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RU-2861354-C2 - METHOD AND PRODUCTION SYSTEM FOR PRODUCING SUCCINIC ANHYDRIDE BY HYDROGENATION OF MALEIC ANHYDRIDE

RU2861354C2RU 2861354 C2RU2861354 C2RU 2861354C2RU-2861354-C2

Abstract

FIELD: chemical industry. SUBSTANCE: group of inventions relates to a method for producing succinic anhydride by hydrogenation of maleic anhydride and to a production system for its implementation. Method comprises mixing a solution of maleic anhydride with hydrogen to obtain a first liquid-phase feed material with hydrogen dispersed in the liquid phase, wherein the ratio of the volumetric flow rate of hydrogen, expressed in Nm 3 /h, to the volumetric flow rate of the maleic anhydride solution, expressed in m 3 /h, is in the range from 5:1 to 50:1. Next, a first hydrogenation reaction is carried out by passing the first liquid-phase feed material from bottom to top through one or more fixed beds of a first maleic anhydride hydrogenation catalyst located in a first reaction unit, to obtain a first reaction effluent containing succinic anhydride, wherein the first hydrogenation reaction is carried out at a reaction temperature of 40-200°C, a reaction pressure of 0.5-10.0 MPa and an hourly liquid space velocity of 5.0-20.0 h -1 . Then, the first reaction effluent is mixed with additional hydrogen to obtain a second liquid-phase feed material with hydrogen dispersed in the liquid phase, wherein the ratio of the volumetric flow rate of the additional hydrogen, expressed in Nm 3 /h, to the volumetric flow rate of the maleic anhydride solution used in the step of mixing the maleic anhydride solution with hydrogen, expressed in m 3 /h, is in the range from 1:1 to 20:1. And a second hydrogenation reaction is carried out by passing the second liquid-phase feed material from bottom to top through one or more fixed beds of a second maleic anhydride hydrogenation catalyst located in a second reaction unit, to obtain a second reaction effluent containing succinic anhydride, wherein the second hydrogenation reaction is carried out at a reaction temperature of 40-150°C, a reaction pressure of 0.5-10.0 MPa and an hourly liquid space velocity of 0.1-4.0 h -1 . EFFECT: high conversion rate and selectivity. 13 cl, 1 dwg, 6 tbl, 8 ex

Inventors

  • QIAO, Kai
  • YANG, Xiuna
  • ZHOU, FENG
  • LI, Lanpeng
  • RUAN, Zonglin

Dates

Publication Date
20260505
Application Date
20221025
Priority Date
20211028

Claims (20)

  1. 1. A method for producing succinic anhydride by hydrogenating maleic anhydride, comprising the following stages:
  2. 1) mixing a solution of maleic anhydride with hydrogen to obtain a first liquid phase feedstock with hydrogen dispersed in the liquid phase, wherein the ratio of the volumetric flow rate of hydrogen, expressed in Nm3 /h, to the volumetric flow rate of the maleic anhydride solution, expressed in m3 /h, is in the range of 5:1 to 50:1;
  3. 2) carrying out a first hydrogenation reaction by passing a first liquid-phase starting material from the bottom up through one or more fixed beds of a first maleic anhydride hydrogenation catalyst located in a first reaction unit, under the conditions of the first hydrogenation reaction, to obtain a first reaction effluent containing succinic anhydride, wherein the first hydrogenation reaction is carried out under the following conditions: the reaction temperature is 40-200°C, the reaction pressure is 0.5-10.0 MPa and the liquid hourly space velocity is 5.0-20.0 h -1 ;
  4. 3) mixing the first reaction effluent from the first reaction unit with additional hydrogen to produce a second liquid phase feedstock with hydrogen dispersed in the liquid phase, wherein the ratio of the volumetric flow rate of the additional hydrogen, expressed in Nm3 /h, to the volumetric flow rate of the maleic anhydride solution used in step (1), expressed in m3 /h, is in the range of from 1:1 to 20:1; and
  5. 4) carrying out a second hydrogenation reaction by passing a second liquid-phase feedstock from the bottom up through one or more fixed beds of a second maleic anhydride hydrogenation catalyst located in a second reaction unit, under the conditions of the second hydrogenation reaction, to obtain a second reaction effluent containing succinic anhydride, wherein the second hydrogenation reaction is carried out under the following conditions: the reaction temperature is 40-150°C, the reaction pressure is 0.5-10.0 MPa and the liquid hourly space velocity is 0.1-4.0 h -1 .
  6. 2. The method of claim 1, wherein the first reaction unit comprises one or more fixed bed, upflow reactors in which one or more fixed beds of the first maleic anhydride hydrogenation catalyst are located, wherein the height to diameter ratio of each fixed bed, upflow reactor is independently in the range of 3-20, preferably in the range of 4-15.
  7. 3. The method of claim 2, wherein the second reaction unit comprises one or more fixed-bed, riser reactors in which one or more fixed beds of the second maleic anhydride hydrogenation catalyst are located, wherein the height-to-diameter ratio of each fixed-bed, riser reactor in the second reaction unit is less than that of the fixed-bed, riser reactor in the first reaction unit and is in the range of 0.1-2.5, preferably in the range of 0.5-2.0.
  8. 4. The method according to any one of the preceding claims, in which the first and second maleic anhydride hydrogenation catalysts in each case independently comprise a nickel-based catalyst support, wherein the nickel -based catalyst support is selected from SiO2 , Al2O3 , SiO2 - Al2O3 , TiO2 , activated carbon, molecular sieves or combinations thereof; preferably, the nickel-based catalyst support contains 5-40% nickel calculated as nickel oxide and 60-95% of the support relative to the weight of the catalyst.
  9. 5. The method according to any one of the preceding claims, wherein the maleic anhydride solution used in step (1) has a maleic anhydride content of 0.03-0.3 g/ml, preferably 0.05-0.2 g/ml;
  10. Preferably, benzene, toluene, xylene, acetone, tetrahydrofuran, γ-butyrolactone, methylacetone, cyclohexanone, ethyl acetate, diethyl succinate, ethylene glycol monomethyl ether, or combinations thereof are selected as the solvent used in the maleic anhydride solution.
  11. 6. The process according to any one of the preceding claims, wherein the degree of conversion of maleic anhydride in the first hydrogenation reaction in step (2) is controlled within the range of 50-95%, preferably 55-85%.
  12. 7. The method according to any of the preceding claims, further comprising the following step:
  13. 5) fractionating the second reaction effluent from the second reaction unit to obtain a product comprising succinic anhydride; or, alternatively,
  14. 5') directing the second reaction effluent from the second reaction unit to gas-liquid separation to obtain a liquid-phase stream containing succinic anhydride, fractionating one portion of the obtained liquid-phase stream to obtain a product representing succinic anhydride, and returning the remaining portion of the obtained liquid-phase stream back to stage (2) and/or stage (4) for subsequent reaction.
  15. 8. The method according to paragraph 7, wherein:
  16. in step (5') the ratio of the mass flow rate of the liquid phase stream returned back to step (2) to the mass flow rate of the maleic anhydride solution used in step (1) is in the range of 1:20 to 9:10, preferably in the range of 1:5 to 3:5; and
  17. in step (5') the ratio of the mass flow rate of the liquid phase stream returned back to step (4) and the mass flow rate of the maleic anhydride solution used in step (1) is in the range of 0:1 to 4:5, preferably in the range of 0:1 to 3:10;
  18. preferably, the mass flow rate of the liquid phase stream returned back to step (2) is greater than the mass flow rate of the liquid phase stream returned back to step (4).
  19. 9. A method according to any of the preceding claims, wherein:
  20. in step (1), the ratio of the volumetric flow rate of hydrogen, expressed in Nm3 /h, to the volumetric flow rate of the maleic anhydride solution, expressed in m3 /h, is in the range from 10:1 to 30:1; and/or

Description

Field of technology to which the present invention relates The present invention relates to the field of succinic anhydride production technology and, in particular, relates to a method and production system for producing succinic anhydride by hydrogenating maleic anhydride. Prior art of the present invention Currently, succinic anhydride production methods mainly include succinic acid dehydration, biological fermentation, and maleic anhydride catalytic hydrogenation. Among these, the maleic anhydride catalytic hydrogenation method (also known as maleic anhydride) is the succinic anhydride production method with the highest conversion and yield, making it most suitable for large-scale industrial application. However, the hydrogenation of maleic anhydride to produce succinic anhydride is a highly exothermic reaction (ΔH = 128 kJ/mol). The reaction heat cannot be removed in a timely manner when traditional trickle-bed hydrogenation is used, resulting in inability to control the reaction temperature, localized hot spots in one or more catalyst beds, serious side reactions, and similar processes. It becomes impossible to regulate the safety, degree of conversion and selectivity of the reaction process. Document CN103570650A discloses a method for the continuous production of succinic anhydride and the co-production of succinic acid by hydrogenating maleic anhydride. This method utilizes a two-stage hydrogenation reactor system, in which the first-stage hydrogenation reactor is a fixed-bed hydrogen reactor with reaction liquid entering from the bottom and exiting from the top. The second-stage hydrogenation reactor is a trickle-bed hydrogen reactor with reaction liquid entering from the top and exiting from the bottom. External circulation is used to remove reaction heat to regulate the average operating temperature of the entire reactor and to ensure a balanced temperature within the reactor. In this method, a flow regime with hydrogen and reaction liquid moving in the same upward direction is employed in the first-stage reactor. Due to the significant heat release during the maleic anhydride hydrogenation reaction, traditional technologies cannot ensure uniform mixing and distribution of materials, nor can they ensure a uniform reaction progression or resolve localized hot spots. In the second-stage reactor, which is a trickle-bed reactor, the co-directional downflow is even less capable of ensuring timely heat removal and resolving localized hot spots. Document CN105801536B proposes a method for producing succinic anhydride via the liquid-phase selective hydrogenation of maleic anhydride. The method utilizes a two-stage, low-temperature, low-pressure reaction process with two reactors, a first-stage reactor and a second-stage reactor, respectively, used in series. Maleic anhydride, solvent, and hydrogen are fed into the first-stage reactor for partial catalytic selective hydrogenation. After the reaction, the residual maleic anhydride, the resulting succinic anhydride mixed solution, and the solvent are fed into the second-stage reactor for complete catalytic selective hydrogenation. The product from the second-stage reactor is then sent for gas-liquid separation and distillation to obtain succinic anhydride. This method utilizes liquid-phase hydrogenation with hydrogen and a reaction liquid in two-stage reaction systems. Due to the large amount of heat released during the maleic anhydride hydrogenation reaction, it is difficult to address the concentrated heat release and localized hot spots during the early stages of the reaction. It is also difficult to prevent deep hydrogenation and reduced selectivity caused by backmixing and uneven distribution of materials during the later stages of the reaction. Brief summary of the present invention In order to eliminate the disadvantages of the prior art, according to the present invention, a method and a production system for producing succinic anhydride by hydrogenating maleic anhydride are proposed, and it becomes possible to effectively solve the problems of concentrated heat release and the ease of forming local hot spots during the hydrogenation of maleic anhydride and maintain a relatively high degree of conversion and selectivity in the process of hydrogenating maleic anhydride. In order to achieve the above objectives, according to one aspect of the present invention, a method for producing succinic anhydride by hydrogenating maleic anhydride is provided, comprising the following steps: 1) mixing a solution of maleic anhydride with hydrogen to obtain a first liquid phase feedstock with hydrogen dispersed in the liquid phase, wherein the ratio of the volumetric flow rate of hydrogen, expressed in Nm3 /h, to the volumetric flow rate of the maleic anhydride solution, expressed in m3 /h, is in the range of 5:1 to 50:1; 2) carrying out a first hydrogenation reaction by passing a first liquid-phase feedstock from the bottom up through one or more fixed beds of a