KR-20260065928-A - FCC product vapor separation method for improved product recovery

KR20260065928AKR 20260065928 AKR20260065928 AKR 20260065928AKR-20260065928-A

Abstract

Systems and processes for separating a decomposed hydrocarbon mixture. A main fractionator separates the decomposed hydrocarbon mixture into overhead, side draw, and bottom fractions containing C1 to C6+ hydrocarbons. An overhead condensation and high-pressure separation system partially condenses the overhead and compresses the uncondensed vapor to produce a compressed gas fraction and a compressed liquid fraction. A first distillation column receives the compressed liquid fraction and separates it into a first overhead vapor and a first bottom fraction. A second distillation column separates the first bottom fraction into a second overhead and a second bottom fraction. An absorber receives and contacts a portion of the side draw liquid fraction and the second bottom fraction with the compressed gas fraction in a countercurrent flow to produce an absorber overhead fraction and an absorber bottom fraction containing offgas. These systems are useful for integrating existing FCC/RFCC units into petrochemical complexes.

Inventors

귀벨리올루 갈립 에이치.
미탈 수밋
마리 라마 라오
브레켄리지 저스틴

Assignees

루머스 테크놀로지 엘엘씨

Dates

Publication Date: 20260511
Application Date: 20241016
Priority Date: 20231019

Claims (20)

As a hydrocarbon separation system, A flow line for transporting a decomposed reaction effluent comprising a hydrocarbon mixture including methane (C1) to heavy (C12+) hydrocarbons from one or more cracking reactors; Main fractionator - said main fractionator is configured to receive said hydrocarbon mixture, said main fractionator is configured to separate said hydrocarbon mixture into overhead vapor containing C1 to C6+ hydrocarbons, a side draw liquid fraction, and a bottoms product fraction -; A main fractionator overhead condensation and high-pressure separation system configured to partially condense the overhead steam and compress the uncondensed steam to produce a compressed gas fraction and a compressed liquid fraction; A first distillation column configured to receive the compressed liquid fraction and separate the compressed liquid fraction into a first overhead vapor fraction and a first bottom fraction; and A second distillation column configured to accommodate the first bottom fraction and separate the first bottom fraction into a second overhead fraction and a second bottom fraction; A system comprising an absorber configured to receive and contact the above-mentioned side discharge liquid fraction and a portion of the above-mentioned second bottom fraction and the above-mentioned compressed gas fraction in a countercurrent flow, and to produce an absorber overhead fraction and an absorber bottom fraction containing offgas.
In paragraph 1, The above-mentioned first distillation column is sized and configured to operate flexibly as a demethanator in a first operating mode and as a decarbonizer in a second operating mode; A system in which the absorber is sized and configured to flexibly operate to recover off-gas containing methane and essentially not containing C2 hydrocarbons in the first operating mode, and to recover off-gas containing methane and C2 hydrocarbons in the second operating mode.
In paragraph 1, A system in which the second distillation column is sized and configured to flexibly operate as a debutane carbonizer in the first operating mode and as a depentane carbonizer in the second operating mode.
In paragraph 1, A flow line for supplying the lower fraction of the absorber to the main fractionator overhead condensation and high-pressure separation system; and A system further comprising one or both of the flow lines for supplying the first overhead vapor fraction to the main fractionator overhead condensation and high-pressure separation system.
In paragraph 1, The above compressed liquid fraction comprises a first compressed liquid fraction containing C4 to C6+ hydrocarbons and a second compressed liquid fraction containing C1 to C6+ hydrocarbons, and the hydrocarbon separation system comprises A flow line for supplying a portion of the first compressed liquid fraction to the absorber; A flow line for supplying a second portion of the above-mentioned compressed liquid fraction as reflux to the main fractionator; and A system further comprising a flow line for supplying the second compressed liquid fraction to the first distillation column.
In paragraph 1, The system further comprises a heat exchanger configured to generate an absorber side discharge fraction and to receive a cooled absorber side discharge fraction, and the system further comprises a heat exchanger configured to cool the absorber side discharge fraction and to generate the cooled absorber side discharge fraction.
In paragraph 1, A heat exchange system positioned downstream of the main fractionator and upstream of the absorber—the heat exchange system comprises two or more heat exchangers configured to cool the main fractionator side effluent and produce cooled main fractionator side effluent supplied to the absorber—; and A system further comprising a flow control system configured to divert a portion of the cooled main fractionator side discharge as reflux to the main fractionator and supply the remainder of the cooled main fractionator side discharge to the absorber.
In Paragraph 7, A system further comprising a second heat exchange system for cooling the lower fraction of the main separator, wherein the heat exchange system and the second heat exchange system are configured to heat water through the side discharge of the main separator and the lower fraction of the main separator to generate a medium-pressure or high-pressure steam stream.
In Paragraph 7, A system comprising at least one of the two or more heat exchangers of the heat exchange system configured to reboil a bottom stream recovered from the first distillation column and return the heated reboiled bottom stream to the first distillation column.
In paragraph 1, The above high-pressure separation system is, A heat exchanger and a condensate drum for partially condensing the overhead steam to produce a first liquid fraction and an overhead steam fraction; A first stage compressor configured to compress the overhead vapor fraction and produce a compressed overhead vapor fraction; A separator configured to separate condensate from the above-mentioned compressed overhead vapor fraction and to produce a compressed vapor fraction and a compressed liquid fraction; A second stage compressor configured to further compress the above-mentioned compressed steam fraction and generate a second stage compressor effluent; A high-pressure separator configured to separate the liquid and vapor contained in the second stage compressor effluent and the compressed liquid fraction to produce a high-pressure separation system liquid stream and the compressed gas fraction; and A system comprising a mixing system configured to mix the second stage compressor effluent with the absorber bottom stream and the first distillation column overhead vapor fraction upstream of the high-pressure separator.
In paragraph 1, It further includes a second distillation column overhead system, wherein the second distillation column overhead system is A heat exchanger for partially condensing the overhead fraction of the second distillation column; A drum for separating the above partially condensed second distillation column overhead fraction into a second distillation column overhead liquid fraction and a second distillation column overhead vapor fraction; A knockout drum for collecting any liquid mixed in the overhead vapor fraction of the second distillation column to generate knockout vapor and knockout liquid; A compressor for compressing the above knockout steam to produce a compressed product; A flow line for supplying a portion of the overhead liquid fraction of the second distillation column to the second distillation column as reflux; and A system comprising a flow line for recovering the remainder of the overhead liquid fraction of the second distillation column as a mixed olefin-rich product.
In Paragraph 11, A mixing system for forming a combined product by mixing the above-mentioned compressed product and the above-mentioned mixed olefin-rich product; and A system further comprising one or both of the flow lines for supplying the knockout liquid to the main fractionator.
In paragraph 1, A reaction system further comprising one or more of the above-mentioned decomposition reactors, wherein the decomposition reactors are configured to produce C2 to C5 olefins and aromatics including benzene, toluene, and mixed xylene as target reaction products.
As a hydrocarbon separation process, A step of transferring a decomposed reaction effluent containing a hydrocarbon mixture containing methane (C1) to heavy (C12+) hydrocarbons to a main fractionator—said that the main fractionator receives said hydrocarbon mixture and separates said hydrocarbon mixture into an overhead vapor, a side discharge liquid fraction, and a bottom product fraction containing C1 to C6+ hydrocarbons—; A step of supplying the overhead steam to a main fractionator overhead condensation and high-pressure separation system to partially condense the overhead steam and compress the uncondensed steam to produce a compressed gas fraction and a compressed liquid fraction; A step of supplying the compressed liquid fraction to a first distillation column to separate the compressed liquid fraction into a first overhead vapor fraction and a first bottom fraction; A step of supplying the first bottom fraction to a second distillation column to separate the first bottom fraction into a second overhead fraction and a second bottom fraction; and A hydrocarbon separation process comprising the step of contacting a portion of the side discharge liquid fraction and the second bottom fraction with the compressed gas fraction in a counterflow in an absorber to produce an absorber overhead fraction and an absorber bottom fraction containing off-gas.
In Paragraph 14, A step of operating the above-mentioned first distillation column as a demethanizer during a first time period and as a decarbonizer during a second time period; and A hydrocarbon separation process further comprising the step of recovering off-gas containing methane and essentially not containing C2 hydrocarbons during the first time period, and operating the absorber to recover off-gas containing methane and C2 hydrocarbons during the second time period.
In Paragraph 14, A hydrocarbon separation process in which the second distillation column is sized and configured to flexibly operate as a debutane carbonizer in the first operating mode and as a depentane carbonizer in the second operating mode.
In Paragraph 14, The step of supplying the lower fraction of the absorber to the main fractionator overhead condensation and high-pressure separation system; and A hydrocarbon separation process further comprising one or both of the step of supplying the first overhead steam fraction to the main fractionator overhead condensation and high-pressure separation system.
In Paragraph 14, The above-mentioned compressed liquid fraction comprises a first compressed liquid fraction containing C4 to C6+ hydrocarbons and a second compressed liquid fraction containing C1 to C6+ hydrocarbons, and the process further comprises the steps of supplying a first portion of the first compressed liquid fraction to the absorber, supplying the second compressed liquid fraction to the first distillation column, and supplying a second portion of the first compressed liquid fraction to the main fractionator as reflux, a hydrocarbon separation process.
In Paragraph 14, The absorber is also configured to generate an absorber side discharge fraction and to receive a cooled absorber side discharge fraction, and the process further comprises the step of cooling the absorber side discharge fraction to generate the cooled absorber side discharge fraction.
In Paragraph 14, In a heat exchange system positioned downstream of the main fractionator and upstream of the absorber—the heat exchange system comprises two or more heat exchangers—a step of cooling the main fractionator side effluent to produce cooled main fractionator side effluent supplied to the absorber; A step of diverting a portion of the cooled main fractionator side effluent as reflux to the main fractionator and supplying the remainder of the cooled main fractionator side effluent to the absorber; and A process comprising, in addition to the step of cooling the lower fraction of the main separator in the second heat exchange system.

Description

FCC product vapor separation method for improved product recovery The embodiments of the present disclosure generally relate to the efficient separation of cracked hydrocarbons or other reaction products by a catalyst. Fluid catalytic cracking (FCC) units and residue fluid catalytic cracking (RFCC) units within a refinery complex are generally designed to produce finished products. The finished products often consist of offgases comprising lighter hydrocarbons (rich in methane and ethane), a mixture of olefin-grade products recovered as a light fraction (containing mainly ethylene, propylene, and butylene, and possibly C5 olefins), as well as heavier hydrocarbon fractions including gasoline. An example of a separation system according to conventional industrial practice is illustrated in FIG. 1 (prior art). To simplify the method, only the main equipment is illustrated. Various components of the separation system are illustrated to provide an overall understanding of the system, but those skilled in the art will recognize that many components that may exist, such as pumps, compressors, exchangers, valves, bypass lines, control systems, and others, are not illustrated. The separation system comprises a main fractionator (102A), a main fractionator overhead and high-pressure separation system (104A), a primary absorber (108A), a secondary absorber (108AA), and a separation zone including a decarbonizer (180A) and a debutizer (190A). The primary products recovered from the separation system include a fuel gas (C1, C2) fraction (140AA), an LPG (C3, C4) fraction (150AA), a naphtha range fraction (160A), and a heavy fraction (170A). Among other fractions, other fractions, such as various intermediate hydrocarbon cuts (not exemplified) recovered from the main fractionator (102A), may also be recovered. The decomposed reaction effluent (112) may be fed to a main fractionator (102A) to separate the decomposed reactor effluent into a bottom fraction (heavy product fraction) (170A), one or more side discharge fractions (192A, 101A), one or more additional side discharge liquid fractions (not exemplified), and overhead steam (118A). The side discharge liquid fraction portion (101A) may be fed to a secondary absorber (108AA), while the overhead steam (118A) may be processed through a fractionator overhead and high-pressure separation system (104A), which may include a cooler, flash drum, compressor, pump, etc. The separation system (104A) provides wild naphtha (122), primary gas (C1-C4 rich) (130A), and liquid intermediate (132A). The streams (122 and 130A) are fed to the primary absorber (108A), from which fuel gas (140A) is recovered at the top, which is also fed to the secondary absorber (108AA) to remove C5+ range hydrocarbons. The stream (140AA) recovered from the secondary absorber (108AA) is mixed with a refined fuel gas header based on properties and requirements. The side discharge (101A) from the main fractionator (102A) is used as the absorption medium in the secondary absorber (108AA). The bottom liquid (142A) from the secondary absorber (108AA) is recycled back to the main fractionator (102A). The liquid intermediate (132A) from the system (104A) is fed to the decarbonizer (180A), which removes the C1-C2 fraction and sends the remaining liquid (182A) to the debutizer (190A). The debutizer (190A) separates the liquid (182A) into an LPG fraction (150AA) and a naphtha fraction (160A). A portion (192AA) of the naphtha fraction (160A) is fed to the primary absorber (108A) for the recovery of the C3 and C4 fractions as described above. This stream recirculation rate directly affects the recovery of LPG from the system and controls the scale of most of the equipment. The naphtha liquid (160A) is a product intended for mixing into the gasoline pool after necessary processing (such as sulfur removal). As the use of electric vehicles gains momentum, demand for gasoline on the road is expected to slow or decrease significantly in the coming years. Consequently, conventional separation methods for FCC units may become unsuitable. As traditional FCC/RFCC units move away from gasoline production and shift toward lighter molecules/BTX-rich naphtha, conventionally used FCC separation units, such as those exemplified in Fig. 1, may not be satisfactory for processing reactor effluent into end-user products. In one embodiment, the embodiments herein relate to a hydrocarbon separation system. The hydrocarbon separation system comprises a flow line for transporting a hydrocarbon mixture comprising methane (C1) to heavy (C12+) hydrocarbons from one or more cracking reactors. The separation system further comprises a main fractionator, the main fractionator is configured to receive the hydrocarbon mixture, and the main fractionator is configured to separate the hydrocarbon mixture into an overhead vapor, a side discharge liquid fraction, and a bottom product fraction comprising C1 to C6+ hydrocarbons. The main fractionator overhe