Resource utilization system and method for acetic acid-containing wastewater in acrylic acid production

Abstract

The invention discloses a resource utilization system and method for acetic acid-containing wastewater in acrylic acid production, which are used for resource utilization of a large amount of acetic acid-containing wastewater generated in industrial production of acrylic acid through cooperation of multiple working sections. Acetic acid and acrylic acid contained in the wastewater are separated and synthesized to obtain 99.5 wt% butyl acetate and 50 wt% sodium polyacrylate aqueous solution products. The method has the advantages of low equipment investment cost, flexible production, continuous process, long reaction retention time, wide available concentration range of acetic acid and acrylic acid raw materials, high conversion per pass of n-butyl alcohol, environmental friendliness and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of compound synthesis, and particularly relates to a resource utilization system and method for acetic acid-containing wastewater in acrylic acid production. Background Art

[0002] In the industrial production of acrylic acid, a large amount of wastewater containing acetic acid is produced. The components of the wastewater are: 9% acetic acid, 0.8% acrylic acid, and a small amount of high-boiling impurities, and the rest are water. Due to the high COD concentration of organic matter in the wastewater, it cannot be directly treated by biochemical treatment. At present, the wastewater is mixed with other wastes and then sent to the incinerator for incineration treatment, resulting in defects such as high energy consumption and production costs. This also makes it impossible to fully utilize the effective components (acetic acid and acrylic acid) in the acetic acid wastewater to produce downstream products such as butyl acetate.

[0003] n-Butyl acetate is abbreviated as butyl acetate, and its chemical formula is CH3COO(CH2)3CH3. It is an excellent organic solvent with good solubility for ethyl cellulose, cellulose acetate butyrate, polystyrene, methyl acetate resin, chlorinated rubber and various natural gums. At present, n-butyl acetate is mainly produced by batch production in kettle, that is, acetic acid is added to a reactor filled with excess n-butanol, and acetic acid and n-butanol are reacted under a certain temperature, pressure and catalyst to generate n-butyl acetate. There is a lot of n-butanol residue, and the reaction conversion rate is not high. In addition, due to the presence of the ternary azeotropic system of water, n-butanol and n-butyl acetate, the separation of n-butyl acetate and excess n-butanol is extremely difficult. Therefore, in the production process of n-butyl acetate, problems such as large reactor volume, poor reaction effect, and high impurity content often occur. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a system and method for resource utilization of acetic acid-containing wastewater in acrylic acid production.

[0005] The technical solutions adopted are as follows: A resource utilization system for acetic acid-containing wastewater in acrylic acid production, comprising an acetic acid wastewater concentration and separation module, an acetic acid storage tank, an acrylic acid storage tank, a n-butyl acetate preparation module and a sodium polyacrylate preparation module, wherein the acetic acid discharge port of the acetic acid wastewater concentration and separation module is sequentially connected to the acetic acid storage tank and the n-butyl acetate preparation module, and the acrylic acid discharge port of the acetic acid wastewater concentration and separation module is sequentially connected to the acrylic acid storage tank and the sodium polyacrylate preparation module; The n-butyl acetate preparation module includes a n-butyl alcohol storage tank, a first static mixer, a multi-stage series reactor, a distillation tower and a n-butyl acetate storage tank. The discharge ports of the acetic acid storage tank and the n-butyl alcohol storage tank are respectively connected to the feed port of the first static mixer, the discharge port of the first static mixer is connected to the multi-stage series reactor, and the discharge port of the multi-stage series reactor is sequentially connected to the distillation tower and the n-butyl acetate storage tank.

[0006] Furthermore, the multi-stage series reactor comprises a first-stage reactor, a second-stage reactor and a third-stage reactor, the top discharge port of the first static mixer is connected to the first-stage reactor, the second-stage reactor and the third-stage reactor in sequence, the top circulation of the first-stage reactor is connected to a reactor-one phase separator, the top circulation of the second-stage reactor is connected to a reactor-two phase separator, the top circulation of the third-stage reactor is connected to a reactor-three phase separator, the top discharge port of the third-stage reactor is connected to a distillation tower, and the bottom of the third-stage reactor is circulated and connected to the first-stage reactor through a catalyst circulation cooler.

[0007] Furthermore, the acetic acid wastewater concentration and separation module includes a liquid membrane concentration device, an acetic acid wastewater vacuum distillation kettle and an acetic acid wastewater distillation tower. The liquid membrane concentration device is connected to the acetic acid wastewater vacuum distillation kettle and the acetic acid wastewater distillation tower in sequence, and the top gas phase outlet of the acetic acid wastewater distillation tower is connected to the acetic acid storage tank through a condenser.

[0008] Furthermore, the sodium polyacrylate preparation module includes a sodium polyacrylate first-stage reactor, a sodium polyacrylate second-stage reactor, a sodium polyacrylate storage tank, a second static mixer, a sodium sulfite storage tank, a potassium polysulfate storage tank and a sodium hydroxide storage tank. The acrylic acid storage tank is sequentially connected to the sodium polyacrylate first-stage reactor, the sodium polyacrylate second-stage reactor and the sodium polyacrylate storage tank. The sodium sulfite storage tank and the potassium polysulfate storage tank are connected to the second static mixer after being merged. The discharge port of the second static mixer is connected to the sodium polyacrylate first-stage reactor, and the discharge port of the sodium hydroxide storage tank is connected to the sodium polyacrylate second-stage reactor.

[0009] A method for resource utilization of acetic acid-containing wastewater in acrylic acid production using the above system comprises the following steps: 1) The acetic acid wastewater generated in the acrylic acid production process is first concentrated by a liquid phase membrane concentration device. The concentrated acetic acid wastewater first enters the acetic acid wastewater vacuum distillation kettle to remove heavy components, and then enters the acetic acid wastewater distillation tower. The gas phase at the top of the tower enters the acetic acid storage tank after condensation, and the liquid phase at the bottom of the tower enters the acrylic acid storage tank; 2) n-Butanol and catalyst p-toluenesulfonic acid are added to the n-Butanol storage tank, and the materials in the acetic acid storage tank and the n-Butanol storage tank enter the first static mixer for full mixing, and the mixed materials enter the first-stage reactor, the second-stage reactor and the third-stage reactor in turn for reaction, and at the same time, the first phase separator, the second phase separator and the third phase separator reflux the organic phase discharged from the top of the first-stage reactor, the second-stage reactor and the third-stage reactor respectively, and the aqueous phase is treated by wastewater removal; the gas phase of the third-stage reactor enters the distillation tower for distillation, and after condensation in the top condenser of the distillation tower, the n-butyl acetate product is extracted from the top of the distillation tower and stored in the n-butyl acetate storage tank, and a small amount of acetic acid and the catalyst that have not been completely reacted at the bottom of the third-stage reactor flow into the first-stage reactor for recycling; 3) The material in the acrylic acid storage tank enters the sodium polyacrylate first-stage reactor, sodium sulfite is added to the sodium sulfite storage tank, potassium persulfate is added to the potassium persulfate storage tank, the materials in the sodium sulfite storage tank and the potassium persulfate storage tank enter the second static mixer for full mixing, the mixed materials enter the sodium polyacrylate first-stage reactor for reaction, the material in the sodium hydroxide storage tank enters the sodium polyacrylate second-stage reactor, after full reaction, the sodium polyacrylate aqueous solution in the sodium polyacrylate second-stage reactor enters the sodium polyacrylate storage tank for storage.

[0010] Furthermore, in step 2), the temperature in the first-stage reactor is 100°C, the temperature in the second-stage reactor is 100-126°C, and the temperature in the third-stage reactor is 126°C.

[0011] Furthermore, in step 3), the temperature in the first-stage sodium polyacrylate reactor is 70°C, and the temperature in the second-stage sodium polyacrylate reactor is 50°C.

[0012] Furthermore, in step 2), the molar ratio of n-butanol to acetic acid is 1:1.1-1.5.

[0013] Furthermore, the dosage of the catalyst p-toluenesulfonic acid is 1-1.5% of the mass of n-butanol.

[0014] Furthermore, the mass fraction of acetic acid in the acetic acid storage tank is 60% to 90%, and the mass fraction of acrylic acid in the acrylic acid storage tank is 80% to 90%.

[0015] The beneficial effects of the present invention are: 1) Acetic acid wastewater is initially concentrated using liquid membrane, and the water phase flowing out of the liquid membrane can be reused in the acrylic acid workshop. The operation is simple and saves steam consumption in the wastewater concentration process; 2) The raw materials react in a liquid phase multi-stage series continuous device, and the reaction process is carried out step by step. Acetic acid and n-butanol do not need to be gasified and directly enter the reactor. The liquid-liquid mass transfer is sufficient and energy consumption is saved. The material stays in the reactor for a long time, the n-butanol conversion rate is improved, and the impurity content is reduced, so that n-butyl acetate with a content of more than 99.5% can be produced; 3) Using 60~90% acetic acid aqueous solution instead of anhydrous acetic acid as raw material, the production cost is low, the liquid phase multi-stage series continuous device has stable production, suitable reaction time, high production efficiency, and can greatly increase the production of n-butyl acetate; 4) A small amount of acrylic acid in acetic acid wastewater can be separated to obtain an acrylic acid aqueous solution with a mass fraction of 80% to 90%, and the above acrylic acid aqueous solution can be used to produce sodium polyacrylate products; 5) The whole process is a continuous reaction, the product quality is stable, and the materials are recycled, which can better achieve the effect of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the process of the present invention.

[0017] In the figure: 1. liquid membrane concentration device; 2. vacuum distillation kettle for acetic acid wastewater; 3. distillation tower for acetic acid wastewater; 4. acetic acid storage tank; 5. n-butanol storage tank; 6. first static mixer; 7. first-stage reactor; 8. second-stage reactor; 9. third-stage reactor; 10. reactor one phase separator; 11. reactor two phase separator; 12. reactor three phase separator; 13. distillation tower; 14. n-butanol acetic acid storage tank; 15. acrylic acid storage tank; 16. first-stage reactor for sodium polyacrylate; 17. second-stage reactor for sodium polyacrylate; 18. sodium polyacrylate storage tank; 19. second static mixer; 20. sodium sulfite storage tank; 21. potassium persulfate storage tank; 22. sodium hydroxide storage tank. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0019] like Figure 1As shown, a liquid phase multi-stage series continuous device includes a liquid phase membrane concentration device 1, an acetic acid wastewater vacuum distillation kettle 2, an acetic acid wastewater distillation tower 3, an acetic acid storage tank 4, an n-butanol storage tank 5, a first static mixer 6, a first-stage reactor 7, a second-stage reactor 8, a third-stage reactor 9, a first-stage reactor phase separator 10, a second-stage reactor phase separator 11, a third-stage reactor phase separator 12, a distillation tower 13, an n-butyl acetate storage tank 14, an acrylic acid storage tank 15, a sodium polyacrylate first-stage reactor 16, a sodium polyacrylate second-stage reactor 17, a sodium polyacrylate storage tank 18, a second static mixer 19, a sodium sulfite storage tank 20, a potassium persulfate storage tank 21, and a sodium hydroxide storage tank 22. The top discharge port of the liquid phase membrane concentration device 1 is connected to the acetic acid wastewater vacuum distillation kettle 2, the top discharge port of the acetic acid wastewater vacuum distillation kettle 2 is connected to the acetic acid wastewater distillation tower 3, the top discharge port of the acetic acid wastewater distillation tower 4 is connected to the acetic acid storage tank 5, and the bottom discharge port of the acetic acid wastewater distillation tower 3 is connected to the acrylic acid storage tank 15. The acetic acid storage tank 4 and the n-butanol storage tank 5 are respectively connected to the first static mixer 6, the top discharge port of the first static mixer 6 is connected to the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 in sequence, the top of the first-stage reactor 7 is connected to a kettle-phase separator 10, the upper organic phase of the kettle-phase separator 10 is refluxed to the first-stage reactor 6, and the lower aqueous phase is treated by wastewater treatment, the top of the second-stage reactor 8 is connected to a kettle-two phase separator 11, the upper organic phase of the kettle-two phase separator 11 is The product is refluxed to the second-stage reactor 8, and the lower aqueous phase is treated with wastewater. A three-phase separator 12 is arranged on the top of the third-stage reactor 9, and the upper organic phase of the three-phase separator 12 is refluxed to the third-stage reactor 9, and the lower aqueous phase is treated with wastewater. The top of the third-stage reactor 9 is connected to a distillation tower 13, and the bottom of the third-stage reactor 9 is circulated to the first-stage reactor 7 through a catalyst circulation cooler. The top discharge port of the distillation tower 13 is connected to the top condenser of the distillation tower 13 and then connected to the n-butyl acetate storage tank 14. The bottom discharge port of the acrylic acid storage tank 15 is connected to the sodium polyacrylate first-stage reactor 16 and the sodium polyacrylate second-stage reactor 17 in sequence, the sodium sulfite storage tank 20 and the potassium persulfate storage tank 21 are connected together and then connected to the second static mixer 19, the top discharge port of the second static mixer 19 is connected to the sodium polyacrylate first-stage reactor 16, the bottom discharge port of the sodium hydroxide storage tank 22 is connected to the sodium polyacrylate second-stage reactor 17, and the bottom discharge port of the sodium polyacrylate second-stage reactor 17 is connected to the sodium polyacrylate storage tank 18.

[0020] Example 1

[0021] 1) The acetic acid wastewater (acetic acid 9wt%, acrylic acid 0.8wt%) generated in the acrylic acid production process has a mass flow rate of 5004.33kg / h, which is first concentrated by a liquid membrane concentration device 1. The water phase flowing out of the liquid membrane is reused in the acrylic acid production workshop, with a mass flow rate of 4197.83kg / h; the acetic acid wastewater (acetic acid 56wt%, acrylic acid 5wt%) concentrated by the liquid membrane has a mass flow rate of 806.50kg / h and enters the acetic acid wastewater vacuum distillation kettle 2 to remove the heavy components; the heavy components are removed for hazardous waste treatment, with a mass flow rate of 15.81kg / h. The acetic acid wastewater with heavy components removed enters the acetic acid wastewater distillation tower 3, and the top gas phase (60wt% acetic acid aqueous solution) enters the acid storage tank 4 after condensation, with a mass flow rate of 750.65 kg / h; the bottom liquid phase enters the acrylic acid storage tank 15 after cooling, with a mass flow rate of 44.48kg / h (90wt% acrylic acid aqueous solution).

[0022] 2) n-Butanol and catalyst are added to n-Butanol storage tank 5, and the materials in acetic acid storage tank 4 and n-Butanol storage tank 5 enter into first static mixer 6 and are fully mixed by first static mixer 6, the mass flow rate of 60wt% acetic acid is 750.65kg / h, the mass flow rate of n-Butanol is 370.61 kg / h, the catalyst is p-toluenesulfonic acid, the dosage is 1.5% of the mass of n-Butanol, and the mass flow rate is 5.56kg / h (it only needs to be added when starting and feeding, and no fresh addition is required after subsequent recovery and application cycle), the mixed materials enter into first-stage reactor 7, second-stage reactor 8 and third-stage reactor 9 in turn for reaction, and at the same time, the first reactor phase separator 10, the second reactor phase separator 11 and the third reactor phase separator 12 condense and reflux the top discharge organic phase of the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9, For wastewater treatment, the water phase flow rate of the phase separator 10 of kettle one is 233.62 kg / h, the water phase flow rate of the phase separator 11 of kettle two is 116.81 kg / h, the water phase flow rate of the phase separator 12 of kettle three is 38.94 kg / h, the volume of the first-stage reactor 7 and the second-stage reactor 8 is 2000 L, the volume of the third-stage reactor 9 is 1000 L, the reaction temperature of the first-stage reactor 7 is controlled at 100°C, the reaction temperature of the second-stage reactor 8 is controlled at 100~126°C, and the reaction temperature of the third-stage reactor 9 is controlled at 126°C.

[0023] The gas phase of the third-stage reactor 9 enters the distillation tower 13 for distillation. After condensation in the top condenser of the distillation tower 13, the n-butyl acetate product is extracted from the top of the distillation tower 13 and stored in the n-butyl acetate storage tank 14. The top extraction amount is 542.85 kg / h. A small amount of acetic acid and catalyst that have not been completely reacted at the bottom of the third-stage reactor 9 flows into the first-stage reactor 7 for recycling. The flow rate of the bottom liquid is 18.90 kg / h.

[0024] 3) The acrylic acid in the acrylic acid storage tank 15 enters the sodium polyacrylate first-stage reactor 16 (90wt% acrylic acid aqueous solution) with a mass flow rate of 44.48kg / h. Sodium sulfite is added to the sodium sulfite storage tank 20, and potassium persulfate is added to the potassium persulfate storage tank 21. The materials in the sodium sulfite storage tank 20 and the potassium persulfate storage tank 21 enter the second static mixer 19 and are fully mixed by the second static mixer 19. The mass flow rate of sodium sulfite is 1.92kg / h, and the mass flow rate of potassium persulfate is 1.90kg / h. The mixed materials enter the sodium polyacrylate first-stage reactor 16. The 30wt% sodium hydroxide solution in the sodium hydroxide storage tank 22 enters the sodium polyacrylate second-stage reactor 17 with a mass flow rate of 74.07 kg / h. The reaction temperature of the sodium polyacrylate first-stage reactor 16 is controlled to be 70°C, and the reaction temperature of the sodium polyacrylate second-stage reactor 17 is controlled to be 50°C. The sodium polyacrylate (50 wt %) aqueous solution product in the sodium polyacrylate second-stage reaction kettle 17 enters the sodium polyacrylate storage tank 18 for storage.

[0025] In this embodiment, the content of n-butyl acetate product is 99.5%, the one-way conversion rate of n-butanol is 99%, and the one-way yield of n-butyl acetate is 93%.

[0026] Example 2

[0027] 1) The acetic acid wastewater (acetic acid 9wt%, acrylic acid 0.8wt%) generated in the acrylic acid production process has a mass flow rate of 4337.09kg / h, which is first concentrated by a liquid membrane concentration device 1. The water phase flowing out of the liquid membrane is reused in the acrylic acid production workshop, with a mass flow rate of 3732.92kg / h; the acetic acid wastewater (acetic acid 65wt%, acrylic acid 6wt%) concentrated by the liquid membrane has a mass flow rate of 604.17kg / h and enters the acetic acid wastewater vacuum distillation kettle 2 to remove the heavy components; the heavy components are removed for hazardous waste treatment, with a mass flow rate of 11.85kg / h. The acetic acid wastewater with the heavy components removed enters the acetic acid wastewater distillation tower 3, and the top gas phase (70wt% acetic acid aqueous solution) enters the acid storage tank 4 after condensation, with a mass flow rate of 557.63 kg / h; the bottom liquid phase enters the acrylic acid storage tank 15 after cooling, with a mass flow rate of 38.55kg / h (90wt% acrylic acid aqueous solution).

[0028] 2) n-Butanol and catalyst are added to n-butanol storage tank 5, and the materials in acetic acid storage tank 4 and n-butanol storage tank 5 enter the first static mixer 6 and are fully mixed by the first static mixer 6. The mass flow rate of 70wt% acetic acid is 557.63kg / h, and the mass flow rate of n-butanol is 370.61 kg / h. The catalyst is p-toluenesulfonic acid, and its dosage is 1.3% of the mass of n-butanol, and its mass flow rate is 4.82 kg / h (it only needs to be added when starting up and feeding, and no fresh addition is required after subsequent recovery and application cycle). The mixed materials enter the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 in turn for reaction. At the same time, the first phase separator 10, the second phase separator 11 and the third phase separator 12 condense and reflux the organic phase discharged from the top of the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9, and the aqueous phase is treated by wastewater. The aqueous phase flow rate of the first phase separator 10 is 153.83 kg / h, the water phase flow rate of the kettle two-phase separator 11 is 76.92 kg / h, the water phase flow rate of the kettle three-phase separator 12 is 25.64kg / h, the volume of the first-stage reactor 7 and the second-stage reactor 8 is 2000 L, the volume of the third-stage reactor 9 is 1000 L, the reaction temperature of the first-stage reactor 7 is controlled at 100 ℃, the reaction temperature of the second-stage reactor 8 is controlled at 100~126 ℃, and the reaction temperature of the third-stage reactor 9 is controlled at 126℃.

[0029] The gas phase of the third-stage reactor 9 enters the distillation tower 13 for distillation. After condensation in the top condenser of the distillation tower, the n-butyl acetate product is extracted from the top of the distillation tower and stored in the n-butyl acetate storage tank 14. The top extraction rate is 525.34 kg / h. A small amount of acetic acid and catalyst that have not been completely reacted at the bottom of the third-stage reactor 9 flows into the first-stage reactor 7 for recycling. The flow rate of the bottom liquid is 14.65 kg / h.

[0030] 3) The acrylic acid in the acrylic acid storage tank 15 enters the sodium polyacrylate first-stage reactor 16 (90wt% acrylic acid aqueous solution) with a mass flow rate of 38.55kg / h. Sodium sulfite is added to the sodium sulfite storage tank 20, and potassium persulfate is added to the potassium persulfate storage tank 21. The materials in the sodium sulfite storage tank 20 and the potassium persulfate storage tank 21 enter the second static mixer 19 and are fully mixed by the second static mixer 19. The mass flow rate of sodium sulfite is 1.66 kg / h, and the mass flow rate of potassium persulfate is 1.65 kg / h. The mixed materials enter the sodium polyacrylate first-stage reactor 16. The 30wt% sodium hydroxide solution in the sodium hydroxide storage tank 22 enters the sodium polyacrylate second-stage reactor 17 with a mass flow rate of 64.20 kg / h. The reaction temperature of the sodium polyacrylate first-stage reactor 16 is controlled to be 70°C, and the reaction temperature of the sodium polyacrylate second-stage reactor 17 is controlled to be 50°C. The sodium polyacrylate (50 wt %) aqueous solution product in the sodium acrylate second-stage reactor 17 enters the sodium polyacrylate storage tank 18 for storage.

[0031] In this embodiment, the content of n-butyl acetate product is 99.5%, the one-way conversion rate of acetic acid is 94%, and the one-way yield of n-butyl acetate is 90%.

[0032] Example 3

[0033] 1) The acetic acid wastewater (acetic acid 9wt%, acrylic acid 0.8wt%) generated in the acrylic acid production process has a mass flow rate of 4003.47kg / h, which is first concentrated by a liquid membrane concentration device 1. The water phase flowing out of the liquid membrane is reused in the acrylic acid production workshop, with a mass flow rate of 3511.40kg / h; the acetic acid wastewater (acetic acid 73wt%, acrylic acid 7wt%) concentrated by the liquid membrane has a mass flow rate of 492.07kg / h and enters the acetic acid wastewater vacuum distillation kettle 2 to remove the heavy components; the heavy components are removed for hazardous waste treatment, with a mass flow rate of 9.65kg / h. The acetic acid wastewater with heavy components removed enters the acetic acid wastewater distillation tower 3, and the top gas phase (80wt% acetic acid aqueous solution) enters the acid storage tank 4 after condensation, with a mass flow rate of 450.39 kg / h; the bottom liquid phase enters the acrylic acid storage tank 15 after cooling, with a mass flow rate of 40.03kg / h (90wt% acrylic acid aqueous solution).

[0034] 2) n-Butanol and catalyst are added to n-Butanol storage tank 5, and the materials in acetic acid storage tank 4 and n-Butanol storage tank 5 enter into first static mixer 6 and are fully mixed by first static mixer 6. The mass flow rate of 80wt% acetic acid is 450.39kg / h, the mass flow rate of n-Butanol is 370.61 kg / h, and the catalyst is p-toluenesulfonic acid, the dosage of which is 1.2% of the mass of n-Butanol, and the mass flow rate is 4.45 kg / h (only needs to be added when starting up and feeding, and no fresh addition is required after subsequent recovery and application cycle), the mixed materials enter the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 in turn for reaction, and at the same time, the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 are condensed and refluxed by the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 The organic phase of the top discharge is treated by the first-stage phase separator 10, the second-stage phase separator 11 and the third-stage phase separator 12, and the water phase is treated by wastewater removal. The water phase flow rate of the first-stage phase separator 10 is 107.51kg / h, the water phase flow rate of the second-stage phase separator 11 is 53.75kg / h, and the water phase flow rate of the third-stage phase separator 12 is 17.92kg / h. The volumes of the first-stage reactor 7 and the second-stage reactor 8 are 2000 L, and the volume of the third-stage reactor 9 is 1000 L. The reaction temperature of the first-stage reactor 7 is controlled to be 100 ℃, and the reaction temperature of the second-stage reactor 8 is controlled to be 100~126 ℃, control the reaction temperature of the third-stage reactor 9 to 126℃.

[0035] The gas phase of the third-stage reactor 9 enters the distillation tower 13 for distillation. After condensation in the top condenser of the distillation tower 13, the n-butyl acetate product is extracted from the top of the distillation tower 13 and stored in the n-butyl acetate storage tank 14. The top extraction amount is 531.17 kg / h. A small amount of acetic acid and catalyst that have not been completely reacted at the bottom of the third-stage reactor 9 flows into the first-stage reactor 7 for recycling. The flow rate of the bottom liquid is 11.06 kg / h.

[0036] 3) The acrylic acid in the acrylic acid storage tank 15 enters the sodium polyacrylate first-stage reactor 16 (80wt% acrylic acid aqueous solution) with a mass flow rate of 40.03kg / h. Sodium sulfite is added to the sodium sulfite storage tank 20, and potassium persulfate is added to the potassium persulfate storage tank 21. The materials in the sodium sulfite storage tank 20 and the potassium persulfate storage tank 21 enter the second static mixer 19 and are fully mixed by the second static mixer 19. The mass flow rate of sodium sulfite is 1.54kg / h, and the mass flow rate of potassium persulfate is 1.52kg / h. The mixed materials enter the sodium polyacrylate first-stage reactor 16. The 30wt% sodium hydroxide solution in the sodium hydroxide storage tank 22 enters the sodium polyacrylate second-stage reactor 17 with a mass flow rate of 59.26 kg / h. The reaction temperature of the sodium polyacrylate first-stage reactor 16 is controlled to be 70°C, and the reaction temperature of the sodium polyacrylate second-stage reactor 17 is controlled to be 50°C. The sodium polyacrylate (50 wt %) aqueous solution product in the sodium polyacrylate second-stage reaction kettle 17 enters the sodium polyacrylate storage tank 18 for storage.

[0037] In this embodiment, the content of n-butyl acetate product is 99.5%, the one-way conversion rate of acetic acid is 99%, and the one-way yield of n-butyl acetate is 91%.

[0038] Example 4

[0039] 1) The acetic acid wastewater (9wt% acetic acid, 0.8wt% acrylic acid) generated in the acrylic acid production process has a mass flow rate of 3669.84kg / h, which is first concentrated by a liquid membrane concentration device 1. The water phase flowing out of the liquid membrane is reused in the acrylic acid production workshop, with a mass flow rate of 3265.57kg / h; the acetic acid wastewater (82wt% acetic acid, 7wt% acrylic acid) concentrated by the liquid membrane has a mass flow rate of 404.27kg / h and enters the acetic acid wastewater vacuum distillation kettle 2 to remove the heavy components; the heavy components are removed for hazardous waste treatment, with a mass flow rate of 7.93kg / h. The acetic acid wastewater with the heavy components removed enters the acetic acid wastewater distillation tower 3, and the top gas phase (90wt% acetic acid aqueous solution) enters the acid storage tank 4 after condensation, with a mass flow rate of 366.98 kg / h; the bottom liquid phase enters the acrylic acid storage tank 15 after cooling, with a mass flow rate of 29.36kg / h (90wt% acrylic acid aqueous solution).

[0040] 2) n-Butanol and catalyst are added to n-Butanol storage tank 5, and the materials in acetic acid storage tank 4 and n-Butanol storage tank 5 enter into first static mixer 6 and are fully mixed by first static mixer 6. The mass flow rate of 90wt% acetic acid is 366.98kg / h, the mass flow rate of n-Butanol is 370.61 kg / h, and the catalyst is p-toluenesulfonic acid, the dosage of which is 1% of the mass of n-Butanol, and the mass flow rate is 3.71 kg / h (only needs to be added when starting up and feeding, and no fresh addition is required after subsequent recovery and application cycle), the mixed materials enter the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 in turn for reaction, and at the same time, the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 are condensed and refluxed by the first-stage reactor 7, the second-stage reactor 8 and the third-stage reactor 9 The organic phase of the top discharge is treated by the first-stage phase separator 10, the second-stage phase separator 11 and the third-stage phase separator 12 for condensation and reflux, and the water phase is treated by wastewater removal. The water phase flow rate of the first-stage phase separator 10 is 75.48kg / h, the water phase flow rate of the second-stage phase separator 11 is 37.74kg / h, and the water phase flow rate of the third-stage phase separator 12 is 12.58kg / h. The volumes of the first-stage reactor 7 and the second-stage reactor 8 are 2000 L, and the volume of the third-stage reactor 9 is 1000 L. The reaction temperature of the first-stage reactor 7 is controlled to be 100 ℃, and the reaction temperature of the second-stage reactor 8 is controlled to be 100~126 ℃, control the reaction temperature of the third-stage reactor 9 to 126℃.

[0041] The gas phase of the third-stage reactor 9 enters the distillation tower 13 for distillation. After condensation in the top condenser of the distillation tower 13, the n-butyl acetate product is extracted from the top of the distillation tower 13 and stored in the n-butyl acetate storage tank 14. The top extraction amount is 531.17 kg / h. A small amount of acetic acid and catalyst that have not been completely reacted at the bottom of the third-stage reactor 9 flows into the first-stage reactor 7 for recycling. The flow rate of the bottom liquid is 8.06 kg / h.

[0042] 3) The acrylic acid in the acrylic acid storage tank 15 enters the sodium polyacrylate first-stage reactor 16 (80wt% acrylic acid aqueous solution) with a mass flow rate of 36.70kg / h. Sodium sulfite is added to the sodium sulfite storage tank 20, and potassium persulfate is added to the potassium persulfate storage tank 21. The materials in the sodium sulfite storage tank 20 and the potassium persulfate storage tank 21 enter the second static mixer 19 and are fully mixed by the second static mixer 19. The mass flow rate of sodium sulfite is 1.41kg / h, and the mass flow rate of potassium persulfate is 1.40 kg / h. The mixed materials enter the sodium polyacrylate first-stage reactor 16. The 30wt% sodium hydroxide solution in the sodium hydroxide storage tank 22 enters the sodium polyacrylate second-stage reactor 17 with a mass flow rate of 54.32 kg / h. The reaction temperature of the sodium polyacrylate first-stage reactor 16 is controlled to be 70°C, and the reaction temperature of the sodium polyacrylate second-stage reactor 17 is controlled to be 50°C. The sodium polyacrylate (50 wt %) aqueous solution product in the sodium polyacrylate second-stage reaction kettle 17 enters the sodium polyacrylate storage tank 18 for storage.

[0043] In this embodiment, the content of n-butyl acetate product is 99.5%, the one-way conversion rate of acetic acid is 99%, and the one-way yield of n-butyl acetate is 91%.

Claims

1. A resource utilization system for acetic acid-containing wastewater in acrylic acid production, characterized in that: The method comprises an acetic acid wastewater concentration and separation module, an acetic acid storage tank (4), an acrylic acid storage tank (15), a n-butyl acetate preparation module and a sodium polyacrylate preparation module, wherein the acetic acid discharge port of the acetic acid wastewater concentration and separation module is connected in sequence to the acetic acid storage tank (4) and the n-butyl acetate preparation module, and the acrylic acid discharge port of the acetic acid wastewater concentration and separation module is connected in sequence to the acrylic acid storage tank (15) and the sodium polyacrylate preparation module; The n-butyl acetate preparation module comprises an n-butyl alcohol storage tank (5), a first static mixer (6), a multi-stage series reactor, a distillation tower (13) and an n-butyl acetate storage tank (14), wherein the discharge ports of the acetic acid storage tank (4) and the n-butyl alcohol storage tank (5) are respectively connected to the feed port of the first static mixer (6), the discharge port of the first static mixer (6) is connected to the multi-stage series reactor, and the discharge port of the multi-stage series reactor is sequentially connected to the distillation tower (13) and the n-butyl acetate storage tank (14).

2. The resource utilization system of acetic acid-containing wastewater in acrylic acid production according to claim 1, characterized in that: The multi-stage series reactor comprises a first-stage reactor (7), a second-stage reactor (8) and a third-stage reactor (9); the top discharge port of the first static mixer (6) is connected to the first-stage reactor (7), the second-stage reactor (8) and the third-stage reactor (9) in sequence; the top of the first-stage reactor (7) is circulatedly connected to a reactor-one phase separator (10); the top of the second-stage reactor (8) is circulatedly connected to a reactor-two phase separator (11); the top of the third-stage reactor (9) is circulatedly connected to a reactor-three phase separator (12); the top discharge port of the third-stage reactor (9) is connected to a distillation tower (13); and the bottom of the third-stage reactor (9) is circulatedly connected to the first-stage reactor (7) via a catalyst circulation cooler.

3. The resource utilization system of acetic acid-containing wastewater in acrylic acid production according to claim 2, characterized in that: The acetic acid wastewater concentration and separation module comprises a liquid phase membrane concentration device (1), an acetic acid wastewater vacuum distillation kettle (2) and an acetic acid wastewater distillation tower (3); the liquid phase membrane concentration device (1) is connected to the acetic acid wastewater vacuum distillation kettle (2) and the acetic acid wastewater distillation tower (3) in sequence; and the tower top gas phase outlet of the acetic acid wastewater distillation tower (3) is connected to an acetic acid storage tank (4) via a condenser.

4. The resource utilization system of acetic acid-containing wastewater in acrylic acid production according to claim 3, characterized in that: The sodium polyacrylate preparation module comprises a sodium polyacrylate first-stage reactor (16), a sodium polyacrylate second-stage reactor (17), a sodium polyacrylate storage tank (18), a second static mixer (19), a sodium sulfite storage tank (20), a potassium polysulfate storage tank (21) and a sodium hydroxide storage tank (22); the acrylic acid storage tank (15) is connected to the sodium polyacrylate first-stage reactor (16), the sodium polyacrylate second-stage reactor (17) and the sodium polyacrylate storage tank (18) in sequence; the sodium sulfite storage tank (20) and the potassium polysulfate storage tank (21) are connected to the second static mixer (19) after being joined; the discharge port of the second static mixer (19) is connected to the sodium polyacrylate first-stage reactor (16); and the discharge port of the sodium hydroxide storage tank (22) is connected to the sodium polyacrylate second-stage reactor (17).

5. A method for resource utilization of acetic acid-containing wastewater in acrylic acid production using the system as claimed in claim 4, characterized in that: The steps include: 1) The acetic acid wastewater generated in the acrylic acid production process is first concentrated by a liquid phase membrane concentration device (1). The concentrated acetic acid wastewater first enters an acetic acid wastewater vacuum distillation kettle (2) to remove heavy components, and then enters an acetic acid wastewater distillation tower (3). The gas phase at the top of the tower enters an acetic acid storage tank (4) after condensation, and the liquid phase at the bottom of the tower enters an acrylic acid storage tank (15); 2) n-butanol and a catalyst, p-toluenesulfonic acid, are added to the n-butanol storage tank (5), and the materials in the acetic acid storage tank (4) and the n-butanol storage tank (5) enter the first static mixer (6) for thorough mixing. The mixed materials enter the first stage reactor (7), the second stage reactor (8) and the third stage reactor (9) in sequence for reaction. At the same time, the first reactor phase separator (10), the second reactor phase separator (11) and the third reactor phase separator (12) are respectively used to separate the first stage reactor (7), the second stage reactor (8) and the third stage reactor (9). The organic phase discharged from the top of the reactor (8) and the third-stage reactor (9) is refluxed, and the aqueous phase is treated by wastewater treatment; the gas phase of the third-stage reactor (9) enters the distillation tower (13) for distillation, and after condensation in the top condenser of the distillation tower (13), the n-butyl acetate product is extracted from the top of the distillation tower (13) and stored in the n-butyl acetate storage tank (14); a small amount of acetic acid and catalyst that have not been completely reacted at the bottom of the third-stage reactor (9) flows into the first-stage reactor (7) for recycling; 3) The material in the acrylic acid storage tank (15) enters the sodium polyacrylate first-stage reactor (16), sodium sulfite is added to the sodium sulfite storage tank (20), potassium persulfate is added to the potassium persulfate storage tank (21), the materials in the sodium sulfite storage tank (20) and the potassium persulfate storage tank (21) enter the second static mixer (19) for thorough mixing, the mixed materials enter the sodium polyacrylate first-stage reactor (16) for reaction, the material in the sodium hydroxide storage tank (22) enters the sodium polyacrylate second-stage reactor (17), after thorough reaction, the sodium polyacrylate aqueous solution in the sodium polyacrylate second-stage reactor (17) enters the sodium polyacrylate storage tank (18) for storage.

6. The method according to claim 5, characterized in that In step 2), the temperature in the first-stage reactor (7) is 100°C, the temperature in the second-stage reactor (8) is 100-126°C, and the temperature in the third-stage reactor (9) is 126°C.

7. The method according to claim 6, characterized in that In step 3), the temperature in the sodium polyacrylate first-stage reaction kettle (16) is 70°C, and the temperature in the sodium polyacrylate second-stage reaction kettle (17) is 50°C.

8. The method according to claim 7, characterized in that In step 2), the molar ratio of n-butanol to acetic acid is 1:1.1-1.

5.

9. The method according to claim 8, characterized in that The dosage of the catalyst p-toluenesulfonic acid is 1-1.5% of the mass of n-butanol.

10. The method according to claim 9, characterized in that The mass fraction of acetic acid in the acetic acid storage tank (4) is 60% to 90%, and the mass fraction of acrylic acid in the acrylic acid storage tank (15) is 80% to 90%.

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