SYSTEM AND METHOD FOR PRODUCING UN-HYDROGENATED AND HYDROGENATED C9+ COMPOUNDS

Abstract

A system and method for processing pyrolysis gasoline is disclosed. The system and method involves separating a pyrolysis gasoline stream to produce a first stream comprising primarily un-hydrogenated C.sub.9+ compounds. The separating of the pyrolysis e gasoline occurs without hydrogenation being carried out on the pyrolysis gasoline before the separating.

Claims

1. A method of processing pyrolysis gasoline, the method comprising: separating a pyrolysis gasoline stream to produce a first stream comprising primarily un-hydrogenated C.sub.9+ compounds.

2. The method of claim 1 wherein the first stream comprises 98 to 100 wt. % C.sub.9+ compounds.

3. The method of claim 1 further comprising: hydrogenating a portion of the first stream to produce a second stream comprising hydrogenated C.sub.9+ hydrogenated compounds.

4. The method of claim 3, wherein the hydrogenating of the first portion of the first stream is carried out under reaction conditions comprising a temperature in a range of 100° C. to 200° C., a pressure in a range of 10 bar to 30 bar, a WHSV of 2 h.sup.−1 to 8 h.sup.−1, and in the presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

5. The method of claim 3 further comprising: separating the second stream to produce a third stream comprising hydrogenated wash oil and a fourth stream comprising hydrogenated C.sub.9+ residue.

6. The method of claim 5 wherein third stream comprises 0 to 90 wt. % wash oil and the fourth stream comprises 10 to 100 wt. % hydrogenated C.sub.9+ compounds.

7. The method of claim 5, further comprising: subjecting the third stream to reaction conditions to hydrogenate the third stream.

8. The method of claim 1, wherein the separating of the pyrolysis gasoline stream comprises: distilling the pyrolysis gas stream in a depentanizer column to produce a fifth stream comprising primarily C.sub.4+ compounds and a sixth stream comprising primarily C.sub.6+ compounds.

9. The method of claim 8 wherein the separating of the pyrolysis gasoline stream further comprises: distilling the sixth stream in a deoctanizer column to produce a seventh stream comprising primarily C.sub.6 to C.sub.8 compounds and the first stream.

10. The method of claim 9 comprising: hydrogenating the seventh stream to produce an eighth stream comprising benzene, toluene, and xylene.

11. The method of claim 10, wherein the hydrogenating of the seventh stream is carried out under reaction conditions comprising a temperature in a range of 100° C. to 200° C., a pressure in a range of 10 bar to 30 bar, a WHSV of 2 h.sup.−1 to 8 h.sup.−1, and in presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

12. The method of claim 8 further comprising: processing the fifth stream in a stabilizer to produce a ninth stream comprising fuel gas and a tenth stream comprising primarily C.sub.4 and C.sub.5 compounds.

13. The method of claim 12 further comprising: hydrogenating the tenth stream to produce an eleventh stream comprising primarily C.sub.4 and C.sub.5 compounds.

14. The method of claim 13, wherein the hydrogenating of the tenth stream is carried out under reaction conditions comprising a temperature in a range of 40° C. to 140° C., a pressure in a range of 20 bar to 40 bar, a WHSV of 10 h.sup.−1 to 16 h.sup.−1, and in presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

15. The method of claim 13 further comprising subjecting the eleventh stream to cracking conditions to form C.sub.2 to C.sub.4 light olefins, LPG, and H.sub.2.

16. A method of processing pyrolysis gasoline, the method comprising: concurrently producing (1) a first stream comprising primarily un-hydrogenated C.sub.9+ compounds and (2) a second stream comprising hydrogenated C.sub.9+ hydrogenated compounds, wherein the producing comprises separating a pyrolysis gasoline stream to produce the first stream comprising primarily un-hydrogenated C.sub.9+ compounds and hydrogenating a portion of the first stream to produce the second stream comprising hydrogenated C.sub.9+ hydrogenated compounds.

17. The method of claim 16 further comprising: producing a stream comprising primarily un-hydrogenated C.sub.4+ compounds.

18. A method of processing pyrolysis gasoline, the method comprising: separating a pyrolysis gasoline stream to produce a first stream comprising primarily un-hydrogenated C.sub.9+ compounds; hydrogenating a portion of the first stream to produce a second stream comprising hydrogenated C.sub.9+ compounds; separating the second stream to produce a third stream comprising hydrogenated wash oil and a fourth stream comprising hydrogenated C.sub.9+ residue, wherein the separating of the pyrolysis gasoline stream comprises: distilling the pyrolysis gas stream in a depentanizer column to produce a fifth stream comprising primarily C.sub.4+ compounds and a sixth stream comprising primarily C.sub.6+ compounds; distilling the sixth stream in a deoctanizer column to produce a seventh stream comprising primarily C.sub.6 to C.sub.8 compounds and the first stream; processing the fifth stream in a stabilizer to produce a ninth stream comprising fuel gas and a tenth stream comprising primarily C.sub.4 and C.sub.5 compounds; and combining the third stream, the seventh stream, and the tenth stream to form a combined stream and flowing the combined stream to a reactor.

19. The method of claim 18, further comprising: subjecting the combined stream to reaction conditions sufficient to form a reactor effluent.

20. The method of claim 19 further comprising: processing the reactor effluent to produce a BTX stream, a stream comprising primarily hydrogenated wash oil, a fuel gas stream and a stream comprising primarily C.sub.5 compounds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0021] FIG. 1 shows a system for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds, according to embodiments of the invention;

[0022] FIG. 2 shows a process for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds, according to embodiments of the invention;

[0023] FIG. 3 shows a system for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ and hydrogenated wash oil compounds, according to embodiments of the invention; and

[0024] FIG. 4 shows a process for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ and hydrogenated wash oil compounds, according to embodiments of the invention.

[0025] FIG. 5 shows a system and process for processing pyrolysis gasoline to produce un-hydrogenated C.sub.9+ and un-hydrogenated wash oil compounds, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Gasoline hydrogenation units (GHU) are commonly used to saturate unstable compounds such as diolefins and styrene found in pyrolysis gasoline. Olefins and sulfur compounds are also hydrogenated to meet final product specifications. After hydrogenation, different product cuts are separated based on downstream demand. For example, after hydrogenation of pyrolysis gasoline, a C.sub.9+ cut is normally separated at the deoctanizer to produce hydrogenated wash oil and hydrogenated C.sub.9+ residue. This process, however, does not contribute to meeting the demand for un-hydrogenated C.sub.9+ products. A solution to address this deficiency of the conventional process has been discovered. The discovered process is premised on separating un-hydrogenated C.sub.9+ hydrocarbons from pyrolysis gasoline upstream of a GHU so that un-hydrogenated C.sub.9+ hydrocarbons can be recovered as a product and as hydrogenated C.sub.9+ hydrocarbons can likewise be recovered as a product.

[0027] FIG. 1 shows system 10 for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds (e.g., un-hydrogenated hydrocarbons), according to embodiments of the invention. FIG. 2 shows process 20 for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds, according to embodiments of the invention. System 10 may be used to implement process 20.

[0028] According to embodiments of the invention, process 20 includes, at block 200, separating pyrolysis gasoline stream 100, in separation unit 121 to produce stream 101 (C.sub.9+ compounds/stream), which comprises primarily un-hydrogenated C.sub.9+ compounds. Wash oil is used to control the build-up of polymers on cracked gas compressors, turbines, seals, and heat exchangers. A good wash oil has a fairly high initial boiling point so that it won't immediately flash to vapor, combined with a high C.sub.9+ aromatic content for dissolving polymeric compounds. The wash oil described herein is hydrogenated to saturate the dienes before using to control the build-up of polymers. Stream 101 may include 10 to 100 wt. % C.sub.9+ compounds and all ranges and values there between, including ranges of 10 to 20 wt. %, 20 to 30 wt. %, 30 to 40 wt. %, 40 to 50 wt. %, 50 to 60 wt. %, 60 to 70 wt. %, 70 to 80 wt. %, 80 to 90 wt. %, and 90 to 100 wt. %, and 0 to 90 wt. % wash oil and all ranges and values there between, including ranges of 0 to 10%, 10 to 20%, 20 to 30%, 30 to 40%, 40 to 50%, 50 to 60%, 60 to 70%, 70 to 80%, 80 to 90%, and 90 to 100%.

[0029] According to embodiments of the invention, block 201 includes flowing at least a portion of stream 101 to GHU reactor 115 and hydrogenating that portion or all of stream 101 in GHU reactor 115 to produce stream 102 comprising hydrogenated C.sub.9+ compounds (e.g., hydrogenated hydrocarbons). In other words, in embodiments of the invention, all of stream 101 may be hydrogenated or, as shown in FIG. 1, stream 101 may be separated into stream 101-1 and stream 101-2 and only stream 101-1 is hydrogenated in GHU reactor 115. In some embodiments, GHU reactor 115 is not operated and, instead, is bypassed such that stream 101 is flowed to flash drum 116 so that only un-hydrogenated C.sub.9+ compounds are produced. In this way, system 10 is adapted to have the flexibility to produce (1) only un-hydrogenated C.sub.9+ compounds (GHU reactor 115 not operated), (2) un-hydrogenated C.sub.9+ compounds and hydrogenated C.sub.9+ compounds (GHU reactor 115 operated to process only a portion of the un-hydrogenated C.sub.9+ compounds), or (3) only hydrogenated C.sub.9+ compounds (GHU reactor 115 operated to process all of the un-hydrogenated C.sub.9+compounds). According to embodiments of the invention, the reaction conditions in GHU reactor 115 include a temperature in a range of 100 to 200° C. and all ranges and values there between including ranges of 100 to 110° C., 110 to 120° C., 120 to 130° C., 130 to 140° C., 140 to 150° C., 150 to 160° C., 160 to 170° C., 170 to 180° C., 180 to 190° C., and 190 to 200° C., a pressure in a range of 10 to 30 bar and all ranges and values there between including ranges of 10 to 12 bar, 12 to 14 bar, 14 to 16 bar, 16 to 18 bar, 18 to 20 bar, 20 to 22 bar, 22 to 24 bar, 24 to 26 bar, 26 to 28 bar, and 28 to 30 bar, a WHSV of 2 to 8 h.sup.−1 and all ranges and values there between including ranges of 2 to 3 h.sup.−1, 3 to 4 h.sup.−1, 4 to 5 h.sup.−1, 5 to 6 h.sup.−1, 6 to 7 h.sup.−1, and 7 to 8 h.sup.−1, and in the presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

[0030] At block 202, according to embodiments of the invention, stream 102, which comprises hydrogenated C.sub.9+ compounds is flowed to flash drum 116, wherein stream 102 is separated to produce stream 103 comprising hydrogenated wash oil and stream 104 comprising hydrogenated C.sub.9+ compounds. In embodiments of the invention, stream 103 comprises 0 to 90 wt. % wash oil and all ranges and values there between including ranges of 0 to 10 wt. %, 10 to 20 wt. %, 20 to 30 wt. %, 30 to 40 wt. %, 40 to 50 wt. %, 50 to 60 wt. %, 60 to 70 wt. %, 70 to 80 wt. %, and 80 to 90 wt. %, and stream 104 comprises 10 to 100 wt. % hydrogenated C.sub.9+ compounds and all ranges and values there between including ranges of 10 to 20 wt. %, 20 to 30 wt. %, 30 to 40 wt. %, 40 to 50 wt. %, 50 to 60 wt. %, 60 to 70 wt. %, 70 to 80 wt. %, 80 to 90 wt. %, and 90 to 100 wt. %.

[0031] In embodiments of the invention, separating pyrolysis gasoline stream 100 (at block 200) comprises, as shown at block 201-1, distilling the pyrolysis gas stream in depentanizer column 112 to produce stream 105 as an overhead stream comprising primarily C.sub.4 and C.sub.5 compounds and stream 106 as a bottoms stream comprising primarily C.sub.6+ compounds. In this way, according to embodiments of the invention, a C.sub.4 to C.sub.5 fraction is separated as an un-hydrogenated stream upstream of any GHU. This provides an advantage where valuable diene components can be separated from this stream. In embodiments of the invention, separating pyrolysis gasoline stream 100 further includes, at block 201-2, flowing stream 106 from depentanizer column 112 to deoctanizer column 113 and distilling stream 106 in deoctanizer column 113 to produce stream 107 comprising primarily C.sub.6 to C.sub.8 compounds and un-hydrogenated C.sub.9+ compounds/stream 101. More specifically, at deoctanizer column 113, un-hydrogenated BTX is flowed from the top for deoctanizer column 113 and un-hydrogenated C.sub.9+ compounds are flowed from the bottom of deoctanizer column 113. The un-hydrogenated C.sub.9+ compounds can be used un-hydrogenated or, if necessary, can be hydrogenated by passing through GHU reactor 115. This is possible because system 10 has the flexibility to be operated in any mode, either hydrogenated, un-hydrogenated, or a combination of both. In embodiments of the invention, a separation flash drum can be installed before GHU reactor 115, where an overhead un-hydrogenated wash oil and bottom un-hydrogenated C.sub.9+ residue can be produced. The separation of the un-hydrogenated C.sub.9+ compounds/stream 101 can require the operation of deoctanizer column 113 at low temperature, for example, 70 to 100° C. and all ranges and values there between including ranges of 70 to 75° C., 75 to 80° C., 80 to 85° C., 85 to 90 ° C., 90 to 95 ° C., and 95 to 100 ° C., on the reboiler and at high vacuum, for example 0.04 to 0.9 bara and ranges and values there between including ranges of 0.04 to 0.1 bara, 0.1 to 0.2 bara, 0.2 to 0.3 bara, 0.3 to 0.4 bara, 0.4 to 0.5 bara, 0.5 to 0.6 bara, 0.6 to 0.7 bara, 0.7 to 0.8 bara, and 0.8 to 0.9 bara. Low temperature can be achieved by using the reboiler condensate. And to reduce fouling, a fouling inhibitor can be injected in the deoctanizer column and/or the depentanizer column. Thus, as shown in FIG. 1, TBC package 120 supplies 4-tert-Butylcatechol (TBC), an organic chemical compound, as a fouling inhibitor to depentanizer column 112 and deoctanizer column 113.

[0032] Process 20 may further include, at block 203, flowing stream 107 from deoctanizer column 113 to GHU reactor 114 and hydrogenating stream 107 in GHU reactor 114 to produce stream 108 comprising benzene, toluene, and xylene. According to embodiments of the invention, the reaction conditions in GHU reactor 114 include a temperature in a range of 100° C. to 200° C. and all ranges and values there between including ranges of 100 to 110° C., 110 to 120° C., 120 to 130° C., 130to 140° C., 140 to 150° C., 150 to 160° C., 160 to 170° C., 170 to 180° C., 180 to 190° C., and 190 to 200° C., a pressure in a range of 10 to 30 bar and all ranges and values there between including ranges of 10 to 12 bar, 12 to 14 bar, 14 to 16 bar, 16 to 18 bar, 18 to 20 bar, 20 to 22 bar, 22 to 24 bar, 24 to 26 bar, 26 to 28 bar, and 28 to 30 bar, a WHSV of 2 to 8 h.sup.−1 and all ranges and values there between including ranges of 2 to 3 h.sup.−1, 3 to 4 h.sup.−1, 4 to 5 h.sup.−1, 5 to 6 h.sup.−1, 6 to 7 h.sup.−1, and 7 to 8 h.sup.−1, and in the presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

[0033] According to embodiments of the invention, process 20, includes, at block 204, flowing stream 105 from depentanizer column 112 to stabilizer 117 and processing stream 105 in stabilizer 117 to produce stream 109 comprising fuel gas and stream 110 comprising primarily C.sub.4 and C.sub.5 compounds. Block 205 involves flowing stream 110 from stabilizer 117 to GHU reactor 118 and hydrogenating stream 110, in GHU reactor 118, to produce stream 111 comprising primarily hydrogenated C.sub.4 and C.sub.5 compounds, in embodiments of the invention. According to embodiments of the invention, the reaction conditions in GHU reactor 118 includes a temperature in a range of 40 to 140° C. and all ranges and values there between including ranges of 40 to 50° C., 50 to 60° C., 60 to 70° C., 70 to 80° C., 80 to 90° C., 90 to 100° C., 100 to 110° C., 110 to 120° C., 120 to 130° C., and 130 to 240° C., a pressure in a range of 20 to 40 bar and all ranges and values there between including ranges of 20 to 22 bar, 22 to 24 bar, 24 to 26 bar, 26 to 28 bar, 28 to 30 bar, 30 to 32 bar, 32 to 34 bar, 34 to 36 bar, 36 to 38 bar, and 38 to 40 bar, a WHSV of 10 to 16 h.sup.−1 and all ranges and values there between including ranges of 10 to 11 h.sup.−1, 11 to 12 h.sup.−1, 12 to 13 h.sup.−1, 13 to 14 h.sup.−1, 14 to 15 h.sup.−1, and 15 to 16 h.sup.−1, and in the presence of a catalyst comprising Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3.

[0034] Process 20 may further include, at block 206, flowing stream 111 from GHU reactor 118 to cracker 119 and subjecting stream 111 to cracking conditions in cracker 119 to form C.sub.2 to C.sub.4 light olefin, LPG, and H.sub.2 in cracker effluent stream 122.

[0035] FIG. 3 shows system 30 for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds, according to embodiments of the invention. FIG. 4 shows process 40 for processing pyrolysis gasoline to produce a stream comprising primarily un-hydrogenated C.sub.9+ compounds, according to embodiments of the invention. System 30 may be used to implement process 40. System 30, according to embodiments of the invention, includes the elements 100 to 122 of system 10 as well as further elements 300 to 309. Likewise, process 40, in embodiments of the invention, includes operating elements 100 to 122 to carry out steps of blocks 200 to 206 as described in process 20.

[0036] Process 40 as implemented by system 30, like process 20 implemented by system 10, includes blocks 200 to 206, in embodiments of the invention, except that GHU reactor 118 is not required as reactor 304 can hydrogenate stream 110 and GHU reactor 114 is similarly not required. Process 40 further includes, at block 400, routing stream 103, stream 107, and stream 110 to feed drum 300 where they are combined to form combined stream 301. Hydrogenation of the combined stream 301 may be carried out by injecting hydrogen stream 302, as shown at block 401, to form hydrogenated combined stream 303. Block 402 involves, in embodiments of the invention, flowing hydrogenated combined stream 303 to reactor 304, where hydrogenated combined stream 303 is subjected to reaction conditions sufficient to saturate diolefins and partially saturate the olefins. According to embodiments of the invention, stream 305 is used to heat hydrogenated combined stream 303 in heat exchanger 306. At block 403, stream 305 is separated in separator 307 to form vapor stream 308 comprising water and H.sub.2 and stream 309. At block 404, stream 309 is split into two portions, stream 309-1 and stream 309-2. In embodiments of the invention, at block 405, stream 309-2 is recycled to reactor 304. At block 406, stream 309-1 is separated to form a BTX stream, a stream comprising primarily hydrogenated wash oil, a fuel gas stream and a stream comprising primarily C.sub.5 compounds.

[0037] Although embodiments of the present invention have been described with reference to blocks of FIG. 2 and FIG. 4, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 2 and FIG. 4. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 2 and FIG. 4. It should be noted that, in FIG. 1 and FIG. 3, a stream shown from a first element or apparatus to a second element or apparatus is a disclosure that the first element or apparatus is in fluid communication with the second element or apparatus in a manner such that the flow of the stream shown, or described in the specification, can take place.

[0038] The systems and processes described herein can also include various equipment that is not shown and is known to one of skill in the art of chemical processing. For example, some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, and the like may not be shown.

[0039] In the context of the present invention, at least the following 20embodiments are shown. Embodiment 1 is a method of processing pyrolysis gasoline. The method includes separating a pyrolysis gasoline stream to produce a first stream containing primarily un-hydrogenated C.sub.9+ compounds. Embodiment 2 is the method of embodiment 1 wherein the first stream contains 98 to 100 wt. % C.sub.9+ compounds. Embodiment 3 is the method of embodiment 1 further including hydrogenating a portion of the first stream to produce a second stream containing hydrogenated C.sub.9+ hydrogenated compounds. Embodiment 4 is the method of embodiment 3, wherein the hydrogenating of the first portion of the first stream is carried out under reaction conditions including a temperature in a range of 100° C. to 200° C., a pressure in a range of 10 bar to 30 bar, a WHSV of 2 .sup.−1 to 8 h.sup.−1, and in the presence of a catalyst containing Ni/Al.sub.2O.sub.3 to Pd/A.sub.2O.sub.3. Embodiment 5 is the method of either of embodiments 3 or 4 further including separating the second stream to produce a third stream containing hydrogenated wash oil and a fourth stream containing hydrogenated C.sub.9+ residue. Embodiment 6 is the method of embodiment wherein third stream contains 0 to 90 wt. % wash oil and the fourth stream contains 10 to 100 wt. % hydrogenated C.sub.9+ compounds. Embodiment 7 is the method of either of embodiments 5 or 6, further including subjecting the third stream to reaction conditions to hydrogenate the third stream. Embodiment 8 is the method of embodiment 1, wherein the separating of the pyrolysis gasoline stream includes distilling the pyrolysis gas stream in a depentanizer column to produce a fifth stream containing primarily C.sub.4+ compounds and a sixth stream containing primarily C.sub.6+ compounds. Embodiment 9 is the method of embodiment 8 wherein the separating of the pyrolysis gasoline stream further includes distilling the sixth stream in a deoctanizer column to produce a seventh stream containing primarily C.sub.6 to C.sub.8 compounds and the first stream. Embodiment 10 is the method of embodiment 9 including hydrogenating the seventh stream to produce an eighth stream containing benzene, toluene, and xylene. Embodiment 11 is the method of embodiment 10, wherein the hydrogenating of the seventh stream is carried out under reaction conditions including a temperature in a range of 100° C. to 200° C., a pressure in a range of 10 bar to 30 bar, a WHSV of 2 h.sup.−1 to 8 h.sup.−1, and in presence of a catalyst containing Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3. Embodiment 12 is the method of embodiment 8 further including processing the fifth stream in a stabilizer to produce a ninth stream including fuel gas and a tenth stream containing primarily C.sub.4 and C.sub.5 compounds. Embodiment 13 is the method of embodiment 12 further including hydrogenating the tenth stream to produce an eleventh stream containing primarily C.sub.4 and C.sub.5 compounds. Embodiment 14 is the method of embodiment 13, wherein the hydrogenating of the tenth stream is carried out under reaction conditions including a temperature in a range of 40° C. to 140° C., a pressure in a range of 20 bar to 40 bar, a WHSV of 10 h.sup.−1 to 16 h.sup.−1, and in presence of a catalyst containing Ni/Al.sub.2O.sub.3 to Pd/Al.sub.2O.sub.3. Embodiment 15 is the method of either of embodiments 13 or 14 further including subjecting the eleventh stream to cracking conditions to form C.sub.2 to C.sub.4 light olefins, LPG, and H.sub.2.

[0040] Embodiment 16 is method of processing pyrolysis gasoline. The method includes concurrently producing (1) a first stream containing primarily un-hydrogenated C.sub.9+ compounds and (2) a second stream containing hydrogenated C.sub.9+ hydrogenated compounds, wherein the producing includes separating a pyrolysis gasoline stream to produce the first stream containing primarily un-hydrogenated C.sub.9+ compounds and hydrogenating a portion of the first stream to produce the second stream containing hydrogenated C.sub.9+ hydrogenated compounds. Embodiment 17 is the method of embodiment 16 further including producing a stream containing primarily un-hydrogenated C.sub.4+ compounds.

[0041] Embodiment 18 is a method of processing pyrolysis gasoline. The method includes separating a pyrolysis gasoline stream to produce a first stream containing primarily un-hydrogenated C.sub.9+ compounds and hydrogenating a portion of the first stream to produce a second stream containing hydrogenated C.sub.9+ compounds. The method further includes separating the second stream to produce a third stream containing hydrogenated wash oil and a fourth stream containing hydrogenated C.sub.9+ residue The separating of the pyrolysis gasoline stream includes distilling the pyrolysis gas stream in a depentanizer column to produce a fifth stream containing primarily C.sub.4+ compounds and a sixth stream containing primarily C.sub.6+ compounds. The method also includes distilling the sixth stream in a deoctanizer column to produce a seventh stream containing primarily C.sub.6 to C.sub.8 compounds and the first stream. In addition, the method includes processing the fifth stream in a stabilizer to produce a ninth stream containing fuel gas and a tenth stream containing primarily C.sub.4 and C.sub.5 compounds. The method further includes combining the third stream, the seventh stream, and the tenth stream to form a combined stream and flowing the combined stream to a reactor. Embodiment 19 is the method of embodiment 18, further including subjecting the combined stream to reaction conditions sufficient to form a reactor effluent. Embodiment 20 is the method of embodiment 19 further including processing the reactor effluent to produce a BTX stream, a stream containing primarily hydrogenated wash oil, a fuel gas stream and a stream containing primarily C.sub.5 compounds.

EXAMPLES

[0042] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.

Example 1

Producing Un-hydrogenated C.SUB.9+ Compounds from Pyrolysis Gasoline

[0043] A first cut model was built in Aspen-Plus V10 Software. Simulations were performed according to an embodiment of the current disclosure as shown in FIG. 5. Separated streams containing C.sub.4-C.sub.5 compounds, un-hydrogenated C.sub.6 to C.sub.8 compounds, un-hydrogenated wash oil, un-hydrogenated C.sub.9+ residues were obtained from a pyrolysis gasoline stream. The pyrolysis gasoline stream contained C.sub.4 compounds, C.sub.5 compounds, benzene, toluene, xylene, styrene, indene, indane, dicyclopentadiene (DCPD), methyldicyclopentadiene (MDCPD), and others (e.g. other C.sub.6-C.sub.8 paraffinic and olefinic components, and C.sub.9+ paraffinic, olefinic, napthenic and aromatic components). The pyrolysis gasoline stream was distilled in a depentanizer column to obtain a stream containing the C.sub.4 and C.sub.5 compounds from the top of the column, and a C.sub.6+ stream containing un-hydrogenated C.sub.6+ compounds from the bottom of the column. The C.sub.6+ stream contained benzene, toluene, xylene, styrene, indene, indane, DCPD, MDCPD and the other. The C.sub.6+ stream was distilled in a deoctanizer column to obtain a C.sub.6-8 stream containing un-hydrogenated C.sub.6 to C.sub.8 compounds from the top of the column, and a C.sub.9+ stream containing un-hydrogenated C.sub.9+ compounds from the bottom of the column. The C.sub.6-8 stream contained benzene, toluene, xylene and a portion of other (e.g. C.sub.6-C.sub.8 paraffinic and olefinic components). The C.sub.9+ stream contained styrene, indene, indane, DCPD, MDCPD and a portion of the other (e.g. C.sub.9+ paraffinic, olefinic, napthenic and aromatic components). The C.sub.9+ stream was separated in a separation flash drum to obtain a stream containing un-hydrogenated wash oil from the top and a stream containing un-hydrogenated C.sub.9+ residues from the bottom. The compositions, flow rate of the streams are provided in Tables 1-7. A TBC package, containing 4-tert-Butylcatechol (TBC) as fouling inhibitor, was supplied to the depentanizer column, deoctanizer column and the flash drum to reduce fouling.

TABLE-US-00001 TABLE 1 Pyrolysis gasoline stream Compounds Ton/hour C.sub.4 0.59 C.sub.5 11.16 Benzene 14.07 Toluene 2.94 Xylene 0.31 Styrene 1.39 Indene 0.58 Indane 0.22 DCPD 1.95 MDCPD 0.3 Others 6.97 Total 40.49

TABLE-US-00002 TABLE 2 C.sub.4-C.sub.5 stream Compounds Ton/hour C.sub.4 0.59 C.sub.5 11.16 Total 11.75

TABLE-US-00003 TABLE 3 C.sub.6+ stream Compounds Ton/hour Benzene 14.07 Toluene 2.94 Xylene 0.31 Styrene 1.39 Indene 0.58 Indane 0.22 DCPD 1.95 MDCPD 0.3 Others 6.97 Total 28.74

TABLE-US-00004 TABLE 4 C.sub.6-8 stream Compounds Ton/hour Benzene 14.00 Toluene 2.78 Xylene 0.2 Others 3.72 Total 20.7

TABLE-US-00005 TABLE 5 C.sub.9+ stream Compounds Ton/hour Styrene 0.71 Indene 0.58 Indane 0.22 DCPD 1.86 MDCPD 0.3 Others 4.59 Total 8.04

TABLE-US-00006 TABLE 6 Wash oil Compounds Ton/hour Styrene 0.65 Indene 0.48 Indane 0.18 DCPD 1.55 MDCPD 0.18 Others 3.32 Total 6.35

TABLE-US-00007 TABLE 7 C.sub.9+ residue stream Compounds Ton/hour Styrene 0.06 Indene 0.1 Indane 0.04 DCPD 0.31 MDCPD 0.12 Others 1.05 Total 1.69

[0044] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.