Device for producing alkali by capturing carbon dioxide in industrial waste gas

Abstract

The utility model relates to a device for producing alkali by capturing carbon dioxide in industrial waste gas, which belongs to the technical field of industrial waste gas treatment and comprises a capturing unit for treating the industrial waste gas and capturing carbon dioxide and ammonia gas in the industrial waste gas; the first reaction unit is used for introducing carbon dioxide and ammonia gas in the industrial waste gas into the carbonization cleaning tower for reaction to generate ammonium carbonate; the second reaction unit is used for reacting the ammonium carbonate with the sodium chloride solution to generate sodium bicarbonate and ammonium chloride and separating the sodium bicarbonate from the ammonium chloride; the third reaction unit I is used for carrying out steam calcination on the separated sodium bicarbonate to generate a Na2CO3 product; and the third reaction unit II is used for cooling and crystallizing the separated ammonium chloride to generate an ammonium chloride product. According to the utility model, not only can effective recovery and cyclic utilization of carbon dioxide be realized, but also valuable chemical products can be generated through multiple reactions and resource conversion.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial waste gas treatment, and particularly relates to a device for capturing carbon dioxide in industrial waste gas and producing caustic soda. BACKGROUND

[0002] In the process of rapid development of modern industry, the large emission of industrial waste gas has become a very serious environmental challenge. Among them, the over-emission of carbon dioxide, as the primary greenhouse gas, has a very far-reaching and irreversible impact on global warming. Under this background, capturing carbon dioxide from industrial waste gas is of great significance, not only can effectively reduce the total amount of greenhouse gas emissions into the atmosphere, but also can achieve effective recycling of resources, which is highly consistent with the advanced concept of sustainable development.

[0003] The caustic soda industry has always played a vital role in the chemical industry. The traditional caustic soda process has always been strongly dependent on high-purity carbon dioxide gas sources. However, industrial waste gas contains a considerable amount of carbon dioxide resources, which undoubtedly creates an excellent opportunity for carbon dioxide capture and caustic soda production. With the increasingly stringent environmental standards and the deep-rooted concept of resource recycling in society, the research and breakthrough of carbon dioxide capture and caustic soda production technology in industrial waste gas is of great significance in promoting the green transformation of the chemical industry and actively responding to the various crises caused by climate change. CONTENT OF THE UTILITY MODEL

[0004] The utility model application provides a kind of carbon dioxide capture and caustic soda production device in industrial waste gas, to solve the technical problems of how to realize carbon dioxide capture and caustic soda production in industrial waste gas in prior art partly or entirely. The technical scheme of the utility model application is as follows:

[0005] A kind of carbon dioxide capture and caustic soda production device in industrial waste gas, comprising: capture unit, processing in industrial waste gas, capturing carbon dioxide CO2 and ammonia NH3 in industrial waste gas;First reaction unit, carbon dioxide CO2 and ammonia NH3 in industrial waste gas are introduced into carbonization cleaning tower and react, to generate ammonium carbonate (NH4) 2CO3;Second reaction unit, ammonium carbonate (NH4) 2CO3 and sodium chloride NaCl solution are reacted to generate sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl, and sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl are separated;Third reaction unit one, the separated sodium bicarbonate NaHCO3 is steam calcined to generate Na2CO3 product;Third reaction unit two, the separated ammonium chloride NH4Cl is cooled and crystallized to generate NH4Cl product.

[0006] Optionally, the industrial waste gas carbon dioxide capture and alkali production device further comprises a dissolving unit and a third reaction unit three, the dissolving unit dissolves the Na2CO3 product to form a Na2CO3 solution, and the third reaction unit three reacts the Na2CO3 solution and the urea CO(NH2)2 to generate the NaOCN product.

[0007] Optionally, the industrial waste gas carbon dioxide capture and alkali production device further comprises a carbon dioxide capture and conveying unit and an ammonia gas capture and conveying unit, the carbon dioxide capture and conveying unit captures the carbon dioxide after the steam calcination of the sodium bicarbonate NaHCO3, and conveys the carbon dioxide into the first reaction unit; the ammonia gas capture and conveying unit captures the ammonia gas generated by the decomposition of the NH4Cl product, and conveys the ammonia gas into the first reaction unit.

[0008] Optionally, the industrial waste gas carbon dioxide capture and alkali production device further comprises a carbon dioxide and ammonia gas capture and conveying unit, the carbon dioxide and ammonia gas capture and conveying unit captures the carbon dioxide and the ammonia gas generated by the reaction of the Na2CO3 solution and the urea CO(NH2)2, and conveys the carbon dioxide and the ammonia gas into the first reaction unit.

[0009] The beneficial effects obtained by the present application are as follows:

[0010] (1) In the present application, the carbon dioxide CO2 generated by steam calcination of NaHCO3 is captured and conveyed back to the carbonization washing tower to further supplement and recover the carbon dioxide CO2 in the industrial waste gas, the ammonia gas NH3 generated by the decomposition of ammonium chloride NH4Cl is captured and sent back to the carbonization washing tower to further supplement and recover the ammonia gas NH3 in the industrial waste gas, the carbon dioxide CO2 and the ammonia gas NH3 generated by the generation of sodium cyanate NaOCN can also further supplement and recover the carbon dioxide CO2 and the ammonia gas NH3 in the industrial waste gas, forming a carbon dioxide CO2 recycling closed loop, an ammonia gas NH3 recycling closed loop and a carbon dioxide CO2 and ammonia gas NH3 recycling closed loop, the capture and recovery of the carbon dioxide CO2 not only reduces the emission of waste gas, reduces the influence of greenhouse gases and reduces the pollution to the environment.

[0011] (2) in the practical new type application, carbon dioxide and ammonia gas reaction generates ammonium carbonate (NH4) 2CO3, ammonium carbonate (NH4) 2CO3 and sodium chloride NaCl reaction generates sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl, NaHCO3 is generated sodium carbonate Na2CO3 (soda ash) by steam calcination reaction, NH4Cl is obtained by cooling crystallization pure chlorination, Na2CO3 solution and urea reaction generates sodium cyanate NaOCN, carbon dioxide CO2 and ammonia gas NH3 in industrial waste gas are converted into valuable chemical products: sodium carbonate Na2CO3 product, ammonium chloride NH4Cl product, sodium cyanate NaOCN product, these products are widely used in chemical fertilizer production, chemical synthesis, agriculture and other industrial fields, can provide important raw materials for related industries, improve industrial efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical scheme in the embodiment of the practical new type application, the drawings needed to be used in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the practical new type application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0013] Figure 1 It is the component schematic diagram of the industrial waste gas carbon dioxide capture alkali preparation device of the practical new type application;

[0014] Figure 2 It is the flow schematic diagram of the working mode of the industrial waste gas carbon dioxide capture alkali preparation device of the practical new type application;

[0015] Figure 3 It is the working principle schematic diagram of the industrial waste gas carbon dioxide capture alkali preparation device of the practical new type application;

[0016] The drawings are used to provide further understanding of the practical new type application, and constitute a part of the specification, together with the embodiments of the practical new type application, to explain the practical new type application, and do not constitute the limitation of the practical new type application. DETAILED DESCRIPTION

[0017] The technical scheme in the embodiment of the practical new type application will be clearly and completely described below in combination with the drawings in the embodiment of the practical new type application, obviously, the described embodiment is only a part of the embodiment of the practical new type application, rather than all the embodiments; based on the embodiment in the practical new type application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the practical new type application.

[0018] In the description of the utility model application, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model application. In order to make the purpose, technical scheme and advantages of the utility model application more clear, the utility model application embodiments will be further described in detail below with reference to the drawings.

[0019] As shown in Figure 1 The utility model discloses an industrial waste gas carbon dioxide trapping caustic soda device, including: trapping unit 100, carries out processing to industrial waste gas, traps carbon dioxide CO2 and ammonia NH3 in industrial waste gas, first reaction unit 200, carbon dioxide CO2 and ammonia NH3 in industrial waste gas are passed into carbonization washing tower and are reacted, and ammonium carbonate (NH4) 2CO3 is formed, second reaction unit 300, ammonium carbonate (NH4) 2CO3 and sodium chloride NaCl solution are reacted, and sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl are formed, and sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl are separated, third reaction unit one 401, the sodium bicarbonate NaHCO3 separated is carried out steam calcination and is generated Na2CO3 product, third reaction unit two 402, the separated ammonium chloride NH4Cl is carried out cooling crystallization and is generated NH4Cl product.

[0020] In some embodiments, the first reaction unit 200 includes a carbonization washing tower, the carbonization washing tower is provided with an air inlet for introducing carbon dioxide and ammonia in industrial waste gas respectively, the carbonization washing tower is provided with a gas distributor, so that carbon dioxide and ammonia can be uniformly mixed and fully contacted, and the carbonization washing tower is also provided with a plurality of spraying devices, the plurality of spraying devices can spray appropriate amount of water mist, so that carbon dioxide CO2 and ammonia NH3 can react to generate ammonium carbonate (NH4) 2CO3, and the reacted ammonium carbonate (NH4) 2CO3 can be discharged from the bottom discharge port of the carbonization washing tower.

[0021] In some embodiments, the second reaction unit 300 comprises a reaction kettle, which is provided with an ammonium carbonate solution inlet and a sodium chloride solution inlet, and a pipeline connected to a precise metering device to ensure that the two are fed in proportion. The reaction kettle has a powerful stirrer to ensure that the solution is mixed quickly and thoroughly. The mixed solution after the reaction flows into a settling tank, which can use a caustic washing machine to separate the sodium bicarbonate and ammonium chloride based on their solubility differences. The sodium bicarbonate precipitates at the bottom of the tank, and the ammonium chloride solution is in the upper layer. The tank bottom is connected to a filter through a discharge port to remove impurities and obtain relatively pure sodium bicarbonate. The upper layer of ammonium chloride solution is then fed into a subsequent processing device through an overflow pipeline, which can be cooled and crystallized to obtain ammonium chloride crystals.

[0022] In some embodiments, the third reaction unit one 401 comprises a steam calcination furnace, which is internally provided with a material tray that is resistant to high temperature and uniformly distributed, for placing sodium bicarbonate materials; the steam calcination furnace comprises a steam generating device to control the steam input amount and temperature, so that the steam can fully contact with the sodium bicarbonate for calcination reaction; the steam calcination furnace is provided at the top with an exhaust port to discharge the furnace gas containing carbon dioxide, water vapor and possibly some impurity gases generated during the reaction, and at the bottom with a discharge port, through which the calcined sodium carbonate product can be discharged and enter the subsequent cooling and packaging processes. The entire steam calcination furnace has a well-sealed structure to ensure a stable and safe reaction environment.

[0023] In some embodiments, the third reaction unit two 402 comprises a cooling crystallizer, which comprises a tank body with a jacket, and a cooling medium such as cooling water can be introduced into the jacket to control the cooling temperature in the tank. The tank body is provided with a stirring paddle to uniformly cool the ammonium chloride solution and prevent local supercooling. The tank body is provided at the top with a solution inlet connected to an ammonium chloride solution source, and at the bottom with a discharge port for discharging the crystallized ammonium chloride product. The cooling crystallizer can also include a temperature sensor and a liquid level meter to monitor and control the crystallization process in real time, ensuring the production of high-purity, uniformly sized ammonium chloride products.

[0024] Therefore, in the industrial waste gas carbon dioxide capturing and alkali making device, the integrated multiple reaction units can accurately treat the industrial waste gas, capture the carbon dioxide CO2 and ammonia NH3 in the industrial waste gas, and reduce the pollution to the environment; the first reaction unit reacts the carbon dioxide and the ammonia to generate ammonium carbonate (NH4)2CO3 through the carbonization washing tower, thereby providing high-purity raw materials for subsequent reactions; the second reaction unit reacts the sodium chloride solution and the ammonium carbonate to generate sodium bicarbonate and ammonium chloride, and effectively separates the sodium bicarbonate and the ammonium chloride through the alkali washing machine; the third reaction unit one converts the sodium bicarbonate into sodium carbonate through the steam calcination technology, and the third reaction unit two produces high-purity ammonium chloride through the cooling crystallization technology, thereby realizing the production of the sodium carbonate Na2CO3 product and the ammonium chloride NH4Cl product, achieving the effective recovery and recycling of the carbon dioxide, generating valuable chemical products through multiple reactions and resource conversion, achieving a good balance between environmental protection and economic benefits, and greatly adapting to the sustainable development demand of current industrial production.

[0025] Optionally, the industrial waste gas carbon dioxide capturing and alkali making device further comprises a dissolving unit 500 and a third reaction unit three 403; the dissolving unit 500 dissolves the Na2CO3 product to form a Na2CO3 solution; and the third reaction unit three 403 reacts the Na2CO3 solution and urea CO(NH2)2 to generate a NaOCN product.

[0026] In some embodiments, the dissolving unit comprises a dissolving tank, a Na2CO3 product feeding port and a solvent water inlet are arranged at the top of the dissolving tank, and flow control devices are arranged on the Na2CO3 product feeding port and the solvent water inlet; a stirrer is arranged in the dissolving tank to promote dissolution; and a discharge port is arranged at the bottom of the dissolving tank; meanwhile, the third reaction unit three 403 comprises a reaction tank, a stirring device is arranged in the reaction tank, the stirring device can mix the sodium carbonate solution and the urea sufficiently, a feeding port is arranged at the top of the reaction tank, conveying pipelines of the sodium carbonate solution and the urea are connected to the feeding port respectively, and precise metering devices are arranged on the conveying pipelines to control the feeding ratio; a heating jacket can be wrapped around the tank body of the reaction tank to adjust and maintain the temperature required by the reaction; a discharge port is arranged at the bottom of the reaction tank, a filter is connected to the discharge port, and the filter is used for separating the NaOCN product generated by the reaction from other impurities or substances that are not completely reacted; and a pressure monitoring and safety valve is arranged to ensure that the reaction is carried out safely and stably.

[0027] In the industrial waste gas carbon dioxide capturing and alkali making device, sodium cyanate NaOCN is generated through the reaction of urea and Na2CO3, the added value of the sodium carbonate product is further improved, the sodium cyanate can be used in various industries such as chemical fertilizers and plastics, and the recycling of resources is promoted; while the carbon dioxide is effectively captured and the sodium carbonate and the ammonium chloride are generated, higher-value products are generated through the dissolving and reaction processes, the resource utilization and the environmental protection goals in the waste gas treatment process are realized, and the economic benefits and the environmental protection effects are further improved.

[0028] Optionally, the industrial waste gas carbon dioxide capture and alkali production device further comprises: a carbon dioxide capture and conveying unit and an ammonia gas capture and conveying unit, the carbon dioxide capture and conveying unit captures the carbon dioxide generated in the steam calcination of the sodium bicarbonate NaHCO3 and conveys the carbon dioxide into the first reaction unit, and the ammonia gas capture and conveying unit captures the ammonia gas generated in the decomposition of the NH4Cl product and conveys the ammonia gas into the first reaction unit.

[0029] In some embodiments, the ammonia gas capture and conveying unit comprises a gas collecting hood, a condenser, a gas conveying pipe and a fan, the gas collecting hood collects the ammonia gas generated in the decomposition of the ammonium chloride, the condenser removes water vapor impurities in the ammonia gas, the gas conveying pipe connects the gas collecting hood and the first reaction unit, and the fan provides power to stably convey the ammonia gas along the pipe to the first reaction unit, thereby ensuring the recycling of the ammonia gas.

[0030] In the present application, the carbon dioxide capture and conveying unit can capture the carbon dioxide generated in the steam calcination of the sodium bicarbonate NaHCO3 and timely convey the carbon dioxide into the first reaction unit (carbonation cleaning tower) for secondary recycling, which not only reduces the carbon dioxide emission, but also improves the utilization rate and reaction efficiency of the carbon dioxide in the reaction of the ammonium carbonate (NH4)2CO in the first reaction unit, thereby improving the efficiency and quality of the ammonium carbonate generation; the ammonia gas capture and conveying unit can capture and convey the ammonia gas released in the decomposition of the NH4Cl product and return the ammonia gas to the first reaction unit, thereby ensuring the utilization rate and reaction efficiency of the ammonia gas in the reaction of the ammonium carbonate (NH4)2CO in the first reaction unit and improving the efficiency and quality of the ammonium carbonate generation.

[0031] Optionally, the industrial waste gas carbon dioxide capture and alkali production device further comprises: a carbon dioxide and ammonia gas capture and conveying unit, the carbon dioxide and ammonia gas capture and conveying unit captures the carbon dioxide and ammonia gas generated in the reaction of the Na2CO3 solution and the urea CO(NH2)2 and conveys the carbon dioxide and ammonia gas into the first reaction unit.

[0032] In some embodiments, the carbon dioxide and ammonia gas capture and conveying unit comprises a gas collecting hood, a gas pipe, a compressor and a purification device, the gas collecting hood is located above the third reaction unit three 403 and collects the gases such as carbon dioxide and ammonia gas after the reaction, the gas pipe connects the gas collecting hood, the compressor is installed on the gas pipe to provide gas conveying power, the purification device is used to remove impurities and moisture in the gas to ensure the purity of the gas, and the purified carbon dioxide and ammonia gas are conveyed into the carbonation cleaning tower of the first reaction unit through the pipe.

[0033] In this utility model application, the carbon dioxide and ammonia capture and transport unit can capture carbon dioxide and ammonia generated during the reaction of Na2CO3 solution and urea, and transport them to the first reaction unit in a timely manner. This achieves dual gas capture and transport, avoids the waste of carbon dioxide and ammonia, ensures the optimized ratio of carbon dioxide and ammonia during the reaction of ammonium carbonate (NH4)2CO in the first reaction unit, improves the efficiency and quality of ammonium carbonate production, and enhances the overall environmental performance and sustainability of the carbon dioxide capture and alkali production device in industrial waste gas.

[0034] like Figure 2 As shown, based on the aforementioned carbon dioxide capture and alkali production device for industrial waste gas, the flowchart illustrating the working principle of the device includes:

[0035] Step S100: Treat the industrial waste gas to capture carbon dioxide (CO2) and ammonia (NH3) in the industrial waste gas;

[0036] Specifically, step S100 includes: the industrial waste gas treatment process encompasses multiple treatment operations, including at least dust removal, filtration, and separation of the industrial waste gas to obtain carbon dioxide (CO2) and ammonia (NH3) from it. Through dust removal, filtration, and separation, impurities and harmful pollutants in the waste gas can be effectively removed, purifying the gas, reducing environmental pollution emissions, and meeting environmental quality requirements. Obtaining carbon dioxide and ammonia opens up pathways for resource recycling, improves resource utilization, reduces raw material costs for enterprises, and facilitates subsequent carbon dioxide capture. This ensures a more abundant and higher-quality raw material supply for alkali production, strongly promoting the smooth operation of the alkali production process and improving the stability and economy of the entire production process.

[0037] Step S200: Carbon dioxide (CO2) and ammonia (NH3) in industrial waste gas are passed into a carbonization cleaning tower to generate ammonium carbonate (NH4)2CO3;

[0038] Specifically, step S200 includes:

[0039] In the industrial waste gas treatment process, when industrial waste gas rich in carbon dioxide (CO2) and ammonia (NH3) is introduced into the carbonization cleaning tower, under the internal environmental conditions of the tower, the carbon dioxide (CO2), ammonia (NH3), and water (H2O) in the waste gas meet and, under the synergistic effect of suitable temperature, pressure, and uniform mixing, undergo a chemical reaction to produce ammonium carbonate (NH4)2CO3. The reaction equation is as follows:

[0040] 2NH3+CO2+H2O→(NH4)2CO3.

[0041] Thus, the chemical reaction is relatively mild in terms of reaction conditions and equipment requirements, reducing the difficulty and cost of industrial implementation. It can convert carbon dioxide and ammonia in waste gas, achieve preliminary integration and utilization of resources, reduce harmful gas emissions, and meet environmental protection concepts. At the same time, carbon dioxide CO2 and ammonia NH3 originally existing in the form of gas in industrial waste gas are converted into ammonium carbonate (NH4)2CO3. Ammonium carbonate (NH4)2CO3 is relatively stable and easy to handle and use, and is an important intermediate product for subsequent processes such as alkali production. It provides a key link for the entire industrial waste gas treatment and resource recycling chain, and helps to improve the quality and yield of products such as alkali.

[0042] Step S300: reacting ammonium carbonate (NH4)2CO3 and sodium chloride NaCl solution in the reaction tower to generate sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl, and separating sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl;

[0043] Specifically, step S300 includes:

[0044] In the reaction tower, ammonium carbonate (NH4)2CO3 and sodium chloride NaCl solution are reacted to generate sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl, and the reaction equation of ammonium carbonate (NH4)2CO3 and sodium chloride NaCl solution is:

[0045] (NH4)2CO 3+2 NaCl→2NaHCO3+2NH4Cl.

[0046] In some embodiments, sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl are separated by a caustic washing machine, which generally refers to a device for processing alkali substances such as sodium bicarbonate, sodium hydroxide, etc. In production, such a device is often used to remove by-products such as ammonium chloride from the solution to improve the purity of the main product. The caustic washing machine device can be a simple filter device or a complex continuous flow system, depending on the properties of the mixture being processed and the separation requirements. Specifically, in the separation process of sodium bicarbonate (NaHCO3) and ammonium chloride (NH4Cl), the caustic washing machine uses the difference in solubility of different substances in solution to adjust the temperature, pH, and other conditions of the solution, through filtration, cleaning, and washing steps, to ultimately separate sodium bicarbonate (NaHCO3) and ammonium chloride (NH4Cl), thereby obtaining pure products.

[0047] Thus, first, the raw materials ammonium carbonate and sodium chloride used in the chemical reaction are relatively cheap and easy to obtain, and the reaction process can produce two products with wide application: sodium bicarbonate and ammonium chloride. Sodium bicarbonate can be widely used in cleaning agents, food leavening agents and pharmaceutical products, while ammonium chloride can be widely used in agricultural fertilizers, chemical reagents and metal surface treatment. Second, the reaction process is simple and the reaction conditions are mild. The reaction is carried out at room temperature, avoiding the energy consumption and equipment wear caused by high temperature operation. The reaction occurs in an aqueous solution, which has good reaction control. The yield of the product can be optimized by adjusting the concentration of the reactants and the reaction time. In addition, the sodium bicarbonate generated in the reaction is usually precipitated in solid form, which is easy to separate and purify, so that the yield of sodium bicarbonate product is high. The generated ammonium chloride is dissolved in water, which can be further extracted by evaporation and concentration to ensure the quality of the product. In addition, the reaction has little effect on the environment and belongs to green chemistry. There is no harmful waste gas or pollutant generated in the reaction process, which has great application potential in industrial production, reduces the production cost and environmental pollution risk, and has outstanding performance in the comprehensive benefits of chemical production.

[0048] Step S400: Steam calcination of the separated sodium bicarbonate NaHCO3 to generate Na2CO3 product, and cooling crystallization of ammonium chloride NH4Cl to generate NH4Cl product.

[0049] Specifically, step S400 includes:

[0050] The reaction equation of sodium bicarbonate NaHCO3 in the solution after the reaction is:

[0051] 2NaHCO3→Na2CO3+CO2+H2O.

[0052] Thus, first, the calcination or thermal decomposition reaction of sodium bicarbonate is usually carried out at high temperature, and the temperature needs to reach between 300°C and 400°C to ensure the high efficiency of the reaction and the high purity of the product; after heating, sodium bicarbonate will decompose into sodium carbonate, carbon dioxide and water, that is, the calcination reaction can convert sodium bicarbonate into more stable and widely used sodium carbonate Na2CO3 (soda ash), which can be widely used in glass manufacturing, fertilizer production, detergents and chemical synthesis and other technical fields. Thus, the calcination reaction of sodium bicarbonate NaHCO3 not only provides an effective way for the production of sodium carbonate, but also helps the recovery and utilization of carbon dioxide; in addition, by controlling the temperature of the ammonium chloride solution, ammonium chloride will be precipitated from the saturated solution to form crystals, impurities can be effectively excluded, ensuring the high purity of the prepared ammonium chloride product, and ammonium chloride can be precipitated in solid form, which is convenient for subsequent separation, drying and packaging, thereby improving the production efficiency of ammonium chloride product, and without the need for complex equipment and high energy consumption, the operation is simple and the cost is low, and ammonium chloride can be widely used as a fertilizer or industrial raw material.

[0053] In step S400, during the steam calcination process of NaHCO3, the furnace gas is released after condensation and washing, and the carbon dioxide CO2 is transported to the carbonation washing tower.

[0054] In some embodiments, first, in the aforementioned steam calcination furnace, sodium bicarbonate (NaHCO3) is decomposed into sodium carbonate (Na2CO3), carbon dioxide (CO2) and water (H2O) by heating, and the calcination process is usually carried out at high temperature (about 300°C to 400°C), and the furnace gas contains carbon dioxide, water vapor and possibly some impurity gases; then, the furnace gas first enters a cooling device (such as a cooling tower, a cooler, etc.), and during the cooling process, the gas temperature gradually decreases, and the water vapor condenses into liquid water; the cooled furnace gas enters a washing device, which is usually filled with a washing liquid (such as water or a weak acid solution), and the washing liquid can absorb the soluble substances, dust and impurities in the gas when the furnace gas passes through the washing tower, ensuring the purity of the carbon dioxide; finally, after condensation and washing, the carbon dioxide in the furnace gas is separated from the mixed gas, and a relatively pure carbon dioxide gas stream is obtained, which can be further treated or compressed, stored or transported to the carbonation washing tower to participate in subsequent chemical reactions. Thus, the carbon dioxide is extracted from the furnace gas and recaptured, which helps to save resources and reduce greenhouse gas emissions, and the purity of the carbon dioxide after washing is high, the recycling of carbon dioxide can promote the continuous progress of the reaction, and the carbon dioxide can be used as a raw material to participate in the synthesis of ammonium carbonate (NH4)2CO3, thereby improving the economic efficiency and production efficiency of the reaction.

[0055] In step S400, ammonium chloride NH4Cl is cooled and crystallized to generate NH4Cl product, including the following steps:

[0056] Step S401: cooling ammonium chloride solution: when the ammonium chloride solution reaches the saturated state, the solution is gradually cooled by controlling the temperature, and as the temperature decreases, the solubility of ammonium chloride decreases, and the ammonium chloride in the solution will precipitate from the solution to form ammonium chloride solid crystals. The crystallization process is affected by temperature and solution concentration. The cooled ammonium chloride crystals will usually deposit at the bottom of the solution, which can be separated from the mother liquor by filtration, centrifugation and other methods.

[0057] Step S402: drying treatment: the separated ammonium chloride crystals need to be dried to remove residual moisture. Common drying methods include hot air drying, vacuum drying, etc. If there are impurities in the crystallization process, the impurities can be removed by re-crystallization, filtration, and cooling and crystallization again to obtain ammonium chloride with higher purity.

[0058] Step S403: NH4Cl product: the dried pure ammonium chloride crystals form NH4Cl product, which can be crushed and packaged as needed for further use as fertilizer or chemical reagent.

[0059] In the present application, cooling and crystallization is a mature separation and purification method, which is simple to operate and has relatively low equipment investment. High-purity ammonium chloride product can be obtained by cooling and crystallization, which is suitable for the production of high-purity chemical reagents or fertilizers. The cooling and crystallization process is energy-saving and does not produce a large amount of waste gas or wastewater, which has important application value in industrial production.

[0060] The working mode of the industrial waste gas carbon dioxide capture alkali device further includes step S500: ammonium chloride NH4Cl is decomposed to generate ammonia gas NH3, which can enter the carbonization washing tower.

[0061] In some embodiments, ammonium chloride NH4Cl is decomposed at high temperature to generate ammonia gas NH3 and hydrogen chloride HCl, which is usually carried out at a temperature of about 350-450 DEG C, and its reaction formula is:

[0062] NH4Cl→NH3+HCl.

[0063] In some embodiments, the generated ammonia gas NH3 and hydrogen chloride HCl usually coexist in the reaction furnace. In order to ensure the purity of ammonia gas, the hydrogen chloride HCl and other impurities can be removed by gas separation method. After cooling and purification, the ammonia gas NH3 enters the carbonization washing tower, where it reacts with water and carbon dioxide CO2 to form ammonium carbonate (NH4)2CO3.

[0064] In the utility model application, through the decomposition of ammonium chloride to generate ammonia, and the ammonia enters the carbonization cleaning tower, the content of ammonia is supplemented and increased, which not only helps to form ammonium carbonate (NH4) 2CO3, but also can be recycled, and has remarkable effect on improving production efficiency and reducing pollution.

[0065] The working mode of the industrial waste gas carbon dioxide capture alkali production device further comprises the step S600 of sending the Na2CO3 product into a caustic soda dissolving machine to form a Na2CO3 solution, and reacting the Na2CO3 solution and urea CO(NH2)2 to generate a NaOCN product.

[0066] In some embodiments, the Na2CO3 product is sent into a caustic soda dissolving machine to form a Na2CO3 solution, and then the Na2CO3 solution is reacted with urea CO(NH2)2 to generate a NaOCN (sodium cyanate) product. Specifically, the caustic soda dissolving machine is a device for dissolving alkaline substances, usually using water or other solvents, and under certain temperature and pressure, the Na2CO3 product is completely dissolved in water or other solvents, and the Na2CO3 product is finally converted into a Na2CO3 saturated solution or a Na2CO3 concentrated solution.

[0067] In some embodiments, the Na2CO3 solution is mixed with urea CO(NH2)2, which is usually carried out at moderate temperature, and the reaction can also be promoted under heating conditions, and the reaction generates sodium cyanate NaOCN and ammonia NH3, and the reaction equation is:

[0068] Na2CO3+CO(NH2)2→NaOCN+NH3+CO2.

[0069] After the reaction is completed, the sodium cyanate NaOCN can be separated by filtration, crystallization, drying and the like to obtain pure NaOCN product, and the sodium cyanate NaOCN product can be widely used in chemical fertilizer, pesticide production, chemical synthesis and the like.

[0070] In the step S600, in the reaction of the Na2CO3 solution and urea CO(NH2)2, carbon dioxide CO2 and ammonia NH3 are generated, which can supplement the carbon dioxide CO2 and ammonia NH3 in the industrial waste gas.

[0071] In some embodiments, the carbon dioxide CO2 and ammonia NH3 generated by the reaction of the Na2CO3 solution and urea CO(NH2)2 not only can provide raw materials for chemical synthesis and fertilizer production, but also can effectively supplement and recover the carbon dioxide in the industrial waste gas, effectively reduce the emission of the industrial waste gas, and reduce the influence of greenhouse gases,

[0072] Therefore, in the utility model application, first, the carbon dioxide CO2 generated in the steam calcination of NaHCO3 is captured and transported back to the carbonization washing tower to further supplement and recover the carbon dioxide CO2 in the industrial waste gas, after the decomposition of ammonium chloride NH4Cl to generate ammonia gas, the ammonia gas NH3 is captured and sent back to the carbonization washing tower to further supplement and recover the ammonia gas NH3 in the industrial waste gas, the carbon dioxide CO2 and ammonia gas NH3 generated at the same time of generating sodium cyanate NaOCN can also further supplement and recover the carbon dioxide CO2 and ammonia gas NH3 in the industrial waste gas, forming a carbon dioxide CO2 recycling closed loop, an ammonia gas NH3 recycling closed loop and a carbon dioxide CO2 and ammonia gas NH3 recycling closed loop, the capture and recovery of carbon dioxide CO2 not only reduces the emission of waste gas, reduces the influence of greenhouse gas and reduces the pollution to the environment; in addition, the carbon dioxide reacts with ammonia gas to generate ammonium carbonate (NH4)2CO3, in step S300, ammonium carbonate (NH4)2CO3 reacts with sodium chloride NaCl to generate sodium bicarbonate NaHCO3 and ammonium chloride NH4Cl, NaHCO3 is generated by steam calcination reaction to generate sodium carbonate Na2CO3 (soda ash), NH4Cl is obtained by cooling crystallization to obtain pure chlorination, Na2CO3 solution reacts with urea to generate sodium cyanate NaOCN, the carbon dioxide CO2 and ammonia gas NH3 in the industrial waste gas are converted into valuable chemical products: sodium carbonate Na2CO3 product, ammonium chloride NH4Cl product, sodium cyanate NaOCN product, these products are widely used in chemical fertilizer production, chemical synthesis, agriculture and other industrial fields, can provide important raw materials for related industries, improve industrial efficiency.

[0073] Therefore, the industrial waste gas carbon dioxide capture alkali device of the utility model application can not only realize the effective recovery and recycling of carbon dioxide, but also generate valuable chemical products through multiple reactions and resource conversion, achieve a good balance between environmental protection and economic benefits, play an important role in reducing waste gas emission, improving resource utilization efficiency, reducing environmental pollution and improving enterprise efficiency, and greatly meet the sustainable development needs of current industrial production.

[0074] The utility model application and its implementation mode are described above, and this description is not restrictive, and the drawings only show one of the implementation modes of the utility model application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired thereby, without departing from the creative purpose of the utility model application, similar structural modes and embodiments are not creatively designed, which should belong to the protection scope of the utility model application.

Claims

1. A device for capturing carbon dioxide from an industrial exhaust gas for production of caustic, characterized in that, The industrial waste gas carbon dioxide capture and alkali production device comprises: a capture unit for treating industrial waste gas, capturing carbon dioxide and ammonia in the industrial waste gas; a first reaction unit for introducing the carbon dioxide and ammonia in the industrial waste gas into a carbonization washing tower for reaction to generate ammonium carbonate; a second reaction unit for reacting the ammonium carbonate and a sodium chloride solution to generate sodium bicarbonate and ammonium chloride, and separating the sodium bicarbonate and the ammonium chloride; and a third reaction unit one for steam calcining the separated sodium bicarbonate to generate Na2CO3 product; and a third reaction unit two for cooling and crystallizing the separated ammonium chloride to generate ammonium chloride product.

2. The device for capturing carbon dioxide from industrial exhaust gas and producing caustic soda according to claim 1, characterized in that, The industrial waste gas carbon dioxide capture and alkali production device further comprises a dissolution unit and a third reaction unit three, the dissolution unit dissolves the Na2CO3 product to form a Na2CO3 solution, and the third reaction unit three reacts the Na2CO3 solution and urea to generate NaOCN product.

3. The device for capturing carbon dioxide from industrial exhaust gas and producing caustic soda according to claim 1, characterized in that, The industrial waste gas carbon dioxide capture and alkali production device further comprises a carbon dioxide capture and delivery unit and an ammonia capture and delivery unit, the carbon dioxide capture and delivery unit captures carbon dioxide after steam calcination of the sodium bicarbonate, and delivers the carbon dioxide to the first reaction unit; and the ammonia capture and delivery unit captures ammonia generated by decomposition of the ammonium chloride product, and delivers the ammonia to the first reaction unit.

4. The device for capturing carbon dioxide from industrial exhaust gas and producing caustic soda according to claim 1, characterized in that, The industrial waste gas carbon dioxide capture and alkali production device further comprises a carbon dioxide and ammonia capture and delivery unit, the carbon dioxide and ammonia capture and delivery unit captures carbon dioxide and ammonia generated by reaction of the Na2CO3 solution and urea, and delivers the carbon dioxide and ammonia to the first reaction unit.

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