Production system for treating phosphoric acid-containing wastewater and byproduct potassium dihydrogen phosphate

Abstract

The utility model relates to the technical field of wastewater treatment, in particular to a production system for treating phosphoric acid-containing wastewater and byproduct potassium dihydrogen phosphate, which comprises a neutralization kettle respectively communicated with a raffinate acid liquor conveying pipeline and a decolorized resin regenerated alkali liquor conveying pipeline, a liquid outlet of the first filtering device is communicated with a second filtering device, a liquid outlet of the second filtering device is communicated with a first decoloration treatment device, a decoloration liquid outlet of the first decoloration treatment device is communicated with a second decoloration treatment device, a decoloration liquid outlet of the second decoloration treatment device is communicated with a concentration device, and a concentrated liquid outlet of the concentration device is communicated with a crystallization kettle; a discharge port of the crystallization kettle is communicated with the separation device, a discharge port of the separation device is communicated with the drying device, and a discharge port of the drying device is communicated with the product storage tank. According to the production system, the recovery treatment of the raffinate acid liquor and the decolorized resin regenerated alkali liquor is realized, the monopotassium phosphate product is obtained, and the economic benefit is increased for enterprises.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to a production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate. Background Art

[0002] Potassium dihydrogen phosphate is an important chemical product, which is widely used in industries such as agriculture, industry, food, and medicine. In industry, it is used as a buffer and a culture medium; in agriculture, it is used as a highly efficient phosphorus and potassium compound fertilizer, which has many excellent effects such as increasing production and income, optimizing quality, lodging resistance, pest and disease resistance, and preventing premature senility; in the food industry, potassium hydrogen phosphate can be used as a fermentation agent, a flavoring agent, a leavening agent, etc.; in medicine, the compound potassium hydrogen phosphate injection composed of potassium dihydrogen phosphate and potassium hydrogen phosphate belongs to parenteral nutrition drugs and is used as a phosphorus supplement.

[0003] Traditional production of potassium dihydrogen phosphate requires first mining phosphate rock, preparing phosphoric acid, and then reacting with potassium salt to obtain potassium dihydrogen phosphate. In recent years, the process of using industrial raffinate acid to prepare potassium dihydrogen phosphate has gradually attracted attention. In the process of producing gluconolactone by fermentation method, phosphoric acid is needed for esterification reaction. After the reaction, the phosphoric acid concentration in the raffinate acid solution is as high as 30-50%. Direct discharge or neutralization discharge will greatly increase the load of the biochemical treatment system. In addition, in the process of producing gluconolactone by fermentation method, decolorizing resin is needed for product decolorization. Waste alkali liquid is generated during the regeneration process of the decolorizing resin. If directly discharged, it will cause environmental pollution. Therefore, in view of the above problems, it is necessary to develop a production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is: aiming at the deficiencies of the prior art, to provide a production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate. By using this production system, the recovery treatment of wastewater can be realized, and potassium dihydrogen phosphate by-products can also be obtained, which increases the economic benefits for enterprises.

[0005] To solve the above technical problem, the technical solution of the utility model is:

[0006] A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate, comprising a neutralization kettle connected to a raffinate acid liquid conveying pipeline and a decolorizing resin regeneration alkali liquid conveying pipeline respectively. The discharge port of the neutralization kettle is connected to a first filtering device, the liquid outlet of the first filtering device is connected to a second filtering device, the liquid outlet of the second filtering device is connected to a first decolorizing treatment device, the decolorized liquid outlet of the first decolorizing treatment device is connected to a second decolorizing treatment device, the decolorized liquid outlet of the second decolorizing treatment device is connected to a concentration device, the concentrated liquid outlet of the concentration device is connected to a crystallization kettle, the discharge port of the crystallization kettle is connected to a separation device, the discharge port of the separation device is connected to a drying device, and the discharge port of the drying device is connected to a product storage tank.

[0007] As an improved technical solution, the neutralization kettle comprises a kettle body. The top of the kettle body is provided with a feed inlet and a neutralizing agent inlet, the bottom of the kettle body is provided with a discharge port, the outside of the kettle body is provided with a jacket, the inside of the kettle body is provided with a stirring shaft, one end of the stirring shaft is connected to a motor, the upper and lower parts of the stirring shaft are respectively provided with a conical stirring barrel with a hollow structure. The top and bottom of the conical stirring barrel are open, and a plurality of stirring rods are arranged on the outer wall of the conical stirring barrel. A trapezoidal stirring plate is arranged in the middle of the stirring shaft.

[0008] As an improved technical solution, the first filtering device is a plate and frame filter press, and the second filtering device is a precision filter.

[0009] As an improved technical solution, the first decolorizing treatment device is a decolorizing resin column.

[0010] As an improved technical solution, the second decolorizing treatment device is a decolorizing kettle. The decolorizing kettle comprises a kettle body. The top of the kettle body is provided with a feed inlet and a decolorizing agent inlet, the bottom of the kettle body is provided with a decolorized liquid outlet, the outside of the kettle body is provided with a jacket, the inside of the kettle body is provided with a stirring shaft, one end of the stirring shaft is connected to a motor, a stirring frame is arranged on the stirring shaft, a plurality of spiral blades are arranged on the stirring frame, and stirring rods are arranged between adjacent two spiral blades.

[0011] As an improved technical solution, the separation device is a centrifuge.

[0012] As an improved technical solution, the concentration device is a multi-effect vacuum concentrator.

[0013] After adopting the above technical solutions, the beneficial effects of the present utility model are:

[0014] A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate includes a neutralization kettle connected to a raffinate acid liquid conveying pipeline and a decolorizing resin regeneration alkali liquid conveying pipeline respectively. The discharge port of the neutralization kettle is connected to a first filtration device, the liquid outlet of the first filtration device is connected to a second filtration device, the liquid outlet of the second filtration device is connected to a first decolorization treatment device, the decolorized liquid outlet of the first decolorization treatment device is connected to a second decolorization treatment device, the decolorized liquid outlet of the second decolorization treatment device is connected to a concentration device, the concentrated liquid outlet of the concentration device is connected to a crystallization kettle, the discharge port of the crystallization kettle is connected to a separation device, the discharge port of the separation device is connected to a drying device, and the discharge port of the drying device is connected to a product storage tank. The raffinate acid liquid and the decolorizing resin regeneration alkali liquid in the production of gluconolactone enter the neutralization kettle along the raffinate acid liquid conveying pipeline and the decolorizing resin regeneration alkali liquid conveying pipeline respectively. After the neutralization reaction to adjust the pH to acidic, the material liquid after the neutralization reaction enters the first filtration device for filtration. The filtrate collected after filtration enters the second filtration device, and the filtrate collected after filtration enters the interior of the first decolorization treatment device. The decolorized liquid after the decolorization treatment enters the second decolorization treatment device, the decolorized liquid after the decolorization treatment enters the concentration device again, the concentrated liquid obtained after concentration enters the crystallization kettle again, the crystal material liquid obtained after cooling crystallization enters the separation device again, the crystal material obtained after separation enters the drying device again, and the potassium dihydrogen phosphate product obtained after drying is stored in the product storage tank. The above production system is reasonably designed, realizing the recovery and treatment of the raffinate acid liquid and the decolorizing resin regeneration alkali liquid, and obtaining the potassium dihydrogen phosphate product, increasing the economic benefits for the enterprise.

[0015] Since the neutralization kettle includes a kettle body, the top of the kettle body is provided with a feed inlet and a neutralizing agent inlet, the bottom of the kettle body is provided with a discharge port, the outside of the kettle body is provided with a jacket, the inside of the kettle body is provided with a stirring shaft, one end of the stirring shaft is connected to a motor, the upper and lower parts of the stirring shaft are respectively provided with a conical stirring barrel with a hollow structure, the top and bottom of the conical stirring barrel are open, and a plurality of stirring rods are provided on the outer wall of the conical stirring barrel. A trapezoidal stirring plate is provided in the middle of the stirring shaft. In actual production, the extraction acid liquid and the resin regeneration alkali liquid enter the interior of the kettle body from the feed inlet, and the neutralizing agent (potassium hydroxide) enters the interior of the kettle body from the neutralizing agent inlet. The heat medium in the jacket is used to provide the temperature required for the neutralization reaction. After the motor is started, it drives the stirring shaft, the conical stirring barrel with a hollow structure, the trapezoidal stirring plate and a plurality of stirring rods to stir and mix the material liquid in the kettle body, promoting the neutralization reaction. The material liquid after the reaction ends is discharged from the discharge port. The neutralization kettle with the above structure is reasonably designed, which can promote the full contact reaction of the raffinate acid liquid, the decolorizing resin regeneration alkali liquid and the neutralizing agent.

[0016] Since the first filtration device is a plate and frame filter press and the second filtration device is a precision filter. The plate and frame filter press of the first filtration device can effectively remove the insoluble substances in the material liquid after the neutralization reaction; the insoluble substances in the material liquid can be further removed through the precision filter.

[0017] Since the first decolorization treatment device is a decolorization resin column, the filler in the decolorization resin column can effectively adsorb the pigments in the filtrate.

[0018] Since the second decolorization treatment device is a decolorization kettle, the decolorization kettle includes a kettle body. The top of the kettle body is provided with a feed inlet and a decolorizing agent inlet, the bottom of the kettle body is provided with a decolorized liquid outlet, the outside of the kettle body is provided with a jacket, and the inside of the kettle body is provided with a stirring shaft. One end of the stirring shaft is connected to a motor, the stirring shaft is provided with a stirring frame, the stirring frame is provided with a plurality of spiral blades, and stirring rods are arranged between adjacent two spiral blades. The liquid material treated by the first decolorization treatment device enters the inside of the decolorization kettle, and a decolorizing agent (potassium hypochlorite) is added. The heat medium in the jacket provides the temperature required for the oxidation decolorization reaction. The motor drives the stirring shaft, the stirring frame, the spiral blades and the stirring rods to fully stir and mix the decolorizing agent and the liquid material, greatly improving the decolorization efficiency. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to the present invention;

[0020] Among them, 1 - raffinate acid liquid transfer pipeline, 2 - decolorization resin regeneration caustic liquid transfer pipeline, 3 - neutralization kettle, 4 - first filtration device, 5 - second filtration device, 6 - first decolorization treatment device, 7 - second decolorization treatment device, 8 - concentration device, 9 - crystallization kettle, 10 - separation device, 11 - drying device, 12 - product storage tank. Detailed Embodiments

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate, as Figure 1As shown in the figure, it includes a neutralization kettle 3 respectively connected to the raffinate acid liquid conveying pipeline 1 and the decolorizing resin regeneration alkali liquid conveying pipeline 2. The discharge port of the neutralization kettle 3 is connected to a first filtering device 4 (a plate and frame filter press with a filter cloth pore size of 300 - 400 meshes). The liquid outlet of the first filtering device 4 is connected to a second filtering device 5 (a precision filter with a pore size of 5 - 10 microns). The liquid outlet of the second filtering device 5 is connected to a first decolorization treatment device 6 (a decolorizing resin column filled with weakly polar macroporous adsorption resin). The decolorized liquid outlet of the first decolorization treatment device 6 is connected to a second decolorization treatment device 7 (a decolorization kettle). The decolorized liquid outlet of the second decolorization treatment device 7 is connected to a concentration device 8 (a multi-effect concentrator, specifically a four-effect concentrator). The concentrated liquid outlet of the concentration device 8 is connected to a crystallization kettle 9 (including a kettle body, with a feed port and a discharge port respectively provided at the top and bottom of the kettle body, a jacket provided outside the kettle body, a stirring shaft provided inside the kettle body, one end of the stirring shaft connected to a motor, a plurality of trapezoidal stirring plates provided on the stirring shaft, a liquid outlet provided on one side of the lower part of the kettle body, and a filter screen provided at a position corresponding to the liquid outlet on the inner wall of the kettle body). The discharge port of the crystallization kettle 9 is connected to a separation device 10 (a suspension centrifuge). The discharge port of the separation device 10 is connected to a drying device 11 (a fluidized bed). The discharge port of the drying device 11 is connected to a product storage tank 12.

[0023] In actual production, the raffinate acid liquid and the decolorizing resin regeneration alkali liquid in the production of glucono delta-lactone respectively enter the neutralization kettle along the raffinate acid liquid conveying pipeline and the decolorizing resin regeneration alkali liquid conveying pipeline. After the neutralization reaction to adjust the pH to acidic, the material liquid after the neutralization reaction enters the first filtering device for filtration (which can effectively remove the insoluble substances in the material liquid after the neutralization reaction). The filtrate collected after filtration then enters the second filtering device (which can further remove the insoluble substances in the material liquid). The filtrate collected after filtration then enters the interior of the first decolorization treatment device (the pigment in the filtrate can be effectively adsorbed by the filler in the decolorizing resin column). The decolorized liquid after the decolorization treatment enters the second decolorization treatment device. The decolorized liquid after the decolorization treatment then enters the concentration device. The concentrated liquid obtained after concentration then enters the crystallization kettle. The crystal material liquid obtained after cooling crystallization then enters the separation device. The crystal material obtained after separation enters the drying device through a conveyor belt or a screw conveyor. The potassium dihydrogen phosphate product obtained after drying is stored in the product storage tank. The above production system is reasonably designed, realizes the recovery treatment of the raffinate acid liquid and the decolorizing resin regeneration alkali liquid, and obtains the potassium dihydrogen phosphate product, increasing the economic benefits for the enterprise.

[0024] Among them, the neutralization kettle 3 includes a kettle body. The top of the kettle body is provided with a feed inlet and a neutralizing agent inlet. The bottom of the kettle body is provided with a discharge outlet. The outside of the kettle body is provided with a jacket. The inside of the kettle body is provided with a stirring shaft. One end of the stirring shaft is connected to a motor. The upper and lower parts of the stirring shaft are respectively provided with conical stirring barrels with a hollow structure. The top and bottom of the conical stirring barrels with a hollow structure are open, and a plurality of stirring rods are provided on the outer wall of the conical stirring barrels. The middle part of the stirring shaft is provided with a trapezoidal stirring plate. In actual production, the extracted acid solution and the resin regeneration alkali solution enter the inside of the kettle body from the feed inlet, and the neutralizing agent (potassium hydroxide) enters the inside of the kettle body from the neutralizing agent inlet. The heat medium in the jacket is used to provide the temperature required for the neutralization reaction. After the motor is started, it drives the stirring shaft, the conical stirring barrels with a hollow structure, the trapezoidal stirring plate and the plurality of stirring rods to stir and mix the liquid material inside the kettle body, promoting the progress of the neutralization reaction. The liquid material after the reaction is discharged from the discharge outlet. The neutralization kettle with the above structure is reasonably designed, which can promote the full contact reaction of the raffinate acid solution, the decolorized resin regeneration alkali solution and the neutralizing agent.

[0025] Among them, the second decolorization treatment device 7 is a decolorization kettle. The decolorization kettle includes a kettle body. The top of the kettle body is provided with a feed inlet and a decolorizing agent inlet. The bottom of the kettle body is provided with a decolorized liquid outlet. The outside of the kettle body is provided with a jacket. The inside of the kettle body is provided with a stirring shaft. One end of the stirring shaft is connected to a motor. A stirring frame is provided on the stirring shaft. A plurality of spiral blades are provided on the stirring frame. Stirring rods are provided between two adjacent spiral blades. The liquid material after being treated by the first decolorization treatment device enters the inside of the decolorization kettle, and the decolorizing agent (potassium hypochlorite) is added. The heat medium in the jacket is used to provide the temperature required for the oxidative decolorization reaction. The motor drives the stirring shaft, the stirring frame, the spiral blades and the stirring rods to fully stir and mix the decolorizing agent and the liquid material, greatly improving the decolorization efficiency.

[0026] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A production system for treating wastewater containing phosphoric acid and by-producing potassium dihydrogen phosphate, characterized in that, It includes a neutralization kettle connected to the raffinate acid liquid conveying pipeline and the decolorizing resin regeneration alkali liquid conveying pipeline respectively. The discharge port of the neutralization kettle is connected to a first filtration device. The liquid outlet of the first filtration device is connected to a second filtration device. The liquid outlet of the second filtration device is connected to a first decolorization treatment device. The decolorized liquid outlet of the first decolorization treatment device is connected to a second decolorization treatment device. The decolorized liquid outlet of the second decolorization treatment device is connected to a concentration device. The concentrated liquid outlet of the concentration device is connected to a crystallization kettle. The discharge port of the crystallization kettle is connected to a separation device. The discharge port of the separation device is connected to a drying device. The discharge port of the drying device is connected to a product storage tank.

2. The production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, wherein, The neutralization kettle includes a kettle body. The top of the kettle body is provided with a feed inlet and a neutralizing agent inlet. The bottom of the kettle body is provided with a discharge port. The outside of the kettle body is provided with a jacket. The inside of the kettle body is provided with a stirring shaft. One end of the stirring shaft is connected to a motor. The upper and lower parts of the stirring shaft are respectively provided with conical stirring barrels with a hollow structure. The top and bottom of the conical stirring barrel are open, and a plurality of stirring rods are provided on the outer wall of the conical stirring barrel. A trapezoidal stirring plate is provided in the middle of the stirring shaft.

3. A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, characterized in that, The first filtration device is a plate and frame filter press, and the second filtration device is a precision filter.

4. A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, characterized in that, The first decolorization treatment device is a decolorizing resin column.

5. A production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, characterized in that, The second decolorization treatment device is a decolorization kettle. The decolorization kettle includes a kettle body. The top of the kettle body is provided with a feed inlet and a decolorizing agent inlet. The bottom of the kettle body is provided with a decolorized liquid outlet. The outside of the kettle body is provided with a jacket. The inside of the kettle body is provided with a stirring shaft. One end of the stirring shaft is connected to a motor. A stirring frame is provided on the stirring shaft. A plurality of spiral blades are provided on the stirring frame, and a stirring rod is provided between two adjacent spiral blades.

6. The production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, wherein, The separation device is a centrifuge.

7. The production system for treating phosphoric acid-containing wastewater and by-producing potassium dihydrogen phosphate according to claim 1, characterized in that, The concentration device is a multi-effect vacuum concentrator.

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