Patent Application
20220315847
The present invention generally relates to the processing of pyrolysis gasoline (pygas). More specifically, the present invention relates to a process of processing pyrolysis gasoline to produce un-hydrogenated C9+ hydrocarbons and hydrogenated C9+ hydrocarbons.
A common process in the refining of hydrocarbon feedstocks, such as naphtha, is steam cracking. In the steam cracking (pyrolysis) process, the hydrocarbon feedstock is superheated in a reactor to temperatures as high as 750-950° C. For the cracking process, a dilution steam generator supplies dilution steam to the reactor to reduce the partial pressure of the hydrocarbons. The superheated hydrocarbons are then rapidly cooled (quenched) to stop the reactions after a certain point to optimize cracking product yield. Pyrolysis gasoline is one of the products of the cracking process and may include components such as aromatics, olefins, and/or diolefins, among others. Typically, the pygas is hydrogenated before further processing to produce finished products such as benzene, toluene, and xylene (BTX).
Gasoline hydrogenation units (GHU) are commonly used in the chemical industry to saturate unstable compounds such as diolefins and styrene. Olefins and sulfur compound 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 C9+ cut is normally separated at a deoctanizer to produce hydrogenated wash oil and hydrogenated C9+ residue.
WO 2018/002810 A1 relates to a separation system for separating a feed stream comprising C6+ hydrocarbons, the system comprising: i) a first distillation column for producing a first light stream comprising C6− hydrocarbons and a first heavy stream comprising C7+ hydrocarbons, wherein the first distillation column is operated between a lowest pressure and a highest pressure, ii) a second distillation column for producing a second light stream comprising C6− hydrocarbons and a second heavy stream comprising C7+ hydrocarbons, wherein the second distillation column is operated between a lowest pressure and a highest pressure, wherein the lowest pressure of the second distillation column is higher than the highest pressure of the highest distillation column and iii) a heat exchanger comprising a first reboiler for reboiling a part of the first heavy stream to produce a first boiled heavy stream and a second condenser for condensing the second light stream to produce a second condensed light stream, wherein the first reboiler and the second condenser are arranged such that heat released from the second condenser is used as heat for the first reboiler.
As described above, conventional processes for processing of pyrolysis gasoline produce hydrogenated C9+ hydrocarbons. However, there is also a demand for un-hydrogenated C9+ hydrocarbons. As far as is known, presently, there is no process that produces both un-hydrogenated and hydrogenated products concurrently. A solution to address this deficiency of conventional processes has been discovered. The disclosed process is premised on separating un-hydrogenated C9+ hydrocarbons from pyrolysis gasoline upstream of a GHU so that un-hydrogenated C9+ hydrocarbons can be recovered as a product and/or hydrogenated C9+ hydrocarbons can be recovered as a product. The discovered process provides the flexibility of producing (1) only un-hydrogenated C9+ hydrocarbons (separation upstream of GHU and not further hydrogenated), (2) un-hydrogenated C9+ hydrocarbons and hydrogenated C9+ hydrocarbons (separation upstream of GHU and GHU operated to process only a portion of the un-hydrogenated C9+ hydrocarbons), or (3) only hydrogenated C9+ hydrocarbons (GHU operated to process all of the un-hydrogenated C9+ hydrocarbons).
Embodiments of the invention include a method of processing pyrolysis gasoline, where the method involves separating a pyrolysis gasoline stream to produce a first stream comprising primarily un-hydrogenated C9+ compounds. According to embodiments of the invention, the separating of the pyrolysis gasoline is carried out upstream of the hydrogenation unit.
Embodiments of the invention include a method of processing pyrolysis gasoline to concurrently produce a first stream comprising primarily un-hydrogenated C9+ compounds and a second stream comprising hydrogenated C9+ hydrogenated compounds. The method includes separating a pyrolysis gasoline stream to produce the first stream comprising primarily un-hydrogenated C9+ compounds and further includes hydrogenating a portion of the first stream to produce the second stream comprising hydrogenated C9+ hydrogenated compounds.
The following includes definitions of various terms and phrases used throughout this specification.
The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%.
The terms “wt. %”, “vol. %” or “mol. %” refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol. % of component.
The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.
The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.
The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.
The use of the words “a” or “an” when used in conjunction with the term “comprising,” “including,” “containing,” or “having” in the claims or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”
The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
The process of the present invention can “comprise,” “consist essentially of,” or “consist of” particular ingredients, components, compositions, etc., disclosed throughout the specification.
The term “primarily,” as that term is used in the specification and/or claims, means greater than any of 50 wt. %, 50 mol. %, and 50 vol. %. For example, “primarily” may include 50.1 wt. % to 100 wt. % and all values and ranges there between, 50.1 mol. % to 100 mol. % and all values and ranges there between, or 50.1 vol. % to 100 vol. % and all values and ranges there between.
Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.
For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
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 C9+ cut is normally separated at the deoctanizer to produce hydrogenated wash oil and hydrogenated C9+ residue. This process, however, does not contribute to meeting the demand for un-hydrogenated C9+ products. A solution to address this deficiency of the conventional process has been discovered. The discovered process is premised on separating un-hydrogenated C9+ hydrocarbons from pyrolysis gasoline upstream of a GHU so that un-hydrogenated C9+ hydrocarbons can be recovered as a product and as hydrogenated C9+ hydrocarbons can likewise be recovered as a product.
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 (C9+ compounds/stream), which comprises primarily un-hydrogenated C9+ 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 C9+ 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. % C9+ 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%.
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 C9+ compounds (e.g., hydrogenated hydrocarbons). In other words, in embodiments of the invention, all of stream 101 may be hydrogenated or, as shown in
At block 202, according to embodiments of the invention, stream 102, which comprises hydrogenated C9+ 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 C9+ 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 C9+ 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. %.
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 C4 and C5 compounds and stream 106 as a bottoms stream comprising primarily C6+ compounds. In this way, according to embodiments of the invention, a C4 to C5 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 C6 to C8 compounds and un-hydrogenated C9+ compounds/stream 101. More specifically, at deoctanizer column 113, un-hydrogenated BTX is flowed from the top for deoctanizer column 113 and un-hydrogenated C9+ compounds are flowed from the bottom of deoctanizer column 113. The un-hydrogenated C9+ 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 C9+ residue can be produced. The separation of the un-hydrogenated C9+ 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
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−1 and all ranges and values there between including ranges of 2 to 3 h−1, 3 to 4 h−1, 4 to 5 h−1, 5 to 6 h−1, 6 to 7 h−1, and 7 to 8 h−1, and in the presence of a catalyst comprising Ni/Al2O3 to Pd/Al2O3.
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 C4 and C5 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 C4 and C5 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−1 and all ranges and values there between including ranges of 10 to 11 h−1, 11 to 12 h−1, 12 to 13 h−1, 13 to 14 h−1, 14 to 15 h−1, and 15 to 16 h−1, and in the presence of a catalyst comprising Ni/Al2O3 to Pd/Al2O3.
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 C2 to C4 light olefin, LPG, and H2 in cracker effluent stream 122.
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 H2 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 C5 compounds.
Although embodiments of the present invention have been described with reference to blocks of
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.
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 C9+ compounds. Embodiment 2 is the method of embodiment 1 wherein the first stream contains 98 to 100 wt. % C9+ 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 C9+ 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 −1 to 8 h−1, and in the presence of a catalyst containing Ni/Al2O3 to Pd/A2O3. 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 C9+ 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 C9+ 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 C4+ compounds and a sixth stream containing primarily C6+ 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 C6 to C8 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−1 to 8 h−1, and in presence of a catalyst containing Ni/Al2O3 to Pd/Al2O3. 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 C4 and C5 compounds. Embodiment 13 is the method of embodiment 12 further including hydrogenating the tenth stream to produce an eleventh stream containing primarily C4 and C5 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−1 to 16 h−1, and in presence of a catalyst containing Ni/Al2O3 to Pd/Al2O3. Embodiment 15 is the method of either of embodiments 13 or 14 further including subjecting the eleventh stream to cracking conditions to form C2 to C4 light olefins, LPG, and H2.
Embodiment 16 is method of processing pyrolysis gasoline. The method includes concurrently producing (1) a first stream containing primarily un-hydrogenated C9+ compounds and (2) a second stream containing hydrogenated C9+ hydrogenated compounds, wherein the producing includes separating a pyrolysis gasoline stream to produce the first stream containing primarily un-hydrogenated C9+ compounds and hydrogenating a portion of the first stream to produce the second stream containing hydrogenated C9+ hydrogenated compounds. Embodiment 17 is the method of embodiment 16 further including producing a stream containing primarily un-hydrogenated C4+ compounds.
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 C9+ compounds and hydrogenating a portion of the first stream to produce a second stream containing hydrogenated C9+ compounds. The method further includes separating the second stream to produce a third stream containing hydrogenated wash oil and a fourth stream containing hydrogenated C9+ 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 C4+ compounds and a sixth stream containing primarily C6+ compounds. The method also includes distilling the sixth stream in a deoctanizer column to produce a seventh stream containing primarily C6 to C8 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 C4 and C5 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 C5 compounds.
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.
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
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.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 62/874,401, filed Jul. 15, 2019, the entire contents of which are hereby incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/056588 | 7/13/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62874401 | Jul 2019 | US |
