocarbons is also formed. The first gaseous product is then contacted with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. to form a second gaseous product which contains hydrogen and which is substantially free of hydrocarbon. The second gaseous product is admixed with the feed hydrocarbon tq-form the stream and a normally gaseous hydrocar- Ben is added to the system ahead of one of said reaction zones, liquid product being withdrawn from the system. .;.The normally gaseous hydrocarbons may suitably be natural gas and the components thereof. Specifically, therlormally gaseous hydrocarbons may comprise or include methane, ethane, propane, the butanes, ethylene, propylene, the butylenes, the diolefins, such as butadienes,.and the like. While mixtures of these hydrocarbons may be used, it may sometimes be preferred and it is contemplated that it is within the purview of this: invention to use purified hydrocarbons, such as methane, ethane, or propane. Natural gas hydrocarbons such as methane and ethane will be preferred.

-The hydrocarbon feed stock of the present in vention may include fractions boiling in the range from. aboutv 100 up to about 1000" F. Suitably the hydrocarbon feed stocks are the normally liquid hydrocarhens and may include gasoline, kerosene, gas oil, heating 0i1,--.components thereof, and mixtures of components of these several fractions. Crude petroleum may be charged to the process of the present invention but it; will be preferred to charge the crude residue after removal of the lighter and more volatile fractions there-- from. It is contemplated in the practice of the present invention that hydrocarbons having a low hydrogen to carbon. ratio will form a preferred feed stock of the present invention.

The hydrocarbon conversion operation of the present invention may include any hydrocarbon conversion whercinthe hydrocarbon is contacted at an elevated temperature withv hydrogen. Such. processes may include the so-called hydrofining, hydrocracking, hydrogenation, and the like, operations. Such hydrogen treatment processes may suitably be conducted at a temperature in the range from about 500 to about 1000 F. with a preferred temperature range from about 600 to about 900 F.

Pressures may suitably range from about 15 to about 900 pounds per square inch gauge with a preferred range from about 15 to about 600 pounds per square inch gauge.

The hydrocarbon conversion catalyst may suitably be any hydrocarbon conversion catalyst which is employed in the hydrogen treatment of hydrocarbons, such as petroleum hydrocarbons. Illustrative of such conversion catalysts may be mentioned the metals, oxides and sulfides of chromium, nickel, molybdenum, cobalt, platinum, palladium, tungsten, titanium, and the like. These catalysts may be employed as mixtures; for example, the hydrocarbon conversion catalyst may be molybdenum oxide, sulfide, cobalt molybdate, which is a mixture of cobaltous oxide and molybdic trioxide, platinum as the metal or as compounds of the metal, nickel and tungsten sulfide, and mixtures thereof, and the like.

The catalyst employed in the second reaction zone of the present invention is suitably cobalt molybdate which is a mixture of cobaltous oxide and molybdic trioxide. The cobaltous oxide and molybdic trioxide may be em:- ployed in a preferred ratio of mole per mole as the catalyst in the second reaction zone but the ratio of cobaltous oxide to molybdic trioxide may range from 0.1:1 to 1:01 of cobaltous oxide per mole of molybdic trioxide.

Both the hydrocarbon conversion catalysts and the cobalt molybdate used in the second reaction zone of the present invention may suitably be employed as a supported catalyst. For example, the hydrocarbon conversion catalyst may be supported on a suitable support in an amount in the range from about 1.0 to about 50.0 weight percent but with a preferred amount of approximately 15.0 weight percent of the catalyst.

The amount of cobalt molybdate on the support used in the second reaction zone may range from about 1.0 to 25.0 weight percent with a preferred amount of approximately 15.0 weight percent of the total catalyst. Suitable supports for the catalyst employed in the first reaction zone and the second reaction zone may include alumina, zirconia, magnesia, silica, silica-alumina, Filtrol kieselguhr, Floridan, and the like. Preferred supports are pure alpha and gamma alumina.

In the first reaction zone where the hydrocarbons are converted, the hydrocarbons may contact the hydrocarbon conversion catalyst at space velocities in the range from about 0.5 to about 15 v./v./hr. Some variations in the space velocities within the range given are permissible depending on the feed stock. With gas oils, space velocities from about 0.5 to about 5 v./v./hr. are particularly useful while with naphthas space velocities from about 1 to about 10-v./v./hr. may be used. With crude petroleum residues and other asphaltic-containing' feed stocks, space velocities from about 0.25 to about 5 v./v./hr. are suitably used.

In the second reaction zone of the present invention the gaseous product contacts the catalyst at a suitable space velocity which may range from about 1 to about 500 volumes of gaseous product per volume of catalyst per hour, with a preferred space velocity from about"-50 tacted with the catalyst in the vapor phase.

The pressures employed in the second reaction zone of the present invention may range from about pound absolute to about 1000 pounds per square inch gauge with a preferred pressure of about atmospheric. Lowpressures are desirable and give the most satisfactory results in the second stage of the present invention.

The reaction zones of the present invention may be arranged with the catalyst provided as a fixed bed or the reaction may be conducted in either or both of the reaction zones employing the so-called fluidized powder technique wherein the catalyst is suspended in vaporized hydrocarbons. The reaction may be conducted in either the first or second reaction zones or both in a suspension or slurry of the catalyst in the hydrocarbons.

The persent invention is quite advantageous and useful in that hydrocarbons are treated with hydrogen in a circulatory system where only hydrocarbons are added and a normally gaseous hydrocarbon, the hydrogen being produced in situ from the gaseous products produced in rfllCPI'OCCSS and from the added gaseous hydrocarbons, if desired. The gaseous hydrocarbons where employed in the practice of the persent invention may be added into the circulatory system either with the feed stock or prior to the contacting of the gaseous hydrocarbon product from the first operation with the catalyst in the second reaction zone. By operating in this manner, the only material withdrawn is the liquefied product and the only added components are hydrocarbons both liquid and normally gaseous.

The invention will be further illustrated by reference to the drawing in which the single sheet is in the form of a flow diagram of a preferred mode.

Referring to the drawing, numeral 11 designates a charge line through which a liquefied hydrocarbon feed such as a crude residue containing asphaltic components is introduced into the system and then introduced by way of line 12 into a heater or furnace 13 provided with heating coil 14 and heating means illustrated by burners 15.

The heated and at least partially vaporized hydrocarbon feed is then discharged by way of line 16 into line 17 where it admixes with a hydrogen-containing gas flowing in line 17 from a source which will be described further. The heated hydrocarbons and hydrogen-containing gas pass into a first reaction zone 18 containing a bed 19 of a hydrocarbon conversion catalyst which may be a platinum-containing catalyst or a molybdenum-eontaining catalyst, such as cobalt molybdate. In reaction zone 19 conditions are maintained to convert the hydrocarbons or to remove sulfur and deleterious compounds and the like from the hydrocarbons or to increase the hydrogen to carbon ratio of the hydrocarbons as may be desired. The converted hydrocarbons then issue from reaction zone 18 by way of line 20 and are discharged thereby into a separation zone 21 wherein a separation is made between the normally gaseous product which contains hydrocarbons and the liquid product.

The liquid product is withdrawn from separation zone 21 by line 22 and is discharged into a distillation zone 23 which, for purposes of illustration, is shown as a single distillation tower. It is to be understood, however, that distillation zone 23 may suitably include a plurality of fractional distillation towers equipped with all auxiliary equipment necessary for precise separation among the various components of the product introduced by line 22. Such auxiliary equipment may include vaporliquid contacting means, such as hell cap trays, suitable packing and the like and will include means for inducing reflux and cooling and condensing means. In anyevent, the conditions in distillation zone 23 are adjusted by heating means illustrated by steam coil 24 to adjust temperature and pressure conditions in zone 23 for removal of light products by line 25, intermediate products by

lines

26 and 27, and heavier fractions by line 28. The fractions recovered by

lines

25, 26, and .27 maybe further processed and may suitably be used as motor fuel components of high octane number.

The gaseous products are separated in separator 21 from the liquid products and withdrawn by line 29 controlled by valve 30 and introduced into line 31 for contacting with cobalt molybdate catalyst in reaction zone 32 arranged as a bed33 therein. Under the conditions .in which the gaseous product contacts the catalyst in reaction zone 32, the hydrocarbons therein are substantially completely converted to hydrogen. The gaseous product from reaction zone 32 is withdrawn therefrom by line 17 and introduced thereby into reaction zone 18 in admixture with the hydrocarbons in line 16.

Since the gaseous product in line 29 may contain impurities, such as hydrogen sulfide, ammonia and water, it may suitably be treated by routing all or part of the gases in line 29 through a scrubbing zone generally indicated by the numeral .34, the gases being introduced into zone 34 by line 35 controlled by valve 36, valve in line 29 either being partly or completely closed. In scrubbing zone 34 the gaseous mixture contacts a scrubbing solution such as aqueous monoor diethanol amine, and the like, introduced thereto by line 37 controlled by valve 38. The used or spent scrubbing solution is discharged from zone 34 by line 39 controlled by valve 40 for revivification or regeneration in means not shown for re-use in zone 34. The scrubbed gases which may comprise essentially methane and the like are discharged by line 41 controlled by valve 42 into line 29 and thence into line 31.

Since the gas in line 17 may not contain a suificient amount of hydrogen in accordance with the present invention, natural gas or methane, and the like, may be introduced into line 30 by way of line 43 controlled valve 44. The natural gas or components thereof on pas sage through the reaction zone 32 are substantially coin} pletely converted to hydrogen under the conditions set out hereinbefore.

Likewise, natural gas may be introduced with the feed hydrocarbons in line 11 and then pass into heater 13, Provision is made for introducing such natural gas by line 45 controlled by valve 46.

It will be seen from the foregoing description taken with the drawing that an improved method for treating hydrocarbons with hydrogen has been provided in that the only components added to the system are hydrocarbons which will include both liquid and normally gaseous hydrocarbons. Thus, in accordance with the present invention, a method is provided whereby high hydrogen to carbon ratios normally gaseous hydrocarbons, such as methane, ethane, propane and the like, may be combined with low hydrogen to carbon ratio hydrocarbons, such ascrude residua, reduced crudes, asphaltic fractions, and the like, to produce hydrocarbon fractions having a-higher hydrogen to carbon ratio than the liquid hydrocarbon feed stock. These higher and more desirable hydrogen to carbon ratio fractions may include gasoline, middle distillates, such as heating oils, lubricating oils and the like.

Also in the present invention a method is provided for removal of undesirable contaminants, such as sulfur, nitrogen, oxygen, and undesirable metallic compounds frequently encountered in crude residues and the like;- This is accomplished by treating such hydrocarbon frac tions with hydrogen whereby the deleterious compounds are converted and/ or placed in a condition whereby they may be readily removed.

In the second stage of the present invention. it is" essential that cobalt molybdate or a mixture of CObHltOllSf oxide and molybdic trioxide beemployed sincecatalyst under conditions set out hereinbefore selectivelyconverts hydrocarbons to hydrogen forming a substantially pure hydrogen under the selected conditionsr The present invention is also desirable in that in the-cit culatory; system the reaction zonewhere the hydtoc'arbons are converted may be sized for the passage and contact of the hydrocarbons in admixture with the hydrogen formed in the process wherein the second reaction zone will be of smaller size by virtue of the passage of only the gaseous product from the first reaction zone therethrough together with any added natural gas or the like. Suitably the size of the first reaction zone to the size of the second reaction zone may be in a ratio in the range from about 100:1 to about 5:1.

Another advantage of the present invention is that the hydrogen produced in the present invention is produced in a heated condition and does not have to pass through the heater 13 since the second reaction zone may suitably be at a higher temperature than the first reaction zone.

Many modifications of the present invention may be performed without departing from the spirit and scope of the claims.

This application contains subject matter common to an application entitled Method of Making Hydrogen, sleirial No. 587,566, filed May 28, 1956, for Prentiss S.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and to secure by Letters Patent is:

1. In a circulatory system in which a normally liquid low hydrogen to carbon ratio hydrocarbon is contacted with a cobalt molybdate catalyst in the presence of hydrogen at a temperature within the range of 500 to 1000 F. and at a pressure within the range of 15 to 900 pounds per square inch gauge in a first reaction zone and in which normally gaseous and normally liquid hydrocarbon products are formed, the method including the step of contacting said normally gaseous product with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. whereby said hydrogen is formed from said gaseous hydrocarbon product and only hydrocarbons are added to the system.

2. A method in accordance with claim 1 in which a normally gaseous hydrocarbon is added to said gaseous hydrocarbon product prior to contacting same with said catalyst in said second reaction zone.

3. A method in accordance with claim 1 in which a normally gaseous hydrocarbon is added to said normally liquid hydrocarbon prior to contacting same with said catalyst in said first reaction zone.

4. In a circulatory system in which a normally liquid hydrocarbon is contacted with a low hydrogen to carbon ratio hydrocarbon conversion catalyst in the presence of hydrogen at a temperature within the range of 500 to 1000 F. and at a pressure within the range of 15 to 900 pounds per square inch gauge in a first reaction zone and in which normally gaseous and normally liquid hydrocarbon products are formed, the method including the step of contacting said normally gaseous product with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. whereby said hydrogen is formed from said gaseous hydrocarbon product and only hydrocarbons are added to the system.

5. In a circulatory system in which a normally liquid low hydrogen to carbon ratio hydrocarbon is contacted with a platinum-containing catalyst in the presence of hydrogen at a temperature within the range of 500 to 1000 F. and at a pressure within the range of 15 to 900 pounds per square inch gauge in a first reaction zone and in which normally gaseous and normally liquid hydrocarbon products are formed, the method including the step of contacting said normally gaseous product with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. whereby said hydrogen is formed from said gaseous hydrocarbon products and only hydrocarbons are added to the system.

6. In a circulatory system in which a normally liquid low hydrogen to carbon ratio hydrocarbon is contacted with a molybdenum-containing catalyst in the presence of hydrogen at a temperature within the range of 500 to 1000 F. and at a pressure within the range of 15 to 900 pounds per square inch gauge in a first reaction zone and in which normally gaseous and liquid hydrocarbon products are formed, the method including the step of contacting said normally gaseous product with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. whereby said hydrogen is formed from said gaseous hydrocarbon product and only hydrocarbons are added to the system.

7. A circulatory method for treating low hydrogen to carbon ratio hydrocarbons in a circulatory system in which only hydrocarbons are charged which comprises establishing a stream of a liquid feed hydrocarbon, contacting said stream with a hydrocarbon conversion catalyst in a first reaction zone at a temperature within the range of 500 to 1000 F. and at a pressure within the range of 15 to 900 pounds per square inch gauge to form a normally liquid hydrocarbon product and a first normally gaseous product containing hydrocarbon, contacting at least a potion of the first normally gaseous product with a cobalt molybdate catalyst in a second reaction zone at a temperature within the range of 850 to 1600 F. to form a second gaseous product containing hydrogen and substantially free of hydrocarbon, admixing said second gaseous product with said feed hydrocarbon to form said stream, adding a normally gaseous hydrocarbon to said system ahead of one of said reaction zones, and withdrawing said liquid product from said system.

8. A method in accordance with claim 7 in which the i normally gaseous hydrocarbon is added to the feed hydrocarbon.

9. A method in accordance with claim 7 in which the normally gaseous hydrocarbon is added to the first gaseous product.

References Cited in the file of this patent

Claims

1. IN A CIRCULATORY SYSTEM IN WHICH A NORMALLY LIQUID LOW HYDROGEN TO CARBON RATIO HYDROCARBON IS CONTACTED WITH A COBALT MOLYBDATE CATALYST IN THE PRESENCE OF HYDROGEN AT A TEMPERATURE WITHIN THE RANGE OF 500* TO 1000* F. AND AT A PRESSURE WITHIN THE RANGE OF 15 TO 900 POUNDS PER SQUARE INCH GAUGE IN A FIRST REACTION ZONE AND IN WHICH NORMALLY GASEOUS AND NORMALLY LIQUID HYDROCARBON PRODUCTS ARE FORMED, THE METHOD INCLUDING