Acid hydrocarbon flash separation equipment for alkylation production device
By installing an acid-hydrocarbon mixture separator at the hydrocarbon phase outlet of the flash heat extraction tank, the coalescing crude filler composed of acid-philic fibers and surface-modified metal wires is used to separate hydrocarbons and acids, and the problem of short separation time and insufficient separation in the hydrocarbon phase in the prior art is solved, and the improvement of the acid-hydrocarbon separation effect and the stable operation of the device for a long period of time is achieved.
Patent Information
- Application Number
- CN202311742040.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-18
- Publication Date
- 2025-06-20
AI Technical Summary
In the prior art, the hydraulic hydrocarbon phase outlet design of the flash heat extraction tank is insufficient, resulting in a short separation time of acid hydrocarbons in the hydrocarbon phase and insufficient separation degree, which in turn leads to a high acid boundary in the acid hydrocarbon separation tank, and the recovery acid pump needs to operate overload, and there is a risk of fluctuation of the overcurrent self-stop device.
The acid-hydrogen mixture separator is installed at the hydrocarbon phase outlet of the flash heat extraction tank, including an upper baffle, a lower baffle and a crude filler layer. The coalesced crude filler composed of acid-philic fibers and surface modified metal wires are used to separate hydrocarbons and acids, thereby increasing the separation space of the hydrocarbon phase acid-hydrocarbons and improving the separation effect of acid-hydrocarbons.
By optimizing the hydrocarbon phase outlet structure, the amount of acid in the hydrocarbon phase belt is reduced, the acid storage volume of the acid hydrocarbon separation tank is reduced, the start time and operating load of the recovery acid pump, the sulfur content of the product is increased, and the load of the subsequent alkali washing process is reduced.
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Figure CN120168988A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of petrochemical production equipment, and relates to an acid-hydrocarbon flash separation device for an alkylation production unit. Background Art
[0002] In SINOALKY sulfuric acid alkylation, it is mixed with concentrated sulfuric acid recycled from a flash heat extraction tank and recycled hydrocarbons recycled from a coalescing separator in an alkylation reactor to carry out an alkylation reaction. The post-reaction logistics enters the flash heat extraction tank for preliminary acid-hydrocarbon separation. In the flash heat extraction tank, after the acid-hydrocarbon mixture coalesces through an acid-hydrocarbon coalescing filler, the gaseous isobutane is sent to a refrigeration compressor through a gas outlet, and after compression and cooling, it returns to the alkylation reactor. The hydrocarbon phase enters a coalescing separation tank through a hydrocarbon phase outlet. After being separated by coalescing internal components in the coalescing separation tank, most of the recycled hydrocarbons return to the alkylation reactor, a small part of the reaction products at the top are sent to a downstream refining unit for refining and separation, and the waste acid at the bottom is sent to a waste acid treatment unit for incineration treatment. The acid phase is recycled through an acid outlet to the alkylation reactor to continue participating in the alkylation reaction.
[0003] In the prior art, a simple anti-impact baffle is provided above the hydrocarbon phase outlet of the flash heat extraction tank to prevent the unseparated acid-hydrocarbon mixture from directly entering downstream equipment along with the hydrocarbon phase outlet. It is mainly manifested that when operating at full load, the acid content in the hydrocarbon phase of the flash heat extraction tank is relatively large, and the downstream acid-hydrocarbon separation tank cannot timely separate and remove the acid stored in the effluent, resulting in a relatively high acid interface level in the acid-hydrocarbon separation tank. The acid recovery pump needs to operate with overload, and there is a risk of fluctuation of the overcurrent self-stop device. The reasons for analysis are: first, it is limited by the too low hydrocarbon phase outlet of the flash heat extraction tank and the relatively low hydrocarbon phase liquid level in the tank, resulting in a short acid-hydrocarbon separation time and insufficient separation degree in the hydrocarbon phase. Second, only a simple anti-impact baffle is provided above the hydrocarbon phase outlet of the flash heat extraction tank, and the preliminary separation of the hydrocarbon phase cannot be further achieved. Summary of the Invention
[0004] The purpose of the present invention is to provide an acid-hydrocarbon flash separation device for an alkylation production unit, which optimizes the structure of the hydrocarbon phase extraction outlet of the flash heat extraction tank, increases the acid-hydrocarbon separation space of the hydrocarbon phase, improves the acid-hydrocarbon separation effect, and keeps the alkylation unit running smoothly in a long cycle.
[0005] The technical solution of the present invention is: an acid-hydrocarbon flash separation device for an alkylation production unit, including a flash heat extraction tank, and the flash heat extraction tank is provided with a hydrocarbon phase outlet. An acid-hydrocarbon mixture separator is provided at the hydrocarbon phase outlet, and the acid-hydrocarbon mixture separator is composed of an upper baffle, a lower baffle and a rough separation filler layer. The lower baffle is located below the hydrocarbon phase outlet, and the upper baffle is located above the hydrocarbon phase outlet. The outer edge of the upper baffle is larger than that of the lower baffle and is overlapped with the lower baffle, and the rough separation filler layer is installed at the overlapping part of the upper baffle and the lower baffle.
[0006] The upper and lower parts of the coalescence rough separation packing layer are supported by wire meshes, and the coalescence rough separation packing is installed in the middle. The coalescence rough separation packing is composed of a mixture of acidophilic fibers and surface-modified metal wires, and the coalescence rough separation packing has irregular micropores. The acidophilic fibers are a 904L + non-metallic fiber composite, the non-metallic fibers are modified PP non-metallic fibers, and the surface-modified metal wires are 316SS (molybdenum-containing stainless steel) metal wires. The area of the rough separation packing layer is 1.5 - 2 m 2 , preferably 1.8 m 2 , and the height is 600 - 800 mm, preferably 700 mm.
[0007] The alkylation production device includes an alkylation reactor, a flash heat extraction tank, and a coalescence separation tank. The alkylation reactor is provided with a first-stage feed inlet, a second-stage feed inlet, a third-stage feed inlet, a circulating acid inlet, and a reaction effluent outlet. The coalescence separation tank is provided with a hydrocarbon phase inlet, a circulating hydrocarbon outlet, a product outlet, and a spent acid outlet. The flash heat extraction tank is provided with a liquid distributor, a bubble cap distributor, a coalescence flash packing, a gas phase outlet, and a hydrocarbon phase outlet. The top of the flash heat extraction tank is provided with an acid-hydrocarbon inlet, and the bottom is provided with an acid outlet. The reaction effluent outlet of the coalescence separation tank is connected to the acid-hydrocarbon inlet, the acid outlet is connected to the circulating acid inlet, the hydrocarbon phase outlet is connected to the hydrocarbon phase inlet provided in the coalescence separation tank, and the gas phase outlet is connected to a refrigeration compressor. The circulating hydrocarbon outlet of the coalescence separation tank is connected to the first-stage feed inlet through a circulating hydrocarbon pipeline, the product outlet is connected to a refining unit, and the spent acid outlet is connected to a spent acid treatment unit. The material of the coalescence flash packing is a composite winding material of modified PP non-metallic fibers and 316SS metal wires.
[0008] The acid-hydrocarbon flash separation equipment for the alkylation production device of the present invention installs an acid-hydrocarbon mixture separator at the hydrocarbon phase outlet of the flash heat extraction tank, and uses the coalescence rough separation packing composed of a mixture of acidophilic fibers and surface-modified metal wires to separate hydrocarbons and acids, increasing the acid-hydrocarbon separation space in the hydrocarbon phase and improving the acid-hydrocarbon separation effect. Compared with the prior art, the beneficial effects of the present invention are: ① The acid content in the hydrocarbon phase at the hydrocarbon phase outlet is reduced, the acid level at both sides of the coalescence separation tank is reduced from about 80% to below 30%, and the acid pocket level at the bottom is 90% - 100%, and the acid storage capacity of the acid-hydrocarbon separation tank is significantly reduced. ② The start-up time of the recycled acid pump is reduced, and it is changed from continuous operation at full load to intermittent operation for 1 - 2 h on Tuesdays and Fridays, maintaining a constant acid storage capacity in the acid-hydrocarbon separation tank. ③ The sulfur content of the product is reduced, and the total sulfur content in the reaction effluents of the coalescence separation tank and the coalescence separation tank is reduced by nearly 70% respectively. ④ The acid content is reduced, reducing the load of the subsequent caustic washing process. Description of the Drawings
[0009] Figure 1 is a schematic diagram of the acid-hydrocarbon flash separation equipment for the alkylation production device of the present invention;
[0010] Figure 2 is a schematic diagram of the structure of the acid-hydrocarbon mixture separator at the hydrocarbon phase outlet;
[0011] Figure 3 Schematic diagram of the structure of the rough separation packing
[0012] Figure 4 Schematic diagram of the process flow of the alkylation unit
[0013] Figure 5 Schematic diagram of the structure of the prior art acid-hydrocarbon flash separation equipment
[0014] Wherein: 1 - flash heat extraction tank, 2 - hydrocarbon phase outlet, 3 - upper baffle, 4 - rough separation packing layer, 5 - lower baffle, 6 - liquid distributor, 7 - bubble cap distributor, 8 - coalescing flash packing, 9 - gas phase outlet, 10 - gas-liquid interface, 11 - acid-hydrocarbon mixture separator, 12 - acid-hydrocarbon interface, 13 - acid-hydrocarbon inlet, 14 - acid outlet, 15 - impact prevention baffle, 19 - hydrocarbon phase inlet, 20 - alkylation reactor, 21 - second-stage feed inlet, 22 - first-stage feed inlet, 23 - recycle hydrocarbon pipeline, 24 - recycle acid inlet, 25 - third-stage feed inlet, 26 - coalescing separation tank, 27 - reaction effluent outlet, 28 - recycle hydrocarbon outlet, 29 - product outlet, 30 - spent acid outlet Detailed implementation manners
[0015] The present invention will be described in detail below in conjunction with embodiments and the drawings. The protection scope of the present invention is not limited to the embodiments, and any modification made by those skilled in the art within the scope defined by the claims also falls within the protection scope of the present invention
[0016] The alkylation production device is as shown in Figure 4 and includes an alkylation reactor 20, a flash heat extraction tank 1 and a coalescing separation tank 26. The alkylation reactor is provided with a first-stage feed inlet 22, a second-stage feed inlet 21, a third-stage feed inlet 25, a recycle acid inlet 24 and a reaction effluent outlet 27. The coalescing separation tank 26 is provided with a hydrocarbon phase inlet 19, a recycle hydrocarbon outlet 28, a recycle hydrocarbon pipeline 23, a product outlet 29 and a spent acid outlet 30. As shown in Figure 1 , the flash heat extraction tank is provided with a liquid distributor 6, a bubble cap distributor 7, a coalescing flash packing 8, a gas phase outlet 9 and a hydrocarbon phase outlet 2. The material of the coalescing flash packing 8 is a composite winding material of modified PP non-metallic fiber and 316SS metal wire. The top of the flash heat extraction tank is provided with an acid-hydrocarbon inlet 13, and the bottom is provided with an acid outlet 14. The reaction effluent outlet 27 of the coalescing separation tank of the alkylation reactor is connected to the acid-hydrocarbon inlet 13, the acid outlet 14 is connected to the recycle acid inlet 24, the hydrocarbon phase outlet 2 is connected to the hydrocarbon phase inlet 19 provided in the coalescing separation tank, and the gas phase outlet 9 is connected to the refrigeration compressor. The recycle hydrocarbon outlet 28 of the coalescing separation tank is connected to the first-stage feed inlet 22 through the recycle hydrocarbon pipeline 23, the product outlet 29 is connected to the refining unit, and the spent acid outlet 30 is connected to the spent acid treatment unit
[0017] The reaction raw materials pretreated by the upstream unit are sent to the alkylation reactor in three separate paths, where they are mixed with the recycled acid from the flash heat extraction tank and the recycled hydrocarbon from the coalescing separator to undergo an alkylation reaction. The reaction effluent enters the flash heat extraction tank for preliminary acid-hydrocarbon separation. In the flash heat extraction tank, after the acid-hydrocarbon mixture coalesces through the acid-hydrocarbon coalescing packing, the gaseous isobutane is sent to the refrigeration compressor through the gas outlet, and after compression and cooling, it returns to the alkylation reactor. The hydrocarbon phase enters the coalescing separation tank through the hydrocarbon phase outlet. After separation in the coalescing separation tank, most of the recycled hydrocarbon returns to the alkylation reactor, and a small portion of the reaction products at the top are sent to the refining unit for refining and separation, while the spent acid at the bottom is sent to the spent acid treatment unit for incineration treatment. The acid phase returns to the alkylation reactor through the recycled hydrocarbon outlet to continue participating in the alkylation reaction.
[0018] The acid-hydrocarbon flash separation equipment for the alkylation production device of the present invention is as Figures 1 to 3 shown. An acid-hydrocarbon mixture separator 11 is provided at the hydrocarbon phase outlet in the flash heat extraction tank. The acid-hydrocarbon mixture separator is composed of an upper baffle 3, a lower baffle 5, and a rough separation packing layer 4. The lower baffle is located below the hydrocarbon phase outlet, and the upper baffle is located above the hydrocarbon phase outlet. The outer edge of the upper baffle is larger than that of the lower baffle and is arranged overlapping with the baffle. The rough separation packing layer is installed at the overlapping part of the upper baffle and the lower baffle. The rough separation packing layer 4 is supported by wire meshes up and down and is filled with coalescing rough separation packing in the middle. The coalescing rough separation packing is composed of a mixture of acidophilic fibers and surface-modified metal wires, and the coalescing rough separation packing has irregular micropores. The acidophilic fibers are a 904L + non-metallic fiber composite, the non-metallic fibers are modified PP non-metallic fibers, and the surface-modified metal wires are 316SS (molybdenum-containing stainless steel) metal wires. Considering the viscosity, flow rate, and pressure parameters of the acid-hydrocarbon phase comprehensively, the optimized installation cross-sectional area of the rough separation packing is 1.8m 2 . Considering the viscosity and pressure difference parameters of the acid-hydrocarbon phase comprehensively, the optimized installation height of the rough separation packing is preferably 700mm.
[0019] By installing the rough separation packing layer at the overlapping part of the upper baffle and the lower baffle and using the coalescing rough separation packing to separate the acid-hydrocarbon mixture by coalescence, the acid content carried by the recycled hydrocarbon is further reduced. The irregular microporous structure of the coalescing rough separation packing composed of acidophilic fibers and surface-modified metal wires provides a microporous channel with a huge internal surface for the effluent. On the one hand, it can directionally induce sulfuric acid to converge on the inner surface of the channel and spread into a liquid film, and continuously update with the flow, increasing the contact probability between sulfuric acid and gasified hydrocarbon phases. On the other hand, a large number of acid droplets polymerize into sheets on the inner surface of the channel, which is beneficial for sulfuric acid to leave the carrier and settle to the bottom of the flash tank quickly to be stratified with the hydrocarbon phase, realizing the self-gasification heat removal process of the acid-hydrocarbon mixture and the preliminary separation process of the acid and hydrocarbon.
[0020] After a sour hydrocarbon mixture separator is installed in the flash heat extraction tank, the hydrocarbon liquid level (gas-liquid interface 10) increases by 1.0 to 1.5 m, preferably 1.2 to 1.3 m. The increase in the hydrocarbon phase liquid level will effectively increase the sedimentation and separation time of acid and hydrocarbon in the flash heat extraction tank, thereby improving the acid-hydrocarbon separation effect and reducing the acid content in the hydrocarbon phase.
Claims
1. An acid-hydrocarbon flash separation device for an alkylation production unit, comprising a flash heat extraction tank (1), and the flash heat extraction tank is provided with a hydrocarbon phase outlet (2); characterized in that: An acid-hydrocarbon mixture separator (11) is provided at the hydrocarbon phase outlet. The acid-hydrocarbon mixture separator is composed of an upper baffle (3), a lower baffle (5) and a rough separation packing layer (4); the lower baffle is located below the hydrocarbon phase outlet, and the upper baffle is located above the hydrocarbon phase outlet; the outer edge of the upper baffle is larger than that of the lower baffle and is overlapped with the lower baffle, and the rough separation packing layer is installed at the overlapping part of the upper baffle and the lower baffle.
2. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 1, characterized in that: The upper and lower parts of the rough separation packing layer (4) are supported by wire meshes, and coalescing rough separation packing is installed in the middle.
3. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 2, characterized in that: The coalescing rough separation packing is composed of a mixture of acidophilic fibers and surface-modified metal wires, and the coalescing rough separation packing has irregular micropores.
4. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 3, characterized in that: The acidophilic fibers are 904L + non-metal fiber composites, the non-metal fibers are modified PP non-metal fibers, and the surface-modified metal wires are 316SS metal wires.
5. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 1, characterized in that: The area of the rough separation packing layer is 1.5 to 2 m 2 , preferably 1.8 m 2 , and the height is 600 to 800 mm, preferably 700 mm.
6. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 1, characterized in that: The alkylation production device includes an alkylation reactor (20), a flash heat extraction tank (1) and a coalescing separation tank (26). The alkylation reactor is provided with a first-stage feed inlet (22), a second-stage feed inlet (21), a third-stage feed inlet (25), a circulating acid inlet (24) and a reaction effluent outlet (27); the coalescing separation tank (26) is provided with a hydrocarbon phase inlet (19), a circulating hydrocarbon outlet (28), a product outlet (29) and a spent acid outlet (30).
7. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 6, characterized in that: The flash heat extraction tank (1) is provided with a liquid distributor (6), a bubble cap distributor (7), a coalescing flash packing (8), a gas phase outlet (9) and a hydrocarbon phase outlet (2). An acid-hydrocarbon inlet (13) is provided at the top of the flash heat extraction tank, and an acid outlet (14) is provided at the bottom; the reaction effluent outlet (27) of the coalescing separation tank is connected to the acid-hydrocarbon inlet (13), the acid outlet (14) is connected to the circulating acid inlet (24), the hydrocarbon phase outlet (2) is connected to the hydrocarbon phase inlet (19) provided on the coalescing separation tank, and the gas phase outlet (9) is connected to a refrigeration compressor; the circulating hydrocarbon outlet (28) of the coalescing separation tank is connected to the first-stage feed inlet (22) through a circulating hydrocarbon pipeline (23), the product outlet (29) is connected to a refining unit, and the spent acid outlet (30) is connected to a spent acid treatment unit.
8. The acid-hydrocarbon flash separation device for an alkylation production unit according to claim 6, characterized in that: The material of the coalescing flash packing (8) is: a composite winding material of modified PP non-metal fibers and 316SS metal wires.