Continuous apparatus and method for the co-production of fumaric acid and malic acid

Abstract

The application discloses a kind of continuous equipment and preparation method for coproduction fumaric acid and malic acid, the continuous equipment includes raw material tank, feed pump, layer type multistage overflow reaction tower, material pressure regulating valve, material tank, separator, crystallizer, washing crystallizer group, dryer and drying tower group, the preparation method for coproduction fumaric acid and malic acid is that raw material succinic anhydride, warm water and ionic liquid catalyst are 50-30:20:1-2 according to mass ratio in above-mentioned continuous equipment are processed after being fed, reaction, separation, purification, crystallization, drying, and high-purity fumaric acid and malic acid are obtained.The ionic liquid catalyst is used in succinic anhydride coproduction fumaric acid and malic acid reaction for the first time in the application, and continuous production equipment is designed, need not evaporation concentration and can be directly cooled crystallization, can greatly shorten reaction time, reduce energy consumption and production cost, and solve the technical problems, such as the difficulty of continuous production, preparation process complexity, catalyst recycling difficulty and the like in existing preparation method.

Description

Technical Field

[0001] This invention relates to equipment and methods for producing fumaric acid and malic acid, specifically to a continuous equipment and method for co-producing fumaric acid and malic acid. Background Technology

[0002] In the process of producing fumaric acid from maleic anhydride, the common catalyst is the organic compound thiourea. A certain amount of sulfuric acid is added during the reaction to increase the reaction activity, which leads to severe equipment corrosion, yellowing of the product, and difficulty in recycling and processing. In the process of preparing malic acid by hydration of fumaric acid, multiple evaporation and concentration are usually required to remove excess water solvent, which is a complex process with high energy consumption.

[0003] Chinese Patent Publication No. CN1202478A discloses a combined production process for fumaric acid and malic acid. The process steps are as follows: A decolorized maleic acid solution with a mass concentration of 20-50% is reacted at 150-220℃ and 0.2-1.0 MPa, cooled to room temperature, centrifuged and filtered, fumaric acid crystals are collected, washed with water, and dried to obtain the fumaric acid product. The mother liquor is passed through an ion exchange column, heated and concentrated, cooled to room temperature, crystallized, centrifuged and filtered, malic acid crystals are collected, and then dried to obtain the malic acid product. Advantages include: no catalyst reaction, fumaric acid yield of 40-56%, malic acid yield of 20-50%, and reuse of the secondary mother liquor, which can reduce production costs. However, this process suffers from problems such as long reaction time, low production efficiency, intermittent feeding and discharging, and inability to achieve continuous production.

[0004] Chinese Patent Publication No. CN103121936B discloses a continuous malic acid synthesis apparatus and its preparation method, comprising a titanium reactor assembly. One end of the titanium reactor assembly is connected to a feed pump, and the other end is connected to a flash reactor. A steam recovery unit is connected externally to the flash reactor. The titanium reactor assembly is composed of multiple titanium reactors connected in series with progressively decreasing heights. This invention connects the individual reactors in a batch production process through pipelines and employs a DCS control system to achieve continuous operation of processes such as feeding, reaction, cooling, and discharging. However, the material in this synthesis apparatus relies on mechanical stirring, resulting in high energy consumption, and the mechanical seal is prone to leakage, affecting the stable operation of the continuous process. Summary of the Invention

[0005] Objective of the Invention: To address the technical problems existing in the prior art, this invention aims to provide a device for the co-production of fumaric acid and malic acid that enables continuous production, has low energy consumption, and high production efficiency. This invention also provides a method for preparing the co-production of fumaric acid and malic acid.

[0006] Technical solution: The continuous production equipment for co-production of fumaric acid and malic acid described in this invention includes a raw material tank, a multi-stage overflow reaction tower, a material tank, a separator, a crystallizer, a washing crystallizer group, a dryer, and a drying tower group;

[0007] The layered multi-stage overflow reaction tower is made of titanium and includes a material inlet at the top, an internal overflow tray, and a material outlet at the bottom. The material inlet is connected to the raw material tank via a feed pump and a pipeline, and the material outlet is connected to the material tank via a discharge pressure stabilizing valve and a pipeline.

[0008] The separator is connected to the raw material tank, washing crystallizer, and crystallizer group via pipelines;

[0009] The crystallizer group consists of two crystallizers connected in series, and is then connected to the dryer and drying tower group through pipelines;

[0010] The drying tower group consists of two drying towers connected in parallel, one in use and one on standby. The drying towers are equipped with molecular sieves and are connected to the raw material tank.

[0011] Both the raw material tank and the material tank are equipped with a stirring device, and the overflow tray is composed of a tray and a plate.

[0012] Furthermore, the multi-stage overflow reaction tower is equipped with an external heat-insulating and heating jacket.

[0013] Furthermore, the number of overflow trays is 6-10.

[0014] Furthermore, to achieve solid-liquid separation of the product slurry, various types of separators can be selected, such as rotary centrifuges, filter presses, and vacuum filters.

[0015] Furthermore, the crystallizer assembly is used for cooling crystallization, and various types of crystallizers can be selected, such as indirect heat exchange kettle-type cooling crystallizers and OSLO fluidized bed cooling crystallizers.

[0016] The preparation method for co-producing fumaric acid and malic acid according to the present invention comprises the following steps:

[0017] (a) Add maleic anhydride, warm water, and ionic liquid catalyst to a raw material tank in proportion, and stir and mix at 60-100℃ to form a mixture. The mixture is then fed into the multi-stage overflow reactor through the material inlet at the top of the reactor using a feed pump. The temperature at the top of the reactor is set at 160-200℃, the pressure inside the reactor is maintained at 0.5-1MPa, and the liquid flow rate is 3-15m / s. 3 / h, the mixture passes through each overflow tray in sequence, with a residence time of 2-10 minutes on each tray. As the mixture overflows from the upper tray to the lower tray, the temperature continuously increases by 2-6℃ on each tray, and the pressure continuously decreases by 5-10 kPa on each tray. The product mixture obtained after the reaction is discharged from the material outlet at the bottom of the multi-stage overflow reaction tower and enters the material tank through the discharge pressure stabilizing valve.

[0018] (b) The product mixture is flash-evaporated in the material tank to form a slurry. The filter residue obtained by solid-liquid separation of the slurry is crude fumaric acid, and the filtrate is malic acid solution.

[0019] (c) The filtrate is subjected to two-step cooling crystallization in the crystallizer group, and then the malic acid product is obtained by the dryer. The remaining liquid is a mixture of catalyst and water, which is dehydrated in the drying tower group to obtain the catalyst, which is then put into the raw material tank for reuse.

[0020] (d) The filter residue is treated by washing, crystallizing and drying to obtain fumaric acid product.

[0021] Furthermore, in step (a), the temperature of the warm water is 60-80°C.

[0022] Furthermore, in step (a), the ionic liquid catalyst is an acidic pyridine-based ionic liquid catalyst, selected from one of [HSO3-bpy][HSO4], [HSO3-bpy][CH3COOH], [HSO3-bpy][BF4], and [HSO3-bpy]Cl. Ionic liquids, as catalysts, have the dual functions of solvent and catalyst, which can shorten the reaction time, reduce the amount of water solvent used, eliminate the need for traditional multiple evaporation and concentration, and overcome the defects of commonly used acidic catalysts, such as corrosion of equipment and impact on product color.

[0023] Furthermore, in step (a), the mass ratio of maleic anhydride, warm water, and ionic liquid catalyst is 50-30:20:1-2.

[0024] Furthermore, in step (a), the outlet pressure of the discharge pressure regulating valve is set to 0.1-0.12 MPa.

[0025] Furthermore, in step (b), the product mixture is flash-evaporated in the material tank to form a slurry because the fumaric acid contained in the product mixture has extremely low solubility. After flash evaporation, it will precipitate out instantly, making the product mixture appear as a slurry.

[0026] Furthermore, in step (c), the two-step cooling crystallization is carried out in two crystallizers. In the first crystallizer, the temperature is reduced from 59-61℃ to 54-56℃ at a cooling rate of 0.8-1.2℃ / h, and in the second crystallizer, the temperature is reduced from 54-56℃ to 44-46℃ at a cooling rate of 3.5-4.5℃ / h. In the first cooling step, the cooling rate is controlled to ensure that the malic acid crystals generated are uniform in size and have a smooth surface, making it difficult to form needle-like crystals. In the second cooling step, under the induction of the already generated malic acid crystals, the cooling rate is accelerated, which can maintain the malic acid crystal form and increase the crystallization rate, reduce crystallization time, and reduce energy consumption.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0028] (1) It can be continuously produced. Through the self-designed continuous equipment, the process is simple, the equipment is streamlined, the investment in the device is small, and the area occupied is small. The layered multi-stage overflow reaction tower adopted has no mechanical stirring, which reduces back mixing. It relies on gravity to realize the flow of materials in the tower. The structure is simple, the operation is flexible, no external power is required, and the production cost is saved.

[0029] (2) Low energy consumption and high production efficiency. By using a separate multi-stage overflow reaction tower, the reaction time is shortened from the original 4-10h to 0.2-1h. At the same time, ionic liquid is used as a catalyst for the co-production of fumaric acid and malic acid. The malic acid solution obtained from the reaction does not need to be evaporated and concentrated multiple times. Only two-step cooling crystallization is required, which shortens the crystallization time from the original 15-20h to 4-8h. This greatly shortens the reaction time, reduces energy consumption, improves production efficiency, and reduces production costs.

[0030] (3) The conversion rate of maleic anhydride in the raw material of the present invention is over 98%, and the purity of fumaric acid and malic acid obtained is over 99%. The ionic liquid catalyst is easy to recycle and reuse, is environmentally friendly, and does not damage the equipment. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a continuous production line for co-producing fumaric acid and malic acid, as described in Embodiment 1 of the present invention. Detailed Implementation

[0032] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0033] As attached Figure 1 As shown in the figure: 1. Raw material tank; 2. Feed pump; 3. Layered multi-stage overflow reaction tower; 4. Overflow tray; 5. Discharge pressure regulating valve; 6. Material tank; 7. Separator; 8. Crystallizer; 9. Washing crystallizer; 10. Dryer; 11. Drying tower group.

[0034] The schematic diagram of the continuous production equipment for co-producing fumaric acid and malic acid is attached. Figure 1 3, a multi-stage overflow reactor with a volume of 3m³ 3 The tray is 3m high and includes 6 overflow trays 4. It is equipped with an external heat insulation and heating jacket. The tray length of the overflow tray 4 is 0.6m and the tray height is 0.3m. Those skilled in the art can further select the number of overflow trays according to specific preparation requirements.

[0035] Example 1: The preparation method for co-producing fumaric acid and malic acid comprises the following steps:

[0036] (a) 100 kg of maleic anhydride, 40 kg of 60°C warm water, and 2 kg of ionic liquid catalyst [HSO3-bpy][HSO4] are added to raw material tank 1 and stirred at 60°C to form a mixture. The mixture is then pumped into the multi-stage overflow reactor 3 through the material inlet at the top of the multi-stage overflow reactor 3. The temperature at the top of the reactor is set to 160°C, the pressure inside the reactor is maintained at 0.5 MPa, and the liquid flow rate is 15 m / s. 3 / h, the mixture passes through each overflow tray 4 in sequence, with a residence time of 2min on each tray. As the mixture overflows from the upper tray to the lower tray, the temperature increases continuously by 2℃ per tray and the pressure decreases continuously by 5kPa per tray. The product mixture obtained after the reaction is discharged from the material outlet at the bottom of the multi-stage overflow reaction tower 3. The outlet pressure stabilizing valve 5 controls the outlet pressure to 0.1MPa. The product mixture enters the material tank 6 through the outlet pressure stabilizing valve 5.

[0037] (b) The product mixture is flash-evaporated in material tank 6 to form a slurry. The filter residue obtained by solid-liquid separation of the slurry is crude fumaric acid, and the filtrate is malic acid solution.

[0038] (c) The concentration of malic acid in the filtrate is 71.3%. It undergoes two-step cooling crystallization in crystallizer group 9. In the first crystallizer, the temperature is reduced from 60°C to 55°C at a cooling rate of 1°C / h. In the second crystallizer, the temperature is reduced from 55°C to 45°C at a cooling rate of 4°C / h. After passing through dryer 10, 67.3 kg of malic acid product with a purity of 99.2% is obtained. The remaining liquid is a mixture of catalyst and water. After dehydration in drying tower group 11, the catalyst is obtained and then enters raw material tank 1 for reuse.

[0039] (d) The filter residue was processed by washing crystallizer 8 and drying equipment 10 to obtain 58.1 kg of fumaric acid product with a purity of 99.1%.

[0040] Example 2: The preparation method for co-producing fumaric acid and malic acid comprises the following steps:

[0041] (a) Add 150 kg of maleic anhydride, 100 kg of 70°C warm water, and 10 kg of ionic liquid catalyst [HSO3-bpy][HSO4] to raw material tank 1. Stir and mix at 70°C to form a mixture. The mixture is then pumped into the multi-stage overflow reactor 3 through the material inlet at the top of the multi-stage overflow reactor 3. The temperature at the top of the reactor is set to 180°C, the pressure inside the reactor is maintained at 0.75 MPa, and the liquid flow rate is 6 m / s². 3 / h, the mixture passes through each overflow tray 4 in sequence, with a residence time of 8min on each tray. As the mixture overflows from the upper tray to the lower tray, the temperature increases continuously by 4℃ per tray and the pressure decreases continuously by 8kPa per tray. The product mixture obtained after the reaction is discharged from the material outlet at the bottom of the multi-stage overflow reaction tower 3. The outlet pressure stabilizing valve 5 controls the outlet pressure to 0.12MPa. The product mixture enters the material tank 6 through the outlet pressure stabilizing valve 5.

[0042] (d) The product mixture is flash-evaporated in material tank 6 to form a slurry. The filter residue obtained by solid-liquid separation of the slurry is crude fumaric acid, and the filtrate is malic acid solution.

[0043] (c) The concentration of malic acid in the filtrate is 70.9%. It undergoes two-step cooling crystallization in crystallizer group 9. In the first crystallizer, the temperature is reduced from 59°C to 54°C at a cooling rate of 1.2°C / h. In the second crystallizer, the temperature is reduced from 54°C to 44°C at a cooling rate of 4.5°C / h. After passing through dryer 10, 101.2 kg of malic acid product with a purity of 99.1% is obtained. The remaining liquid is a mixture of catalyst and water. After dehydration in drying tower group 11, the catalyst is obtained and then enters raw material tank 1 for reuse.

[0044] (d) The filter residue was processed by washing crystallizer 8 and drying equipment 10 to obtain 87.6 kg of fumaric acid product with a purity of 99.3%.

[0045] Example 3: The preparation method for co-producing fumaric acid and malic acid comprises the following steps:

[0046] (a) Add 200 kg of maleic anhydride, 100 kg of 80°C warm water, and 6 kg of ionic liquid catalyst [HSO3-bpy][HSO4] to raw material tank 1. Stir and mix at 80°C to form a mixture. The mixture is then fed into the multi-stage overflow reactor 3 through the material inlet at the top of the multi-stage overflow reactor 3 via a feed pump. The temperature at the top of the reactor is set to 200°C, the pressure inside the reactor is maintained at 1 MPa, and the liquid flow rate is 3 m / s². 3 / h, the mixture passes through each overflow tray 4 in sequence, with a residence time of 10min on each tray. As the mixture overflows from the upper tray to the lower tray, the temperature increases continuously by 6℃ per tray and the pressure decreases continuously by 10kPa per tray. The product mixture obtained after the reaction is discharged from the material outlet at the bottom of the multi-stage overflow reaction tower 3. The discharge pressure stabilizing valve 5 controls the outlet pressure to 0.1MPa. The product mixture enters the material tank 6 through the discharge pressure stabilizing valve 5.

[0047] (b) The product mixture is flash-evaporated in material tank 6 to form a slurry. The filter residue obtained by solid-liquid separation of the slurry is crude fumaric acid, and the filtrate is malic acid solution.

[0048] (c) The concentration of malic acid in the filtrate is 71.5%. It undergoes two-step cooling crystallization in crystallizer group 9. In the first crystallizer, the temperature is reduced from 61°C to 56°C at a cooling rate of 0.8°C / h. In the second crystallizer, the temperature is reduced from 56°C to 46°C at a cooling rate of 3.5°C / h. After passing through dryer 10, 134.8 kg of malic acid product with a purity of 99.4% is obtained. The remaining liquid is a mixture of catalyst and water. After dehydration in drying tower group 11, the catalyst is obtained and then enters raw material tank 1 for reuse.

[0049] (d) The filter residue was processed by washing crystallizer 8 and drying equipment 10 to obtain 117.1 kg of fumaric acid product with a purity of 99.2%.

Claims

1. A process for the production of fumaric acid and malic acid as co-products, characterized in that, The preparation method uses equipment including a raw material tank (1), a layered multi-stage overflow reaction tower (3), a material tank (6), a separator (7), a crystallizer (8), a washing crystallizer group (9), a dryer (10), and a drying tower group (11); The layered multi-stage overflow reaction tower (3) includes a material feeding port at the top, an internal overflowable tower plate (4), and a material discharging port at the bottom. The material feeding port is connected to the raw material tank (1) through a feeding pump (2) and a pipeline. The material discharging port is connected to the material tank (6) through a discharging pressure stabilizing valve (5) and a pipeline. The number of layers of the overflowable tower plate (4) is 6-10. The separator (7) is connected to the material tank (6), the washing crystallizer (8), and the crystallizer group (9) through a pipeline. The crystallizer group (9) is formed by connecting two crystallizers in series and is connected to the dryer (10) and the drying tower group (11) through a pipeline. The drying tower group (11) is formed by connecting two drying towers in parallel, one for use and one for standby. The drying towers are filled with molecular sieves and are connected to the raw material tank (1). The raw material tank (1) and the material tank (6) are both provided with stirring devices. The overflowable tower plate (4) is composed of a tower plate and a tower plate. The co-production of fumaric acid and malic acid is prepared according to the following steps: (a) the raw material maleic anhydride, warm water and ionic liquid catalyst are added into the raw material tank (1) and stirred to mix uniformly to form a mixed solution at 60-100°C, the mixed solution is pumped into the layer type multi-stage overflow reaction tower (3) through the material inlet at the top of the layer type multi-stage overflow reaction tower (3) by the feed pump (2), the temperature at the top of the reaction tower is set to 160-200°C, the pressure in the kettle is kept at 0.5-1 MPa, the liquid flow rate is 3-15 m 3 / h, the mixed solution passes through each layer of overflow tower plate (4) in turn, the residence time of the mixed solution at each tower plate is 2-10 min, the temperature of the mixed solution is continuously increased by 2-6°C for each tower plate, and the pressure is continuously reduced by 5-10 kPa for each tower plate, the product mixed solution obtained after the reaction of the mixed solution is discharged from the material outlet at the bottom of the layer type multi-stage overflow reaction tower (3) and enters the material tank (6) through the discharge pressure stabilizing valve (5); the mass ratio of the maleic anhydride, warm water and ionic liquid catalyst is 50-30:20:1-2; the ionic liquid catalyst is selected from one of [HSO3-bpy][HSO4], [HSO3-bpy][CH3COOH], [HSO3-bpy][BF4] and [HSO3-bpy]Cl; the outlet pressure of the discharge pressure stabilizing valve (5) is set to 0.1-0.12 MPa; (b) The product mixture is treated by flash evaporation in the material tank (6) to form a slurry-like material. The slurry-like material is separated by the separator (7) to obtain fumaric acid crude products and malic acid solution. (c) The filtrate is subjected to two-step cooling crystallization in the crystallizer group (9) and then dried in the dryer (10) to obtain malic acid products. The remaining liquid is a mixture of catalyst and water, which is dehydrated in the drying tower group (11) to obtain the catalyst, which is then reused in the raw material tank (1). The two-step cooling crystallization is carried out in two crystallizers. The temperature in the first crystallizer is reduced from 59-61℃ to 54-56℃, and the temperature in the second crystallizer is reduced from 54-56℃ to 44-46℃. The cooling rate of the first crystallizer is 0.8-1.2℃ / h, and the cooling rate of the second crystallizer is 3.5-4.5℃ / h. (d) The filter residue is treated by the washing crystallizer (8) and the dryer (10) to obtain fumaric acid products.

2. The process for the production of fumaric acid and malic acid as a co-product according to claim 1, characterized in that, The layered multi-stage overflow reaction tower (3) is externally provided with a heat preservation heating jacket.

3. The process for the production of fumaric acid and malic acid as a co-product according to claim 1, characterized in that, In step (a), the temperature of the hot water is 60-80℃.

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