Method for modifying ionic liquid alkylation system for sulfuric acid alkylation

Abstract

The invention relates to a method for modifying an ionic liquid alkylation system for sulfuric acid alkylation, and the method comprises the following steps: providing a special subsystem for sulfuric acid alkylation, which comprises a sulfuric acid alkylation reactor and a self-vaporizing acid-hydrocarbon separator, a feeding pipeline of the ionic liquid alkylation system is communicated with a raw material inlet of the sulfuric acid alkylation reactor, and a reaction effluent outlet of the sulfuric acid alkylation reactor is communicated with a feeding hole of the self-vaporization acid-hydrocarbon separator; the self-vaporizing acid hydrocarbon separator is configured to separate a reaction effluent of the sulfuric acid alkylation reactor into a gas phase hydrocarbon, an acid phase, and a liquid phase hydrocarbon comprising alkylate. According to the present invention, the ionic liquid alkylation system technology is modified to be used for sulfuric acid alkylation, such that the device energy consumption and the device investment are reduced, the labor intensity of the operator is reduced, the process is simplified, the high salinity wastewater discharge and the alkali liquid consumption of the device are substantially reduced, and the clean production is achieved.

Description

Technical Field

[0001] The present disclosure relates to a method for modifying an ionic liquid alkylation system for sulfuric acid alkylation. Background Art

[0002] With increasingly stringent environmental regulations and the continuous upgrading of gasoline standards, the current National VI B standard strictly limits the volume fraction of olefins, aromatics, oxygen, etc. in gasoline. Alkylate oil with high octane number, good anti-knock performance, low vapor pressure, low sulfur content, and no olefins and aromatics has become an ideal gasoline blending component. Increasing the capacity of alkylation units and improving the octane number of alkylation products have become the best choice to improve the cleanliness, environmental protection and combustion efficiency of gasoline.

[0003] Alkylate oil is produced by the alkylation reaction of isobutane and butene under the action of an acid catalyst. According to the type of acid used in the catalyst, it can be divided into liquid acid alkylation technologies such as hydrofluoric acid alkylation technology, sulfuric acid alkylation technology, ionic liquid alkylation, and solid acid alkylation technology. Since HF is a highly toxic substance and is easy to diffuse at room temperature and pressure, it can easily cause potential risks to the environment and personnel. In the past two decades, new alkylation units no longer use this technology, or it has been replaced by sulfuric acid alkylation technology. Solid alkylation catalysts have been proven to have difficulties in commercialization due to rapid scaling and deactivation of the catalyst. In recent years, UOP has cooperated with Chervon to develop ionic liquid C4 alkylation technology. The UOP website announced that a hydrofluoric acid alkylation unit was modified in 2017 and planned to be put into production in 2020, but no follow-up reports have been seen. At present, there are several ionic liquid alkylation units built in China, and some problems have occurred during operation. The document "Causes and Countermeasures for Deactivation of Composite Ionic Liquid Catalysts in Alkylation Units" (Refining Technology and Engineering, Vol. 52, No. 3, 2022) reports: "During the trial operation of the unit, the composite ionic liquid catalyst was deactivated many times due to various reasons, resulting in the unit running continuously for less than one month." The document "Corrosion Analysis and Countermeasures for Ionic Liquid Alkylation Process" (Scientific Management, No. 5, 2023) reports: "Ionic liquids themselves have little corrosion to production equipment. However, in the production process of ionic liquid alkylation units, ionic liquids will react chemically with water to generate hydrogen chloride and chloride salts, and organic chlorides in alkane oil products will also generate hydrogen chloride during the hydrogenation removal process. Therefore, the corrosion problem of the post-treatment system of the reaction effluent of the ionic liquid alkylation unit is more prominent, posing a safety hazard."

[0004] Sulfuric acid is colourless and odourless, unlike HF, HNO3, HCl and other acids that are easy to volatilise, and it also has a very long history of industrial use. Its safety is better than that of the hydrofluoric acid method. Most of the acid-related parts of the sulfuric acid alkylation process can use carbon steel equipment, and the corrosion of the device is controllable. The reaction raw materials do not need to be strictly refined. The alkylation waste acid is completely cracked and regenerated, and there is no secondary pollution problem such as solid waste and acid-soluble oil, and the waste acid regeneration technology is reliable. Sulfuric acid alkylation technology has become the mainstream alkylation technology selected by today's oil refining companies. The exploration of sulfuric acid catalytic systems in alkylation methods has a long history and has been studied by different teams of academic and industrial institutions. It also has a long history of industrial application. The sulfuric acid alkylation process generally consists of four parts: raw material pretreatment, alkylation reaction, compression refrigeration, effluent refining, product fractionation and chemical treatment. The companies that have commercialized sulfuric acid alkylation technology mainly include DuPont, ExxonMobil, Lummus and Sinopec. The sulfuric acid alkylation technologies used in China mainly include: DuPont's process, Lummus' CDAlky process, Sinopec's SINOALKY process and other DuPont-like processes. Due to the differences in the physical and chemical properties of sulfuric acid catalysts, the optimal process conditions in the alkylation reactor and the different requirements of sulfuric acid-catalyzed alkylation processes, ionic liquid alkylation itself is not suitable for the commercialization of sulfuric acid-catalyzed alkylation methods. Summary of the invention

[0005] The purpose of the present disclosure is to provide a method for transforming an ionic liquid alkylation system for sulfuric acid alkylation, which can reduce the energy consumption and investment of the device, reduce the labor intensity and operating costs of operators, simplify the process, achieve clean production, and improve the safety of the device.

[0006] In order to achieve the above object, the present disclosure provides a method for transforming an ionic liquid alkylation system for sulfuric acid alkylation, wherein the ionic liquid alkylation system comprises a feed pipeline, a feed pretreatment unit, an ionic liquid alkylation reactor, a cyclone separation unit and a fractionation unit; the cyclone separation unit comprises an effluent coalescing settler;

[0007] The method comprises the following steps:

[0008] S1: providing a dedicated subsystem for sulfuric acid alkylation, the dedicated subsystem for sulfuric acid alkylation comprising a sulfuric acid alkylation reactor and a self-steaming acid hydrocarbon separator, connecting a feed line of the ionic liquid alkylation system to a feed inlet of the sulfuric acid alkylation reactor, and connecting a reaction effluent outlet of the sulfuric acid alkylation reactor to a feed inlet of the self-steaming acid hydrocarbon separator; the self-steaming acid hydrocarbon separator is configured to separate the reaction effluent of the sulfuric acid alkylation reactor into gas phase hydrocarbons, acid phase and liquid phase hydrocarbons containing alkylate oil;

[0009] S2: connecting the liquid hydrocarbon outlet of the self-steaming acid hydrocarbon separator to the feed inlet of the effluent coalescing settler of the ionic liquid alkylation system, wherein the effluent coalescing settler is configured to perform acid hydrocarbon separation on the liquid hydrocarbon phase from the self-steaming acid hydrocarbon separator;

[0010] S3: connecting the first outlet of the liquid hydrocarbon phase of the effluent coalescing settler to the inlet of the fractionation unit of the ionic liquid alkylation system, and obtaining alkylate oil from the fractionation product outlet of the fractionation unit.

[0011] Optionally, the method further comprises: connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the feed inlet of the sulfuric acid alkylation reactor through a circulating acid phase pipeline;

[0012] Optionally, a new acid feed line is connected to the raw material inlet of the sulfuric acid alkylation reactor;

[0013] The liquid hydrocarbon phase second outlet of the effluent coalescing settler is connected to the feed inlet of the sulfuric acid alkylation reactor through a circulating hydrocarbon phase pipeline.

[0014] Optionally, the sulfuric acid alkylation reactor is a static mixed sulfuric acid alkylation reactor, wherein a plurality of static mixing internals are arranged in series and / or in parallel;

[0015] The self-steaming acid hydrocarbon separator comprises a self-steaming coalescence separation internal component and an acid hydrocarbon phase preliminary separation internal component.

[0016] Optionally, the ionic liquid alkylation system further comprises a compression refrigeration unit, and the method further comprises: connecting the gas phase hydrocarbon outlet of the self-gasifying acid hydrocarbon separator to the compression refrigeration unit inlet of the ionic liquid alkylation system, the compression refrigeration unit being configured to compress the gas phase hydrocarbon from the self-gasifying acid hydrocarbon separator into a cooling liquid phase, and returning the cooling liquid phase to the sulfuric acid alkylation reactor for recycling.

[0017] Optionally, the ionic liquid alkylation system further comprises one or more of a dryer, an alkali washing and water washing device, a flash tank and a waste ionic liquid treatment unit; the cyclone separation unit further comprises a cyclone separator and a settler;

[0018] The method further includes: stopping the dryer, the ionic liquid alkylation reactor, the cyclone separator and the waste ionic liquid treatment unit; allowing the raw material to enter the raw material inlet of the sulfuric acid alkylation reactor after being pretreated by the raw material pretreatment unit;

[0019] The alkaline washing water scrubber and the flash tank are deactivated.

[0020] Optionally, the method further comprises: providing a spent acid regeneration unit, and connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the inlet of the spent acid regeneration unit.

[0021] Optionally, the ionic liquid alkylation system further comprises a hydrodechlorination reactor and a product degassing tower sequentially connected to the product outlet of the fractionation unit, and the method further comprises: deactivating the hydrodechlorination reactor and the product degassing tower to obtain alkylate oil and circulating hydrocarbons from the product outlet of the fractionation unit.

[0022] Optionally, the method of using the modified sulfuric acid alkylation system comprises: allowing the reaction raw materials and isoparaffins after the raw material pretreatment unit to enter the sulfuric acid alkylation reactor in stages, and contact with sulfuric acid to carry out sulfuric acid alkylation reaction; the reaction effluent of the sulfuric acid alkylation reactor enters the self-steaming acid hydrocarbon separator, and is separated into gas phase hydrocarbons, liquid phase hydrocarbons and acid phase by the self-steaming acid hydrocarbon separator; allowing the liquid phase hydrocarbons to enter the effluent coalescing and settling vessel for settling and acid removal to obtain acid-removed liquid phase hydrocarbons, and a part of the acid-removed liquid phase hydrocarbons enters the fractionation unit, and obtains alkylate oil through fractionation.

[0023] Optionally, the method of using the modified sulfuric acid alkylation system further comprises:

[0024] Returning a portion of the acid phase from the self-steaming acid hydrocarbon separator to the sulfuric acid alkylation reactor as a circulating acid phase; and allowing another portion of the acid phase to enter a spent acid regeneration unit;

[0025] Allowing the gaseous hydrocarbons from the self-gasifying acid hydrocarbon separator to enter the compression refrigeration unit of the ionic liquid alkylation system for cooling and compression, and returning the resulting cooled liquid phase to the sulfuric acid alkylation reactor for continued use;

[0026] Another portion of the deacidified liquid-phase hydrocarbon is returned to the sulfuric acid alkylation reactor as circulating hydrocarbon.

[0027] Optionally, the conditions of the sulfuric acid alkylation reaction include: in the sulfuric acid alkylation reactor, the volume fraction of sulfuric acid is 10-70%, preferably 40-60%, the reaction temperature is -20°C to 100°C, preferably -10°C to 50°C, and the reaction pressure is 0.1MPa-2MPa; the residence time of the raw material in the sulfuric acid alkylation reactor is 0.5-30min; the molar ratio of isoparaffin to olefin is 1-50:1, preferably 2-30:1, and further preferably 4-15:1.

[0028] Through the above technical scheme, the present invention further reduces the energy consumption and investment of the device by transforming the ionic liquid alkylation process for sulfuric acid alkylation, reduces the labor intensity of operators, simplifies the process and reduces the investment of the device, greatly reduces the high-salt wastewater discharge and alkali solution consumption of the device, and realizes clean production.

[0029] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0031] Figure 1 The present invention is a schematic diagram of an ionic liquid alkylation device in the prior art.

[0032] Figure 2 Schematic diagram of a sulfuric acid catalytic alkylation unit disclosed in the present invention.

[0033] Figure 3 is a schematic diagram of a SINOALKY sulfuric acid alkylation dedicated subsystem disclosed in the present invention;

[0034] Figure 4 Schematic diagram of the decommissioning or updating components of the ionic liquid catalyzed alkylation unit disclosed in the present invention.

[0035] Description of Reference Numerals

[0036] Figure 1 Among them, 11: hydrocarbon feed line; 12: feed pretreatment unit; 13: dryer; 14: refrigerant feed line; 15: circulating hydrocarbon phase feed line; 16: ionic liquid alkyl reactor; 17: primary hydrocyclone; 18: secondary hydrocyclone; 19: primary settler; 20: secondary settler; 21: effluent coalescing settler; 22: alkali wash water scrubber; 23: flash tank; 24: compression refrigeration unit; 25: fractionation unit; 26: hydrodechlorination reactor; 27: product degassing tower.

[0037] Figure 2 In the figure, 11': hydrocarbon feed line; 12': feed pretreatment unit; 14': refrigerant feed line; 15': circulating hydrocarbon phase feed line; 21': effluent coalescing settler; 24': compression refrigeration unit; 25': fractionation unit; 160: sulfuric acid alkylation reactor; 290: self-vaporizing acid hydrocarbon separator; 300: spent acid regeneration unit; 230: pipeline.

[0038] Figure 3Among them, 245: circulating hydrocarbon; 246: refrigerant isobutane; 240: new acid feed line; 241: reaction effluent; 242: circulating acid feed line; 244: gas phase hydrocarbon; 247: liquid phase hydrocarbon; 248: acid discharge line; 291: self-vaporization coalescence separation internals. DETAILED DESCRIPTION

[0039] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0040] The present invention provides a method for modifying an ionic liquid alkylation system for sulfuric acid alkylation.

[0041] The ionic liquid alkylation system comprises a feed pipeline, a feed pretreatment unit, an ionic liquid alkylation reactor, a cyclone separation unit and a fractionation unit; the cyclone separation unit comprises an effluent coalescing settler;

[0042] The method comprises the following steps:

[0043] S1: providing a dedicated subsystem for sulfuric acid alkylation, the dedicated subsystem for sulfuric acid alkylation comprising a sulfuric acid alkylation reactor and a self-steaming acid hydrocarbon separator, connecting a feed line of the ionic liquid alkylation system to a feed inlet of the sulfuric acid alkylation reactor, and connecting a reaction effluent outlet of the sulfuric acid alkylation reactor to a feed inlet of the self-steaming acid hydrocarbon separator; the self-steaming acid hydrocarbon separator is configured to separate the reaction effluent of the sulfuric acid alkylation reactor into gas phase hydrocarbons, acid phase and liquid phase hydrocarbons containing alkylate oil;

[0044] S2: connecting the liquid hydrocarbon outlet of the self-steaming acid hydrocarbon separator to the feed inlet of the effluent coalescing settler of the ionic liquid alkylation system, wherein the effluent coalescing settler is configured to perform acid hydrocarbon separation on the liquid hydrocarbon phase from the self-steaming acid hydrocarbon separator;

[0045] S3: connecting the first outlet of the liquid hydrocarbon phase of the effluent coalescing settler to the inlet of the fractionation unit of the ionic liquid alkylation system, and obtaining alkylate oil from the fractionation product outlet of the fractionation unit.

[0046] The transformation method disclosed in the present invention can reduce the energy consumption and investment of the device, reduce the labor intensity and operating costs of operators, simplify the process, achieve clean production, and improve the safety of the device.

[0047] According to an embodiment of the present disclosure, the method further comprises: connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the raw material inlet of the sulfuric acid alkylation reactor through a circulating acid phase pipeline; optionally, connecting a new acid feed line to the raw material inlet of the sulfuric acid alkylation reactor. The above embodiment is conducive to maintaining the concentration of the sulfuric acid catalyst in the sulfuric acid alkylation reactor.

[0048] According to one embodiment of the present disclosure, the method further comprises: connecting the liquid hydrocarbon phase second outlet of the effluent coalescing settler to the feed inlet of the sulfuric acid alkylation reactor through a circulating hydrocarbon phase pipeline.

[0049] According to one embodiment of the present disclosure, the sulfuric acid alkylation reactor is a static mixed sulfuric acid alkylation reactor, and a plurality of static mixing internals are arranged inside the static mixed sulfuric acid alkylation reactor, and the plurality of mixing internals are arranged in series and / or in parallel; the self-steaming acid hydrocarbon separator includes a self-steaming coalescing separation internal and an acid hydrocarbon phase preliminary separation internal; the self-steaming coalescing separation internal is arranged at the feed inlet of the self-steaming acid hydrocarbon separator, and the self-steaming coalescing separation internal includes a first coalescing internal and a first support; the present disclosure does not impose any special restrictions on the material and structure of the first coalescing internal, for example, it can be a metal and non-metal composite double-wire coalescing internal; the acid hydrocarbon phase preliminary separation internal is arranged at the liquid hydrocarbon phase outlet of the self-steaming separator, and the acid hydrocarbon phase preliminary separation internal includes a guide plate, a second coalescing internal and a second support; the second coalescing internal can be an inclined plate type coalescing structure, or a metal and non-metal composite double-wire coalescing internal. In one embodiment, the static mixed sulfuric acid alkylation reactor may include one or more nozzles, and the one or more nozzles are used to generate an acid phase or a hydrocarbon phase. In another embodiment, different sulfuric acid alkylation reactor configurations may be used to provide a mixture of acid and hydrocarbon phases.

[0050] According to one embodiment of the present disclosure, the effluent coalescing settler can receive the liquid hydrocarbon phase preliminarily separated from the self-steaming acid hydrocarbon separator, and the hydrocarbon phase from the self-steaming acid hydrocarbon separator may not be completely separated from the acid phase; for example, the hydrocarbon phase from the self-steaming acid hydrocarbon separator may contain an entrained acid phase; the effluent coalescing settler is configured to separate the entrained acid phase from the hydrocarbon phase. The effluent coalescing settler may include at least one or more coalescing internals, and the multiple coalescing internals are arranged in series or in parallel. The material of the coalescing internals has a higher affinity for the acid phase than for the hydrocarbon phase, and the coalescing material can be fully wetted by the acid phase. The above embodiment is conducive to better separation of the acid phase and the hydrocarbon phase. In one embodiment, the self-steaming acid hydrocarbon separator can be re-provided by a sulfuric acid alkylation system or modified from an ionic liquid phase and hydrocarbon phase separation container in an ionic liquid alkylation unit.

[0051] According to one embodiment of the present disclosure, the ionic liquid alkylation system further includes a compression refrigeration unit, and the method further includes: connecting the gas phase hydrocarbon outlet of the self-gasifying acid hydrocarbon separator to the compression refrigeration unit inlet of the ionic liquid alkylation system, and the compression refrigeration unit is configured to compress the gas phase hydrocarbons from the self-gasifying acid hydrocarbon separator into a cooling liquid phase, and return the cooling liquid phase to the sulfuric acid alkylation reactor for recycling.

[0052] According to one embodiment of the present disclosure, the ionic liquid alkylation system further includes one or more of a dryer, an alkaline washing and water scrubber, a flash tank, and a waste ionic liquid treatment unit; the cyclone separation unit further includes a cyclone separator and a settler; the method further includes: deactivating the dryer, the ionic liquid alkylation reactor, the cyclone separator, and the waste ionic liquid treatment unit; allowing the raw material to enter the raw material inlet of the sulfuric acid alkylation reactor after being pretreated by the raw material pretreatment unit; and deactivating the alkaline washing and water scrubber and the flash tank.

[0053] In one embodiment, the deactivation of the ionic liquid alkylation reactor may be temporary or permanent, and the deactivated components of the ionic liquid alkylation unit may be moved, dismantled, discarded, or temporarily or permanently retained in their original locations. In the above embodiment, the dryer of the original ionic liquid alkylation system is deactivated, which reduces the energy consumption and investment of the unit, and reduces the labor intensity of operators; the hydrocyclone separator at the outlet of the original ionic liquid alkylation reactor is deactivated, which can simplify the process and reduce the investment of the unit; the logistics at the outlet of the original effluent coalescing settler does not need to undergo an alkali washing process, which greatly reduces the discharge of high-salt wastewater and alkali liquid consumption of the unit, realizes clean production, simplifies the process, reduces the operating cost of the unit, and greatly reduces the labor intensity of operators.

[0054] In one embodiment, the flash tank can be used for other purposes, for example, it can be used as a sulfuric acid alkylation waste acid dehydrogenation tank. In one embodiment, the settler of the ionic liquid alkylation system can be kept in service, for example, a coalescing internal can be provided in the settler for separation of the acid phase and the hydrocarbon phase.

[0055] According to one embodiment of the present disclosure, the method further includes: providing a waste acid regeneration unit, connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the inlet of the waste acid regeneration unit. In one embodiment, the waste ion liquid treatment unit can be moved, dismantled, discarded, or can be temporarily or permanently retained in the original position; the waste acid regeneration unit can be newly configured or the waste acid can be collected and outsourced for treatment. In one embodiment, the modification method further includes connecting the outlet of the waste acid regeneration unit to the raw material inlet of the sulfuric acid alkylation reactor to feed at least a portion of the regenerated sulfuric acid catalyst into the sulfuric acid alkylation reactor. In the above-mentioned embodiment, the waste ion liquid treatment unit is abandoned or dismantled, and the sulfuric acid alkylation device after modification greatly reduces the generation of a large amount of solid hazardous waste during the waste ion liquid treatment process.

[0056] According to one embodiment of the present disclosure, the ionic liquid alkylation system further comprises a hydrodechlorination reactor and a product degassing tower sequentially connected to the product outlet of the fractionation unit, and the method further comprises: deactivating the hydrodechlorination reactor and the product degassing tower, and obtaining alkylate oil and circulating hydrocarbons from the product outlet of the fractionation unit. In one embodiment, the fractionation unit of the ionic liquid alkylation unit can be improved to provide an improved and simplified fractionation unit for the sulfuric acid alkylation system, for example, it can include improving or refurbishing at least one distillation tower from the fractionation unit of the ionic liquid alkylation unit to provide an improved fractionation unit for the sulfuric acid alkylation system. In another embodiment, improving the fractionation unit of the ionic liquid alkylation unit can include reducing one or more distillation towers in the sulfuric acid alkylation fractionation unit, deactivating the hydrodechlorination reactor and the product degassing tower of the fractionation unit of the ionic liquid, and eliminating the need to separate the HCl-rich C3 fraction from the hydrocarbon phase. The above implementation method makes the distillation unit system "dry" and almost corrosion-free, greatly improving the safety of the device; the hydrodechlorination reactor and product degassing tower after the original ionic liquid distillation unit are shut down, the process is simplified, and the corrosion and energy consumption of the distillation system are greatly reduced.

[0057] According to one embodiment of the present disclosure, a method for using the modified sulfuric acid alkylation system includes: allowing the reaction raw materials and isoparaffins after the raw material pretreatment unit to enter the sulfuric acid alkylation reactor in stages, and contact with sulfuric acid to carry out sulfuric acid alkylation reaction; the reaction effluent of the sulfuric acid alkylation reactor enters the self-steaming acid hydrocarbon separator, and is separated into gas phase hydrocarbons, liquid phase hydrocarbons and acid phase by the self-steaming acid hydrocarbon separator; allowing a part of the acid phase to return to the sulfuric acid alkylation reactor as a circulating acid, and allowing another part of the acid phase from the self-steaming acid hydrocarbon separator to enter a spent acid regeneration unit; allowing the liquid phase hydrocarbons to enter the effluent coalescing and settling vessel for sedimentation and acid removal to obtain acid-removed liquid phase hydrocarbons, allowing a part of the acid-removed liquid phase hydrocarbons to return to the sulfuric acid alkylation reactor as a circulating hydrocarbon, and another part of the acid-removed liquid phase hydrocarbons to enter the fractionation unit, and obtain alkylate oil and a small amount of isoparaffins through fractionation, and the obtained isoparaffins are returned to the sulfuric acid alkylation reactor for continuous use. The gaseous hydrocarbons from the self-gasifying acid hydrocarbon separator enter the compression refrigeration unit for cooling and compression, which mainly contain unreacted isoparaffins. After compression and cooling, they are returned to the sulfuric acid alkylation reactor as a refrigerant for continued use.

[0058] According to one embodiment of the present disclosure, the raw material includes various hydrocarbon streams from a refinery gas separation unit, a coal liquefaction unit, or a naphtha catalytic cracking unit, an intermediate distillate cracking unit, a steam cracking unit, or a paraffin cracking unit, including FCC tail gas, FCC light hydrocarbons, coking unit tail gas, and hydrocracking unit light hydrocarbons. In one embodiment, the hydrocarbon stream contains isoparaffins and / or olefins. The olefin-containing hydrocarbon stream can be selected from FCC tail gas, coking unit tail gas, polyolefin unit tail gas, MTO unit tail gas, FCC light hydrocarbons, coking unit light hydrocarbons, Fischer-Tropsch synthesis unit light hydrocarbons, and catalytic cracking light hydrocarbons; it can also be selected from any two or more olefins with a carbon number of C2 to C10. The logistics containing isoparaffins include, but are not limited to, FCC light hydrocarbons, hydrocracking light hydrocarbons, coking unit light hydrocarbons, and Fischer-Tropsch synthesis unit light hydrocarbons. The raw material may contain a mixture of two or more isoparaffins. In one embodiment, the isoparaffin feed stream for the sulfuric acid catalyzed alkylation process may comprise isobutane, which may be commercially available from, for example, a hydrocracking unit, a butane isomerization unit.

[0059] In one embodiment, olefins and isoparaffins in the feed hydrocarbon stream may participate in a sulfuric acid catalyzed isoparaffin-olefin alkylation reaction. In another embodiment, olefins in the feed hydrocarbon stream may undergo an oligomerization reaction when contacted with a sulfuric acid catalyst in a sulfuric acid alkylation reactor, and the sulfuric acid catalyzed olefin oligomerization reaction may occur under the same or similar conditions as the sulfuric acid catalyzed olefin-isoparaffin alkylation.

[0060] According to one embodiment of the present disclosure, the dedicated subsystem for sulfuric acid alkylation is a SINOALKY dedicated subsystem for sulfuric acid alkylation. The existing ionic liquid (IL) alkylation unit is converted into a SINOALKY sulfuric acid alkylation system, which may be referred to as "IL / SINOALKY conversion" herein. In one embodiment, it is achieved by replacing and / or cutting off one or more components of the ionic liquid alkylation unit, by making one or more components of the ionic liquid alkylation unit suitable for the SINOALKY alkylation process, and / or by connecting one or more components of the SINOALKY sulfuric acid alkylation system to one or more components of the ionic liquid alkylation unit. During the IL / SINOALKY conversion process, one or more components of the ionic liquid alkylation unit may be cut off, for example, by closing one or more valves, and / or by removing, sealing or replacing lines or internal connections between two or more ionic liquid alkylation unit components.

[0061] In one embodiment, the SINOALKY sulfuric acid alkylation dedicated subsystem may include a static mixed sulfuric acid alkylation reactor. The sulfuric acid alkylation reactor may be configured for one or more sulfuric acid-catalyzed hydrocarbon conversion reactions, such as isoparaffin-olefin alkylation.

[0062] In one embodiment, the SINOALKY sulfuric acid alkylation dedicated subsystem includes multiple hydrocarbon feed pipelines, which can be connected to the sulfuric acid alkylation reactor as a whole, and at least a portion of the multiple hydrocarbon feed pipelines, such as the distal portion, can be extended to the internal space of the sulfuric acid alkylation reactor; the multiple hydrocarbon feed pipelines can be a part or component of the sulfuric acid alkylation reactor. In one embodiment, at least one hydrocarbon feed pipeline can be re-provided as a component of the sulfuric acid alkylation system, and at least one hydrocarbon feed pipeline of the sulfuric acid alkylation system is connected to a component of the ionic liquid alkylation unit, and the IL / SINOALKY modification method includes disconnecting the ionic liquid alkylation reactor from the at least one hydrocarbon feed line to deactivate the ionic liquid alkylation reactor; the ionic liquid alkylation reactor can be moved, removed, discarded, or can be temporarily or permanently retained in the original position.

[0063] In one embodiment of the IL / SINOALKY conversion process, the sulfuric acid alkylation reactor can be connected to the at least one hydrocarbon feed line via the multiple hydrocarbon feed lines, and at least one hydrocarbon feed line can be connected to the sulfuric acid alkylation reactor via the at least one hydrocarbon feed line and the multiple hydrocarbon feed lines. The at least one hydrocarbon feed can be processed, for example, by a feedstock pretreatment unit located upstream of the multiple hydrocarbon feeds.

[0064] In one embodiment, the feed pipeline includes at least a raw material feed line, a refrigerant feed line, a circulating acid phase feed line and a circulating hydrocarbon phase feed line. The multiple hydrocarbon feeds may include at least one nozzle or a plurality of nozzles used in combination. In one embodiment, multiple hydrocarbon feeds are fed to the sulfuric acid alkylation reactor to form a mixture containing a sulfuric acid phase and a hydrocarbon phase in the sulfuric acid alkylation reactor. The mixture contains a dispersed sulfuric acid phase and a continuous hydrocarbon phase. In one embodiment, the mixture contains an emulsion containing droplets of sulfuric acid catalyst suspended in a liquid hydrocarbon phase, and the droplets are uniformly suspended in the hydrocarbon phase to provide a uniform emulsion. The sulfuric acid phase may also be referred to herein as a sulfuric acid catalyst phase or an acid phase. It is understood that, for example, a small portion of the used sulfuric acid catalyst downstream of the sulfuric acid alkylation reactor is extracted and can be regenerated and recycled by high-temperature cracking, for example, including entering a small portion of the acid phase from the sub-vaporized acid hydrocarbon separator into a spent acid regeneration unit for regeneration and recycling.

[0065] The feedstock pretreatment unit also includes a selective hydrogenation unit or a light hydrocarbon removal tower unit for treating an olefin-containing feed stream. For example, the selective hydrogenation is used to remove butadiene or acetylenes; the light hydrocarbon removal tower is used to remove a small amount of light components, part of the water or most of the oxygen-containing compounds to reduce the acid consumption of the sulfuric acid alkylation unit.

[0066] According to one embodiment of the present disclosure, the modified sulfuric acid catalyzed alkylation system comprises one or more deactivated ionic liquid alkylation unit components. "Deactivated ionic liquid alkylation unit components" refers to one or more components of an ionic liquid alkylation unit that are temporarily or permanently withdrawn from service. One or more deactivated ionic liquid alkylation unit components may be disconnected from one or more retained components of the ionic liquid alkylation unit. "Retained components" of the ionic liquid alkylation unit means one or more components from the ionic liquid alkylation unit that are retained in their original or modified form for implementing the sulfuric acid alkylation process, and may be retained in place adjacent to one or more components of the sulfuric acid alkylation unit. In another embodiment, one or more deactivated ionic liquid alkylation unit components may be removed and / or discarded, for example, the deactivated ionic liquid alkylation unit components may include the ionic liquid alkylation reactor 16.

[0067] After the IL / SINOALKY revamp is completed, the resulting sulfuric acid alkylation system can be put into operation according to the appropriate startup procedures.

[0068] According to one embodiment of the present disclosure, the conditions of the sulfuric acid alkylation reaction include: in the sulfuric acid alkylation reactor, the volume fraction of sulfuric acid is 10-70%, preferably 40-60%, the reaction temperature is -20°C to 100°C, preferably -10°C to 50°C, and more preferably -10°C to 20°C; the reaction pressure is 0.1MPa-2MPa, and the pressure of the sulfuric acid alkylation reactor needs to keep the reactants in the liquid phase; the residence time of the raw material in the sulfuric acid alkylation reactor is 0.5-30min; the molar ratio of isoparaffin to olefin is 1-50:1, preferably 2-30:1, and more preferably 4-15:1.

[0069] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0070] Example 1

[0071] like Figures 1 to 4 As shown, Figure 1 This is a simplified flowchart of the ionic liquid alkylation process reported in the literature (Volume 52, Issue 3 of Catalysts and Auxiliary Agents). This embodiment provides a method for modifying an ionic liquid alkylation system for SINOALKY sulfuric acid alkylation, wherein the original ionic liquid alkylation system comprises a hydrocarbon feed line 11, a feed pretreatment unit 12, a dryer 13, a refrigerant feed line 14, a circulating hydrocarbon phase feed line 15, an ionic liquid alkylation reactor 16, a primary hydrocyclone 17, a secondary hydrocyclone 18, a primary settler 19, a secondary settler 20, an effluent coalescing settler 21, an alkali washing water washer 22, a flash tank 23, a compression refrigeration unit 24, a fractionation unit 25, a hydrodechlorination reactor 26, and a product degassing tower 27.

[0072] The transformation method of this embodiment includes: stopping the dryer 13, the ionic liquid alkylation reactor 16, the primary cyclone separator 17 and the secondary cyclone separator 18 in the original ionic liquid alkylation device, stopping the alkali washing water washer 22 and the flash tank 23, allowing the raw material to enter the sulfuric acid alkylation reactor after passing through the raw material pretreatment unit, connecting the feed pipeline included in the ionic liquid alkylation system with the raw material inlet of the sulfuric acid alkylation reactor, and connecting the outlet of the raw material pretreatment unit 12' to the raw material inlet of the ionic liquid alkylation reactor 160;

[0073] A SINOALKY sulfuric acid alkylation dedicated subsystem 200 is provided, the sulfuric acid alkylation dedicated subsystem 200 comprises a sulfuric acid alkylation reactor 160 and a self-steaming acid hydrocarbon separator 290, wherein the feed inlet of the self-steaming acid hydrocarbon separator is connected to the reaction effluent outlet of the sulfuric acid alkylation reactor; the self-steaming acid hydrocarbon separator is configured to separate the reaction effluent of the sulfuric acid alkylation reactor into gas phase hydrocarbons, acid phase and liquid phase hydrocarbons containing alkylate oil;

[0074] The gas phase hydrocarbon outlet of the self-gasifying acid hydrocarbon separator is connected to the inlet of the compression refrigeration unit 24' of the ionic liquid alkylation system, and the compression refrigeration unit 24' is configured to compress the gas phase hydrocarbon from the self-gasifying acid hydrocarbon separator into a cooling liquid phase, and return the cooling liquid phase to the sulfuric acid alkylation reactor 160 for recycling; the acid phase outlet of the self-gasifying acid hydrocarbon separator is connected to the raw material inlet of the sulfuric acid alkylation reactor through a circulating acid phase pipeline; the raw material inlet of the sulfuric acid alkylation reactor is connected to a new acid feed line;

[0075] Connecting the liquid hydrocarbon outlet of the self-steaming acid hydrocarbon separator 290 to the feed port of the effluent coalescing settler 21' of the ionic liquid alkylation system, wherein the effluent coalescing settler 21' is configured to separate the liquid hydrocarbon phase from the self-steaming acid hydrocarbon separator into acid hydrocarbons; temporarily stopping the primary settler 19 and the secondary settler 20;

[0076] The first outlet of the liquid hydrocarbon phase of the effluent coalescing settler 21' is connected to the inlet of the fractionation unit 25' of the ionic liquid alkylation system, and the alkylate oil is obtained from the outlet of the fractionation product of the fractionation unit; the second outlet of the liquid hydrocarbon phase of the effluent coalescing settler is connected to the feed inlet of the sulfuric acid alkylation reactor through a circulating hydrocarbon phase pipeline; the hydrodechlorination reactor 26 and the product degassing tower 27 of the ionic liquid alkylation system are stopped;

[0077] The waste ionic liquid treatment unit 28 is deactivated; a waste acid regeneration unit 300 is provided, and the acid phase outlet of the self-gasifying acid hydrocarbon separator is connected to the inlet of the waste acid regeneration unit.

[0078] like Figure 2 and Figure 3 As shown, the modified sulfuric acid alkylation unit 100 includes a feed pretreatment unit 12', a hydrocarbon feed line 11', a compression refrigeration unit 24', an effluent coalescing settler 21' and a fractionation unit 25' from an ionic liquid alkylation unit; a SINOALKY sulfuric acid alkylation dedicated subsystem 200 is provided, and the SINOALKY sulfuric acid alkylation dedicated subsystem 200 includes a sulfuric acid alkylation reactor 160, a self-steaming acid hydrocarbon separator 290, and the self-steaming acid hydrocarbon separator includes a self-steaming coalescing separation internal provided at the feed inlet;

[0079] Some components of the original ionic liquid alkylation unit are temporarily retained for use in the sulfuric acid alkylation unit 100 , including a feed pretreatment unit 12 , a hydrocarbon feed line 11 , an effluent coalescing settler 21 , a compression refrigeration unit 24 and a fractionation unit 25 .

[0080] use Figure 2-3The method of the sulfuric acid alkylation unit shown includes: allowing the reaction raw materials and isoparaffins after the raw material pretreatment unit 12' to enter the sulfuric acid alkylation reactor 160 in stages, and contact with sulfuric acid to carry out sulfuric acid alkylation reaction; the reaction effluent of the sulfuric acid alkylation reactor 160 enters the self-gasifying acid hydrocarbon separator 290, and is separated into gas phase hydrocarbons, acid phase and liquid phase hydrocarbons containing alkylate oil by the self-gasifying acid hydrocarbon separator 290; most of the acid phase from the self-gasifying acid hydrocarbon separator 290 is returned to the sulfuric acid alkylation reactor 160 as a circulating acid phase, and a small part of the acid phase enters the spent acid regeneration unit 300; the liquid phase hydrocarbons from the self-gasifying acid hydrocarbon separator 290 enter the effluent coalescing settler 21', most of the liquid phase hydrocarbons from which the acid phase is removed are returned to the sulfuric acid alkylation reactor 160 as circulating hydrocarbons, and a small part of the liquid phase hydrocarbons enter the fractionation unit 25', and the alkylate oil is obtained by fractionation.

[0081] The post-etherification C4 raw materials of the refinery (wherein the molar ratio of isoparaffin to olefin is 1.1-1.5:1, the isoparaffin is isobutane, and the olefin is 1-butene, trans-2-butene, cis-2-butene) enter the raw material and raw material pretreatment unit, and the alkylation reaction is carried out using the modified sulfuric acid alkylation unit to obtain the alkylation reaction effluent. In the sulfuric acid alkylation reactor, the volume fraction of sulfuric acid is 40%-60%, the reaction temperature is 0-15°C, and the reaction pressure is 0.05-1.0MPa; the residence time of the raw material in the sulfuric acid alkylation reactor is 1-10min.

[0082] According to statistics, the cost of modifying the original ionic liquid alkylation system for sulfuric acid alkylation can save 70-80% compared with building a new sulfuric acid alkylation unit.

[0083] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0084] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0085] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for modifying an ionic liquid alkylation system for sulfuric acid alkylation, characterized in that: The ionic liquid alkylation system comprises a feed pipeline, a feed pretreatment unit, an ionic liquid alkylation reactor, a cyclone separation unit and a fractionation unit; the cyclone separation unit comprises an effluent coalescing settler; The method comprises the following steps: S1: providing a dedicated subsystem for sulfuric acid alkylation, the dedicated subsystem for sulfuric acid alkylation comprising a sulfuric acid alkylation reactor and a self-steaming acid hydrocarbon separator, connecting a feed line of the ionic liquid alkylation system to a feed inlet of the sulfuric acid alkylation reactor, and connecting a reaction effluent outlet of the sulfuric acid alkylation reactor to a feed inlet of the self-steaming acid hydrocarbon separator; the self-steaming acid hydrocarbon separator is configured to separate the reaction effluent of the sulfuric acid alkylation reactor into gas phase hydrocarbons, acid phase and liquid phase hydrocarbons containing alkylate oil; S2: connecting the liquid hydrocarbon outlet of the self-steaming acid hydrocarbon separator to the feed inlet of the effluent coalescing settler of the ionic liquid alkylation system, wherein the effluent coalescing settler is configured to perform acid hydrocarbon separation on the liquid hydrocarbon phase from the self-steaming acid hydrocarbon separator; S3: connecting the first outlet of the liquid hydrocarbon phase of the effluent coalescing settler to the inlet of the fractionation unit of the ionic liquid alkylation system, and obtaining alkylate oil from the fractionation product outlet of the fractionation unit.

2. The method according to claim 1, wherein: The method further comprises: connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the feed inlet of the sulfuric acid alkylation reactor through a circulating acid phase pipeline; Optionally, a new acid feed line is connected to the raw material inlet of the sulfuric acid alkylation reactor; The liquid hydrocarbon phase second outlet of the effluent coalescing settler is connected to the feed inlet of the sulfuric acid alkylation reactor through a circulating hydrocarbon phase pipeline.

3. The method according to claim 1, wherein: The sulfuric acid alkylation reactor is a static mixed sulfuric acid alkylation reactor, wherein a plurality of static mixing internals are arranged in series and / or in parallel; The self-steaming acid hydrocarbon separator comprises a self-steaming coalescence separation internal component and an acid hydrocarbon phase preliminary separation internal component.

4. The method according to claim 1, wherein: The ionic liquid alkylation system further includes a compression refrigeration unit, and the method further includes: connecting the gas phase hydrocarbon outlet of the self-gasifying acid hydrocarbon separator to the compression refrigeration unit inlet of the ionic liquid alkylation system, and the compression refrigeration unit is configured to compress the gas phase hydrocarbons from the self-gasifying acid hydrocarbon separator into a cooling liquid phase, and return the cooling liquid phase to the sulfuric acid alkylation reactor for recycling.

5. The method according to claim 1, wherein: The ionic liquid alkylation system further includes one or more of a dryer, an alkali washing and water washing device, a flash tank, and a waste ionic liquid treatment unit; the cyclone separation unit further includes a cyclone separator and a settler; The method further includes: stopping the dryer, the ionic liquid alkylation reactor, the cyclone separator and the waste ionic liquid treatment unit; allowing the raw material to enter the raw material inlet of the sulfuric acid alkylation reactor after being pretreated by the raw material pretreatment unit; The alkaline washing water scrubber and the flash tank are deactivated.

6. The method according to claim 1, wherein: The method further comprises: providing a spent acid regeneration unit, and connecting the acid phase outlet of the self-gasifying acid hydrocarbon separator to the inlet of the spent acid regeneration unit.

7. The method according to claim 1, wherein: The ionic liquid alkylation system further comprises a hydrodechlorination reactor and a product degassing tower which are sequentially connected to the product outlet of the fractionation unit. The method further comprises: deactivating the hydrodechlorination reactor and the product degassing tower to obtain alkylate oil and circulating hydrocarbon from the product outlet of the fractionation unit.

8. The method according to claim 1, wherein: The method of using the modified sulfuric acid alkylation system comprises: allowing the reaction raw materials and isoparaffins after the raw material pretreatment unit to enter the sulfuric acid alkylation reactor in stages, and contact with sulfuric acid to carry out sulfuric acid alkylation reaction; the reaction effluent of the sulfuric acid alkylation reactor enters the self-steaming acid hydrocarbon separator, and is separated into gas phase hydrocarbons, liquid phase hydrocarbons and acid phase by the self-steaming acid hydrocarbon separator; allowing the liquid phase hydrocarbons to enter the effluent coalescing and settling vessel for settling and acid removal to obtain acid-removed liquid phase hydrocarbons, and a part of the acid-removed liquid phase hydrocarbons enters the fractionation unit, and obtains alkylate oil through fractionation.

9. The method according to claim 8, wherein: Methods of using the modified sulfuric acid alkylation system also include: Returning a portion of the acid phase from the self-steaming acid hydrocarbon separator to the sulfuric acid alkylation reactor as a circulating acid phase; and allowing another portion of the acid phase to enter a spent acid regeneration unit; Allowing the gaseous hydrocarbons from the self-gasifying acid hydrocarbon separator to enter the compression refrigeration unit of the ionic liquid alkylation system for cooling and compression, and returning the resulting cooled liquid phase to the sulfuric acid alkylation reactor for continued use; Another portion of the deacidified liquid-phase hydrocarbon is returned to the sulfuric acid alkylation reactor as circulating hydrocarbon.

10. The method according to any one of claims 8 or 9, wherein: The conditions of the sulfuric acid alkylation reaction include: in the sulfuric acid alkylation reactor, the volume fraction of sulfuric acid is 10-70%, preferably 40-60%, the reaction temperature is -20°C to 100°C, preferably -10°C to 50°C, and the reaction pressure is 0.1MPa-2MPa; the residence time of the raw material in the sulfuric acid alkylation reactor is 0.5-30min; the molar ratio of isoparaffin to olefin is 1-50:1, preferably 2-30:1, and more preferably 4-15:1.

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