US3281351A - Production of ethylene, butadiene, carbon black feedstock and benzene from a cracked naphtha - Google Patents

Description

R. E. GILLILAND ETAL 3,281,351

N CARBON BLACK FE HTHA Oct. 25, 1966 EDSTOCK PRODUCTION OF ETHYLE E, BUTADIENE,

AND BENZENE FROM A CRACKED NAP 4 Sheets-Sheerl l Filed OCC. 16, 1964 3,28 ,351 EEDsTocK ETAL Oct. 25, 1966 R. E. GILLILAND HYLENE, BUTADIENE,

PRODUCTION OF ET CARBON BLACK F AND BENZENE FROM A CRACKED NAPHTHA 4 Sheets-Sheet Filed Oct. 16, 1964 0d 25, 1965 R. E. GILLILAND ETAL PRODUCTION OF ETHYLENE, BUTADIENE, CARBON BLACK FEEDSTOCK AND BENZENE FROM A CRACKED NAPHTHA 4 Shee 11s-Sheet 5 Filed OCb. 16, 1964 Oct. 25, 1966 R E. GILLILAND ETAL 3,281,351

PRODUCTION OF ETHYzLENE, BUTADIENE, CARBON BLACK FEEDSTOCK Filed Oct. 16, `1964 AND BENZENE FROM A CRACKED NAPHTHA 4 Sheets-Sheet 4 ,ef 2 A TTOPN VS United States Patent O 3,281,351 PRDUCTIUN F ETHYLENE, BUTADEENE, CAR- BON BLACK FEEDSTCK AND BENZENE FROM A CRACKED NAPHTHA Robert E. Gilliland, Donald 1K. MacQueen, and Rolland E. Dixon, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Filed (let. 16, 1964, Ser. No. 404,333 4 Claims. (Cl. 208-67) naphtha cracking and olefin dehydrogenation are combned in a process wherein ethylene and butadiene are produced. By the practice of our invention, relatively low priced products of that reaction are -combined and processed for the production of relatively high priced products.

An object of our invention is to produce ethylene, butadiene, benzene and a carbon black feed stock from naphtha.

Another object of our invention is to produce a high quality carbon black feed stock and benzene from fuel oil, gasoline, and butene deoiler kettle products from a butadiene and ethylene producing process.

Other aspects, objects and the advantages of our invention are apparent in the written description, the drawing and the claims.

According to our invention, a hydrocarbon stream is cracked and the effluent separated to produce fuel oil, gasoline, butene, butadiene, propylene and ethylene. The butadiene rand ethylene are recovered as products. The butene is dehydrogenated to produce additional butadiene. The propylene is disproportionated to produce additional quantities of ethyene and butene, with the butene being fed to the dehydrogenation step. Isobutylene removed from the butene prior to dehydrogenation, the gasoline and the fuel oil, are hydrotreated and the effluent solvent extracted to remove aromatics, the parains and olens being recycled to the cracking step. The aromatic portion is further separated to produce benzene and a high aromatic stream which is blended with the fuel oil to produce a high quality carbon black feed stock. The eflluent of the butene dehydrogenation and the C2 fraction of the propylene disproportionation are recycled to the separation train of the hydrocarbon cracking eiiiuent.

In this application, disproportionation is used to mean the conversion of a hydrocarbon into similar hydrocarbons of higher and lower numbers of carbon atoms per molecule. The process is especially applicable to nontertiary base aliphatic olefins, that is, olens having no carbon chain branching at a double bond carbon atom, having from 3 to 6 carbon atoms per molecule. When propylene is disproportionated, approximately equimolar quantities of ethylene and butenes are produced.

Suitable disproportionation catalysts for the practice of our invention include oxides, sulfides and carbonyls of molybdenum and tungsten, supported on silica, alumina, or silica-alumina, or any other suitable disproportionation catalysts. Operating conditions suitable for the catalyst and feed are selected.

Details of some suitable disproportionation processes are given in copending applications Serial No. 307,371,

ICC

Hecklesberg, filed September 9, 1963; Serial No. 313,309, Banks, filed September 27, 1963, now abandoned; Serial No. 336,624, Hecklesberg, led January 9, 1964; and Serial No. 94,996, Banks, led March 13, 1961.

Catalysts, conditions, etc., for use in the dehydrogenation step for producing diolefins from olen feed stocks are well known and need not be discussed in detail. For example, a suitable dehydrogenation process is disclosed in U.S. Patent No. 2,866,790.

Similarly, conditions and catalysts for the hydr-otreating steps are well known. For example, the process disclosed in Hydrocarbon Processing and Petroleum Rener, November 1962, vol. 4l, No. 1l, pages 201-202, is suitable. Suitable catalysts include molybdenum sulfide, nickel sulfide, etc., on alumina or clay.

In the drawing, FIGURE 1 ilustrates a unitized system for naphtha cracking, propylene disproportionation, butene dehydrogenation, hydrotreating and aromatic extraction.

FIGURE 2 is a unitized system for naphtha cracking, propylene disproportionation, butene dehydrogenation, hydrotreating and aromatic extraction, illustrating separation facilities in more detail.

FIGURE 3 illustrates a unitized system for naphtha cracking, propylene disproportionation, butene dehydrogenation, hydrotreating and aromatic extraction, utilizing a simplified separation system.

FIGURE 4 illustrates, in somewhat more detail, hydrotreating and aromatic extraction facilities suitable for use in the system of FIGURE 1, FIGURE 2 or FIGURE 3.

In the system illustrated in FIGURE l, a hydrocarbon suitable for cracking is fed into naphtha cracking reactor 11, and the efuent passed through conduit 13 into separation unit 14. From separation unit 14 a fuel oil stream is removed through conduit 16, a gasoline stream through conduit 17, a C4 hydrocarbon stream through conduit 18, and a C3 hydrocarbon stream `through conduit 19.

The C4 stream of conduit 18 is passed into a butadiene recovery unit 21 from which a purified butadiene stream is removed through conduit 22 and a butene-isobutylene containing stream removed through conduit 23 and passed into isobutylene removal unit 24. The butene containing stream having isobutylene removed therefrom is passed through conduit 26 into butene deoiling unit 27 from which a purified butene stream is passed through conduit 28 into butene dehydrogenation unit 29. The effluent from unit 29 is passed through conduit 31 and returned to separation unit 14.

The C3 stream of conduit 19 is passed into disproportionation reactor 33. The disproportionated effluent is passed through conduit 34 into separation unit 36 from which a C4 olefin stream is passed into butene deoiling unit 27 through conduit 37. The lighter fractions of the effluent in conduit 34 are returned through conduit 38 for recycle to the disproportionation reactor 33. When desired, a separate stream of C2 and lighter hydrocarbons can be removed from separation unit 36 through conduit 41.

The gasoline Stream in conduit 17, the isobutylene stream in conduit 42 and the kettle product from butene deoiling unit 27 in conduit 43 are all fed into hydrotreating unit 46. Hydrogen is added through conduit 47. The euent is passed into aromatic extraction unit 4S from which the parainic and olefinic portions are returned through conduit 49 to naptha cracking unit 11 while the aromatic portions are taken through conduit 51, into a benzene separation unit 52 from which benzene is removed through conduit 53 and a highly aromatic heavier fraction removed through conduit 54 for blending with fuel oil in conduit 16 to .produce the carbon black feed stock which is removed through conduit 56.

In the system illustrated in FIGURE 2, a naptha stream is passed. into naptha cracker 61 through conduit 62 and the etiluent is passed to heat recovery and quench 63 through conduit 64. In the heat recovery and quench section 63, the eliiuent from the naptha cracking furnace is quenched in waste heat boilers, and a two-stage quench tower provides for subsequent cooling by passing vapors upwardly through the tower, the lower section of which is an oil quench and the upper section a multiple water quench. For further conservation of heat, steam is generated in waste heat boilers in the cracking furnace stack gas system. A fuel oil condenses in the quench tower and is removed as a side stream from the circulating quench oil through conduit 65.

The eiuent from the quench tower is compressed and fed. to debutanizer 66 as one vapor stream and two condensate streams. This is accomplished by passing effluent from heat recovery and quench section 63 through compressor 67 into ash chamber 68, the condensate being passed to debutanizer 66 through conduit 69 while the overhead is compressed in compressor 71 and passed to flash chamber 72 from which the condensate is passed to debutanizer 66 through conduit 73 and the vapor is transferred to debutanizer 66 through conduit 74. A debutanized gasoline stream is removed as a bottoms product from debutanizer 66 through conduit 76.

The overhead is further compressed in compressor 77 and passed through an amine treating unit for the removal of CO2 and H28. The effluent from amine treater 78 is passed to caustic wash and dry unit 79 where the efliuent from the amine unit is caustic washed to remove the last traces of acid gases, then water washed. to prevent caustic carry over. The efuent from caustic wash and dry unit 79 is fed to depropanizer 80. The butene and heavier bottoms product from depropanizer 80 is passed through conduit 81 to the butadiene recovery and purification unit, the first stage being a furfural absorber S2. Butadiene is absorbed in absorber 82 and the rich furfural passes into furfural stripper 83, furfural being returned to furfural absorber 32 through conduit 84. The butadiene rich stream passes through conduit 85 into butadiene column 86. A high purity butadiene stream is taken overhead through conduit 87, and the bottoms product, comprising butenes, is passed through conduit 88 into conduit 89 which feeds butene deoiler 90.

The overhead from the furfural absorber is separated into two streams, one stream being passed through conduit 91 into `a cold acid isobutylene removal unit 92 while the other stream is passed. through conduit 93 into butane extraction column 94 which controls the build-up of butanes in the system by removal from this side stream. The debutanized stream from extraction column 94 is passed through conduit 95 and recombined with the stream being fed to isobutylene removal unit 92. The deoiled overhead from butene deoiler 90 is passed into butene dehydrogenation reactor 96 and the eiuent passed through conduit 97 and returned to the separation system for the efiiuent from naphtha cracker 61.

Preferably, the effluent from the dehydrogenation reactor is quenched in a waste heat boiler and is cooled in a stacked oil and water quench tower similar to the naphtha cracking furnace effluent heat recovery and quench system.

The propane and lighter fraction from depropanizer 80 is compressed in compressor 101 and, passed into the primary acetylene removal reactor 102. This unit is operated under high selectivity, low conversion conditions to remove the bulk of C2 and C3 acetylenes, piperidine, and butadiene, without significant losses of ethylene or propylene. Preferably, this stream again is dried to remove water formed from oxygen compounds in the acetylene removal reactor feed and then fed to cooling train 103. Cooling train 103 is a series of refrigerated and recycled. cooled heat exchangers and a centrifugal expander, with corresponding required auxiliary surge tanks,

pumps, etc. A hydrogen rich vapor and a methane rich vapor are removed as by-products, and the remainder of this stream is liquefied and sent to demethanizer 104. Preferably, the demethanizer overhead is recycled through the cooling train for sensible heat recovery and then is produced as a fuel gas by-product. The demethanizer bottoms, primarily ethane, ethylene, propane and propylene, are fed through conduit 106 into deethanizer 107. The deethanizer overhead is fed through conduit 108 into secondary acetylene removal reactor 109, operated at high conversion and low selectivity, t-o bring the acetylene content to a low value. The effluent from the secondary acetylene removal reactor is fed to ethylene fractionator 111 and separated into an overhead ethylene stream and, a bottoms product ethane stream. The ethane stream is removed through conduit 112 while the ethylene stream is passed through conduit 113 to methane stripper 114, with high purity ethylene being removed through conduit 116. Where sufficient demand for ethylene exists, the produced ethane can be cracked to produce additional quantities of ethylene. The overhead from methane stripper 114 contains suicient ethylene to justify reseparation, and this stream is recycled to the suction of cornpressor 101 through conduit 117 as shown.

The bottoms product from deethanizer 107 is passed through conduit 121 to an acetylene removal unit 122. This unit is operated at high conversion, low selectivity, to reduce the methyl acetylene and propadiene concentration suiciently to prevent damage to the disproportionation catalyst. The eiuent from acetylene removal units 122 is fed to disproportionation reactor 123. The effluent from reactor 123 is passed through conduit 124 to propylene splitter 126. The overhead, comprising ethylene and lighter, is recycled to deethanizer 107 through conduit 127. A side draw, primarily propylene and propane, is recycled through conduit 123 to the inlet of reactor 123. The bottoms product, propane and heavier, is fed to depropanizer 131 through conduit 132, and the bottoms product from depropanizer 131 is fed through conduit 133 into the inlet of butene deoiler 90.

The gasoline stream in conduit 76, the stream from isobutylene removal unit 92, comprising isobutylene in the form of an isobutylene polymer, in conduit 136, and the butene deoiler bottoms in conduit 137, are passed to hydrotreater 138 along with hydrogen from conduit 139. rl`he efliuent from hydrotreater 138 is passed to aromatic extraction unit 141, the parains and olefins being recycled to cracking through conduit 142 while the aromatics are passed through conduit 143 to a benzene separation unit 144, the benzene being removed overhead and a highly aromatic heavier hydrocarbon stream being removed from the bottom through conduit 146. The bottoms product from benzene separation unit 144 is combined and blended with fuel oil in conduit 65 to produce a carbon black feed stock of the desired aromaticity, which is removed through conduit 147.

In the system of FIGURE 3, the operation is somewhat similar to the operation of the system illustrated in FIGURE 2, but a much simpler separation system is utilized. A naphtha stream is passed into naphtha cracker 151 through conduit 152 and the efliuent passed to heat recovery and quench 153 through conduit 154. The heat recovery and quench section 153 can be similar to the corresponding section 63 of FIGURE 2. The efliuent from the quench tower is compressed in compressor 156 and compressor 157 and passed into flash chamber 158, the condensate from flash chamber 158 being passed to ash chamber 159. The overhead from flash chamber 158 is passed through caustic Wash and dry unit 161 and compressor 162 into flash chamber 163. The overhead from ash chamber 143 is passed through a heat exchange train 164 into a ash chamber 166. The condensate from chamber 166 is passed into demethanizer 167. The bottoms product from demethanizer 167 is passed into acetylene removal unit 168 and then to ethylene fractionator 169 from which an ethylene product steam is removed overhead and ethane removed from the bottom.y The condensate from flash chamber 163 is passed through a C3 acetylene removal unit 171 into product splitter 172. The overhead from Hash chamber 159 also passes through acetylene removal unit 171 into product splitter 172. 'Ihe overhead from product splitter 172 is passed into the stream comprising the bottoms product frem demethanizer 167 and passed through acetylene removal unit 168 into ethylene fractionator 169. A side draw is taken from product splitter 172 and passed to propylene disproportionation unit 173, with the product from unit 173 being returned to product splitter 17 2.

The bottoms product from products splitter 172 is passed into furfural absorber 176. The rich furfural, comprising butadiene, is passed into furfural stripper 177 and the butadiene containing stream is stripped from the furfural and is passed into the butadiene column 178. Butadiene is removed overhead from column 178 with the bottoms product being recycled to furfural absorber 176. The rainate from absorber 176 is passed into isobutylene removal unit 178, with isobutylene being removed therefrom through conduit 179 and the remaining stream passed to butene deoiler 180. A slip stream, from conduit 181, which transports the rainate from absorber 176 to isobutylene removal unit 178, is taken through butane extractor 182. Butanes are removed as a rainate from extractor 182 while the butenes are recovered and returned to conduit 181. The overhead from butene deoiler 180 is passed into butene dehydrogenation unit 186 and a product stream is returned to compressor 156.

A gasoline stream in conduit 186, the isobutylene t stream in conduit 179, and the bottoms product from butene deoiler 180 in conduit 187, are fed into hydrotreater 191, along with hydrogen from conduit 192. The etlluent from hydrotreater 191 is fed to aromatics extraction unit 193 with paraiiins and oleiins being returned to naphtha cracking through conduit 194 while the aromatic concentrate is passed through conduit 196 into a benzene separation unit 197. Benzene is taken overhead from this unit while a heavier hydrocarbon highly aromatic stream is removed from the bottom and combined and blended with fuel oil from conduit 198 to produce a carbon black feed stock having a desired aromaticity.

It will be recognized that many elements of a complete commercial plant have been omitted from the description of the disclosed embodiments of our invention in the interests of clarity and brevity. In many instances, specific variations can be utilized. For example, any suitable disproportionation catalyst can be used in the disproportionation reactor, any suitable butene dehydrogenation catalyst can be used in the butene dehydrogenation reactor and any suitable hydrotreating catalyst can be used in the hydrotreating reactor. Similarly, separation steps such as fractional distillation, solvent extraction, etc., can be utilized where appropirate and substituted by one skilled in the art. Our invention lies in combination, and, therefore, is not limited to a specific type of cracking, disproportionation, dehydrogenation, or hydrotreating reactor, or specific puriiication or separation steps. Many details of equipment needed in a commercial plant have been omitted, including for example, such things at pumps, valves, control equipment, etc.

FIGURE 4 illustrates the hydrotreating, aromatics eX- traction, and aromatics separation of FIGURE 2 in more detail. Gasoline from conduit 76, isobutylene from conduit 136 and the butene deoiler bottoms in conduit 137 are heated in a heater 201 and fed into a first stage hydrotreater 202. The effluent from treater 202 is treated in a second stage treater 203, the efuent from the treater 203 being condensed in condenser 204 and passed into high pressure separator 206. If desired, a portion of the effluent from treater 202 can be by-passed through conduit 207. The gaseous overhead from separator 206, comprising hydrogen, is recycled or vented as desired or needed While the bottoms product is transmitted to stabilizer 208. The overhead product from stabilizer 208 is fuel gas which is removed through conduit 140, while the bottoms are passed to separator 209 from which is taken a heavy stream through conduit 148 with the overhead being taken to aromatic extraction 141 which includes aromatic extractor 211 and stripper 212. The recycled parati-in and olen stream is taken through conduit 142 and the aromatic stream to benzene separation unit 144 through conduit 143. The benzene outlet 145, the aromatic stream 146, the fuel oil stream 65, and the carbon black feed stock stream 147 are described above in connection with FIGURE 2.

EXAMPLE In an example of the operation of our invention according to FIGURE 2, the stream fed to cracking reactor 61 comprises a wide range naphtha made from a Kuwait crude, the naphtha having a boiling range of to 352 F., a density of 64.3 API and comprising 72 volume percent paraffin (44 per-cent N-paran), 18 percent by volume naphtha and 10 percent by volume aromatics, with substantially no olens. The operating conditions of the various units of the system are given in Table I, and the material balance is presented in Table II, the numbers of these streams corresponding with numbers in FIG- URE 2.

TABLE L OPERATING CONDITIONS 61 Naphtha cracking furnace Steam/HC ratio: 0.7 Outlet pressure: 25 p.s.i.a. Outlet temperature: 1450 to l500 F. Heat recovery and quench Steam generated 315 p.s.i.a. Quench tower inlet: 20 p.s.i.a., 500 F. Quench tower outlet: 18 p.s.i.a., 105 F. lst compressor stage Inlet: 17.7 p.s.i.a., 100 F. Outlet: 48 p.s.i.a., 215 F. 2750 horsepower, 27.435 c.f.m. 1st flash 42 p.s.i.a., 60 F. 2nd compressor stage Inlet: 42 p.s.i.a., 60 F. Outlet: 118 p.s.i.a., 188 F. 2350 horsepower, 7992 c.f.m. 2nd flash p.s.i.a., 60 F. Debutanizer Reux drum: 100 p.s.i.a., 62 F. Reboiler vapor: 110 p.s.i.a., 313 F. 3rd compressor stage Inlet: 100 p.s.i.a., 62 F. Outlet: 255 p.s.i.a., 185 F. 2150 horsepower, 3479 c.f.m. Amine treater Absorber tower: 250 p.s.i.a.; 160 F. in, 135 F.

out 95% CO2 removal Caustic wash and dry Caustic tower: 245 p.s.i.a., 135 F. Water Wash tower: 250 p.s.i.a., 135 F. Dryer inlet: 230 p.s.i.a., 60 F. Dryer outlet: 210 p.s.i.a., 60 F. Depropanizer Reflux drum: 200 p.s.i.a., 0 F. Reboiler vapor: 210 p.s.i.a., 202 F. Furfural absorber Reflux drum: 100 p.s.i.a., 138 F. Reboiler vapor: p.s.i.a., 303 F. Furfural stripper Reflux drum: 65 p.s.i.a., 110 F. Reboiler vapor: 80 p.s.i.a., 329 F.

101 4th compressor stage Inlet: 198 p.s.i.a., 60 F. Outlet: 525 p.s.i.a., 230 F. 1750 horsepower, 1292 c.f.m.

102 Primary acetylene removal unit Girdler G-73 catalyst Reactor conditions: 520 p.s.i.a., 350 F.

103 Cooling train 13 refrigerated and interchanger units in series 97 horsepower centrifugal expander Inlet: 485 p.s.i.a., 55 F. Outlets:

480 p.s.i.a., 10 F. 470 p.s.i.a., 84 F. 466 p.s.i.a., 150 F. Hydrogen separator: 455 p.s.i.a., 200 F.

Demethanizer Reflux drum: 425 p.s.i.a., 142 F.

Reboiler vapor: 435 p.s.i.a., 52 F. Deethanizer Reflux drum.: 400 p.s.i.a., 14 F.

Reboiler vapor: 410 p.s.i.a., 147 F. Secondary acetylene removal unit Girdler G-58 catalyst Iig/C2H2 ratio:

Reactor conditions: 395 p.s.i.a., 350 F. Ethylene fractionator Reflux drum: 290 p.s.i.a., 25 F.

Reboiler vapors: 300 p.s.i.a., 3 F. Methane stripper Reflux drum: 300 p.s.i.a., 29 F.

Reboiler vapors: 310 p.s.i.a., 17 F. C3 acetylene removal unit Girdler G-55 catalyst H2/C3H4 ratio: 2.0

Reactor conditions: 485 p.s.i.a., 350 F. Propylene disproportionation unit Reactor conditions: 460 p.s.i.a., 850 F. Propylene splitter Reflux drum: 420 p.s.i.a., 114 F.

Reboiler vapor: 430 p.s.i.a., 239 F. Propane stripper Reflux drum: 265 p.s.i.a., 123 F.

Reboiler vapor: 275 p.s.i.a., 246 F. Hydrotreater Catalyst Reactor conditions Aromatic extraction unit Benzene separation unit TABLE II.MATERIAL BALANCE-POUNDS PER HOUR STREAM NUMBER Component 624-142 64 69 73 72a 46 81 84 85 87 88 89 91 93 Hydrogen 634 2 0 Carbon Monoxide. 0 0 0 Carbon Dioxide 10 31 0 Methane 12, 036 30 0 Acetylenes 24 33 6 Ethylene. 18, 898 183 Ethane 6, 124 91 Propylene 15, 414 739 Propane 1, 372 120 Isobutane 243 94 Isobutene 2, 006 321 Butene-l 1, 345 1,433 Butadiene 2, 745 1, l431 n-Butane 602 287 Trans-Buteue-2. 1, 777 2, 396 Cis-Butene-2 95 1, 727 (l5-400 Gasoline. 105, 600 34, 841 31, 242 Heating Oil 6, 229 0 Total Hydrocarbons Furfural Water TABLE II.-Continued Component 95 97 106 108 112 113 116 117 121 124 127 128 132 133 Hydrogen 557 Carbon Monoxide. Carbon Dioxide Methane Acetylenes Ethylene Ethane. Propylene- Propane Isobutane- Isobutene...

Butene-l. Butadiene n-Butane TransButene-2 Gis-Butene-Z C4400 Gasoline.

Heating Oil Total Hydr0carb0ns 84, 775

TABLE II.-Continued lisobutylene Hydrogen Fuel Gas GaseA Recycle Fresh line Component Heavier Benzene Polymer Naphtha Naphtha Hydrogen Carbon Monoxide Carbon Dioxide Methane Acetylenes Ethylene Ethane Propane Isobutane Isobutene Butene-l 51 Butadiene 1 n-B utane 6 Trans-Butene-2 6 45 4g Cis-Butene-2 293 (J5-400 F (Gasoline) 1 34,480 400 F-l- (Fuel Oil) Total Hydrocarbons 1 (J5-400 F Composition:

Benzene Heavy Aromatics. N ori-Aromatics- Reasonable variation and modifi-cation are possible Within the scope of our invention which sets forth method and apparatus for producing ethylene, butadiene, benzene,

recycling parafns and olens from said aromatic eX- traction zone to said naphtha cracking Zone; removing a C3 hydrocarbon stream from said separaand a carbon black feed stock, along with by-products, tion zone and passing said C3 hydrocarbon stream from a hydrocarbon stream. into a propylene disproportionation Zone;

We claim: separating the eiiiuent of said disproportionation zone 1. A process for producing ethylene, butadiene, a high and returning a stream therefrom comprising C3 aromatic content `carbon black feedstock, and benzene, hydrocarbons to said separation zone and passing comprising the steps of: a stream therefrom comprising C4 hydrocarbons to cracking a naphtha stream in a naphtha cracking zone;

removing fuel oil from the efliuent of said naphtha cracking zone and passing the remaining portion into a separation zone;

removing a C4 hydrocarbon stream from -said separation Zone and passing said C4 hydrocarbon stream into a butadiene recovery zone;

removing a butadiene stream from said butadiene recovery zone;

said butene deoiling zone; and removing ethylene from said separation zone. 2. A process for producing butadiene, a heavy aromatic content carbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream in a naphtha cracking zone; removing fuel oil from the efuent of said naphtha cracking zone and passing the remaining portion into a first debutanizing zone;

removing a butene-isobutylene stream from said butain Said rSt dehlltahizirlg Z0he Separating e light Stream diene recovery zone and passing said butene-iso- Comprising butene and lighter COIhPOheIltS and a butylene stream into an isobutylene removal zone; gaSOlHe Stream COmPrShg heavier COmPOrlehtS;

removing a butene-containing stream from said isofeeding a light stream from said debutanizing zone to butylene removal zone and passing said bute-nea depropanizing zone; containing stream into a butene deoiling zone; in said depropanizing zone separating a light stream removing a butene stream from said butene deoiling comprising propane and lighter and a heavy stream zone and passing said butene stream to a butene decomprising butanes, butenes and butadienes; hydrogenation zone; feeding said heavy stream from said depropanizer passing the ethuent from said butene dehydrogenation to a butadiene removal zone;

zone to said separation zone; in said butadiene removal zone, separating the butaremoving a gasoline stream from said separation Zone; diene product stream comprising substantially all of removing from said isobutylene removal unit a stream said butadiene and a minor amount of said butenes comprising isobutylene removed in said unit; and a dehydrogenation feed stream comprising subremoving an oil stream from said buteneV deoiling stantially all of said butanes and a predominant zone; amount of said butenes;

passing said gasoline stream, said stream comprising dividing said dehydrogenation feed stream into a major isobutylene and said oil -stream into a hydrotreating portion and a minor portion; zone; feeding said minor portion of said dehydrogenation passing hydrogen into said hydrotreating zone and feed stream to a second debutanizing zone;

hydrotreating said gasoline stream, said stream comin said second debutanizing zone removing a butene prising isobutylene and said oil stream therein; stream and a debutanized stream;

passing the effluent from said hydrotreating zone into combining said debutanized stream with said major an aromatic extraction zone; portion;

passing aromatics from said aromatic extraction zone passing the combined stream of said major portion into a benzene separation Zone; and said debutanized stream to an isobutylene reremoving benzene from said benzene separation zone; moval zone;

removing a heavy aromatic stream from said benzene in said isobutylene removal Zone, separating a stream separation zone; comprising isobutylene from said combined stream;

blending said fuel oil and said heavy aromatic stream passing the remainder of said combined stream into a to produce a carbon black feed stock; butene deoiling zone;

in said deoiling zone removing an oil fraction and passing the remainder to a dehydrogenation zone;

combining the effluent of said dehydrogenation zone with said effiuent from said cracking zone;

passing said gasoline stream, said stream comprising isobutylene and said oil stream into a hyrotreating zone;

passing hydrogen int-o said hydrotreating zone and hydrotreating said gasoline stream, said stream comprising isobutylene and said oil stream therein;

passing the efliuent from said hydrotreating zone into an aromatic extraction zone;

passing aromatics from said aromatic extraction zone into a benzene separation zone;

removing benzene from said benzene separation zone;

removing a heavy aromatic stream from said benzene separation zone;

blending said fuel oil and said heavy aromatic stream to produce a carbon black feed stock; and

recycling paraflins and oleiins from said aromatic extraction zone to said naphtha cracking zone.

3. A process for producing ethylene, butadiene, a high aromatic content carbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream in a naphtha cracking zone;

removing fuel oil from the eiiiuent of said naphtha cracking zoneV and passing the remaining portion into a first debutanizing zone;

in said first debutanizing zone separating a light stream comprising butene and lighter components and a gasoline stream comprising heavier components; feeding a light stream from said debutanizing zone to a depropanizing zone;

in said depropanizing zone separating a light stream comprising propane and lighter and a heavy stream comprising butanes, butenes and butadienes;

feeding said heavy stream from said depropanizer to a butadiene removal zone;

in said butadiene removal zone, separating the butadiene product stream comprising substantially all of said butadiene and a minor amount of said butenes and a dehydrogenation feed stream cornprising substantially all of said butanes and a predominant amount of said butenes;

dividing said dehydrogenation feed stream into a major portion and a minor portion;

feeding said minor portion of said dehydrogenation feed stream to a second dibutanizing zone;

in said second debutanizing zone removing a butene o stream and a debutanized stream;

combining said debutanized stream with said major portion;

passing the combined stream of said major portion and said debutanized stream to an isobutylene removal zone;

in said isobutylene removal zone, separating a stream comprising isobutylene from said combined stream;

passing the remainder of said combined stream into a butene deoiling zone;

in said deoiling zone removing an oil fraction and passing the remainder to a dehydrogenation zone;

combining the eliiuent of said dehydrogenation zone with said effluent from said cracking zone;

passing said gasoline stream, said stream comprising isobutylene and said oil stream into a hydrotreating zone;

passing hydrogen into said hydrotreating zone and hydrotreating said gasoline stream, said stream cornprising isobutylene and said oil stream therein;

passing the efliuent from said hydrotreating zone into an aromatic extraction zone;

passing aromatics from said aromatic extraction zone into a benzene separation zone;

removing benzene from said benzene separation zone;

removing a heavy aromatic stream from said benzene separation zone;

blending said fuel oil and said heavy aromatic stream to produce a carbon black feed stock;

recycling parafiins and olelins from said aromatic extraction zone to said naphtha cracking zone;

removing a C4 hydrocarbon stream from said separation zone and passing said C3 hydrocarbon stream into a propylene disproportionation zone;

separating the efiluent of said disproportionation zone and returning the stream therefrom comprising C2 hydrocarbons to said separation zone and passing a stream therefrom comprising C4 hydrocarbons to said butene deoiling zone; and

removing ethylene from said separation zone.

4. A process for producing butadiene, ethylene, a high aromatic content carbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream;

passing the eiuent of said naphtha cracking zone into a heat recovery and quench zone;

removing a fuel oil stream from said heat recovery and quench zone;

passing the remainder of the effluent of said naphtha cracking zone into a irst flash zone;

passing condensate from said first fiash zone into a second flash zone;

passing vapor from said rst flash zone through a caustic wash and dry treatment into a third flash zone;

passing vapor from said third flash Zone into a fourth flash zone;

passing condensate from said fourth flash zone into a first fractional distillation column;

passing bottoms product from said first fractional distillation column into a second fractionation column;

recovering ethylene overhead from said second fractional distillation column;

passing condensate from said third liash zone and vapor from said second flash zone into a third fractional distillation column;

returning overhead product from said third fractional distillation column to said second fractional distillation column;

removing a side stream from said third fractional distillation column and passing said side stream to a propylene disproportionation unit;

returning the product from said propylene disproportionation zone to said third fractional distillation column;

flashing bottoms product from said third fractional distillation column into a furfural absorber;

recovering butadiene from said furfural absorber;

removing rafiinate from said furfural absorber;

removing butanes from a side stream of said raffinate and returning the remainder of said side stream to an isobutylene removal unit;

removing isobutylene from said isobutylene removal unit;

passing the isobutylene free stream from said isobutylene removal unit into a fourth fractional distillation column;

passing an overhead stream from said fourth fractional distillation column, comprising butenes, into a butene dehydrogenation zone;

returning etiiuent from said butene dehydrogenation zone to said first flash zone;

passing a gasoline stream removed as condensate from said second flash zone, a stream comprising isobutylene from said isobutylene removal unit, and an oil stream removed as a bottoms product from said fourth fractional distillation column into a hydrotreating zone;

blending said fuel oil and said heavy aromatic stream to produce a carbon black feed stock; and

recycling paraffin and olens from said aromatic eX- traction zone to said naphtha cracking zone.

No references cited.

DELBERT E. GANTZ, Primary Examiner.

H. LEVINE, Assistant Examiner.

Claims (1)

1. A PROCESS FOR PRODUCING ETHYLENE, BUTADIENE, A HIGH AROMATIC CONTENT CARBON BLACK FEEDSTOCK, AND BENZENE, COMPRISING THE STEPS OF: CRACKING A NAPHTHA STREAM IN A NAPHTHA CRACKING ZONES; REMOVING FUEL OIL FROM THE EFFUENT OF SAID NAPHTHA CRACKING ZONES AND PASSING THE REMAINING PORTION INTO A SEPARATION ZONE; REMOVING A C4 HYDROCARBON STREAM FROM SAID SEPARATION ZONE AND PASSING SAID C4 HYDROCARBON STREAM INTO A BUTADIENE RECOVERY ZONE; REMOVING A BUTADIENE STREAM FROM SAID BUTADIENE RECOVERY ZONE; REMOVING A BUTENE-ISOBUTYLENE STREAM FROM SAID BUTADIENE RECOVERY ZONE AND PASSING SAID BUTENE-ISOBUTYLENE STREAM INTO AN ISOBUTYLENE REMOVAL ZONE; REMOVING A BUTENE-CONTAINING STREAM FROM SAID ISOBUTYLENE REMOVAL ZONE AND PASSING SAID BUTENECONTAINING STREAM INTO A BUTENE DEOILING ZONE; REMOVING A BUTENE STREAM FROM SAID BUTENE DEOILING ZONE AND PASSING SAID BUTENE STREAM TO A BUTENE DEHYDROGENATION ZONE; PASSING THE EFFUENT FROM SAID BUTENE DEHYDROGENATION ZONE TO SAID SEPARATION ZONE; REMOVING A GASOLINE STREAM FROM SAID SEPARATION ZONE; REMOVING FROM SAID ISOBUTYLENE REMOVAL UNIT A STREAM COMPRISING ISOBUTYLENE REMOVED IN SAID UNIT; REMOVING AN OIL STREAM FROM SAID BUTENE DEOILING ZONE; PASSING SAID GASOLINE STREAM, SAID STREAM COMPRISING ISOBUTULENE AND SAID OIL STREAM INTO A HYDROTREATING ZONE; PASSING HYDROGEN INTO SAID HYDROTREATING ZONE AND HYDROTREATING SAID GASOLINE STREAM, SAID STREAM COMPRISING ISOBUTYLENE AND SAID OIL STREAM THEREIN; PASSING THE EFFLUENT FROM SAID HYDROTREATING ZONE INTO AN AROMATIC EXTRACTION ZONE; PASSING AROMATICS FROM SAID AROMATICS EXTRACTION ZONE INTO A BENZENE SEPARATION ZONE; REMOVING BENZENE FROM SAID BENZENE SEPARATION ZONE; REMOVING A HEAVY AROMATIC STREAM FROM SAID BENZENE SEPARATION ZONE; BLENDING SAID FUEL OIL AND SAID HEAVY AROMATIC STREAM TO PRODUCE A CARBON BLACK FEED STOCK; RECYCLING PARAFFINS AND OLEFINS FROM SAID AROMATIC EXTRACTION ZONE TO SAID NAPHTHA CRACKING ZONE; REMOVING A C3 HYDROCARNON STREAM FROM SAID SEPARATION ZONE AND PASSING SAID C3 HYDROCARBON STREAM INTO A PROPYLENE DISPROPORTIONATION ZONE; SEPARATING THE EFFLUENT OF SAID DISPROPORTIONATION ZONE AND RETURNING A STREAM THEREFROM COMPRISING C3 HYDROCARBONS TO SAID SEPARATION ZONE AND PASSING STREAMS THEREFROM COMPRISING C4 HYDROCARBONS TO SAID BUTENE DEOILING ZONE; AND REMOVING ETHYLENE FROM SAID SEPARATION ZONE.

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