An alkylation reactor

Abstract

The invention relates to an alkylation reactor, comprising: a shell; a liquid ejector, the liquid ejector being communicated with a material inlet; a rotating inner member, the rotating inner member being located in the shell, the rotating inner member comprising an upper top surface and a lower bottom surface opposite to each other and a side wall surrounding the upper top surface and the lower bottom surface, the upper top surface, the lower bottom surface and the side wall forming a first cavity, the side wall being capable of allowing liquid to flow, the material entering the first cavity falling to the bottom of the shell through the side wall to form a liquid holding area, the outlet of the liquid ejector being located in the first cavity; a liquid distributor, the liquid distributor being coaxially arranged with the rotating inner member and being located in the first cavity and below the outlet of the liquid ejector; a driving device, the driving device being connected with the liquid distributor and the bottom surface of the rotating inner member to drive the liquid distributor and the rotating inner member to rotate; and a circulation device, the lower port of the circulation device being in the liquid holding area, the upper port of the circulation device being communicated with the liquid ejector.

Description

Technical Field

[0001] The invention relates to a petroleum refining device, in particular to an alkylation reactor for producing gasoline blending components with isobutane and C3-C5 olefins. Background Art

[0002] Alkylation refers to the chemical reaction process of introducing alkyl groups. Among the various industrial applications of alkylation, the alkylation reaction between isobutane and various low-carbon olefins such as C3-C5 to produce high-octane gasoline blending components is one of the most important industrial applications. In the development of isobutane alkylation technology, sulfuric acid or hydrofluoric acid is mainly used as a catalyst. In recent years, industrial application examples of ionic liquids, solid acids, etc. as alkylation catalysts have emerged, which are said to have more advantages in environmental protection. At present, the first choice of refinery alkylation technology is still liquid acid alkylation technology with sulfuric acid as the main catalyst and a small amount of ionic liquid catalyst.

[0003] The mainstream reactor of the sulfuric acid alkylation industrial unit is a horizontal stirred kettle with a diversion setting as disclosed in US Pat. No. 3,759,318. The subsequent improvement set the mechanical stirring to an eccentric structure. Isobutane, butene and sulfuric acid catalyst flow to the diffuser under the action of the stirring blades to achieve liquid phase dispersion. A heat exchange tube bundle is set in the kettle. The reaction effluent enters the tube bundle after decompression vaporization and cooling, and exchanges heat with the material in the reaction zone. The reactor is equivalent to a combination of a stirred kettle and a tube bundle heat exchanger. This technical solution can achieve isothermal reaction, and the temperature difference in the reaction zone is not more than 1°C.

[0004] Another type of reactor in the sulfuric acid alkylation industrial unit is a static mixer or a packed reactor as disclosed in Chinese patents CN03813573.6 and CN201510124565.5. The hydrocarbon feedstock and sulfuric acid are mixed, mass transferred, and reacted in the static mixer. The effluent leaving the mixer is then vaporized and cooled, and the reaction temperature is controlled by using low-temperature circulating materials.

[0005] Research on sulfuric acid alkylation process and long-term industrial practice show that mixed mass transfer is an important factor affecting the quality of alkylation products. In the alkylation reaction, the addition of isobutane to olefins can generate target products, while the polymerization of olefins themselves generates non-target products with low octane numbers. Therefore, it is necessary to increase the mixing intensity and promote the mass transfer of isobutane, so as to avoid excessive local olefin concentration and reduce side reactions. The mixing effect of several alkylation reactors currently used in industry is not ideal. Chinese patents CN201510262784.X, CN201310503472.4, etc. disclose equipment and processes for the application of supergravity reactors or reactors with rotating packing structures in alkylation processes. In this type of reactor, gas is a continuous phase, hydrocarbon feedstock and acid catalyst are dispersed liquid phases, and have a high mixed mass transfer intensity. Chinese patents CN201611263054.2, CN101679143A, etc. disclose equipment and methods similar to shear emulsifiers containing stators and rotors to achieve alkylation reactions or dispersion processes. This technical solution also has a high mixing mass transfer intensity.

[0006] Chinese patents CN201511021470.7 and CN101679143A propose a staged reaction scheme, in which a rotating packed bed or shear emulsifier is used in the first stage to achieve full mixing and partial reaction, and the second stage enters a packed bed or a stirred tank to complete subsequent reactions at low mixing intensity, solving the residence time problem. However, the newly added packed bed or stirred tank has a low mixing intensity, which will reduce the dispersion of acid hydrocarbons to a certain extent. In addition, the cascade reaction system composed of multiple devices increases the complexity of the reaction system, increases the difficulty of control, and has high equipment costs. Chinese patent CN200820 122788.3 proposes a crystallization reactor that combines a rotating packed bed and a stirred tank. The impeller-type liquid lifter driven by the rotating shaft is used to lift the liquid phase at the bottom of the reactor to the inlet position of the rotating packing, thereby achieving batch mixing, reducing power consumption, increasing crystallization time, and improving crystallization effect. The crystallization reactor uses a liquid lifter coaxial with the rotating bed to achieve internal circulation operation of the rotating packed bed, but the liquid phase lifting efficiency driven by the rotating shaft is low, the internal circulation volume is difficult to control, and there is a conflict with the continuous feed distribution. It is suitable for intermittent operation but not suitable for alkylation process. Summary of the invention

[0007] The object of the present invention is to provide an alkylation reactor to solve the problems of poor acid-hydrocarbon mixed mass transfer, short residence time and poor selectivity of alkylation reaction in the prior art.

[0008] To achieve the above object, the present invention provides an alkylation reactor, comprising:

[0009] A shell, wherein a material inlet and a gas outlet are provided at the top of the shell, and a liquid material outlet is provided at the bottom of the shell;

[0010] at least one liquid injector, the liquid injector being in communication with the material inlet;

[0011] A rotating inner member, the rotating inner member is located in the shell, the rotating inner member includes an upper top surface and a lower bottom surface opposite to each other, and a side wall surrounding the upper top surface and the lower bottom surface, the upper top surface, the lower bottom surface and the side wall form a first cavity, the side wall can allow liquid to flow, the material entering the first cavity falls to the bottom of the shell through the side wall to form a liquid holding area, and the outlet of the liquid ejector is located in the first cavity;

[0012] a liquid distributor, the liquid distributor being coaxially arranged with the rotating inner member and being located in the first cavity and below the outlet of the liquid injector;

[0013] A driving device connected to the bottom surface of the liquid distributor and the rotating inner member to drive the liquid distributor and the rotating inner member to rotate; and

[0014] At least one circulation device, wherein the lower port of the circulation device is in the liquid holding zone, and the upper port of the circulation device is in communication with the liquid ejector.

[0015] The material entering the reactor can enter the first cavity in the rotating inner member through the liquid ejector. The material entering the first cavity falls to the bottom of the shell through the side wall to form a liquid holding area. The lower port of the circulation device is below the liquid level in the liquid holding area. Since the liquid ejector is a liquid ejector, the effect of self-circulation without external power can be achieved.

[0016] The alkylation reactor of the present invention, wherein each liquid ejector is connected to one or more circulation devices. The alkylation reactor of the present invention, wherein a gas isolation device is provided on the upper top surface of the rotating inner member around the first cavity, the gas isolation device can block the gap between the rotating inner member and the upper end surface of the shell, the gas isolation device, the upper top surface of the rotating inner member and the upper end surface of the shell form a second cavity, and the material inlet and the gas outlet are connected to the second cavity.

[0017] In the alkylation reactor of the present invention, the circulation device is located inside the shell and fixed to the shell by a fixing member.

[0018] In the alkylation reactor of the present invention, the circulation device is located outside the shell, the lower port of the circulation device is connected to the outside of the shell and communicates with the inside of the shell, and a stop valve is provided on the circulation device.

[0019] In the alkylation reactor of the present invention, the circulation device is provided with a heat exchange sleeve.

[0020] The alkylation reactor described in the present invention, wherein the lower half of the circulation device is located inside the shell, and the lower port of the circulation device is close to the bottom of the shell, the upper half of the circulation device is located outside the shell, and the upper port of the circulation device is connected to the liquid ejector outside the shell.

[0021] The alkylation reactor of the present invention is characterized in that a heat exchange device is provided at the bottom of the shell.

[0022] In the alkylation reactor of the present invention, the side wall of the rotating internal component is formed by one or more of a wire mesh, a grid and a porous material.

[0023] In the alkylation reactor of the present invention, the rotating internal component is a high shear type internal component composed of a group of stators and rotors.

[0024] The alkylation reactor described in the present invention, wherein the liquid distributor includes a liquid distribution plate located at the bottom and a vertical facade located on the liquid distribution plate, wherein the vertical facade completely encloses the liquid distribution plate, the liquid distribution plate is connected to the driving device, and a plurality of holes are provided on the vertical facade.

[0025] The beneficial effects of the present invention are:

[0026] (1) By arranging a liquid ejector and a circulation device in a reactor with a rotating internal component, the effect of internal circulation of the reactor material is achieved without an external circulation pump, and the circulation amount is controllable, thereby solving the problem of high mixing intensity but short residence time in a reactor with a rotating structure, and meeting the requirements of high mixing intensity and residence time in the minute level in the alkylation reaction. Compared with known solutions, such as a combination of a rotating packed bed in series with a stirred tank and an external pump circulation, the number of equipment is reduced, and the investment and operation complexity are reduced.

[0027] (2) The reactor is divided into an upper rotating internal component zone and a bottom liquid holding zone. The rotating internal component zone realizes high-intensity mixing and partial reaction, while the liquid holding zone completes the remaining reaction and vaporizes and cools down. The heat of the entire reactor is removed by internally circulating materials and vaporized materials, thereby realizing the coupling of mixing, reaction, and heat exchange, which is beneficial to the purpose of improving the selectivity and product quality of the alkylation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the alkylation reactor of the present invention;

[0029] Figure 2 is another structural schematic diagram of the alkylation reactor of the present invention;

[0030] Figure 3 is another structural schematic diagram of the alkylation reactor of the present invention;

[0031] Figure 4 It is a structural schematic diagram of the liquid distributor described in the present invention.

[0032] Wherein, the reference numerals are:

[0033] 1. Material entrance;

[0034] 2. Liquid injector;

[0035] 3. Shell;

[0036] 4. Rotating internal components;

[0037] 5. Circulation device;

[0038] 6. Liquid holding area;

[0039] 7. Fixing parts;

[0040] 8. Driving device;

[0041] 9. Mechanical seal;

[0042] 10. Liquid material outlet;

[0043] 11. Lower bottom surface;

[0044] 12. Liquid distributor;

[0045] 13. Upper top surface;

[0046] 14. Gas outlet;

[0047] 15. Gas isolation device;

[0048] 16. Nozzle;

[0049] 17. Small hole;

[0050] 18. Liquid distribution plate;

[0051] 19. Side wall;

[0052] 20. first cavity;

[0053] 21. Second cavity. DETAILED DESCRIPTION

[0054] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0055] An alkylation reactor comprising:

[0056] A shell 3, wherein a material inlet 1 and a gas outlet 14 are provided at the top of the shell 3, and a liquid material outlet 10 is provided at the bottom of the shell 3;

[0057] at least one liquid injector 2, the liquid injector 2 being in communication with the material inlet 1;

[0058] A rotating inner member 4, the rotating inner member 4 is located in the shell 3, the rotating inner member 4 includes an upper top surface 13 and a lower bottom surface 11 which are opposite to each other, and a side wall 19 which surrounds the upper top surface 13 and the lower bottom surface 11, the upper top surface 13, the lower bottom surface 11 and the side wall 19 form a first cavity 20, the side wall 19 can allow liquid to flow, and the material entering the first cavity 20 falls to the bottom of the shell through the side wall 19 to form a liquid holding area 6, and the outlet of the liquid ejector 2 is located in the first cavity 20;

[0059] a liquid distributor 12, the liquid distributor 12 being coaxially arranged with the rotating inner member 4 and being located in the first cavity 20 and below the outlet of the liquid injector 2;

[0060] A driving device 8 connected to the bottom surface of the liquid distributor 12 and the rotating inner member 4 to drive the liquid distributor 12 and the rotating inner member 4 to rotate; and

[0061] At least one circulation device 5 , wherein the lower port of the circulation device 5 is in the liquid holding zone 6 , and the upper port of the circulation device 5 is communicated with the liquid ejector 2 .

[0062] In the reactor, the material required for the reaction directly enters the liquid injector 2 through the material inlet 1 at the top of the shell 3, and enters the liquid distributor 12 through the liquid injector 2. The liquid distributor 12 rotates at high speed under the rotation drive of the driving device 8, so that the material enters the first cavity 20 of the rotating inner member 4. Since the side wall 19 of the rotating inner member can be used for fluid circulation, and the rotating inner member 4 also rotates at high speed under the rotation drive of the driving device 8, the material can undergo changes such as collision, shearing, film formation, and wire drawing on the side wall 19 of the rotating inner member 4, and the liquid-liquid two phases are continuously combined and dispersed to achieve a fully mixed state. At the same time, the material radially enters the shell 3 through the side wall 19 of the rotating inner member 4, and accumulates at the bottom of the shell 3 to form a liquid holding area 6 under the action of gravity. The lower port of the circulation device 5 is immersed below the liquid level of the liquid holding area 6, and the liquid at the bottom of the shell 3 is circulated to the liquid injector 2 again, so that the unreacted material reacts again.

[0063] The upper top surface 13 and the lower bottom surface 11 of the rotating inner member 4 can isolate the gas-liquid flow, so that the gas-liquid flow in the first cavity 20 can only enter the shell 3 through the side wall 19 of the rotating inner member 4 in the radial direction, and the gas flow in the shell 3 passes through the gap between the rotating inner member 4 and the shell 3, and does not transfer with the material in the rotating inner member 4. At the same time, alkylation is an exothermic reaction, and the reaction temperature is controlled by vaporization heat extraction in the rotating inner member 4, and a heat exchange coil is set at the lower part of the shell 3 to assist in heat extraction.

[0064] As a preferred embodiment of the present invention, each liquid ejector is connected to one or more circulation devices 5, and the circulation device 5 can be a circulation pipe.

[0065] Liquid ejectors are common vacuum equipment and fluid delivery equipment. They use the potential energy of the working fluid to be converted into kinetic energy after passing through a high-speed nozzle, and the local pressure is reduced, thereby pumping the ejected fluid into the mixing chamber. After the two fluids are mixed, the pressure gradually increases through the diffusion section and leaves the liquid ejector. The liquid ejector is used as a feeder, and the working medium is the alkylation reaction raw material, usually isobutane and C3-C5 olefins. According to the requirements of the alkylation reaction, the circulating isobutane from the deisobutanizer and the refrigerant of the compression condensation system are mixed with the raw material and the alkane-olefin molar ratio is adjusted to 8-12 before entering the reactor. The pressure of the above-mentioned material source is generally around 1MPa, which meets the requirements of the liquid ejector passing through the nozzle at high speed. In the conventional alkylation process, the pressure potential energy of the raw material is wasted after passing through the regulating valve. In the present invention, this energy is used to lift the reaction material. The sulfuric acid catalyst can select one or more liquid ejectors, which are mixed with the alkylation reaction raw material as the working medium, or a conventional nozzle is used for feeding, which does not affect the effect of the present invention. The conveying capacity of the liquid ejector is related to the medium. Under the conditions of the present invention, the circulating material from the circulating pipe is a mixed liquid of sulfuric acid and hydrocarbons. The pumping height of the circulating pipe should not be greater than 5m. Under further optimized conditions, the total height from the bottom of the reactor to the feeder is not greater than 3m. By selecting the specifications of the liquid ejector and setting the number of liquid ejectors and circulating pipes, the volume flow ratio of the circulating material and the raw material can be adjusted within the range of 0 to 5 to meet the requirements of the alkylation reaction process.

[0066] As a preferred embodiment of the present invention, a gas isolation device 15 is provided on the upper top surface 13 of the rotating inner component 4 around the first cavity 20, and the gas isolation device 15 can block the gap between the rotating inner component 14 and the upper end surface of the shell 3. The gas isolation device 15, the upper top surface 13 of the rotating inner component 4 and the upper end surface of the shell 3 form a second cavity 21, and the material inlet 1 and the gas outlet 14 are connected to the second cavity 21.

[0067] The gas isolation device 15 between the rotating inner member 4 and the upper end surface of the shell 3 prevents the gas in the shell 3 from passing through the gap between the upper part of the rotating inner member 4 and the upper end surface of the shell 3. The vaporized gas is only allowed to flow through the rotating inner member 4, and then leave from the gas outlet 14 after mass transfer with the feed therein. The small amount of unreacted olefins in the vaporized material can be reabsorbed by the sulfuric acid catalyst in the rotating inner member 14, thereby improving the conversion depth of the olefins. The newly entered material in the liquid ejector 2 is less vaporized because of the lower temperature after decompression and the lower heat transfer intensity on the rotating inner member 4, and the olefin loss can be ignored.

[0068] As a preferred embodiment of the present invention, the circulation device 5 is located inside the housing 3 and is fixed to the housing 3 via a fixing member 7 .

[0069] As a preferred embodiment of the present invention, the circulation device 5 is located outside the shell 3, the lower port of the circulation device 5 is connected to the outside of the shell 3 and communicates with the inside of the shell 3, and a stop valve is provided on the circulation device 5.

[0070] As a preferred embodiment of the present invention, the circulation device 5 is provided with a heat exchange sleeve.

[0071] As a preferred embodiment of the present invention, the lower half of the circulation device 5 is located inside the shell 3, and the lower port of the circulation device 5 is close to the bottom of the shell 3, the upper half of the circulation device 5 is located outside the shell 3, and the upper port of the circulation device 5 is connected to the liquid injector 2 outside the shell 3.

[0072] During the alkylation reaction, mixing intensity and residence time are important factors affecting product quality. In the reactor of the present invention, the role of the rotating internal member 4 is to control the local mixing intensity. The average mixing intensity and residence time of the reactor as a whole can be controlled by combining the internal circulation volume of the circulation device 5 and the liquid holding volume of the liquid holding area 6 at the bottom of the shell 3. Among them, the liquid holding volume of the liquid holding area 6 is equivalent to the average residence time and can be achieved by adjusting the liquid outlet flow rate, that is, conventional liquid level control. The average mixing intensity depends on the ratio of the internal circulation volume and the liquid holding volume through the circulation device under the condition that the form and speed of the rotating internal member 4 remain unchanged. The larger the ratio, the higher the average mixing intensity. In the reactor of the present invention, the circulation device 5 can be selected to be completely placed inside the shell 3, the lower end of the circulation device 5 is fixed in the liquid holding area 6 at the bottom of the shell 3, and the inlet of the circulation device 5 faces the flow direction of the material in the shell 3. In this form, the internal circulation volume depends on the flux of a single circulation pipe and the number of circulation pipes, wherein the flux of a single circulation pipe is mainly determined by the structure of the liquid ejector and the size of the circulation pipe. In a preferred reactor form of the present invention, the lower end of the circulation pipe is connected to the outside of the shell 3 in the liquid holding area 6, the outlet direction is the tangential direction in the same direction as the rotation axis, the circulation pipe is connected to the liquid ejector 2 outside the shell 3, and a stop valve is provided on the circulation pipe. In this preferred form, the flow rate of the liquid along the wall of the shell 3 in the liquid holding area 6 at the bottom of the shell 3 can compensate for the resistance loss in the circulation pipe to a certain extent, and the internal circulation amount can be controlled by the switch of the stop valve through the circulation outside the shell 3. Furthermore, a heat exchange sleeve can be optionally provided on the circulation pipe as an auxiliary facility for cooling the reaction system.

[0073] As a preferred embodiment of the present invention, a heat exchange device is provided at the inner bottom of the shell 3 .

[0074] As a preferred embodiment of the present invention, the side wall 19 of the rotating inner member 4 is formed by one or more of a wire mesh, a grid and a porous material.

[0075] As a preferred embodiment of the present invention, the rotating internal component 4 is a high shear type internal component composed of a stator and a rotor. Since there is concentrated sulfuric acid in the alkylation reaction system, strong corrosion will occur under high linear speed conditions, and the internal component is made of corrosion-resistant material.

[0076] As a preferred embodiment of the present invention, the liquid distributor 12 includes a liquid distribution plate 18 located at the bottom and a vertical facade located on the liquid distribution plate 18, the vertical facade completely encloses the liquid distribution plate 18, the liquid distribution plate 18 is connected to the driving device 8, and a plurality of small holes 17 are provided on the vertical facade.

[0077] The function of the liquid distributor 12 is to receive the material from the liquid injector 2 and, through the rotation driven by the rotating shaft, evenly transfer the material to the annular inner side surface of the rotating inner member 4. Any common liquid distributor that can achieve uniform distribution in the circumferential direction and the axial direction can be used.

[0078] The present invention is further described below in conjunction with the accompanying drawings.

[0079] See also Figure 1 In the alkylation reactor of the present invention, the alkylation raw materials from the pretreatment system, the circulating isobutane for adjusting the alkylene ratio, the circulating refrigerant and other hydrocarbon raw materials and the sulfuric acid catalyst are mixed in the pipeline outside the reactor and enter through the material inlet 1. After entering the reactor, the materials directly enter a group of liquid injectors 2 composed of liquid injectors, and the pressure is reduced through the nozzle in the liquid injector 2, and the acid hydrocarbon emulsion circulating materials from the circulation device 5 are carried, and the pressure is increased after passing through the expansion section of the liquid injector 2, and then flow to the liquid distributor 12. The liquid distributor 12 rotates under the action of the driving device 8, and the materials therein are thrown out to the annular inner side surface of the rotating inner member 4. The rotating inner member 4 rotates synchronously under the action of the driving device 8. Under the action of centrifugal force, the materials pass through the rotating inner member 4, wherein the acid hydrocarbon materials are mixed and partially reacted, and the materials flowing to the outer edge of the rotating inner member 4 are thrown out and enter the liquid holding area 6 at the bottom of the shell 3. The liquid holding area 6 is a liquid continuous phase. The lower port of a group of circulation devices 5 is located below the liquid level of the liquid holding area 6 and is connected to the shell 3 through the circulation pipe fixing member 7. Due to the suction effect of the liquid ejector, the acid hydrocarbon emulsion in the liquid holding zone 6 is partially returned to the liquid ejector 2 through the circulation device 5, and after mixing with the external feed, it passes through the rotating internal component 4 again for further mixing and reaction. When the gasification heat extraction method is adopted, the overall pressure of the reactor is controlled at the saturation pressure of the material, and part of the hydrocarbon material in the acid hydrocarbon emulsion in the liquid holding zone 6 is vaporized, and the vaporized gas leaves the reactor through the gas outlet 14 at the top of the shell 3, taking away the reaction heat, thereby realizing the temperature control of the material in the reactor, and part of the acid hydrocarbon emulsion in the liquid holding zone 6 leaves the reactor through the liquid material outlet 10 at the bottom of the shell 3, and enters the subsequent acid hydrocarbon sedimentation separation and product processing system. Among them, the liquid distributor 12 is coaxially connected to the rotating inner member 4 through the lower bottom surface 11 of the rotating inner member 4, and the upper top surface 13 of the rotating inner member 4 is used for structural stability of the rotating inner member 4 and blocking the passage of materials; the driving device 8 is connected to the driving motor outside the reactor and is connected to the shell 3 through a mechanical seal 9; the liquid level in the liquid holding zone 6 is controlled by conventional liquid level control, and the reactor pressure is adjusted by the temperature and the outlet flow rate of the gas outlet 14.

[0080] See also Figure 2, is another implementation form of the alkylation reactor described in the present invention, the shell 3 is set to two sections with different diameters at the upper and lower ends, the lower end of the circulation device 5 is connected to the shell 3 in the lower liquid holding area 6, passes through the shell 3 in the diameter-changing area, and is connected to the liquid injector 2 outside the shell 3. The alkylation feedstock enters the reactor through the material inlet 1 and drives the circulating material as a working medium. The sulfuric acid catalyst is fed in an independent conventional nozzle 16 and contacts the hydrocarbon feedstock above the rotating internal member 4 after entering the reactor. A gas isolation device 15 is set between the upper top surface 13 of the rotating internal member 4 and the upper end of the shell 3, and a labyrinth seal structure can be selected to block the flow of gas. The bottom surface of the center of the lower section of the shell 3 is raised in height, and the mechanical seal 9 is not immersed below the liquid level in the liquid holding area 6, which is conducive to the long-term operation of the sealing structure. In this preferred form, the gas generated by vaporization must pass through the rotating internal member 4 in reverse flow to leave the reactor, and a stop valve can be set on the part of the circulation device 5 outside the shell 3 to adjust the circulation volume.

[0081] See also Figure 3 , is a schematic diagram of an alkylation reactor in which the circulation device 5 described in the present application is outside the shell 3. The lower end of the circulation device 5 is connected to the shell 3 at a tangent angle, and the direction is consistent with the rotation direction of the rotating shaft. According to the number of circulation devices 5 and the number of liquid injectors 2, one liquid injector 2 can be selected to be connected to multiple circulation devices 5, or other combinations can be set according to the requirements of the circulation amount.

[0082] See also Figure 4 , which is a specific implementation of the liquid distributor described in this application. The bottom of the liquid distributor 12 is a circular liquid distribution plate 18, the center of the liquid distribution plate 18 is connected to the driving device 8, and a circular ring with multiple small holes 17 is vertically arranged on the circumference of the liquid distribution plate 18, and the small holes 17 are for liquid to pass through. Among them, the small holes 17 can be selected from circular holes, slits or other common channel types, and are evenly arranged in the circumference of the circular ring. Different axial heights can select different distribution forms of opening ratios to meet the requirements of uniform axial distribution.

[0083] Reference Example 1

[0084] The alkylation raw material is prepared by mixing isobutane (99%) and 1-butene (99%) standard gas, the mixed gas is 89.1mol% of isobutane, 9.0mol% of 1-butene, and the others are less than 1mol%, and the molar ratio of alkane to alkene is 10. Sulfuric acid is a 95w% analytical pure reagent. The test is carried out using a stator-rotor reactor with a fresh feed rate of 2L / h, the rotating speed of the internal component is 900rpm, the maximum linear speed of the outer edge is 30m / s, and the nitrogen punching is used to maintain the system pressure at 0.5MPa(g). The reactor is equipped with a built-in tube bundle for heat exchange, and the system temperature is controlled at 3°C. The flow rates of the alkylation raw material and sulfuric acid are 1L / h respectively. After heat exchange to 3°C, they enter the internal component area through a nozzle, where the residence time is less than 1s. The material leaving the reactor enters the settler for acid hydrocarbon separation, and the residence time is about 0.5h. The separated sulfuric acid is circulated to the reactor inlet, mixed with the freshly fed alkylation raw material and continued to react, and the separated hydrocarbons are sampled and analyzed. The hydrocarbon composition was analyzed by gas chromatography, and the alkylate product after removing C4 and lighter components was calculated by the linear addition method of alkane octane number, and the product RON was 95.7.

[0085] Reference Example 2

[0086] The alkylation raw material and reactor are the same as those in reference ratio 1. The reactor is connected to a stirred tank. Part of the material in the tank is transported to the reactor circulating material inlet through a circulating pump and enters the reactor together with the fresh raw material to continue the reaction. Part of the material goes to the subsequent settler for acid hydrocarbon separation, that is, the reactor, stirred tank, and pump circulation constitute an external circulation system. The alkylation raw material, sulfuric acid, reactor, and stirred tank are all controlled at 3°C ​​and 0.5MPa(g) by a tube bundle or jacket. The residence time of the material in the reactor is less than 1s, and the residence time in the stirred tank is 15min. The mass flow ratio of the acid hydrocarbon emulsion circulating to the reactor inlet to the fresh feed raw material and catalyst is 5. The material leaving the reactor enters the settler for acid hydrocarbon separation. The separation conditions are the same as those in reference ratio 1. Test results: The RON of the alkylation oil product is 98.5.

[0087] Example 1

[0088] The alkylation raw materials are the same as those in reference ratio 1, and the reactor adopts Figure 1 The type shown, the structure and speed of the rotating internal components are the same as those in reference 1, and a single circulation pipe is set to connect the liquid holding area and the feeder. The output pressure of the raw material pump is 0.9MPa(g), and the reaction temperature and pressure are the same as those in reference 1. Test results: The flow rate of the acid hydrocarbon emulsion in the circulation pipe is measured to be 4.5 times that of the fresh acid hydrocarbon feed, the total average residence time in the reactor is 5min, and the research octane number of the alkylation oil is 98.6.

[0089] The above examples show that when conventional stator-rotor or rotating packed bed reactors are used alone, the residence time in the fully mixed state is short, and when circulating materials are not used, the alkane-olefin ratio in the reaction zone is relatively low, and the product quality is poor. The use of a stirred tank can increase the residence time and can be used as a buffer tank for the circulation of the acid hydrocarbon emulsion, which is beneficial to improving the product quality. However, the mixing degree of the stirred tank is poor, and there is a certain degree of two-phase separation in the acid hydrocarbon emulsion after passing through the conveying pipeline and the stirred tank, which is not conducive to the alkylation reaction process. The use of internal circulation in the reactor effectively improves the mixing process and reduces the acid hydrocarbon separation phenomenon during the transportation process. Under similar conditions, the product quality is equivalent to or slightly better than the external circulation scheme. It can be foreseen that after the reaction system is scaled up, the equipment investment and operation will be significantly better than the external circulation system.

[0090] Example 2

[0091] The alkylation feedstock and reactor were the same as those in Example 1, without nitrogen ramming and tube bundle heat exchange. The temperature of the reaction system was controlled by vaporization to be 3°C, the pressure was the saturation pressure, about 0.06 MPa (g), the flow rate of the acid hydrocarbon emulsion in the circulation tube was measured to be 2.2 times that of the fresh acid hydrocarbon feed, the total average residence time in the reactor was 5 minutes, and the research octane number of the alkylation oil was 97.2. Due to the use of the vaporization heat extraction scheme, the main vaporized component is isobutane, and the circulation volume of a single circulation tube under saturation pressure is reduced, so the overall alkane-olefin ratio of the reaction zone is reduced, which affects the product quality to a certain extent.

[0092] Example 3

[0093] The alkylation feedstock is a mixed hydrocarbon of the industrial alkylation unit feedstock and intermediate streams, and the composition is shown in Table 1.

[0094] Table 1 Alkylation feedstock (V%)

[0095] Components <![CDATA[C3]]> <![CDATA[iC4]]> <![CDATA[nC4]]> <![CDATA[t-2-C4 ＝ ]]> <![CDATA[1-C4 ＝ ]]> <![CDATA[iC4 ＝ ]]> <![CDATA[c-2-C4 ＝ ]]> <![CDATA[iC5]]> <![CDATA[nC 5+ ]]> content 4.1 78.3 8.9 4.1 2.2 0.0 2.1 0.1 0.14

[0096] Reactor used Figure 2 In the preferred form shown, the circulation pipe is connected by Figure 3 The tangent connection shown is a feeder connected to three circulation pipes. The rotating internal component is a metal mesh filler with a rotation speed of 600rpm. The liquid distributor adopts Figure 4 In the form shown, sulfuric acid feed is sprayed directly onto the inner side of the wire mesh packing using a conventional nozzle. The raw material from the industrial device has a pressure of 1.1MPa(g), a flow rate of 2t / h, and a temperature of 3°C. It enters the liquid injector through the feed port. The circulating sulfuric acid has a flow rate of 3.7t / h and a temperature of 3.5°C and enters the reactor through the sulfuric acid nozzle. The gas flow after vaporization is adjusted, and the system temperature is controlled at 3°C ​​and the pressure is 0.06MPa(g). The lifting height of the circulation pipe is 1.2m, the total circulation flow is 18t / h, and the total liquid holding capacity in the liquid holding zone is about 0.8m 3The power consumption of the rotating motor is 16.8kW. After the acid hydrocarbon emulsion leaving the reactor is separated by sedimentation, the acid is recycled back to the reactor, and the hydrocarbon is obtained by passing through the fractionation tower to obtain alkylate oil. According to chromatographic analysis and calculation, the research octane number of the product alkylate oil is 97.8.

[0097] Example 4

[0098] The alkylation feedstock, reactor and process conditions were the same as those in Example 3. The stop valve of one of the circulation pipes was closed, the circulation rate was about 13 t / h, the power consumption of the rotary motor was 13.3 kW, and the research octane number of the product alkylate oil was 97.6.

[0099] Example 5

[0100] The alkylation feedstock, reactor and process conditions were the same as those in Example 3, except that the rotating internal component was replaced by an annular packing composed of grid plates. The circulation flow rate was 18 t / h, the power consumption of the rotating motor was 17.1 kW, and the research octane number of the product alkylate oil was 97.7.

[0101] Example 6

[0102] The alkylation feedstock, reactor and process conditions were the same as those in Example 3. The sulfuric acid catalyst was premixed with the alkylation feedstock outside the reactor through a pipeline mixer and then entered the reactor together from the feeder. The outlet pressure of the sulfuric acid circulation pump increased from 0.3 MPa(g) to 1.1 MPa(g), the internal circulation flow rate was 21 t / h, the power consumption of the rotary motor was 18.5 kW, and the research octane number of the product alkylate oil was 98.2.

[0103] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. An alkylation reactor, characterized in that: include: A shell, wherein a material inlet and a gas outlet are provided at the top of the shell, and a liquid material outlet is provided at the bottom of the shell; at least one liquid injector, the liquid injector being in communication with the material inlet; A rotating inner member, the rotating inner member is located in the shell, the rotating inner member includes an upper top surface and a lower bottom surface opposite to each other, and a side wall surrounding the upper top surface and the lower bottom surface, the upper top surface, the lower bottom surface and the side wall form a first cavity, the side wall can allow liquid to flow, the material entering the first cavity falls to the bottom of the shell through the side wall to form a liquid holding area, and the outlet of the liquid ejector is located in the first cavity; a liquid distributor, the liquid distributor being coaxially arranged with the rotating inner member and being located in the first cavity and below the outlet of the liquid injector; A driving device connected to the bottom surface of the liquid distributor and the rotating internal component to drive the liquid distributor and the rotating internal component to rotate; as well as At least one circulation device, wherein the lower port of the circulation device is in the liquid holding zone, and the upper port of the circulation device is in communication with the liquid ejector.

2. The alkylation reactor according to claim 1, characterized in that: Each liquid ejector is connected to one or more circulation devices.

3. The alkylation reactor according to claim 1, characterized in that: A gas isolation device is provided on the upper top surface of the rotating inner component around the first cavity, and the gas isolation device can block the gap between the rotating inner component and the upper end surface of the shell. The gas isolation device, the upper top surface of the rotating inner component and the upper end surface of the shell form a second cavity, and the material inlet and the gas outlet are connected to the second cavity.

4. The alkylation reactor according to claim 1, characterized in that: The circulation device is located in the shell and is fixed to the shell through a fixing piece.

5. The alkylation reactor according to claim 1, characterized in that: The circulation device is located outside the shell, the lower port of the circulation device is connected to the outside of the shell and communicates with the inside of the shell, and a stop valve is arranged on the circulation device.

6. The alkylation reactor according to claim 5, characterized in that: The circulation device is provided with a heat exchange sleeve.

7. The alkylation reactor according to claim 1, characterized in that: The lower half of the circulation device is located inside the shell, and the lower port of the circulation device is close to the bottom of the shell. The upper half of the circulation device is located outside the shell, and the upper port of the circulation device is connected to the liquid injector outside the shell.

8. The alkylation reactor according to claim 1, characterized in that: A heat exchange device is arranged at the inner bottom of the shell.

9. The alkylation reactor according to claim 1, characterized in that: The side wall of the rotating inner member is formed by one or more of a wire mesh, a grid and a porous material.

10. The alkylation reactor according to claim 1, characterized in that: The rotating internal component is a high shear type internal component composed of a group of stators and rotors.

11. The alkylation reactor according to claim 1, characterized in that: The liquid distributor comprises a liquid distribution plate at the bottom and a vertical facade on the liquid distribution plate. The vertical facade completely encloses the liquid distribution plate. The liquid distribution plate is connected to the driving device. A plurality of holes are arranged on the vertical facade.

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