Production method and device for preparing ammonium / alkali by microreactor

Abstract

The invention relates to a production method and device for preparing ammonium / alkali through a microreactor, and belongs to the technical field of safety, environmental protection, energy conservation and water conservation. The method comprises the following steps: simultaneously feeding a saturated aqueous solution of sodium chloride and a sodium bicarbonate solution into a mixing zone for premixing, and feeding into a reaction zone for reaction through shunting to obtain a reaction mixed solution; crystallizing, filtering, washing and drying the reaction mixed solution to obtain sodium bicarbonate; performing crystallization, chemical sublimation, precipitation and recrystallization on the mother liquor obtained by filtering to obtain ammonium chloride, and recovering ammonia gas generated in the crystallization, chemical sublimation, precipitation and recrystallization processes of the mother liquor; calcining the sodium bicarbonate to obtain sodium carbonate, and recovering carbon dioxide released in the calcining process; the recovered ammonia gas, carbon dioxide and water are prepared into a sodium bicarbonate solution to be used as a reaction base solution. According to the invention, liquid-gas reaction is improved into liquid-liquid reaction, and the microreactors connected in series and in parallel are improved, so that the yield and purity of the product are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of safe, environment-friendly and energy-saving water-saving technology, and particularly relates to a production method and device for preparing ammonium / alkali by using a micro-reactor. BACKGROUND

[0002] At present, a large amount of by-product salt residue is produced in the production process of many chemical products. For example, 4-5 tons, 0.67 tons, 1.1-1.4 tons of sodium chloride salt residue are produced respectively for every ton of hydrazine hydrate, furan phenol and glyphosate. The annual by-product salt residue of the above three products in China is more than 300,000 tons. The main component of the by-product salt residue in chemical production is sodium chloride, and a small amount of sodium carbonate, sodium hydroxide, water and organic matter are also contained. The by-product salt residue is easy to be caked due to the water content and sodium carbonate, which is not conducive to be used as raw material for other corresponding products. Moreover, the by-product salt residue cannot be directly used as raw material for chlor-alkali industry due to the organic amine and phosphine. Most of the factories stack the by-product salt residue or directly pour it into rivers. The long-term stacking of the by-product salt residue not only occupies land, but also causes great threat to the environment. The soluble salt and impurities are lost, the surrounding soil is salinized, the surrounding vegetation is endangered, the surrounding water source and paddy fields are polluted, and the water source is seriously polluted by directly pouring the by-product salt residue into rivers, which directly threatens the safety of drinking water in the downstream.

[0003] At present, there are three main methods for treating the by-product salt residue in chemical production: (1) salt washing method: the salt residue is washed with water or organic solvent to remove the impurities in the salt residue as much as possible. The treated salt is used in chlor-alkali industry. This method is more suitable for by-product salt residue with less impurities and single impurity composition. The disadvantages of this method are the secondary pollution problems of the washing water or organic solvent and the difficulty in industrialization due to the unstable impurity content in the by-product salt residue and the difficulty in washing the impurities. (2) high temperature treatment method: the salt residue is treated at high temperature to decompose the organic impurities in the salt residue into gas at high temperature, so as to remove the organic impurities. The key of this method is the selection of the decomposition equipment. (3) pure alkali preparation method: the salt residue is prepared into saturated brine solution, and then ammonia gas, carbon dioxide gas or solid ammonium carbonate is introduced under certain conditions. After a period of reaction, solid sodium bicarbonate is crystallized and separated. After washing and high temperature decomposition, pure alkali is prepared. The separated mother liquor mainly contains ammonium chloride, and then ammonium chloride is separated by freezing and recycled to the alkali preparation process. The key of this method is to improve the reaction yield and solve the influence of the organic impurities in the salt residue on the product quality. This method is particularly suitable for enterprises which need pure alkali or ammonium chloride, and can realize the recycling of waste residue and the circular economy.

[0004] The existing soda production method has various problems. For example, the existing method for treating the mixed solution of sodium chloride and ammonium chloride by microfiltration and nanofiltration. The method realizes the concentration of sodium chloride and ammonium chloride by microfiltration and nanofiltration, and generates chlorine, hydrogen and ammonia by electrolysis. Although the method can generate clean energy, the nanofiltration membrane and the microfiltration membrane are prone to enrichment of pollutants, and the operation cost is high, which is difficult for general enterprises to accept. For example, the mixed solid waste of sodium chloride and ammonium chloride is used as raw material, liquid alkali reaction, ammonia gas recovery, concentration and crystallization process is used to treat the solid waste, clean ammonia water solution is recovered, and sodium chloride solid is obtained, realizing the effective separation of ammonium chloride and sodium chloride. The method has the problems of poor separation effect, low product purity and quality, low conversion rate of sodium chloride, and excessive NH 4+ ion residues and low quality. SUMMARY

[0005] In view of the above problems, the present application provides a production method and device for preparing ammonium / alkali by using a microreactor. Through improvement of the device and the process, the production cost is reduced, the environment is protected, and the product conversion rate is high.

[0006] The first object of the present application is to provide a production method for preparing ammonium / alkali based on a microreactor, comprising:

[0007] The saturated aqueous solution of sodium chloride and the NH4HCO3 solution are simultaneously introduced into a mixing zone formed by a plurality of microreactors in series for pre-mixing, and then are introduced into a reaction zone formed by a plurality of microreactors in parallel for reaction, to obtain a reaction mixture;

[0008] The reaction mixture is subjected to crystallization, filtration, washing and drying to obtain sodium bicarbonate;

[0009] The mother liquor obtained by filtration is subjected to crystallization, chemical sublimation, separation and recrystallization to obtain ammonium chloride, and the ammonia gas generated in the processes of crystallization, chemical sublimation, separation and recrystallization is recovered;

[0010] The sodium bicarbonate is calcined to obtain sodium carbonate, and the carbon dioxide released in the calcination process is recovered;

[0011] The recovered ammonia gas, carbon dioxide and water are used to prepare the NH4HCO3 solution as the reaction bottom liquid.

[0012] In the embodiment of the present application, the saturated aqueous solution of sodium chloride is prepared by dissolving the sodium chloride obtained by incineration treatment of sodium chloride waste salt in pure water.

[0013] In the embodiment of the present application, the mass concentration of the NH4HCO3 solution is 30-50%.

[0014] In the embodiment of the present application, the flow ratio of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution is 1:1.0-2.0.

[0015] In the embodiment of the present application, the temperature of the mixing zone formed by the microreactors in series is 20-30℃.

[0016] In the embodiment of the present application, the temperature of the reaction zone formed by the microreactors in parallel is 30-50℃, the residence time is 5-10 min, and the pressure is 0.1-0.5 MPa.

[0017] In the embodiment of the present application, the crystallization temperature of the mixed solution is 55-85℃.

[0018] In the embodiment of the present application, the crystallization temperature of the mother liquor is 5-10℃.

[0019] In the embodiment of the present application, the calcination temperature of the sodium bicarbonate is 200-280℃, and the calcination time is 0.5-1 h.

[0020] The second object of the present application is to provide a production device for preparing ammonium / alkali based on microreactors, comprising a mixing zone, a flow divider, a reaction zone and a discharge zone connected in sequence, wherein the mixing zone is formed by a plurality of microreactors in parallel, and the reaction zone is formed by a plurality of microreactors in parallel.

[0021] The mixing zone is used for the premixing of the simultaneously entered saturated aqueous solution of sodium chloride and NH4HCO3 solution.

[0022] The flow divider is used for the flow division of the obtained liquid and for making the divided fluid enter the reaction zone.

[0023] The reaction zone is used for the reaction of the divided fluid to obtain a reaction mixture.

[0024] The discharge zone is used for the crystallization, filtration, washing and drying of the reaction mixture to obtain sodium bicarbonate, for the crystallization, chemical sublimation, precipitation and recrystallization of the obtained mother liquor to obtain ammonium chloride, for the recovery of the ammonia gas produced in the crystallization, chemical sublimation, precipitation and recrystallization process, for the calcination of the sodium bicarbonate to obtain sodium carbonate, for the recovery of the released carbon dioxide in the calcination process, and for the preparation of the recovered ammonia gas, carbon dioxide and water into NH4HCO3 solution as the reaction bottom liquid.

[0025] In the embodiment of the present application, the number of microreactors in series in the mixing zone is at least two.

[0026] In the embodiment of the present application, the number of microreactors in parallel in the reaction zone is at least three.

[0027] The channel structure of the microreactor comprises a chain type, a fish type, a straight flow type, a circular pie type, a pulse variable diameter type, a rectangular flat pipe structure, a rhombic pie type, a pulse variable diameter type, a rectangular flat pipe structure, an enhanced mixing type circular pie type, and a heart shape structure.

[0028] In the embodiment of the present application, the discharge area comprises a sodium bicarbonate area, an ammonium chloride and ammonia gas area, a sodium carbonate and carbon dioxide area, and a recovery area.

[0029] The sodium bicarbonate area and the ammonium chloride and ammonia gas area are connected by a material conveying pipe, the ammonium chloride and ammonia gas area and the sodium carbonate and carbon dioxide area are connected by a material conveying pipe, the recovery area and the ammonium chloride and ammonia gas area and the sodium carbonate and carbon dioxide area are connected by a gas pipe, and the recovery area and the reaction area are connected by a material conveying pipe.

[0030] The sodium bicarbonate area is used for reaction mixture to be subjected to crystallization, filtration, washing, and drying to obtain sodium bicarbonate.

[0031] The ammonium chloride and ammonia gas area is used for mother liquor obtained by filtration in the sodium bicarbonate area to be subjected to crystallization, chemical sublimation, precipitation, and recrystallization to obtain ammonium chloride, and to recover ammonia gas generated in the process of crystallization, chemical sublimation, precipitation, and recrystallization.

[0032] The sodium carbonate and carbon dioxide area is used for sodium bicarbonate to be calcined to obtain sodium carbonate, and to recover carbon dioxide released in the calcination process.

[0033] The recovery area is used for recovered ammonia gas, carbon dioxide, and water to be made into NH4HCO3 solution as a reaction bottom liquid.

[0034] In the embodiment of the present application, the flow divider comprises an inlet area and a flow area, the inlet area and the flow area are connected by a partition plate, the partition plate is provided with a communication hole, the inlet area is horizontally located at the bottom of the flow area, the inlet area is provided with an inlet, and the side wall of the inlet is adjacent to the partition plate of the communication hole.

[0035] A baffle is vertically arranged in the inner cavity of the flow area, a gap is arranged between one end of the baffle and the side wall of the flow divider, and a gap is arranged between the other end of the baffle and the partition plate.

[0036] A perforated plate is further vertically arranged in the inner cavity of the flow area, one end of the perforated plate is fixed on the side wall of the flow divider, and the other end of the perforated plate is fixed on the partition plate.

[0037] The projection point of the baffle on the partition plate is located between the communication hole and the end of the partition plate close to the inlet, and the communication hole is located between the projection points of the baffle and the perforated plate on the partition plate.

[0038] The plurality of holes are away from the communication hole, and a through pipe is horizontally arranged at a position away from the baffle of each hole on the multi-hole plate, and an end of the through pipe away from the hole penetrates through the side wall of the flow divider as an outlet.

[0039] The present application has the following advantages:

[0040] The present application provides a production method and device for preparing alkali by micro-reactor, which improves the process from liquid-gas reaction to liquid-liquid reaction and the device from series connection to parallel connection, thereby improving the yield of sodium chloride and sodium carbonate (the yield of ammonium chloride reaches 94.6-95.5%, and the yield of sodium carbonate reaches 93.4-95.3%) and the purity of the products (the purity of ammonium chloride reaches 99.4-99.6%, and the purity of sodium carbonate reaches 99.5-99.7%).

[0041] The method and device have the advantages of low cost and convenient operation, which greatly reduces the energy loss in the process, improves the economic benefit, and is friendly to the environment. No waste liquid and waste residue are generated in the treatment process, and the waste salt can be completely converted into useful components.

[0042] Other features and advantages of the present application will be described in the following description, and some will become apparent from the description, or will be understood from the practice of the present application. The purposes and other advantages of the present application can be achieved and obtained by the structures indicated in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0044] Figure 1 A flow chart of a production method for preparing ammonium / alkali based on micro-reactor according to an embodiment of the present application is shown;

[0045] Figure 2 A production device for preparing ammonium / alkali based on micro-reactor according to an embodiment of the present application is shown;

[0046] Figure 3 A structural schematic diagram of a flow divider according to an embodiment of the present application is shown;

[0047] Figure 4 A schematic diagram of a chain pipe structure according to an embodiment of the present application is shown;

[0048] Figure 5A schematic diagram of a fish-shaped pipe structure according to an embodiment of the present invention is shown;

[0049] Figure 6 A schematic diagram of a DC-shaped pipe structure according to an embodiment of the present invention is shown;

[0050] Figure 7 A schematic diagram of a disc-type pulse-diameter variable rectangular flat pipe structure according to an embodiment of the present invention is shown;

[0051] Figure 8 A schematic diagram of a rhomboid disc-type pulse-variable rectangular flat pipe structure according to an embodiment of the present invention is shown.

[0052] Figure 9 A schematic diagram of an enhanced hybrid disc-shaped rectangular flat pipe structure according to an embodiment of the present invention is shown;

[0053] Figure 10 A schematic diagram of a heart-shaped pipe structure according to an embodiment of the present invention is shown;

[0054] In the diagram: 1. Feed pump; 2. Pressure gauge; 3. Flow meter; 4. Microreactor; 5. Thermometer; 6. Diverter; 61. Inlet zone; 62. Diverter zone; 63. Baffle; 64. Perforated plate; 65. Pipe; 10. Feeding zone; 20. Mixing zone; 30. Reaction zone; 40. Discharge zone. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] like Figure 1 As shown, a method for preparing ammonium / alkali based on a microreactor according to an embodiment of the present invention includes:

[0057] Step 1: A saturated aqueous solution of sodium chloride and an NH4HCO3 solution are simultaneously introduced into a mixing zone 20 formed by several microreactors 4 connected in series for premixing. Then, the mixture is split and introduced into a reaction zone 30 formed by several microreactors 4 connected in parallel to react, resulting in a reaction mixture.

[0058] Step 2: The reaction mixture is subjected to crystallization, filtration, washing, and drying to obtain sodium bicarbonate;

[0059] Step three, the mother liquor obtained by filtration, crystallization, chemical sublimation, precipitation, recrystallization to obtain ammonium chloride, and recover the mother liquor in the process of crystallization, chemical sublimation, precipitation, recrystallization of ammonia gas;

[0060] Step four, sodium bicarbonate is calcined to obtain sodium carbonate, and the carbon dioxide released in the calcination process is recovered;

[0061] Step five, the recovered ammonia gas, carbon dioxide and water are made into NH4HCO3 solution as the reaction bottom liquid.

[0062] In the embodiment of the application, in step one, the saturated aqueous solution of sodium chloride is prepared by dissolving the sodium chloride obtained by incineration treatment of sodium chloride waste salt in pure water.

[0063] In the embodiment of the application, in step one, the mass concentration of the NH4HCO3 solution is 30-50%.

[0064] In the embodiment of the application, in step one, the flow ratio of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution is 1:1.0-2.0.

[0065] In the embodiment of the application, in step one, the temperature of the mixing zone formed by the microreactors in series is 20-30℃.

[0066] In the embodiment of the application, in step one, the temperature of the reaction zone formed by the microreactors in parallel is 30-50℃, the residence time is 5-10 min, and the pressure is 0.1-0.5 MPa.

[0067] In the embodiment of the application, in step two, the crystallization temperature of the mixed solution is 55-85℃.

[0068] In the embodiment of the application, in step three, the crystallization temperature of the mother liquor is 5-10℃.

[0069] In the embodiment of the application, in step four, the calcination temperature of the sodium bicarbonate is 200-280℃, and the calcination time is 0.5-1 h.

[0070] In the embodiment of the application, in step five, when the ammonia gas and carbon dioxide are recovered with water, the amount-of-substance ratio of the ammonia gas to the carbon dioxide is controlled to be 1:1.0-1.2.

[0071] As shown in Figure 2 The production device for preparing ammonium / alkali based on microreactors according to the embodiment of the application comprises a mixing zone 20, a flow divider 6, a reaction zone 30 and a discharge zone 40 connected in sequence, the mixing zone 20 is formed by a plurality of microreactors 4 connected in parallel, and the reaction zone 30 is formed by a plurality of microreactors 4 connected in parallel;

[0072] The mixing area 20 is used for pre-mixing of the simultaneously entered saturated aqueous solution of sodium chloride and NH4HCO3 solution;

[0073] The flow divider 4 is used for pre-mixing of the obtained liquid and making the obtained liquid flow into the reaction area;

[0074] The reaction area 30 is used for reaction of the obtained liquid flow, and the reaction mixture is obtained;

[0075] The discharge area 40 is used for crystallization, filtration, washing and drying of the reaction mixture to obtain sodium bicarbonate, and the obtained mother liquor is filtered, crystallized, chemically sublimated, precipitated and recrystallized to obtain ammonium chloride, and the ammonia gas produced in the process of crystallization, chemical sublimation, precipitation and recrystallization is recovered; sodium bicarbonate is calcined to obtain sodium carbonate, and the released carbon dioxide is recovered; and the recovered ammonia gas, carbon dioxide and water are used to prepare NH4HCO3 solution as the reaction bottom liquid.

[0076] In the embodiment of the present application, the number of micro-reactors 4 in series in the mixing area 20 is at least two, which ensures sufficient mixing of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution; in the exemplary embodiment of the present application, the number of micro-reactors 4 in series in the mixing area is two.

[0077] The number of micro-reactors 4 in parallel in the reaction area 30 is at least three, so as to further divide the reaction area 30 into small micro-reaction areas, and ensure sufficient reaction of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution; in the exemplary embodiment of the present application, the number of micro-reactors 4 in parallel in the reaction area 30 is three.

[0078] In the embodiment of the present application, the channel structure of the micro-reactor 4 includes chain type, fish type, straight flow type, round pie type pulse variable diameter type rectangular flat pipe structure, oblique square pie type pulse variable diameter type rectangular flat pipe structure, enhanced mixing type round pie type rectangular flat pipe structure, and heart-shaped structure.

[0079] In the embodiment of the present application, Figure 4 a chain type pipe structure is shown, Figure 5 a fish type pipe structure is shown, Figure 6 a straight flow type pipe structure is shown, Figure 7 a round pie type pulse variable diameter type rectangular flat pipe structure is shown, Figure 8 an oblique square pie type pulse variable diameter type rectangular flat pipe structure is shown, Figure 9 an enhanced mixing type round pie type rectangular flat pipe structure is shown, Figure 10 a heart-shaped pipe structure is shown;

[0080] The microreactor 4 of the chain-shaped pipeline structure is composed of a first flow channel and a first flow channel arranged in cross, wherein the flow splitting and flow converging of fluid are realized by arranging a first block in the first flow channel and a second block in the second flow channel, and the relative arrangement of the first block and the second block can change the flow direction to realize the acceleration of the flow rate and improve the mixing effect of the microreactor;

[0081] The microreactor 4 of the fish-shaped pipeline structure is provided with three flow channels for splitting, and the flow channels on both sides are expanded and contracted to realize the purpose of improving the mixing effect and reducing the pressure drop in the system. An elliptical baffle is arranged before the fluid converges, so that the fluid in the central flow channel is split and collides with the fluid on both sides, the mass transfer effect is enhanced, and the collision area is expanded due to the elliptical baffle, so that the pressure drop caused by the convergence is reduced;

[0082] The microreactor 4 of the straight-flow-shaped pipeline structure is provided with a straight-flow-shaped pipeline structure, a conventional structure, a small channel pressure drop, and no dead area in the mixing flow channel, but the mixing capacity is poorer than that of other structures;

[0083] The microreactor 4 of the circular pie-shaped pulse variable-diameter rectangular flat pipeline structure is composed of a plurality of circular pie-shaped structures connected in sequence, and the liquid flows in the microreactor of the pipeline structure, and the pressure in the reactor is increased by variable-diameter to increase the mixing effect of the fluid;

[0084] The microreactor 4 of the oblique square pie-shaped pulse variable-diameter rectangular flat pipeline structure has the same mixing and pressure increasing characteristics as the above-mentioned circular pie-shaped pulse variable-diameter rectangular flat pipeline structure, except that the appearance of the two continuous units is different;

[0085] The microreactor 4 of the enhanced mixing type circular pie-shaped rectangular flat pipeline structure is based on the circular pie-shaped pulse variable-diameter rectangular flat pipeline structure, and a rectangular small baffle is added to increase the collision between the fluids and strengthen the mixing effect;

[0086] The microreactor 4 of the heart-shaped pipeline structure is composed of a plurality of heart-shaped cavities connected in sequence, and the liquid flows in the heart-shaped pipeline structure, and each heart-shaped cavity forms a small counter-stirring area, and the head and tail connection parts are equivalent to the pressurization part, forming a continuous stirring and pressurization system for the liquid, so that the solution reaction is more sufficient.

[0087] In the embodiment of the present application, the discharge area 40 includes a sodium bicarbonate area, an ammonium chloride and ammonia gas area, a sodium carbonate and carbon dioxide area, and a recovery area;

[0088] The sodium bicarbonate area, the ammonium chloride and ammonia area are connected by a material conveying pipeline, the ammonium chloride and ammonia area, the sodium carbonate and carbon dioxide area are connected by a material conveying pipeline, the recovery area is connected with the ammonium chloride and ammonia area, the sodium carbonate and carbon dioxide area by a gas pipeline respectively, and the recovery area and the reaction area are connected by a material conveying pipeline;

[0089] The sodium bicarbonate area is used for obtaining sodium bicarbonate by crystallization, filtration, washing and drying of the reaction mixture;

[0090] The ammonium chloride and ammonia area is used for obtaining ammonium chloride by crystallization, chemical sublimation, precipitation and recrystallization of the mother liquor obtained by filtration of the sodium bicarbonate area, and recycling ammonia generated in the crystallization, chemical sublimation, precipitation and recrystallization process;

[0091] The sodium carbonate and carbon dioxide area is used for obtaining sodium carbonate by calcination of sodium bicarbonate, and recycling carbon dioxide released in the calcination process;

[0092] The recovery area is used for recycling ammonia, carbon dioxide and water to prepare NH4HCO3 solution as a reaction bottom solution, so as to improve the environmental protection of the reaction.

[0093] In the embodiment of the present application, the saturated aqueous solution of sodium chloride and the NH4HCO3 solution are simultaneously introduced into the mixing area through the feeding area 10 connected with the mixing area, so as to conveniently control the feeding ratio of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution.

[0094] The feeding area 10 is composed of two material conveying pipelines, one of which is used for transporting the saturated aqueous solution of sodium chloride, and the other of which is used for transporting the NH4HCO3 solution.

[0095] The material conveying pipelines are respectively provided with a material conveying pump 1, a pressure gauge 2 and a flow meter 3, so as to control the feeding ratio of the saturated aqueous solution of sodium chloride and the NH4HCO3 solution, and the material conveying pump 1, the pressure gauge 2 and the flow meter 3 are sequentially connected in the liquid flow direction.

[0096] As shown in Figure 3 In the embodiment of the present application, the flow divider 6 includes an inlet area 61 and a flow dividing area 62, the inlet area 61 and the flow dividing area 62 are connected by a partition plate, the partition plate is provided with a communication hole, the inlet area 61 is horizontally located at the bottom of the flow dividing area 62, the inlet area 61 is provided with an inlet, the inlet is provided with a side wall adjacent to the partition plate of the communication hole, in the liquid flow direction, the liquid enters the inlet area 61 through the inlet and enters the flow dividing area 62 through the communication hole;

[0097] The inner cavity of the distribution area 62 is vertically provided with a baffle 63, one end of the baffle 63 is provided with a gap between the side wall of the distributor 6, and the other end of the baffle 63 is provided with a gap between the partition plate;

[0098] The inner cavity of the distribution area 62 is further vertically provided with a perforated plate 64, one end of the perforated plate 64 is fixed on the side wall of the distributor 6, and the other end is fixed on the partition plate;

[0099] The projection point of the baffle 63 on the partition plate is located between the communication hole and the end of the partition plate close to the inlet, and the communication hole is located between the projection points of the baffle 63 and the perforated plate 64 on the partition plate;

[0100] The perforated plate 64 is provided with a plurality of holes, and a plurality of holes are away from the communication hole, and each hole of the perforated plate 64 is provided with a through pipe 65 away from the baffle 63, and the end of the through pipe 65 away from the hole penetrates the side wall of the distributor 6 as an outlet.

[0101] In some other embodiments of the present application, a pressure gauge 2 and a flow meter 3 are arranged on the material conveying pipeline between the feeding area 10 and the mixing area 20, and the pressure gauge 2 and the flow meter 3 are connected in sequence according to the liquid flow direction, so as to detect and control the pressure and flow of the liquid entering the reaction area.

[0102] In some other embodiments of the present application, a pressure gauge 2 and a flow meter 3 are arranged on the material conveying pipeline between the distributor 6 and any micro-reactor 4 in the reaction area 30, and the pressure gauge 2 and the flow meter 3 are connected in sequence according to the liquid flow direction, so as to detect and control the pressure and flow of the liquid entering any micro-reactor 4.

[0103] In some other embodiments of the present application, a temperature gauge 5 is arranged in any micro-reactor 4, so as to monitor the temperature of the mixing area and the reaction area.

[0104] The following provides examples of production methods for preparing various products based on micro-reactors:

[0105] Example 1

[0106] The production method for preparing ammonium / alkali based on micro-reactors comprises the following steps:

[0107] (1) Device: refer to Figure 2 Determine the connection mode based on the micro-reactor system, the pipeline type is chain channel + heart-shaped channel, the inner diameter of the pipeline and the liquid holding capacity are determined according to the flow rate and reaction residence time, and the heat transfer medium is heat conducting oil.

[0108] (2)Sodium chloride is dissolved in high-purity water by ultrasonic to prepare a saturated sodium chloride solution, wherein the mass concentration of the sodium chloride aqueous solution is 30%, carbon dioxide is introduced into the ammonia water to form an ammonium bicarbonate solution, wherein the saturated ammonium bicarbonate aqueous solution has a concentration of 30%, the saturated sodium chloride solution and the ammonium bicarbonate solution are continuously injected into a production device based on a micro-reactor in a constant flow manner, the temperature of a mixing zone is controlled to be 30°C, the temperature of a reaction zone is controlled to be 40°C, the residence time in the reactor is 5 min, and the reaction pressure is 0.5 MPa, wherein the molar ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is 1:1.0;

[0109] (3) The mixed solution containing the bicarbonate salt is crystallized to precipitate sodium bicarbonate crystals at a crystallization temperature of 55°C; the sodium bicarbonate crystals are calcined at 200°C for 1 h to obtain a sodium carbonate product, and the generated carbon dioxide gas is recovered;

[0110] (4) The mother liquor after filtration is an aqueous solution containing ammonium chloride and sodium chloride, ammonium chloride crude products are precipitated by low-temperature crystallization, wherein the low-temperature crystallization temperature is 10°C, the ammonium chloride crude products are further refined into ammonium chloride products by recrystallization to reduce the content of sodium chloride impurities to less than 2%, and the residual liquid after low-temperature crystallization and recrystallization is recovered as an aqueous solution containing sodium chloride and ammonium chloride into the mother liquor for repeated use, and ammonia gas generated in the processes of crystallization, chemical sublimation, precipitation and recrystallization is recovered.

[0111] (5) The recovered ammonia gas, carbon dioxide and water are prepared into an NH4HCO3 solution as a reaction bottom liquid.

[0112] The product prepared in Example 1 has a sodium carbonate yield of 93.4%, an ammonium chloride yield of 94.8%, a sodium carbonate purity of 99.6%, an ammonium chloride purity of 99.4%, and a sodium chloride utilization rate of 92.3%.

[0113] Example 2

[0114] The production method for preparing ammonium / alkali based on a micro-reactor includes the following steps:

[0115] (1) Device: Refer to Figure 2 The connection mode based on the micro-reactor system is determined, the pipeline type is chain channel + fish channel, the inner diameter of the pipeline and the liquid holding capacity are determined according to the flow rate and the reaction residence time, and the heat transfer medium is heat conducting oil.

[0116] (2)Sodium chloride is dissolved in high-purity water by ultrasonic to prepare a saturated sodium chloride solution, wherein the mass concentration of the sodium chloride aqueous solution is 30%, carbon dioxide is introduced into the ammonia water to form an ammonium bicarbonate solution, wherein the saturated ammonium bicarbonate aqueous solution has a concentration of 40%, the saturated sodium chloride solution and the ammonium bicarbonate solution are continuously injected into a production device based on a micro-reactor in a constant flow manner, the temperature of a mixing zone is controlled to be 20°C, the temperature of a reaction zone is controlled to be 50°C, the residence time in the reactor is 6 min, and the reaction pressure is 0.5 MPa, wherein the amount-of-substance ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is controlled to be 1:1.1;

[0117] (3) The mixed solution containing the bicarbonate salt is crystallized to precipitate sodium bicarbonate crystals at a crystallization temperature of 65°C; the sodium bicarbonate crystals are calcined at 250°C for 0.8 h to obtain a sodium carbonate product, and the generated carbon dioxide gas is recovered;

[0118] (4) The mother liquor after filtration is an aqueous solution containing ammonium chloride and sodium chloride, ammonium chloride crude products are precipitated by low-temperature crystallization, wherein the low-temperature crystallization temperature is 5°C. The ammonium chloride products are further refined by recrystallization to reduce the content of sodium chloride impurities to less than 2%. The residual liquid after low-temperature crystallization and recrystallization, which is an aqueous solution containing sodium chloride and ammonium chloride, is recovered into the mother liquor for repeated use, and the ammonia gas generated in the processes of crystallization, chemical sublimation, precipitation and recrystallization is recovered.

[0119] (5) The recovered ammonia gas, carbon dioxide and water are prepared into an NH4HCO3 solution as a reaction bottom liquid.

[0120] The product prepared in Example 2 has a sodium carbonate yield of 93.9%, an ammonium chloride yield of 94.6%, a sodium carbonate purity of 99.7%, an ammonium chloride purity of 99.6%, and a sodium chloride utilization rate of 92.7%.

[0121] Example 3

[0122] The production method for preparing ammonium / alkali based on a micro-reactor includes the following steps:

[0123] (1) Device: Refer to Figure 1 The connection mode based on the micro-reactor system is determined, the pipe type is: heart-shaped channel + oblique square pie type pulse variable diameter rectangular flat pipe structure, the pipe inner diameter and the liquid holding capacity are determined according to the flow rate and the reaction residence time, and the heat exchange medium is heat conducting oil.

[0124] (2)Sodium chloride is dissolved in high-purity water by ultrasonic to prepare a saturated sodium chloride solution, wherein the mass concentration of the sodium chloride aqueous solution is 40%, carbon dioxide is introduced into the ammonia water to form an ammonium bicarbonate solution, wherein the saturated ammonium bicarbonate aqueous solution has a concentration of 40%, the saturated sodium chloride solution and the ammonium bicarbonate solution are continuously injected into a production device based on a micro-reactor in a constant flow manner, the temperature of a mixing zone is controlled to be 30°C, the temperature of a reaction zone is controlled to be 50°C, the residence time in the reactor is 7 min, and the reaction pressure is 0.3 MPa, wherein the amount-of-substance ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is controlled to be 1:1.2;

[0125] (3) The mixed solution containing the bicarbonate is crystallized to precipitate sodium bicarbonate crystals at a crystallization temperature of 75°C; the sodium bicarbonate crystals are calcined at 280°C for 0.5 h to obtain a sodium carbonate product, and the generated carbon dioxide gas is recovered;

[0126] (4) The mother liquor after filtration is an aqueous solution containing ammonium chloride and sodium chloride, ammonium chloride crude products are precipitated by low-temperature crystallization, wherein the low-temperature crystallization temperature is 10°C. The ammonium chloride products are further refined by recrystallization to reduce the content of sodium chloride impurities to less than 2%. The residual liquid after low-temperature crystallization and recrystallization, which is an aqueous solution containing sodium chloride and ammonium chloride, is recovered into the mother liquor for repeated use, and the ammonia gas generated in the processes of crystallization, chemical sublimation, precipitation and recrystallization is recovered.

[0127] (5) The recovered ammonia gas, carbon dioxide and water are prepared into an NH4HCO3 solution as a reaction bottom liquid.

[0128] The product prepared in Example 3 has a sodium carbonate yield of 94.3%, an ammonium chloride yield of 95.0%, a sodium carbonate purity of 99.6%, an ammonium chloride purity of 99.5%, and a sodium chloride utilization rate of 92.2%.

[0129] Example 4

[0130] The production method for preparing ammonium / alkali based on a micro-reactor includes the following steps:

[0131] (1) Device: Refer to Figure 1 The connection mode based on the micro-reactor system is determined, the pipe type is fish-shaped + oblique square pie pulse variable-diameter rectangular flat pipe structure, the pipe diameter and the liquid holding capacity are determined according to the flow rate and the reaction residence time, and the heat exchange medium is heat conducting oil.

[0132] (2) Sodium chloride is dissolved in high-purity water by ultrasound to prepare a saturated sodium chloride solution with a mass concentration of 40%. Carbon dioxide is passed into ammonia water to form an ammonium bicarbonate solution with a saturated ammonium bicarbonate solution concentration of 40%. The saturated sodium chloride solution and ammonium bicarbonate solution are injected into a microreactor-based production device in a constant flow manner. The mixing zone temperature is controlled at 20°C, the reaction zone temperature is controlled at 40°C, the residence time in the reactor is 7 min, and the reaction pressure is 0.1 MPa. The molar ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is 1:1.3.

[0133] (3) A mixed solution containing bicarbonate is crystallized at a crystallization temperature of 85°C to obtain sodium bicarbonate product by calcining the sodium bicarbonate crystals at 250°C for 0.8h and recovering the generated carbon dioxide gas.

[0134] (4) The filtered mother liquor is an aqueous solution containing ammonium chloride and sodium chloride. Crude ammonium chloride is precipitated by low-temperature crystallization at 5°C. Further purification by recrystallization yields ammonium chloride, reducing the sodium chloride impurity content to below 2%. The residual liquid from low-temperature crystallization and recrystallization is recycled back into the mother liquor as an aqueous solution containing dissolved sodium chloride and ammonium chloride for reuse. Ammonia gas generated during the crystallization, chemical sublimation, precipitation, and recrystallization processes is also recovered from the mother liquor.

[0135] (5) The recovered ammonia, carbon dioxide and water are used to make NH4HCO3 solution as the reaction base liquid.

[0136] In the product prepared in Example 4, the yield of sodium carbonate was 95.3%, the yield of ammonium chloride was 95.1%, the purity of sodium carbonate was 99.5%, the purity of ammonium chloride was 99.4%, and the utilization rate of sodium chloride was 93.0%.

[0137] Example 5

[0138] The production method for preparing ammonium / alkali based on microreactors includes the following steps:

[0139] (1) Apparatus: Refer to Figure 1 The connection method for the microreactor system was determined, and the pipe types were: a disc-type pulse-variable diameter rectangular flat pipe structure + a rhomboid disc-type pulse-variable diameter rectangular flat pipe structure. The pipe inner diameter and liquid holdup were determined based on the flow rate and reaction residence time, and the heat exchange medium was heat transfer oil.

[0140] (2)Sodium chloride is dissolved in high-purity water by ultrasonic to prepare a saturated sodium chloride solution, wherein the mass concentration of the sodium chloride aqueous solution is 50%, carbon dioxide is introduced into the ammonia water to form an ammonium bicarbonate solution, wherein the concentration of the saturated ammonium bicarbonate aqueous solution is 40%, the saturated sodium chloride solution and the ammonium bicarbonate solution are continuously injected into the production device based on the micro-reactor in a constant flow manner, the temperature of the mixing zone is controlled to be 30°C, the temperature of the reaction zone is controlled to be 50°C, the residence time in the reactor is 8 min, and the reaction pressure is 0.3 MPa, wherein the amount-of-substance ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is controlled to be 1:1.4;

[0141] (3) The mixed solution containing the bicarbonate salt is crystallized to precipitate sodium bicarbonate crystals at a crystallization temperature of 75°C; the sodium bicarbonate crystals are calcined at 280°C for 1 h to obtain a sodium carbonate product, and the generated carbon dioxide gas is recovered;

[0142] (4) The mother liquor after filtration is an aqueous solution containing ammonium chloride and sodium chloride, and ammonium chloride crude products are precipitated by low-temperature crystallization, wherein the low-temperature crystallization temperature is 5°C. The ammonium chloride products are further refined by recrystallization to reduce the content of sodium chloride impurities to less than 2%. The residual liquid after low-temperature crystallization and recrystallization, which is an aqueous solution containing sodium chloride and ammonium chloride, is recovered into the mother liquor for repeated use, and the ammonia gas generated in the processes of crystallization, chemical sublimation, precipitation and recrystallization is recovered.

[0143] (5) The recovered ammonia gas, carbon dioxide and water are prepared into an NH4HCO3 solution as a reaction bottom liquid.

[0144] The product prepared in Example 5 has a sodium carbonate yield of 94.8%, an ammonium chloride yield of 95.5%, a sodium carbonate purity of 99.6%, an ammonium chloride purity of 99.6%, and a sodium chloride utilization rate of 93.6%.

[0145] Example 6

[0146] The production method for preparing ammonium / alkali based on a micro-reactor includes the following steps:

[0147] (1) Device: refer to Figure 1 The connection mode based on the micro-reactor system is determined, the pipeline type is: straight flow + oblique square pie type pulse variable diameter rectangular flat pipeline structure, the inner diameter and the liquid holding capacity of the pipeline are determined according to the flow rate and the reaction residence time, and the heat exchange medium is heat conducting oil.

[0148] (2) The sodium chloride is dissolved in high-purity water by ultrasonic to prepare a saturated sodium chloride solution, wherein the mass concentration of the sodium chloride aqueous solution is 50%, and the carbon dioxide is introduced into the ammonia water to form an ammonium bicarbonate solution, wherein the concentration of the saturated ammonium bicarbonate aqueous solution is 40%. The saturated sodium chloride solution and the ammonium bicarbonate solution are injected into a production device based on a micro-reactor in a constant flow and continuous manner. A micro-reactor system composed of a chain channel and a heart-shaped channel is used. The temperature of the mixing zone is controlled to be 30°C, the temperature of the reaction zone is controlled to be 50°C, the residence time in the reactor is 10 min, and the reaction pressure is 0.3 MPa. The amount-of-substance ratio of the saturated sodium chloride solution to the ammonium bicarbonate solution is controlled to be 1:1.5.

[0149] (3) The mixed solution containing the bicarbonate salt is crystallized to precipitate sodium bicarbonate crystals at a crystallization temperature of 75°C. The sodium bicarbonate crystals are calcined at 280°C for 1 h to obtain a sodium carbonate product, and the generated carbon dioxide gas is recovered.

[0150] (4) The mother liquor after filtration is an aqueous solution containing ammonium chloride and sodium chloride. The ammonium chloride is crystallized from the aqueous solution at a low temperature to precipitate ammonium chloride crude products, wherein the low-temperature crystallization temperature is 5°C. The ammonium chloride crude products are further refined by recrystallization to obtain ammonium chloride products, so that the content of sodium chloride impurities in the ammonium chloride products is reduced to less than 2%. The residual solution after the low-temperature crystallization and the recrystallization is recovered as an aqueous solution containing sodium chloride and ammonium chloride, and is reused as the mother liquor. The ammonia gas generated in the crystallization, the chemical sublimation, the precipitation, and the recrystallization processes is recovered.

[0151] (5) The recovered ammonia gas, carbon dioxide, and water are used to prepare an NH4HCO3 solution as a reaction bottom liquid.

[0152] The product prepared in the present example 6 has a sodium carbonate yield of 94.8%, an ammonium chloride yield of 95.5%, a sodium carbonate purity of 99.6%, an ammonium chloride purity of 99.6%, and a sodium chloride utilization rate of 93.6%.

[0153] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalents. Such modifications or replacements do not change the essence of the corresponding technical solutions, and do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A production method for preparing ammonium / alkali based on a microreactor, characterized in that, include: A saturated aqueous solution of sodium chloride and an NH4HCO3 solution are simultaneously introduced into a mixing zone formed by several microreactors connected in series for premixing. Then, the mixture is diverted into a reaction zone formed by several microreactors connected in parallel to react and obtain a reaction mixture. The reaction mixture was subjected to crystallization, filtration, washing, and drying to obtain sodium bicarbonate; The mother liquor obtained from filtration is subjected to crystallization, chemical sublimation, precipitation, and recrystallization to obtain ammonium chloride, and the ammonia gas generated in the mother liquor during the crystallization, chemical sublimation, precipitation, and recrystallization process is recovered; Sodium bicarbonate is calcined to obtain sodium carbonate, and the carbon dioxide released during the calcination process is recovered. The recovered ammonia, carbon dioxide, and water are used to prepare an NH4HCO3 solution, which is then used as the reaction base liquid.

2. The production method for preparing ammonium / alkali based on a microreactor according to claim 1, characterized in that, The mass concentration of the NH4HCO3 solution is 30-50%.

3. The production method for preparing ammonium / alkali based on a microreactor according to claim 1, characterized in that, The flow rate ratio of the saturated aqueous solution of sodium chloride to the NH4HCO3 solution is 1:1.0 to 2.

0.

4. The production method for ammonium / alkali based on a microreactor according to claim 1, characterized in that, The temperature of the mixing zone formed by the series of microreactors is 20–30°C.

5. The production method for preparing ammonium / alkali based on a microreactor according to claim 1, characterized in that, The temperature of the reaction zone formed by the parallel connection of the microreactors is 30–50°C, the residence time is 5–10 min, and the pressure is 0.1–0.5 MPa.

6. The production method for preparing ammonium / alkali based on a microreactor according to claim 1, characterized in that, The crystallization temperature of the reaction mixture is 55–85°C.

7. The production method for preparing ammonium / alkali based on a microreactor according to claim 1, characterized in that, The crystallization temperature of the mother liquor is 5–10°C.

8. A method for preparing ammonium / alkali based on a microreactor according to any one of claims 1-7, characterized in that, The sodium bicarbonate is calcined at a temperature of 200–280°C for 0.5–1 hour.

9. A production apparatus for preparing ammonium / alkali based on a microreactor, characterized in that, include: The mixing zone, the distributor, the reaction zone, and the discharge zone are connected in sequence. The mixing zone is formed by several microreactors connected in parallel, and the reaction zone is formed by several microreactors connected in parallel. The mixing zone is used for the premixing of saturated aqueous solution of sodium chloride and NH4HCO3 solution that enter simultaneously; The distributor is used to split the premixed liquid and allow the split fluid to enter the reaction zone; The reaction zone is used for the reaction of the diverted fluid to obtain a reaction mixture; The discharge zone is used for the reaction mixture to undergo crystallization, filtration, washing, and drying to obtain sodium bicarbonate; and for the mother liquor obtained by filtration to obtain ammonium chloride through crystallization, chemical sublimation, precipitation, and recrystallization, and to recover the ammonia gas generated in the mother liquor during the crystallization, chemical sublimation, precipitation, and recrystallization process. Sodium bicarbonate is calcined to obtain sodium carbonate, and the carbon dioxide released during the calcination process is recovered; the recovered ammonia, carbon dioxide and water are used to prepare NH4HCO3 solution as the reaction base liquid.

10. A production apparatus for preparing ammonium / alkali based on a microreactor according to claim 9, characterized in that, The number of microreactors connected in series in the mixing zone is at least two.

11. A production apparatus for preparing ammonium / alkali based on a microreactor according to claim 9, characterized in that, The number of microreactors connected in parallel in the reaction zone is at least three.

12. The production apparatus for preparing ammonium / alkali based on a microreactor according to claim 9, characterized in that, The channel structures of the microreactor include chain-type pipe structures, fish-shaped pipe structures, direct-flow pipe structures, disc-type pulse-variable diameter rectangular flat pipe structures, rhombic disc-type pulse-variable diameter rectangular flat pipe structures, enhanced mixing disc-type rectangular flat pipe structures, and heart-shaped pipe structures.

13. A production apparatus for preparing ammonium / alkali based on a microreactor according to claim 9, characterized in that, The discharge zone includes a sodium bicarbonate zone, an ammonium chloride and ammonia zone, a sodium carbonate and carbon dioxide zone, and a recovery zone. The sodium bicarbonate zone, ammonium chloride and ammonia zone are connected by a conveying pipeline, the ammonium chloride and ammonia zone and the sodium carbonate and carbon dioxide zone are connected by a conveying pipeline, the recovery zone is connected to the ammonium chloride and ammonia zone and the sodium carbonate and carbon dioxide zone by gas pipelines, and the recovery zone and the reaction zone are connected by a conveying pipeline. The sodium bicarbonate zone is used for the reaction mixture to undergo crystallization, filtration, washing, and drying to obtain sodium bicarbonate; The mother liquor obtained from filtration in the ammonium chloride and ammonia zone is subjected to crystallization, chemical sublimation, precipitation, and recrystallization to obtain ammonium chloride, and the ammonia generated in the mother liquor during the crystallization, chemical sublimation, precipitation, and recrystallization process is recovered. The sodium carbonate and carbon dioxide zone is used for calcining sodium bicarbonate to obtain sodium carbonate, and for recovering the carbon dioxide released during the calcination process. The recovery zone is used to prepare an NH4HCO3 solution from the recovered ammonia, carbon dioxide, and water for use as the reaction base liquid.

14. A production apparatus for preparing ammonium / alkali based on a microreactor according to any one of claims 9-13, characterized in that, The diverter includes an inlet area and a diverting area, the inlet area and the diverting area are connected by a partition, the partition is provided with a connecting hole, the inlet area is laterally located at the bottom of the diverting area, the inlet area is provided with an inlet, and the side wall of the inlet is adjacent to the partition of the connecting hole; The inner cavity of the diversion zone is vertically provided with a baffle. One end of the baffle has a gap between it and the side wall of the diverter, and the other end has a gap between it and the partition. The inner cavity of the diversion zone is also vertically provided with a perforated plate, one end of which is fixed to the side wall of the diverter and the other end is fixed to the partition plate; The projection point of the baffle on the partition is located between the connecting hole and the end of the partition near the inlet, and the connecting hole is located between the projection points of the baffle and the perforated plate on the partition; The perforated plate has several holes, which are far from the connecting hole. Each hole on the perforated plate is provided with a horizontal through pipe at the location far from the baffle. The end of the through pipe away from the hole passes through the side wall of the distributor and serves as an outlet.

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