Comprehensive utilization system for preparing sodium carbonate from coal chemical mixed brine

Abstract

The utility model discloses a comprehensive utilization system for preparing sodium carbonate from coal chemical industry mixed brine. The comprehensive utilization system comprises a purification and impurity removal unit, a denitration unit, an alkali preparation unit and a waste liquid treatment unit, the purification and impurity removal unit can perform purification and impurity removal operation on the mixed brine; the denitration unit is used for performing multi-stage treatment on the mixed salt solution to obtain solid calcium sulfate and a refined sodium chloride solution; the alkali production unit is provided with an ammoniation and carbonization device and an ammonia distillation device, the refined sodium chloride solution reacts in the ammoniation and carbonization device to generate a sodium bicarbonate precipitation mixed solution and a mother solution containing ammonium chloride, and the alkali production unit treats the sodium bicarbonate solid-liquid mixed solution to generate a sodium carbonate product; the mother liquor containing ammonium chloride reacts in the ammonia distillation device to obtain mixed waste liquor containing calcium chloride; the waste liquid treatment unit is used for receiving and treating mixed waste liquid containing calcium chloride. The method has the advantages of stability, reliability, high production efficiency and low production cost, the mixed bittern is directly used for preparing sodium carbonate and related byproducts without salt separation treatment, and resource recycling is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater resource treatment equipment, and specifically relates to a comprehensive utilization system for preparing soda ash from coal chemical mixed brine. Background Art

[0002] In the process of modern coal processing and utilization, coal chemical wastewater is one of the most difficult high-concentration wastewaters to treat. This high-concentration wastewater mainly includes acidic organic wastewater and other high-concentration wastewater, especially high-salt wastewater, that is, mixed brine. The wastewater has high water temperature, many suspended solids, high salt content, high hardness, and contains a certain amount of organic matter such as glycerol and medium and low carbon chains. Its composition is complex and has strong toxicity to biochemical bacteria. Moreover, due to its strong inhibitory effect on microbial growth, the technical difficulty of this wastewater treatment is much greater than that of ordinary sewage treatment. After phenol-ammonia recovery, this type of wastewater still has the characteristics of oil, high ammonia nitrogen, high phenol, high COD, complex pollution components, poor biodegradability, and high biological toxicity. The existing method for treating coal chemical wastewater is usually to produce clean water for reuse after zero-emission treatment of coal chemical high-salt wastewater, and the concentrated mixed brine in the coal chemical wastewater will pass through the salt separation system and evaporation crystallization system to obtain solid sodium sulfate or sodium chloride. As far as the chemical industry is concerned, sodium sulfate and sodium chloride are by-product salts produced by fine chemicals, petrochemicals, coal chemicals, printing and dyeing, pharmaceuticals, pesticides, coking, metallurgy, phosphorus chemicals and other industries, accounting for more than 90%. The mixed brine at the end of zero-emission treatment of chemical high-salt wastewater cannot be effectively utilized as a resource. The existing treatment methods are salt separation or no salt separation; for sodium salt that is not separated, the environmental definition is hazardous waste, and the disposal technologies mainly include landfill and high-temperature oxidation. Among them, landfill is the main disposal method for industrial waste salt, but the existing landfill method has the following inevitable defects: First, the investment in landfill sites is high, the landfill area is large, and it has a significant impact on the pollution of the soil environment; in addition, due to the small number of rigid landfills in China, the legality and compliance of landfill cannot be effectively guaranteed. The landfill sites are often places with greater safety and environmental pollution risks, and the landfill cost is high. In addition, the high-temperature oxidation method utilizes the property that inert organic impurities in salt slag are easily decomposed and volatilized under high temperature conditions. By decomposing the organic impurities into volatile gases and carbon slag under high temperature conditions, the purpose of partially removing organic impurities can be achieved. However, the high-temperature oxidation method has the problems of high production costs and the conversion of organic phase impurities into carbon slag is not conducive to deep resource utilization, so it is not suitable for popularization.

[0003] In view of the above situation, it is necessary to effectively improve the existing treatment method of coal chemical mixed brine. To this end, the applicant has made active and effective explorations and formed the technical solution to be introduced below. Utility Model Content

[0004] The purpose of the utility model is to provide a stable, reliable, highly efficient and low-cost comprehensive utilization system for preparing soda ash from mixed brine in coal chemical industry, which helps to effectively achieve the purpose of resource recycling and improved economic benefits by setting up a multi-stage processing unit to directly utilize mixed brine to prepare soda ash and related by-products without the need for salt separation treatment.

[0005] The purpose of the utility model is achieved in this way. A comprehensive utilization system for preparing soda ash from mixed brine in coal chemical industry comprises: a purification and impurity removal unit, a denitrification unit, an alkali making unit and a waste liquid treatment unit which are sequentially connected through pipelines; wherein the purification and impurity removal unit is used to receive mixed brine containing sodium sulfate and sodium chloride and can perform purification and impurity removal operations on the mixed brine to obtain treated pure bittern; the denitrification unit is used to receive the bittern containing sodium sulfate and sodium chloride obtained after the treatment by the purification and impurity removal unit, and the bittern can react with calcium chloride added thereto in the denitrification unit to generate a mixed salt solution containing calcium sulfate and sodium chloride, and the denitrification unit can perform multi-stage treatment on the mixed salt solution to obtain high-purity solid calcium sulfate and refined Sodium chloride solution; the alkali making unit is used to receive the refined sodium chloride solution generated in the denitration unit, the alkali making unit is equipped with an ammonia carbonation device and an ammonia evaporation device, and the refined sodium chloride solution reacts with ammonia and carbon dioxide in the ammonia carbonation device to generate a sodium bicarbonate solid-liquid mixture and a mother liquor containing ammonium chloride, the alkali making unit further performs solid-liquid separation and calcination operations on the solid-liquid mixture containing sodium bicarbonate precipitate to generate a sodium carbonate main product, and the mother liquor containing ammonium chloride can enter the ammonia evaporation device to react with lime milk added thereto to generate ammonia and a mixed waste liquid containing calcium chloride; the waste liquid treatment unit is used to receive the mixed waste liquid containing calcium chloride generated by the alkali making unit and perform multi-stage separation treatment on it to obtain a calcium chloride by-product.

[0006] In a specific embodiment of the utility model, the purification and impurity removal unit includes an impurity removal module, a first impurity liquid collection tank I, a mesoporous separation module and a second impurity liquid collection tank II; wherein, the liquid inlet port of the impurity removal module is used to receive a mixed brine containing sodium sulfate and sodium chloride, and remove the magnesium, silicon, fluorine impurities and heavy metals therein and produce a clear liquid, the first impurity liquid collection tank I is connected to the impurity removal module through a pipeline, and the first impurity liquid collection tank I is used to receive the magnesium, silicon, fluorine impurities and heavy metal waste liquid filtered out from the impurity removal module; the mesoporous separation module is connected to the impurity removal module through a pipeline, and the mesoporous separation module is used to receive the mixed brine clear liquid produced by the impurity removal module and adsorb the inert COD therein, and perform acid-base analysis on the inert COD, and the second impurity liquid collection tank II is connected to the mesoporous separation module through a pipeline, and the second impurity liquid collection tank II is used to receive the inert COD analysis liquid output from the mesoporous separation module.

[0007] In another specific embodiment of the utility model, the impurity removal module is equipped with a dosing device and a chelating resin device connected by a pipeline; wherein the dosing device is used to receive a mixed brine containing sodium sulfate and sodium chloride, and the mixed brine can be stirred and reacted with a specific agent in the dosing device to remove magnesium, silicon, and fluorine impurities, and the magnesium, silicon, and fluorine impurities precipitated after the reaction can be transported to the first miscellaneous liquid collection pool I; the chelating resin device is used to receive the mixed brine output after the magnesium, silicon, and fluorine impurities are removed by the dosing device, and the chelating resin device can adsorb heavy metals in the mixed brine and perform analytical treatment after adsorption saturation, and the waste liquid obtained by the analytical treatment will be transported to the first miscellaneous liquid collection pool I.

[0008] In another specific embodiment of the present invention, the mesoporous separation module is provided with a mesoporous molecular sieve device and a analyzing device connected by a pipeline; wherein, the mesoporous molecular sieve device is used to receive the mixed brine output after being processed by the impurity removal module, the mesoporous molecular sieve device is used to adsorb the inert COD in the mixed brine and remove it, and the mesoporous molecular sieve device can transport the mixed brine after the inert COD is removed to the denitrification unit, and the analyzing device is used to perform acid-base analysis operation on the inert COD adsorbed in the mesoporous molecular sieve device, and the analyzing device can transport the waste liquid obtained after the analysis operation to the second impurity collection tank II.

[0009] In another specific embodiment of the utility model, the denitrification unit includes a reaction tank, a first clarification and refining module I, a filter press, a calcium sulfate preparation module, a second clarification and refining module II and an evaporation and concentration device; wherein the reaction tank is used to receive the mixed solution containing sodium sulfate and sodium chloride obtained after being treated by the purification and impurity removal unit, and the mixed solution in the reaction tank reacts chemically with the calcium chloride added thereto to generate calcium sulfate precipitate and sodium chloride solution; the first clarification and refining module I is connected to the output end of the reaction tank through a pipeline, and the first clarification and refining module I is used to receive the calcium sulfate precipitate obtained by the reaction in the reaction tank and the mixed solution containing sodium chloride and perform solid-liquid separation and solution stirring operations, thereby obtaining calcium sulfate precipitate and a uniformly stirred sodium chloride mixed solution; the filter press is connected to the first clarification and refining module I through a pipeline and is used to receive the calcium sulfate precipitate produced from the first clarification and refining module I, and the filter press can perform filter pressing and dehydration treatment on the calcium sulfate precipitate and obtaining a calcium sulfate mud cake and a clear liquid; the calcium sulfate preparation module is connected to the filter press through a pipeline, and the calcium sulfate preparation module is used to receive the calcium sulfate mud cake filtered out by the filter press and perform a refined drying treatment on it, so as to obtain refined calcium sulfate, i.e., a gypsum product; the second clarifying and refining module II is also connected to the filter press through a pipeline, and the second clarifying and refining module II is used to receive the clear liquid filtered out by the filter press and perform a secondary solid-liquid separation and solution stirring operation on it, so as to further separate the calcium sulfate solid that is not separated in the filter press and output it to the filter press, and at the same time obtain a uniformly stirred sodium chloride mixed solution; the evaporation and concentration device is connected to the output end of the first clarifying and refining module I and the output end of the second clarifying and refining module II through a pipeline, the evaporation and concentration device is used to receive the sodium chloride solution output by the first clarifying and refining module I and the second clarifying and refining module II, and the evaporation and concentration device is used to perform evaporation and concentration treatment on the sodium chloride solution.

[0010] In another specific embodiment of the utility model, the first clarification and refining module I is equipped with a first clarification tank I and a first brine refining device I connected by a pipeline, the first clarification tank I is connected to the output end of the reaction tank and is used to receive the calcium sulfate precipitate and the sodium chloride solution generated in the reaction tank, and the first clarification tank I can perform solid-liquid separation on the calcium sulfate precipitate and the sodium chloride solution, and the calcium sulfate precipitate can be deposited at the bottom of the first clarification tank I and further transported to the filter press, the first brine refining device I is also connected to the first clarification tank I through a pipeline and can receive the sodium chloride solution separated in the first clarification tank I, and the first brine refining device I can homogenize the sodium chloride solution by stirring operation and transport the treated sodium chloride solution to the evaporation concentration device; and the second clarification and refining module II is also equipped with a second clarification tank II and a second brine refining device II connected by a pipeline, the first The second clarification tank II is connected to the output end of the filter press through a pipeline, and the second clarification tank II is used to receive the clear liquid produced by the filter press and allow the calcium sulfate therein to precipitate and then re-transport the calcium sulfate precipitate to the filter press, while the second brine refining device II is connected to the second clarification tank II through a pipeline and can receive the sodium chloride solution separated in the second clarification tank II, and the second brine refining device II can also homogenize the sodium chloride solution through stirring operation and transport the treated sodium chloride solution to the evaporation concentration device; the calcium sulfate preparation module is equipped with a crystallization tank and a calcium sulfate refining and drying device connected by a pipeline, and the crystallization tank is connected to the filter press by a pipeline, the crystallization tank is used to receive the calcium sulfate filter cake obtained by the filter press and produce high-concentration calcium sulfate solids, and the calcium sulfate refining and drying device can receive the high-purity calcium sulfate solids produced in the crystallization tank and dry them to remove moisture to generate gypsum products.

[0011] In a further specific embodiment of the present invention, the alkali making unit is further provided with a centrifugal separation device, a calcining device and an ammonia evaporation waste liquid storage tank; the centrifugal separation device is connected with the ammonia carbonization device through a pipeline, and the centrifugal separation device can receive the sodium bicarbonate precipitate output by the ammonia carbonization device and centrifuge it to separate the sodium bicarbonate solid and the mixed mother liquor, the sodium bicarbonate solid can be transported to the calcining device, and the mixed mother liquor can be transported to the ammonia evaporation device; the calcining device is connected with the centrifugal separation device through a pipeline and is used to receive the sodium bicarbonate solid separated by the centrifugal separation device, and the calcining device can precipitate the sodium bicarbonate solid. The sodium hydrogen solid is calcined to obtain a sodium carbonate product, and the carbon dioxide gas and water vapor generated during the calcination process are transported to the ammonia carbonization device; the ammonia evaporation device is used to receive the supernatant output by the ammonia carbonization device and the mixed mother liquor separated by the centrifugal separation device, and lime milk is quantitatively added to the ammonia evaporation device so that the supernatant and the mixed mother liquor react with them to generate ammonia gas and a mixed waste liquid containing calcium chloride, and the ammonia gas generated in the ammonia evaporation device can be transported back to the ammonia carbonization device as a reaction raw material; the ammonia evaporation waste liquid storage tank is connected to the output end of the ammonia evaporation device through a pipeline and can receive and store the mixed waste liquid containing calcium chloride output by the ammonia evaporation device.

[0012] In a further specific embodiment of the present invention, the waste liquid treatment unit is equipped with a cyclone separation tank, a sludge separation device, a waste liquid clarification tank and a calcium chloride preparation device; wherein the cyclone separation tank is connected to the alkali making unit through a pipeline, and the cyclone separation tank is used to receive the mixed waste liquid containing calcium chloride output by the alkali making unit and can separate the impurities therein, and further obtain solid impurities and supernatant; the waste liquid clarification tank is connected to the cyclone separation tank through a pipeline, and the waste liquid clarification tank is used to receive the supernatant separated by the cyclone separation tank and can clarify it to obtain sludge and supernatant, and the sludge obtained in the waste liquid clarification tank can be transported to the sludge separation device; The sludge separation device is connected with the cyclone separation tank and the waste liquid clarification tank through a pipeline, and the sludge separation device can receive the solid impurities obtained from the cyclone separation tank and the sludge obtained from the waste liquid clarification tank and perform filter pressing separation operation on them, thereby obtaining mud cake and filtrate, and the filtrate obtained in the sludge separation device can be transported to the waste liquid clarification tank for clarification treatment; and the calcium chloride preparation device is connected with the waste liquid clarification tank through a pipeline, and the calcium chloride preparation device can receive a part of the supernatant obtained by clarification in the waste liquid clarification tank, and the calcium chloride preparation device can further separate the supernatant and separate it into sodium chloride solution and calcium chloride solution, and finally prepare calcium chloride.

[0013] In yet another specific embodiment of the present invention, the waste liquid clarification tank is also connected to the reaction tank of the denitrification unit through a pipeline, and most of the supernatant clarified in the waste liquid clarification tank can be returned to the reaction tank, thereby replenishing the raw materials required for the reaction in the reaction tank.

[0014] In yet another specific embodiment of the present invention, the calcium chloride preparation device is also connected to the second clarification and refining module II in the denitrification unit through a pipeline, and the sodium chloride solution separated in the calcium chloride preparation device can be refluxed and transported to the second clarification and refining module II.

[0015] After the utility model adopts the above structure, it has the beneficial effects: by setting the purification and impurity removal unit, the denitration unit, the alkali making unit and the waste liquid treatment unit, it can realize the multi-stage efficient treatment of the coal chemical mixed brine, and realize the preparation of gypsum products and the generation of refined sodium chloride solution through the denitration unit, and then use the alkali making unit to realize the preparation of the main product of soda ash, and the subsequent waste liquid treatment unit can also effectively prepare the by-product calcium chloride, so that the mixed brine is directly used to prepare soda ash without the need for salt separation treatment, and the resource utilization of the sodium salt in the mixed brine is realized, so as to ensure the recycling of resources, reduce waste and improve economic benefits; and the system is stable in operation, the conversion rate of sodium salt is above 95%, the main and by-products prepared by it are high in added value, and have broad market prospects, while the comprehensive energy consumption and cost of production are low, and it can solve the landfill problem of coal chemical waste salt, and the disposal of mixed brine is reliable and stable and achieves environmental protection purposes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The figure is a schematic diagram of the overall structure of an embodiment of the utility model.

[0017] In the figure: 1. Purification and impurity removal unit, 11. Impurity removal module, 111. Dosing device, 112. Chelating resin device, 12. First impurity collection tank I, 13. Mesoporous separation module, 131. Mesoporous molecular sieve device, 132. Analysis device, 14. Second impurity collection tank II; 2. Denitrification unit, 21. Reaction tank, 22. First clarification and refining module I, 221. First clarification tank I, 222. First brine refining device I, 23. Filter press, 24. Calcium sulfate preparation module, 241 .Crystallization tank, 242. Calcium sulfate refining and drying device, 25. Second clarification and refining module II, 251. Second clarification tank II, 252. Second brine refining device II, 26. Evaporation and concentration device; 3. Alkali making unit, 31. Ammonia carbonization device, 32. Ammonia evaporation device, 33. Centrifugal separation device, 34. Calcination device, 35. Ammonia evaporation waste liquid storage tank; 4. Waste liquid treatment unit, 41. Cyclone separation tank, 42. Bottom mud separation device, 43. Waste liquid clarification tank, 44. Calcium chloride preparation device. DETAILED DESCRIPTION

[0018] In order to more clearly understand the technical essence and beneficial effects of the present invention, a detailed description will be given below in the form of embodiments. However, the description of the embodiments is not a limitation on the scheme of the present invention. Any equivalent changes made based on the concept of the present invention that are merely formal and not substantial should be regarded as within the scope of the technical scheme of the present invention.

[0019] In the following description, all concepts related to up, down, left, right, front and back directions or orientations are based on Figure 1 The positions shown are for reference only and thus cannot be understood as a special limitation on the technical solution provided by the present utility model.

[0020] See also Figure 1, shows a comprehensive utilization system for preparing soda ash from coal chemical mixed brine, comprising: a purification and impurity removal unit 1, a denitrification unit 2, an alkali making unit 3 and a waste liquid treatment unit 4 which are connected in sequence through pipelines; wherein the purification and impurity removal unit 1 is used to receive a mixed brine containing sodium sulfate and sodium chloride (the mixed brine is the concentrated solution of coal chemical wastewater discharged in the coal chemical industry) and can perform purification and impurity removal operations on the mixed brine to obtain treated product water, i.e., bittern; the denitrification unit 2 is used to receive the product water containing sodium sulfate and sodium chloride obtained after treatment by the purification and impurity removal unit 1, and the product water can react with calcium chloride added thereto in the denitrification unit 2 to generate a mixed salt solution containing calcium sulfate and sodium chloride, and the reaction is Na2SO4+CaCl2=CaSO4↓+2NaCl, and the denitrification unit 2 can also perform multi-stage treatment on the mixed salt solution to obtain high-purity solid calcium sulfate and a refined sodium chloride solution; the alkali-making unit 3 is used to receive the refined sodium chloride solution generated in the denitrification unit 2, and the alkali-making unit 3 is equipped with an ammonia carbonization device 31 and an ammonia evaporation device 32, and the refined sodium chloride solution reacts with ammonia and carbon dioxide in the ammonia carbonization device 31 to generate sodium bicarbonate precipitate and a mother liquor containing ammonium chloride, and the reaction is NaCl+CO2+NH3+H2O=NaHCO3↓+NH4Cl, and the alkali-making unit 3 further performs solid-liquid separation and calcination operations on the solid-liquid mixture containing the sodium bicarbonate precipitate to generate a sodium carbonate main product, and the mother liquor containing ammonium chloride can enter the ammonia evaporation device 32 to react with the lime milk added thereto and generate ammonia and a mixed waste liquid containing calcium chloride; the waste liquid treatment unit 4 is used to receive the mixed waste liquid containing calcium chloride generated by the alkali-making unit 3 and perform multi-stage separation treatment on it to obtain a calcium chloride by-product.

[0021] In this embodiment, the purification and impurity removal unit 1 includes an impurity removal module 11, a first impurity liquid collection tank I12, a mesoporous separation module 13 and a second impurity liquid collection tank II14; wherein the liquid inlet port of the impurity removal module 11 is used to receive a mixed brine containing sodium sulfate and sodium chloride, and remove magnesium, silicon, fluorine impurities and heavy metals therein and produce a clear liquid, the first impurity liquid collection tank I12 is connected to the impurity removal module 11 through a pipeline, and the first impurity liquid collection tank I12 is used to receive the impurity filtered out of the impurity removal module 11. Magnesium, silicon, fluorine impurities and heavy metal waste liquid; the aforementioned mesoporous separation module 13 is connected to the aforementioned impurity removal module 11 through a pipeline, and the mesoporous separation module 13 is used to receive the mixed brine clear liquid produced by the aforementioned impurity removal module 11 and adsorb the inert COD therein, and perform acid-base analysis on the inert COD, and the aforementioned second impurity liquid collection tank Ⅱ14 is connected to the aforementioned mesoporous separation module 13 through a pipeline, and the second impurity liquid collection tank Ⅱ14 is used to receive the inert COD analysis liquid output from the mesoporous separation module 13.

[0022] Furthermore, the impurity removal module 11 is provided with a dosing device 111 and a chelating resin device 112 connected by a pipeline; wherein the dosing device 111 is used to receive a mixed brine containing sodium sulfate and sodium chloride, and the mixed brine can be stirred and reacted with a specific agent in the dosing device 111 to remove magnesium, silicon, and fluorine impurities, and the magnesium, silicon, and fluorine impurities precipitated after the reaction can be transported to the first miscellaneous liquid collection tank Ⅰ12, and the magnesium, silicon, and fluorine impurities can be regularly pumped into the first miscellaneous liquid collection tank Ⅰ12 by a water pump; the chelating resin device 112 is used to receive the mixed brine output after the magnesium, silicon, and fluorine impurities are removed by the dosing device 111, and the chelating resin device 112 can adsorb the heavy metals in the mixed brine and perform analytical treatment after adsorption saturation, and the waste liquid obtained by the analytical treatment will be transported to the first miscellaneous liquid collection tank Ⅰ12.

[0023] Please continue to see Figure 1 The aforementioned mesoporous separation module 13 is equipped with a mesoporous molecular sieve device 131 and an analysis device 132 connected by a pipeline; wherein the aforementioned mesoporous molecular sieve device 131 is used to receive the mixed brine output after being processed by the aforementioned impurity removal module 11, and the mesoporous molecular sieve device 131 is used to adsorb the inert COD in the mixed brine and remove it, and the mesoporous molecular sieve device 131 can transport the mixed brine after the inert COD is removed to the aforementioned denitrification unit 2, and the aforementioned analysis device 132 is used to perform acid-base analysis operation on the inert COD adsorbed in the mesoporous molecular sieve device 131, and the analysis device 13 2 can transport the waste liquid obtained after the analysis operation to the second impurity liquid collection pool II 14; in this embodiment, the adsorption material of the aforementioned mesoporous molecular sieve device 131 is a carbon-based mesoporous-microporous material, which is used to adsorb the inert COD in the mixed brine, thereby purifying the mixed brine to meet the indicators of the subsequent soda ash preparation process, and the mesoporous-microporous adsorption material can be reused after regeneration; and the aforementioned first impurity liquid collection pool I 12 is used to collect the impurities generated in the impurity removal module 11, and then the impurities are reduced and dried before being disposed of by outsourcing; and the analytical liquid in the aforementioned analytical device 132 is reasonably disposed of in accordance with the national standard for the incineration of organic waste liquid.

[0024] In this embodiment, the denitration unit 2 includes a reaction tank 21, a first clarification and refining module I 22, a filter press 23, a calcium sulfate preparation module 24, a second clarification and refining module II 25 and an evaporation and concentration device 26; wherein the reaction tank 21 is used to receive the mixed solution containing sodium sulfate and sodium chloride obtained after the treatment of the purification and impurity removal unit 1, and the mixed solution in the reaction tank 21 reacts chemically with the calcium chloride added thereto to generate a calcium sulfate precipitate and a sodium chloride mixed solution, and the reaction is Na2SO4+CaCl2=CaSO4↓+2NaCl; the first clarification and refining module I 22 and the first clarification and refining module II 25 are connected to the first clarification and refining module II 26, and the first clarification and refining module II 25 is connected to the first clarification and refining module II 26, and the second ... The output end of the reaction tank 21 is connected by a pipeline, and the first clarification and refining module 22 is used to receive the calcium sulfate precipitate obtained by the reaction in the reaction tank 21 and the mixed solution containing sodium chloride and perform solid-liquid separation and solution stirring operations, thereby obtaining the calcium sulfate precipitate and the uniformly stirred sodium chloride mixed solution; the filter press 23 is connected to the first clarification and refining module 22 by a pipeline and is used to receive the calcium sulfate precipitate produced from the first clarification and refining module 22. The filter press 23 can perform filter pressing and dehydration treatment on the calcium sulfate precipitate to obtain a calcium sulfate mud cake and a clear liquid; the calcium sulfate preparation module 24 is connected to the filter press 2 3 is connected by a pipeline, and the calcium sulfate preparation module 24 is used to receive the calcium sulfate mud cake filtered out by the filter press 23 and perform a refined drying treatment on it, so as to obtain refined calcium sulfate, i.e., gypsum byproduct; the second clarifying and refining module II 25 is also connected to the filter press 23 by a pipeline, and the second clarifying and refining module II 25 is used to receive the clear liquid filtered out by the filter press 23 and perform a secondary solid-liquid separation and solution stirring operation on it, the purpose of which is to prevent residual calcium sulfate precipitation from flowing into the waste liquid treatment unit 4. If there is still calcium sulfate precipitation, it will be further precipitated in the second clarifying and refining module II 25. precipitate, thereby further separating the calcium sulfate solid that has not been separated in the filter press 23 and outputting it to the filter press 23, and at the same time obtaining a uniformly stirred sodium chloride solution; the aforementioned evaporation and concentration device 26 is connected to the output end of the aforementioned first clarification and refining module 22 and the output end of the second clarification and refining module II 25 through a pipeline, and the evaporation and concentration device 26 is used to receive the sodium chloride solution output by the first clarification and refining module 22 and the second clarification and refining module II 25, and the evaporation and concentration device 26 is used to evaporate and concentrate the sodium chloride solution, and the evaporation and concentration device 26 can evaporate the sodium chloride solution to a near saturation concentration.

[0025] Furthermore, the first clarification and refining module I22 is provided with a first clarification tank I221 and a first brine refining device I222 which are connected by a pipeline, the first clarification tank I221 is connected to the output end of the reaction tank 21 and is used to receive the calcium sulfate precipitate and the sodium chloride solution generated in the reaction tank 21, and the first clarification tank I221 can perform solid-liquid separation on the calcium sulfate precipitate and the sodium chloride solution, and the calcium sulfate precipitate can be deposited at the bottom of the first clarification tank I221 and further transported to the filter press 23 ... The first brine refining device I222 is also connected to the first clarification tank I221 through a pipeline and can receive the sodium chloride solution separated in the first clarification tank I221. The first brine refining device I222 can mix the sodium chloride solution evenly through a stirring operation and transport the treated sodium chloride solution to the evaporation concentration device 26; and the second clarification refining module II25 also has a second clarification tank II251 and a second brine refining device II252 connected through a pipeline. The second clarification tank II251 is connected to the second clarification tank II251 through a pipeline. The second clarifier II 251 is connected to the output end of the filter press 23 through a pipeline, and the second clarifier II 251 is used to receive the clear liquid produced by the filter press 23 and allow the calcium sulfate therein to precipitate. After that, the calcium sulfate precipitation will be re-transported to the filter press 23, and the second brine refining device II 252 is connected to the second clarifier II 251 through a pipeline and can receive the sodium chloride solution separated in the second clarifier II 251, and the second brine refining device II 252 can also mix the sodium chloride solution evenly through stirring operation and mix the treated sodium chloride solution. The sodium chloride solution is transported to the evaporation concentration device 26; the aforementioned calcium sulfate preparation module 24 is equipped with a crystallization pool 241 and a calcium sulfate refining and drying device 242 connected by a pipeline, and the aforementioned crystallization pool 241 is connected to the aforementioned filter press 23 by a pipeline. The crystallization pool 241 is used to receive the calcium sulfate mud cake obtained by the aforementioned filter press 23 and produce high-concentration calcium sulfate solids. The aforementioned calcium sulfate refining and drying device 242 can receive the high-concentration calcium sulfate solids produced in the crystallization pool 241 and dry them to remove moisture to generate gypsum products.

[0026] Please continue to see Figure 1 , the aforementioned alkali production unit 3 is located at Figure 1The alkali making unit 3 is located at the right side of the middle part, and the alkali making unit 3 is also equipped with a centrifugal separation device 33, a calcining device 34 and an ammonia evaporation waste liquid storage tank 35; the centrifugal separation device 33 is connected with the ammonia carbonization device 31 through a pipeline, and the centrifugal separation device 33 can receive the sodium bicarbonate precipitate output by the ammonia carbonization device 31 and perform a centrifugal separation operation on it to separate the sodium bicarbonate solid and the mixed mother liquor, the sodium bicarbonate solid can be transported to the calcining device 34, and the mixed mother liquor can be transported to the ammonia evaporation device 32; the calcining device 34 is connected with the centrifugal separation device 33 through a pipeline and is used to receive the sodium bicarbonate solid separated by the centrifugal separation device 33, and the calcining device 34 can calcine the sodium bicarbonate solid to obtain a sodium carbonate product. The calcining device 34 is preferably a calcining furnace, and the carbon dioxide gas and water vapor generated during the calcining process can be transported to the aforementioned ammonia carbonization device 31 so that they can be used as reaction raw materials again; the aforementioned ammonia evaporation device 32 is used to receive the supernatant output by the ammonia carbonization device 31 and the mixed mother liquor separated by the centrifugal separation device 33, and lime milk will be quantitatively added to the ammonia evaporation device 32 so that the supernatant and the mixed mother liquor react with them to generate ammonia gas and a mixed waste liquid containing calcium chloride, and the ammonia gas generated in the ammonia evaporation device 32 can be transported back to the ammonia carbonization device 31 as a reaction raw material; the aforementioned ammonia evaporation waste liquid storage tank 35 is connected to the output end of the aforementioned ammonia evaporation device 32 through a pipeline and can receive and store the mixed waste liquid containing calcium chloride output by the aforementioned ammonia evaporation device 32.

[0027] In this embodiment, the aforementioned ammonia evaporation device 32 is equipped with a dosing device and a tower reaction device, and the dosing device can add lime milk to the tower reaction device. The supernatant output by the ammonia carbonization device 31 and the mixed mother liquor separated by the centrifugal separation device 33 can react with the lime milk in the tower reaction device, and the reaction is 2NH4Cl+Ca(OH)2=2NH3↑+CaCl2+2H2O; the reaction temperature is maintained at 110-117°C at the bottom of the tower, and 80-85°C at the top of the tower. The evaporated ammonia gas is then sent to the aforementioned ammonia carbonization device 31 through the tower top fan as a reaction raw material after the temperature drops to 55-60°C.

[0028] Furthermore, the waste liquid treatment unit 4 is equipped with a cyclone separation tank 41, a sludge separation device 42, a waste liquid clarification tank 43 and a calcium chloride preparation device 44; wherein the cyclone separation tank 41 is connected to the alkali making unit 3 through a pipeline, and the cyclone separation tank 41 is used to receive the mixed waste liquid containing calcium chloride output by the alkali making unit 3 and can separate the impurities therein, and further obtain solid impurities and supernatant; the waste liquid clarification tank 43 is connected to the cyclone separation tank 41 through a pipeline, and the waste liquid clarification tank 43 is used to receive the supernatant separated by the cyclone separation tank 41 and can clarify it to obtain sludge and supernatant, and the sludge obtained in the waste liquid clarification tank 43 can be transported to the sludge separation device 42; the sludge separation device 42 is connected to the cyclone separation tank through a pipeline. The sludge separation device 42 is connected to the waste liquid clarification tank 41 and the waste liquid clarification tank 43, and the sludge separation device 42 can receive the solid impurities obtained by the cyclone separation tank 41 and the sludge obtained by the waste liquid clarification tank 43 and perform filter press separation operation on them, thereby obtaining mud cake and filtrate, and the sludge separation device 42 is a plate and frame filter press separation device, and the filtrate obtained in the sludge separation device 42 can be re-transported to the waste liquid clarification tank 43 for clarification treatment; and the calcium chloride preparation device 44 is connected to the waste liquid clarification tank 43 through a pipeline, and the calcium chloride preparation device 44 can receive a part of the supernatant obtained by clarification in the waste liquid clarification tank 43, and the calcium chloride preparation device 44 can further separate the supernatant and separate it into sodium chloride solution and calcium chloride solution, and finally prepare a calcium chloride product.

[0029] Please continue to see Figure 1 The aforementioned waste liquid clarification tank 43 is also connected to the reaction tank 21 of the aforementioned denitrification unit 2 through a pipeline, and most of the supernatant clarified in the waste liquid clarification tank 43 can be returned to the aforementioned reaction tank 21, thereby replenishing the raw materials required for the reaction in the reaction tank 21, thereby maximizing the utilization of resources.

[0030] Furthermore, the aforementioned calcium chloride preparation device 44 is also connected to the first brine refining device Ⅰ222 of the first clarification and refining module Ⅰ22 in the denitrification unit 2 through a pipeline, and the sodium chloride solution separated in the calcium chloride preparation device 44 can be refluxed and transported to the first brine refining device Ⅰ222; and the calcium chloride preparation device 44 is preferably a nanofiltration membrane device, and can separate sodium chloride and calcium chloride, and the nanofiltration water produced by the calcium chloride preparation device 44 will be further separated by the RO membrane, and the nanofiltration water produced by the RO membrane is further separated to obtain sodium chloride solution and transported to the first brine refining device Ⅰ222, thereby replenishing the sodium chloride in the first brine refining device Ⅰ222, and the nanofiltration concentrate of the calcium chloride preparation device 44 is a CaCl2 solution, which can be collected and stored to prepare the by-product calcium chloride.

[0031] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications should also be regarded as the protection scope of the utility model.

[0032] In summary, the technical solution provided by the utility model makes up for the shortcomings of the existing technology, successfully completes the invention task, and faithfully realizes the technical effects stated by the applicant in the technical effect column above.

Claims

1. A comprehensive utilization system for preparing soda ash from coal chemical mixed brine, characterized in that: include: A purification and impurity removal unit (1), a denitrification unit (2), an alkali production unit (3) and a waste liquid treatment unit (4) are connected in sequence through pipelines; wherein the purification and impurity removal unit (1) is used to receive mixed brine containing sodium sulfate and sodium chloride and can perform purification and impurity removal operations on the mixed brine, thereby obtaining treated product water, namely bittern or brine; the denitrification unit (2) is used to receive product water containing sodium sulfate and sodium chloride obtained after treatment by the purification and impurity removal unit (1), and the product water can react with calcium chloride added thereto in the denitrification unit (2) to generate a mixed salt solution containing calcium sulfate and sodium chloride, and the denitrification unit (2) can perform multi-stage treatment on the mixed salt solution to obtain high-purity solid calcium sulfate and refined sodium chloride solution; the alkali production unit (3) is used to receive the .... The refined sodium chloride solution generated by the denitration unit (2) is provided in the alkali making unit (3) with an ammoniation carbonization device (31) and an ammonia evaporation device (32). The refined sodium chloride solution reacts with ammonia and carbon dioxide in the ammoniation carbonization device (31) to generate sodium bicarbonate precipitate and a mother liquor containing ammonium chloride. The alkali making unit (3) further performs solid-liquid separation and calcination operations on the solid-liquid mixture containing the sodium bicarbonate precipitate to generate a sodium carbonate main product, and the mother liquor containing ammonium chloride can enter the ammonia evaporation device (32) to react with lime milk added thereto to generate ammonia and a mixed waste liquid containing calcium chloride. The waste liquid treatment unit (4) is used to receive the mixed waste liquid containing calcium chloride generated by the alkali making unit (3) and perform multi-stage separation treatment on it to obtain a calcium chloride byproduct.

2. A comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 1, characterized in that: The purification and impurity removal unit (1) comprises an impurity removal module (11), a first impurity liquid collection tank I (12), a mesoporous separation module (13) and a second impurity liquid collection tank II (14); wherein the liquid inlet port of the impurity removal module (11) is used to receive mixed brine containing sodium sulfate and sodium chloride, and remove magnesium, silicon, fluorine impurities and heavy metals therein to produce a clear liquid, the first impurity liquid collection tank I (12) is connected to the impurity removal module (11) through a pipeline, and the first impurity liquid collection tank I (12) is used to receive magnesium filtered out from the impurity removal module (11). Silicon fluorine impurities and heavy metal waste liquid; the mesoporous separation module (13) is connected to the impurity removal module (11) by a pipeline, and the mesoporous separation module (13) is used to receive the mixed brine clear liquid produced by the impurity removal module (11) and adsorb the inert COD therein, and perform acid-base analysis on the inert COD, and the second impurity liquid collection tank II (14) is connected to the mesoporous separation module (13) by a pipeline, and the second impurity liquid collection tank II (14) is used to receive the inert COD analysis liquid output from the mesoporous separation module (13).

3. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 2, characterized in that: The impurity removal module (11) comprises a dosing device (111) and a chelating resin device (112) which are connected by a pipeline; wherein the dosing device (111) is used to receive mixed brine containing sodium sulfate and sodium chloride, and the mixed brine can be stirred and reacted with a specific agent in the dosing device (111) to remove magnesium, silicon and fluorine impurities, and the magnesium, silicon and fluorine impurities precipitated after the reaction can be transported to the first impurity collection pool I (12); the chelating resin device (112) is used to receive the mixed brine output after the magnesium, silicon and fluorine impurities are removed by the dosing device (111), and the chelating resin device (112) can adsorb heavy metals in the mixed brine and perform analytical treatment after adsorption saturation, and the waste liquid obtained by the analytical treatment will be transported to the first impurity collection pool I (12).

4. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 2, characterized in that: The mesoporous separation module (13) is provided with a mesoporous molecular sieve device (131) and a decomposition device (132) connected by a pipeline; wherein the mesoporous molecular sieve device (131) is used to receive the mixed brine output after being processed by the impurity removal module (11), the mesoporous molecular sieve device (131) is used to adsorb and remove the inert COD in the mixed brine, and the mesoporous molecular sieve device (131) can transport the mixed brine after the inert COD is removed to the denitrification unit (2), and the decomposition device (132) is used to perform an acid-base decomposition operation on the inert COD adsorbed in the mesoporous molecular sieve device (131), and the decomposition device (132) can transport the waste liquid obtained after the decomposition operation to the second impurity collection tank II (14).

5. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 1, characterized in that: The denitration unit (2) comprises a reaction tank (21), a first clarification and refining module I (22), a filter press (23), a calcium sulfate preparation module (24), a second clarification and refining module II (25) and an evaporation and concentration device (26); wherein the reaction tank (21) is used to receive a mixed solution containing sodium sulfate and sodium chloride obtained after being treated by the purification and impurity removal unit (1), and the mixed solution in the reaction tank (21) reacts chemically with calcium chloride added thereto to generate a calcium sulfate precipitate and a sodium chloride mixed solution; the first clarification and refining module I (22) and the reaction tank (21) are connected to the filter press; The output end of the reaction tank (21) is connected through a pipeline, and the first clarification and refining module I (22) is used to receive the calcium sulfate precipitate obtained by the reaction in the reaction tank (21) and the mixed solution containing sodium chloride and perform solid-liquid separation and solution stirring operations, thereby obtaining the calcium sulfate precipitate and the uniformly stirred sodium chloride solution; the filter press (23) is connected to the first clarification and refining module I (22) through a pipeline and is used to receive the calcium sulfate precipitate produced from the first clarification and refining module I (22), and the filter press (23) can perform filter pressing and dehydration treatment on the calcium sulfate precipitate to obtain a calcium sulfate mud cake and clear liquid; the calcium sulfate preparation module (24) is connected to the filter press (23) through a pipeline, and the calcium sulfate preparation module (24) is used to receive the calcium sulfate mud cake filtered out by the filter press (23) and perform a refined drying process on it, so as to obtain refined calcium sulfate, i.e., gypsum product; the second clarification and refining module II (25) is also connected to the filter press (23) through a pipeline, and the second clarification and refining module II (25) is used to receive the clear liquid filtered out by the filter press (23) and perform a secondary solid-liquid separation and solution stirring operation on it, so as to further separate The calcium sulfate solid not separated in the filter press (23) is separated and outputted to the filter press (23), and a uniformly stirred sodium chloride mixed solution is obtained at the same time; the evaporation and concentration device (26) is connected to the output end of the first clarification and refining module I (22) and the output end of the second clarification and refining module II (25) through a pipeline, and the evaporation and concentration device (26) is used to receive the sodium chloride solution outputted by the first clarification and refining module I (22) and the second clarification and refining module II (25), and the evaporation and concentration device (26) is used to perform evaporation and concentration treatment on the sodium chloride solution.

6. A comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 5, characterized in that: The first clarification and refining module I (22) comprises a first clarification tank I (221) and a first brine refining device I (222) which are connected by a pipeline, the first clarification tank I (221) is connected to the output end of the reaction tank (21) and is used to receive the calcium sulfate precipitate and the sodium chloride mixed solution generated in the reaction tank (21), and the first clarification tank I (221) can perform solid-liquid separation on the calcium sulfate precipitate and the sodium chloride mixed solution, and the calcium sulfate precipitate can be deposited at the bottom of the first clarification tank I (221) and further transported to the filter press (23), the The first brine refining device I (222) is also connected to the first clarification tank I (221) through a pipeline and can receive the sodium chloride solution separated in the first clarification tank I (221), and the first brine refining device I (222) can mix the sodium chloride solution evenly through a stirring operation and transport the treated sodium chloride solution to the evaporation concentration device (26); and the second clarification refining module II (25) also has a second clarification tank II (251) and a second brine refining device II (252) connected by a pipeline, and the second clarification tank II (251) is connected by a pipeline. The pipeline is connected to the output end of the filter press (23), and the second clarifier II (251) is used to receive the clear liquid produced by the filter press (23) and allow the calcium sulfate therein to precipitate and then re-transport the calcium sulfate precipitate to the filter press (23), while the second brine refining device II (252) is connected to the second clarifier II (251) through the pipeline and can receive the sodium chloride solution separated in the second clarifier II (251), and the second brine refining device II (252) can also mix the sodium chloride solution evenly through stirring operation and refine the chlorine solution after the refining process. The sodium sulfate solution is transported to the evaporation concentration device (26); the calcium sulfate preparation module (24) comprises a crystallization pool (241) and a calcium sulfate refining and drying device (242) which are connected by a pipeline, and the crystallization pool (241) and the filter press (23) are connected by a pipeline. The crystallization pool (241) is used to receive the calcium sulfate mud cake obtained by the filter press (23) and produce high-purity calcium sulfate solids, and the calcium sulfate refining and drying device (242) can receive the high-purity calcium sulfate solids produced in the crystallization pool (241) and dry them to remove moisture to generate gypsum products.

7. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 1, characterized in that: The alkali production unit (3) is further provided with a centrifugal separation device (33), a calcining device (34) and an ammonia evaporation waste liquid storage tank (35); the centrifugal separation device (33) is connected to the ammonia carbonization device (31) through a pipeline, and the centrifugal separation device (33) can receive the sodium bicarbonate precipitate output by the ammonia carbonization device (31) and perform a centrifugal separation operation on it to separate the sodium bicarbonate solid and the mixed mother liquor, the sodium bicarbonate solid can be transported to the calcining device (34), and the mixed mother liquor can be transported to the ammonia evaporation device (32); the calcining device (34) is connected to the centrifugal separation device (33) through a pipeline and is used to receive the sodium bicarbonate solid separated by the centrifugal separation device (33), and the calcining device (34) can precipitate the sodium bicarbonate solid. The solid is calcined to obtain a sodium carbonate product, and the carbon dioxide gas and water vapor generated during the calcination process are transported to the ammonia carbonization device (31); the ammonia evaporation device (32) is used to receive the supernatant output by the ammonia carbonization device (31) and the mixed mother liquor separated by the centrifugal separation device (33), and lime milk is quantitatively added to the ammonia evaporation device (32) so that the supernatant and the mixed mother liquor react with them to generate ammonia gas and a mixed waste liquid containing calcium chloride, and the ammonia gas generated in the ammonia evaporation device (32) can be transported back to the ammonia carbonization device (31) as a reaction raw material; the ammonia evaporation waste liquid storage tank (35) is connected to the output end of the ammonia evaporation device (32) through a pipeline and can receive and store the mixed waste liquid containing calcium chloride output by the ammonia evaporation device (32).

8. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 5, characterized in that: The waste liquid treatment unit (4) comprises a cyclone separation tank (41), a sludge separation device (42), a waste liquid clarification tank (43) and a calcium chloride preparation device (44); wherein the cyclone separation tank (41) is connected to the alkali production unit (3) via a pipeline, and the cyclone separation tank (41) is used to receive the mixed waste liquid containing calcium chloride output by the alkali production unit (3) and can separate the impurities therein, and further obtain solid impurities and supernatant; the waste liquid clarification tank (43) is connected to the cyclone separation tank (41) via a pipeline, and the waste liquid clarification tank (43) is used to receive the supernatant separated by the cyclone separation tank (41) and can clarify it to obtain sludge and supernatant, and the sludge obtained by the waste liquid clarification tank (43) can be transported to the sludge separation device (42); the sludge separation device ( The sludge separation device (42) is connected to the cyclone separation tank (41) and the waste liquid clarification tank (43) through a pipeline, and the sludge separation device (42) can receive the solid impurities obtained in the cyclone separation tank (41) and the sludge obtained in the waste liquid clarification tank (43) and perform a filter press separation operation on them, thereby obtaining a mud cake and a filtrate, and the filtrate obtained in the sludge separation device (42) can be transported to the waste liquid clarification tank (43) for clarification treatment; and the calcium chloride preparation device (44) is connected to the waste liquid clarification tank (43) through a pipeline, and the calcium chloride preparation device (44) can receive a part of the supernatant obtained by clarification in the waste liquid clarification tank (43), and the calcium chloride preparation device (44) can further separate the supernatant and separate it into a sodium chloride solution and a calcium chloride solution, and finally prepare calcium chloride.

9. A comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 8, characterized in that: The waste liquid clarification tank (43) is also connected to the reaction tank (21) of the denitrification unit (2) through a pipeline, and most of the supernatant obtained by clarification in the waste liquid clarification tank (43) can be returned to the reaction tank (21), thereby replenishing the raw materials required for the reaction in the reaction tank (21).

10. The comprehensive utilization system for preparing soda ash from coal chemical mixed brine according to claim 8, characterized in that: The calcium chloride preparation device (44) is also connected to the second clarifying and refining module II (25) in the denitrification unit (2) through a pipeline, and the sodium chloride solution separated in the calcium chloride preparation device (44) can be refluxed and transported to the second clarifying and refining module II (25).

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