Composite chlorine dioxide gas preparation equipment and preparation method

Abstract

In order to overcome the problems of crystal blockage and insufficient conversion rate in the existing chlorine dioxide preparation scheme, the invention provides composite chlorine dioxide gas preparation equipment which comprises a front reactor and a main reactor, the front reactor is provided with a front reaction cavity, and the front reaction cavity is used for accommodating a reaction solution of a sodium chlorate solution and hydrochloric acid, so that separated sodium chlorate crystals are deposited in the reaction solution and are subjected to reaction digestion; and the main reactor is used for receiving the gas-liquid mixture without crystal precipitates, which is guided out by the front reactor, so as to continue the reaction. Meanwhile, the invention also discloses a preparation method of the composite chlorine dioxide gas. The composite chlorine dioxide gas preparation equipment provided by the invention thoroughly solves the problem that crystal precipitates are deposited in filler gaps of the main reactor and block the main reactor, greatly improves the utilization rate of raw materials, breaks through the bottleneck of low conversion rate (less than or equal to 50%) of the existing equipment, and achieves the final conversion rate of 90% or above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite chlorine dioxide gas preparation, and particularly relates to a composite chlorine dioxide gas preparation device and a preparation method. BACKGROUND

[0002] Chlorine dioxide (ClO2) is an internationally recognized high-efficiency and safe bactericidal disinfectant, which has the advantages of good bactericidal effect, fast effect, less residue, and no drug resistance, but is unstable in nature and easy to explode, and therefore needs to be prepared on site by a chlorine dioxide generator in water purification applications.

[0003] The current mainstream equipment in the market uses sodium chlorate solution and hydrochloric acid as raw materials, adopts a negative pressure multi-stage reaction process, and is composed of a feeding system, a reaction system, and an absorption system: a metering pump proportionally feeds the raw materials to a reactor, a negative pressure aeration reaction is performed at 55°C to 65°C to generate a gas-liquid mixture, and after being absorbed by a water jet, a disinfectant solution is formed and is introduced into the water to be treated. Although this equipment has a simple structure and is widely used, it has the following key defects: First, the chlorine dioxide conversion rate is extremely low, and is not more than 50% under the best state (verified by Guangzhou Water Purification Co., Ltd. "Chlorine dioxide conversion rate and disinfection dosage analysis"), only reaches the current national standard "Chemical method composite chlorine dioxide generator" (GB-T 20621-2006) qualified product standard (≥50%), and the conversion rate of most drinking water field equipment is at the qualified line, far from the high-efficiency requirement.

[0004] Second, the raw material residue causes health and cost problems. The low conversion rate causes at least 50% of sodium chlorate and a large amount of hydrogen chloride to enter the drinking water with the disinfectant solution. Sodium chlorate, as a disinfection by-product, can oxidize human and animal hemoglobin to cause anemia, and harm the blood circulation and reproductive system (《Production and control of inorganic disinfection by-products of chlorine dioxide in drinking water》points out that the main reason for the over-standard of chlorate in water plants is that the raw materials are not converted); at the same time, the waste of unreacted raw materials increases the preparation cost.

[0005] Therefore, improving the chlorine dioxide conversion rate and eliminating the residue of chlorate in drinking water are the bottlenecks that the industry urgently needs to break through.

[0006] Furthermore, like Figure 2As shown, in the chlorine dioxide preparation equipment, when sodium chlorate solution and hydrochloric acid are mixed, crystals will be generated, which will block the filler and pipeline in the reactor, thereby affecting the chlorine dioxide conversion rate, especially when high-concentration sodium chlorate solution and hydrochloric acid are used, the crystallization blocking problem is more obvious, however, in the existing research, the specific composition and cause of the crystals cannot be understood, therefore, a scheme that can better solve the technical problem has not been proposed, the industry has tried to improve, such as Chen Tianwen et al. in “Current Situation and Development Trend of Chemical Chlorine Dioxide Generator” mentioned that in the chlorine dioxide reactor, the residual liquid in the reaction chamber is emptied at a certain time, and the crystals are diluted and washed with water, but this method wastes a lot of raw materials, cannot solve the problem of low chlorine dioxide conversion rate, and also produces a lot of wastewater, which affects the production efficiency. Another invention patent application CN118976455A discloses a two-stage reaction system, which tries to solve the blocking problem by a front reactor to improve the conversion rate. However, this technology has a fundamental defect: mainly because it mistakenly regards the crystals precipitated from the primary reactor as sodium chloride, and makes the crystals precipitated from the front reactor directly discharged into the filler bed. In fact, this scheme cannot fundamentally solve the problems of blocking and low conversion rate caused by crystallization, on the contrary, the crystals discharged from the primary reactor will be deposited and blocked due to low flow rate, which will also cause the blocking of the filler bed. SUMMARY

[0007] In view of the problems of crystallization blocking and low conversion rate in the existing chlorine dioxide preparation scheme, the present application provides a composite chlorine dioxide gas preparation equipment and a preparation method.

[0008] The technical solution adopted by the present application to solve the above technical problems is as follows: On the one hand, the present application provides a composite chlorine dioxide gas preparation equipment, which comprises a front reactor and a main reactor. The front reactor is provided with a front reaction cavity, which is used to accommodate the reaction liquid of sodium chlorate solution and hydrochloric acid, so that the precipitated sodium chlorate crystals are deposited in the reaction liquid and reacted and dissolved. The main reactor is used to continue the reaction of the gas-liquid mixture without crystal precipitates discharged from the front reactor.

[0009] Optionally, it also comprises a sodium chlorate solution supply device and a hydrochloric acid supply device, the sodium chlorate solution supply device is connected to the front reactor, and the sodium chlorate solution supply device is provided with a heating device and a heat preservation facility.

[0010] Optionally, the front reactor comprises an overflow pipe, the top end of the overflow pipe is inserted into the front reaction cavity to form an overflow port, and a deposition reaction zone for accommodating the reaction liquid and sodium chlorate crystals is formed between the overflow port and the bottom of the front reaction cavity.

[0011] Optionally, the front reactor further comprises a shielding cover, the shielding cover is located in the front reactor cavity, and the shielding cover is located at the periphery of the overflow pipe, the shielding cover separates the deposition reaction zone to form a first deposition reaction zone outside the shielding cover and a second deposition reaction zone inside the shielding cover, the first deposition reaction zone and the second deposition reaction zone are communicated by the bottom of the shielding cover, and the front reactor is provided with a sodium chlorate solution inlet and a hydrochloric acid inlet communicating with the first deposition reaction zone.

[0012] Optionally, the side wall of the shielding cover is provided with a vent hole, and the height of the vent hole is higher than the sodium chlorate solution inlet, the hydrochloric acid inlet and the overflow port.

[0013] Optionally, the main reactor is provided with a filler zone, the filler zone is filled with polyhedral filler, the front reactor is located at the top of the main reactor, and the bottom of the overflow pipe penetrates into the main reactor and extends above the filler zone.

[0014] Optionally, the main reactor is further provided with a flow uniformizing plate, the flow uniformizing plate is located below the overflow pipe, and the overflow pipe is vertically arranged with the flow uniformizing plate.

[0015] Optionally, the main reactor is further provided with at least one flow guide ring, the flow guide ring is located in the filler zone, and the outer edge of the flow guide ring abuts against the inner wall of the filler zone; when the number of the flow guide rings is plural, the plural flow guide rings are arranged in the filler zone from top to bottom.

[0016] Optionally, the side wall of the main reactor is connected with a hot carrier gas pipeline, and the hot carrier gas pipeline is located below the filler zone.

[0017] Optionally, the bottom of the main reactor is connected with a residual liquid leading-out pipeline, and the residual liquid leading-out pipeline is provided with a liquid seal structure.

[0018] Optionally, further comprising a gas-liquid separator, a liquid-carrying gas leading-in pipe, an exhaust pipe and a liquid discharge pipe, the liquid-carrying gas leading-in pipe is connected to the upper part of the filler zone and the gas-liquid separator respectively, the exhaust pipe is connected to the gas-liquid separator and used for leading out the composite chlorine dioxide gas after gas-liquid separation, and the liquid discharge pipe is connected to the gas-liquid separator and the filler zone respectively and used for leading the liquid after gas-liquid separation to the filler zone.

[0019] Optionally, the gas-liquid separator comprises a baffle separation chamber and a sump, the baffle separation chamber is located above the sump, a plurality of baffle plates are arranged in the baffle separation chamber, the bottom surface of the sump is provided with a splash-proof layer, the liquid-carrying gas inlet pipe is connected to the top of the baffle separation chamber, the liquid outlet pipe is connected to the bottom of the sump, and the gas outlet pipe is connected to the side wall of the sump.

[0020] In another aspect, the application provides a method for preparing composite chlorine dioxide gas, comprising the following operation steps: The sodium chlorate solution and hydrochloric acid are introduced into the pre-reaction chamber to mix and form a reaction liquid, and a deposition reaction zone for accommodating the reaction liquid is formed in the pre-reaction chamber, in the deposition reaction zone, sodium chlorate crystals are precipitated in the reaction liquid and react and digest; The gas-liquid mixture without crystal precipitate is introduced into the main reactor for continuous reaction to generate composite chlorine dioxide gas.

[0021] Optionally, the sodium chlorate solution and hydrochloric acid are introduced in a molar ratio of 1: (2.0-2.2) of sodium chlorate to HCl; the mass concentration of the hydrochloric acid is 31%-40%, and the mass concentration of sodium chlorate in the sodium chlorate solution is 30%-67%; the sodium chlorate solution is heated to have a temperature of 25°C-100°C.

[0022] Optionally, the pre-reaction chamber comprises the following reaction process: The deposition reaction zone comprises a second deposition reaction zone and a first deposition reaction zone surrounding the outside of the second deposition reaction zone, the bottom of the first deposition reaction zone and the bottom of the second deposition reaction zone are in communication with each other, the sodium chlorate solution and hydrochloric acid are mixed and reacted in the first deposition reaction zone, sodium chlorate crystals are precipitated and deposited at the bottom of the first deposition reaction zone and the bottom of the second deposition reaction zone under the action of gravity; the liquid part flows through the second deposition reaction zone through the bottom of the first deposition reaction zone, and continuously reacts in the process of flowing; the composite chlorine dioxide gas generated in the first deposition reaction zone and the second deposition reaction zone forms a gas-liquid mixture with the reaction liquid flowing through the second deposition reaction zone and is discharged to the main reactor; in the deposition reaction zone, the precipitation and reaction digestion of sodium chlorate crystals occur simultaneously; first, as the reaction liquid starts to be injected, the deposition amount of sodium chlorate crystals increases, then the reaction rate of sodium chlorate crystals with HCl increases, until the precipitation and consumption of sodium chlorate crystals reach a balance state, the deposition amount of sodium chlorate crystals remains unchanged, and finally, as the injection of the reaction liquid stops, the sodium chlorate crystals gradually decrease and disappear.

[0023] Optionally, the main reactor further comprises the following process: The gas-liquid mixture without crystal precipitates is introduced into the main reactor through the overflow pipe, a flow distribution plate is arranged at the bottom of the overflow pipe, and the gas-liquid mixture contacts the polyhedral filler downward along the outer edge of the flow distribution plate to form a double-wedge-shaped uniform downward flow section on the central section of the main reactor.

[0024] Optionally, the main reactor further comprises the following process: The gas-liquid mixture without crystal precipitates is introduced into the filler zone from the top of the filler zone, and the hot carrier gas is introduced into the bottom of the filler zone. The reaction liquid flows downward on the surface of the polyhedral filler in the filler zone to form a liquid film, and the hot carrier gas flows upward in the filler zone. The reaction liquid in the liquid film continuously reacts to generate composite chlorine dioxide gas and enters the hot carrier gas, and the liquid gas is discharged from the filler zone by dilution of the hot carrier gas.

[0025] Optionally, the main reactor further comprises the following process: During the downward flow of the reaction liquid, the reaction liquid naturally gathers towards the inner wall of the main reactor. The liquid film on the inner wall of the main reactor thickens, the reaction rate decreases, and the flow rate increases. A flow guide ring is arranged on the inner wall of the main reactor. When the reaction liquid contacts the flow guide ring, the liquid film on the inner wall flows radially inward along the upper surface of the flow guide ring, contacts the polyhedral filler downward along the inner surface of the flow guide ring, and forms a double-wedge-shaped uniform downward flow section on the central section of the main reactor again.

[0026] Optionally, the following operation is further included: The liquid gas is introduced into the gas-liquid separator for gas-liquid separation, and the separated liquid is introduced back into the filler zone for continuous reaction.

[0027] The present application is based on the error recognition that the crystalline substance generated in the reaction process is NaCl, which is overturned. As described in CN118976455A invention patent, and as described in "Current Situation and Development Trend of Chemical Chlorine Dioxide Generator" by Chen Tianwen et al. in the Central Laboratory of Fujian University. Due to the error recognition of the industry to the crystalline substance, the corresponding error response technology means is caused, which increases the cost. In view of the technical problem of the crystalline substance causing the blockage of the filler bed, the inventors first prove by quantitative calculation that even if NaClO3 and hydrogen chloride completely react, the sodium chloride generated relative to the sum of the water carried by sodium chlorate solution and hydrochloric acid and the water generated by reaction cannot reach the dissolution saturation precipitation, which proves that the crystalline substance is not sodium chloride as believed by the technicians in the field. Then, the inventors analyze the composition of the precipitated crystal and find that the precipitated crystal is sodium chlorate. It is speculated that the formation mechanism is that, at a certain temperature, Na + , ClO3 - , and water molecules generate hydrated Na + , and hydrated ClO3 -, forming a steady-state system; in a closed container, most of the HCl in hydrochloric acid (especially concentrated hydrochloric acid) exists in the form of HCl • nH2O with H2O, and a small amount of HCl generates hydrated H + and hydrated Cl - , forming a quasi-stable system; when hydrochloric acid is mixed with a sodium chlorate solution to form a reaction liquid, due to the ability of H + and Cl - to compete for water molecules being far stronger than that of Na + and ClO3 - , the equilibrium of the two systems is broken, and in the new system, part of the HCl • nH2O is taken from the hydrated Na + and ClO3 - to form hydrated H + and hydrated Cl - , and Na + and ClO3 - are combined to precipitate sodium chlorate crystals.

[0028] Based on the above findings, the inventors improved the composite chlorine dioxide gas preparation equipment by providing a pre-reactor in the front section of the main reactor. The sodium chlorate solution and hydrochloric acid are mixed and reacted in the pre-reactor, and sodium chlorate crystals are precipitated and deposited at the bottom of the pre-reactor cavity under the action of gravity. In the pre-reactor cavity, HCl in the reaction liquid continuously reacts with the generated sodium chlorate crystals. The precipitation and reaction of sodium chlorate crystals occur simultaneously, and when the precipitation and consumption of sodium chlorate crystals reach an equilibrium state, it ensures that there is no crystal precipitate in the gas-liquid mixture entering the main reactor, avoids the blockage of the filler and pipeline in the main reactor, guarantees the stable operation of the equipment, and completely solves the problem of crystal precipitate deposition in the filler gap of the main reactor and blockage of the main reactor, thereby making it possible to use high-concentration reactants. Since the sodium chlorate crystals are fully reacted and digested in the pre-reactor cavity, the amount of unreacted raw materials entering the subsequent process is reduced, and at the same time, the reaction liquid in the main reactor continues to react, greatly improving the utilization rate of raw materials, breaking through the bottleneck of low conversion rate (≤50%) of existing equipment, and achieving a final conversion rate of 90% or more. The risk of sodium chlorate and other unreacted raw materials entering drinking water with disinfectant is reduced, the health hazards (such as the effects of chlorate on blood circulation and the reproductive system) are reduced, and the preparation cost is also reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic diagram of the composite chlorine dioxide gas preparation equipment provided by the present application; Figure 2 is a photo of crystal blockage of the filler bed in the existing composite chlorine dioxide gas preparation equipment.

[0030] The reference signs in the drawings of the specification are as follows: 1, front reactor; 11, front reaction chamber; 111, first deposition reaction zone; 112, second deposition reaction zone; 12, isolation cover; 121, air hole; 13, hydrochloric acid inlet; 14, sodium chlorate solution inlet; 15, overflow pipe; 151, overflow port; 2, sodium chlorate solution supply device; 21, sodium chlorate solution supply pipeline; 22, sodium chlorate solution metering pump; 23, heating device; 24, heat preservation facility; 3, hydrochloric acid supply device; 31, hydrochloric acid supply pipeline; 32, hydrochloric acid metering pump; 4, main reactor; 41, filler zone; 42, flow equalizing plate; 43, flow guide ring; 44, residual liquid discharge pipeline; 441, liquid seal structure; 45, residual liquid recovery tank; 46, hot carrier gas pipeline; 47, fan; 5, gas-liquid separator; 51, baffle separation chamber; 511, baffle; 52, liquid collecting hopper; 521, splash-proof layer; 53, separation hole plate; 6, liquid-carrying gas inlet pipe; 7, liquid discharge pipe; 8, exhaust pipe; 9, controller. DETAILED DESCRIPTION

[0031] In order to make the technical problems solved by the present application, technical solutions and beneficial effects more clearly, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0032] Referring to Figure 1 The present application provides a composite chlorine dioxide gas preparation equipment, which comprises a front reactor 1 and a main reactor 4. The front reactor 1 is provided with a front reaction chamber 11 for containing the reaction liquid of sodium chlorate solution and hydrochloric acid, so that the precipitated sodium chlorate crystals are deposited in the reaction liquid and react to be digested. The main reactor 4 is used to continue the reaction of the gas-liquid mixture without crystal precipitate discharged from the front reactor 1.

[0033] In order to solve the technical problem of crystal blockage of the filler bed, the inventors first prove by quantitative calculation that even if the sodium chloride generated by the complete reaction of NaClO3 and hydrogen chloride cannot reach the solubility saturation precipitation with respect to the sum of water carried by sodium chlorate solution and hydrochloric acid and the water generated by the reaction, it is proved that the technical personnel in the field think that the precipitated crystals are sodium chloride is wrong; then, the inventors analyze the composition of the precipitated crystals and find that the precipitated crystals are sodium chlorate. It is speculated that the formation mechanism is that at a certain temperature, Na + , ClO3 - and water molecules in the sodium chlorate solution generate hydrated Na + and hydrated ClO3 -, forming a steady-state system; in a closed container, most of the HCl in hydrochloric acid (especially concentrated hydrochloric acid) exists in the form of HCl • nH2O with H2O, and a small amount of HCl generates hydrated H + and hydrated Cl - , forming a quasi-stable system; when hydrochloric acid is mixed with a sodium chlorate solution to form a reaction liquid, due to the ability of H + and ClO3 - to compete for water molecules being far stronger than the ability of Na + and ClO3 - , the equilibrium of the two systems is broken, and in the new system, part of the HCl • nH2O is taken from the hydrated Na + and ClO3 - to form hydrated H + and hydrated Cl - , and Na + and ClO3 - are combined to precipitate sodium chlorate crystals.

[0034] Based on the above findings, the inventors improved the composite chlorine dioxide gas preparation equipment by providing a pre-reactor 1 in the front section of the main reactor 4, mixing sodium chlorate solution and hydrochloric acid in the pre-reactor 1, and precipitating sodium chlorate crystals which are deposited at the bottom of the pre-reaction cavity 11 under the action of gravity; in the pre-reaction cavity 11, HCl in the reaction liquid continuously reacts with the precipitated sodium chlorate crystals; the precipitation and reaction of sodium chlorate crystals occur simultaneously, and when the precipitation and consumption of sodium chlorate crystals reach an equilibrium state, it ensures that there is no crystal precipitate in the gas-liquid mixture entering the main reactor 4, avoids the blockage of the filler and pipeline in the main reactor 4, guarantees the stable operation of the equipment, and completely solves the problem of the deposition and blockage of crystal precipitates in the filler gaps of the main reactor 4, thereby making it possible to use high-concentration reactants: since the sodium chlorate crystals are fully reacted and digested in the pre-reaction cavity 11, the amount of unreacted raw materials entering the subsequent links is reduced, and at the same time, the gas-liquid mixture continues to react in the main reactor 4, which greatly improves the utilization rate of raw materials, breaks through the bottleneck of low conversion rate (≤50%) of existing equipment, and achieves a final conversion rate of 90% or more. Reducing the risk of unreacted sodium chlorate and other raw materials entering drinking water with disinfectant, reducing health hazards (such as the effects of chlorate on blood circulation and the reproductive system), and reducing the cost of preparation.

[0035] In an embodiment, a sodium chlorate solution supply device 2 is also included, which is connected to the pre-reactor 1 through a sodium chlorate solution supply pipeline 21, and a sodium chlorate solution metering pump 22 is arranged on the sodium chlorate solution supply pipeline 21, and the sodium chlorate solution supply device 2 is provided with a heating device 23 and a heat preservation facility 24.

[0036] The heating device 23 is used to increase the temperature of the sodium chlorate solution in the sodium chlorate solution supply device 2. As the temperature of the sodium chlorate solution increases, its solubility also increases. Therefore, the composite chlorine dioxide gas preparation method provided by the present application can use a sodium chlorate solution with a higher concentration (30% to 67%) as the reaction solution. As the concentration of the reactant increases, the reaction rate increases. At the same time, increasing the concentration of the reactant can directly reduce the amount of water in the residual liquid, reduce the discharge amount of the residual liquid, and effectively increase the conversion rate of sodium chlorate and the yield of the product chlorine dioxide and chlorine gas.

[0037] The heat preservation facility 24 is used to keep the temperature of the sodium chlorate solution in the sodium chlorate solution supply device 2 stable, reduce temperature fluctuations, and reduce heating energy consumption.

[0038] It should be noted that the increase in the concentration of the sodium chlorate solution in the composite chlorine dioxide gas preparation method is based on the further improvement after the pre-reactor 1 solves the bottleneck of the crystallization problem. In the existing preparation method, a sodium chlorate solution with a relatively low concentration at room temperature is usually used. The main limiting factor is the crystallization problem. If the concentration of the sodium chlorate solution is increased without solving the crystallization problem, the crystallization blockage problem will be aggravated, and thus the method cannot be actually implemented.

[0039] In an embodiment, the hydrochloric acid supply device 3 is further included, which is connected to the pre-reactor 1 through a hydrochloric acid supply pipeline 31. A hydrochloric acid metering pump 32 is arranged on the hydrochloric acid supply pipeline 31.

[0040] In an embodiment, a controller 9 is further included, which is connected to the sodium chlorate solution metering pump 22 and the hydrochloric acid metering pump 32, respectively, to accurately control the addition amount of hydrochloric acid and sodium chlorate solution, ensure sufficient reaction of the two, and avoid the problems of aggravated crystallization and insufficient reaction caused by unbalanced addition amount.

[0041] In an embodiment, the controller 9 is connected to the heating device 23 to control the temperature of the sodium chlorate solution in the sodium chlorate solution supply device 2, ensure the supply of a high-concentration sodium chlorate solution (avoid concentration limitation caused by low temperature), avoid the precipitation of crystals caused by too low temperature, and improve the reaction rate.

[0042] In an embodiment, the pre-reactor 1 is a cylindrical cavity closed at the top and bottom.

[0043] In an embodiment, the pre-reactor 1 includes an overflow pipe 15, the top end of the overflow pipe 15 is inserted into the pre-reaction cavity 11 to form an overflow port 151, and a deposition reaction area for accommodating reaction liquid and sodium chlorate crystals is formed between the overflow port 151 and the bottom of the pre-reaction cavity 11.

[0044] The overflow port 151 of the overflow pipe 15 is designed to control the liquid level, form a deposition reaction zone, and make sodium chlorate crystals deposit at the bottom of the reaction liquid due to gravity and continue to react. The deposition reaction zone provides sufficient reaction space and time for sodium chlorate crystals, ensures that the crystals are fully dissolved, further improves the conversion rate, and only the gas-liquid mixture without crystals enters the main reactor 4 through the overflow port 151, completely avoiding crystallization from blocking the main reactor 4.

[0045] In an embodiment, the pre-reaction reactor 1 further comprises a isolation cover 12, which is located in the pre-reaction cavity 11, the top end of the isolation cover 12 is connected to the top of the inner cavity of the pre-reaction cavity 11, the bottom of the isolation cover 12 is suspended above the bottom surface of the inner cavity of the pre-reaction cavity 11, and the isolation cover 12 is located at the outer periphery of the overflow pipe 15. The isolation cover 12 separates the deposition reaction zone to form a first deposition reaction zone 111 outside the isolation cover 12 and a second deposition reaction zone 112 inside the isolation cover 12, the first deposition reaction zone 111 and the second deposition reaction zone 112 are communicated at the bottom of the isolation cover 12, and the pre-reaction reactor 1 is provided with a sodium chlorate solution inlet 14 and a hydrochloric acid inlet 13 communicating with the first deposition reaction zone 111, the sodium chlorate solution inlet 14 and the hydrochloric acid inlet 13 are respectively located on the two side walls of the pre-reaction reactor 1.

[0046] The structure design of the isolation cover 12 separating the first deposition reaction zone 111 and the second deposition reaction zone 112 ensures that the sodium chlorate crystals, which are the precipitated crystals in the pre-reaction reactor 1, deposit at the bottom of the pre-reaction cavity 11 under the action of gravity and continuously contact with HCl in the flowing reaction liquid, the double deposition reaction zone design increases the contact opportunity of sodium chlorate crystals with hydrochloric acid, and after the crystal precipitates are completely dissolved, they enter the overflow port 151 of the overflow pipe 15, avoiding unreacted crystals from entering the main reactor 4, and further reducing the risk of subsequent crystal blockage.

[0047] In an embodiment, the pre-reaction reactor 1, the isolation cover 12 and the overflow pipe 15 are all made of non-metallic and acid and alkali corrosion resistant materials, avoiding the structural stability problems caused by corrosion of the reaction liquid and generated gas.

[0048] In an embodiment, the side wall of the isolation cover 12 is provided with a vent hole 121, and the height of the vent hole 121 is higher than the sodium chlorate solution inlet 14, the hydrochloric acid inlet 13 and the overflow port 151.

[0049] The vent hole 121 on the top of the isolation cover 12 can balance the air pressure of the first deposition reaction zone 111 and the second deposition reaction zone 112, and the compound chlorine dioxide gas generated by the first deposition reaction zone 111 can directly enter the second deposition reaction zone 112 through the vent hole 121 to form a gas-liquid mixture and then enter the overflow port 151.

[0050] In an embodiment, the main reactor 4 is made of non-metallic and acid-alkali corrosion-resistant material.

[0051] In an embodiment, the main reactor 4 is provided with a filler zone 41 filled with polyhedral fillers.

[0052] The polyhedral fillers can increase the contact area between the reaction liquid and the carrier gas. During the downward flow of the reaction liquid, a high specific surface area liquid film can be formed through the polyhedral fillers, so that the unreacted raw materials can be fully reacted, and at the same time, the hot carrier gas can flow backward through the pores between the polyhedral fillers to reduce the flow rate of the reaction liquid, dilute and carry away the gas products, thereby further improving the conversion rate of chlorine dioxide.

[0053] The front reactor 1 is located at the top of the main reactor 4, and the bottom of the overflow pipe 15 penetrates into the main reactor 4 and extends above the filler zone 41.

[0054] The front reactor 1 is located at the top of the main reactor 4, and the overflow pipe 15 directly extends above the filler zone 41. The integrated layout shortens the conveying path of the gas-liquid mixture, facilitates equipment integration and maintenance, saves installation space, ensures that the gas-liquid mixture without crystals directly enters the filler zone 41, and prevents the filler from being blocked by crystal deposition.

[0055] In an embodiment, the main reactor 4 is further provided with a flow equalizing plate 42, which is located below the overflow pipe 15, and the overflow pipe 15 and the flow equalizing plate 42 are vertically arranged. The function of the flow equalizing plate 42 is to make the reaction liquid flowing out of the overflow pipe 15 evenly distributed in a ring shape on the filler zone 41 in the main reactor 4, forming a wedge-shaped scattered downward flow, and achieving the effect of dispersing the reaction liquid.

[0056] In an embodiment, the flow equalizing plate 42 is a circular flat plate.

[0057] In an embodiment, the main reactor 4 is further provided with at least one flow guide ring 43 made of non-metallic and acid-alkali corrosion-resistant material. The flow guide ring 43 is located in the filler zone 41, and the outer edge of the flow guide ring 43 abuts against the inner wall of the main reactor 4. When the number of flow guide rings 43 is multiple, the multiple flow guide rings 43 are arranged in the filler zone 41 from top to bottom.

[0058] The function of the flow guide ring 43 is to make the reaction liquid flowing along the inner wall of the main reactor 4 due to the wall flow effect re-distributed evenly to the packing bed again to form a wedge-shaped spread downward flow, avoiding the liquid film thickening and the flow rate accelerating to exceed the liquid film on the surface of the polyhedral packing, and forming residual liquid before the reaction is completed.

[0059] When the height to diameter ratio of the main reactor 4 is large, multiple spaced flow guide rings 43 are needed to be arranged to correct the liquid film distribution multiple times to ensure the uniformity of the liquid film of the reaction liquid in the entire packing area 41.

[0060] In an embodiment, the bottom of the side wall of the main reactor 4 is connected with a hot carrier gas pipeline 46, and the hot carrier gas pipeline 46 is located below the packing area 41.

[0061] The hot carrier gas provides temperature conditions for the reaction in the packing area 41, promotes the forward reaction of sodium chlorate and hydrochloric acid, and improves the reaction rate. Meanwhile, in the packing area 41, the hot carrier gas flows upward and contacts the downward flowing liquid film in counter flow, accelerates the escape of the compound chlorine dioxide gas from the liquid film, promotes the forward reaction, and improves the conversion rate. In addition, the hot carrier gas can dilute the generated high-concentration compound chlorine dioxide gas, eliminate the risk of explosion, and efficiently guide the gas to the subsequent processing link.

[0062] In an embodiment, a fan 47 is arranged on the hot carrier gas pipeline 46, and the controller 9 is connected with the fan 47 for controlling the gas supply rate of the hot carrier gas.

[0063] In an embodiment, the bottom of the main reactor 4 is connected with a residual liquid outlet pipeline 44, and the residual liquid outlet pipeline 44 is provided with a liquid seal structure 441.

[0064] The liquid seal structure 441 is a U-shaped tube structure, which can prevent external air from entering the main reactor 4 and avoid the leakage caused by the entrainment of compound chlorine dioxide gas during the discharge of residual liquid, thereby improving the safety of equipment operation.

[0065] In an embodiment, the residual liquid outlet pipeline 44 is connected with a residual liquid recovery tank 45.

[0066] In an embodiment, a gas-liquid separator 5, a liquid-carrying gas inlet pipe 6, an exhaust pipe 8 and a liquid outlet pipe 7 are further included. The liquid-carrying gas inlet pipe 6 is connected to the upper part of the packing area 41 and the gas-liquid separator 5, respectively. The exhaust pipe 8 is connected with the gas-liquid separator 5 for guiding the compound chlorine dioxide gas after gas-liquid separation. The liquid outlet pipe 7 is connected with the gas-liquid separator 5 and the packing area 41, respectively, for guiding the liquid after gas-liquid separation to the packing area 41.

[0067] The gas-liquid separator 5 separates the liquid in the liquid-carrying gas, ensures that the exported composite chlorine dioxide gas is dry and pure, and facilitates subsequent absorption and utilization.

[0068] In an embodiment, the gas-liquid separator 5 comprises a baffle separation chamber 51 and a liquid collecting hopper 52, the baffle separation chamber 51 is located above the liquid collecting hopper 52, a plurality of baffles 511 are arranged in the baffle separation chamber 51, the bottom surface of the liquid collecting hopper 52 is provided with a splash-proof layer 521, the liquid-carrying gas inlet pipe 6 is connected to the top of the baffle separation chamber 51, the liquid outlet pipe 7 is connected to the bottom of the liquid collecting hopper 52, and the exhaust pipe 8 is connected to the side wall of the liquid collecting hopper 52.

[0069] The baffle separation chamber 51 is formed by a plurality of baffles 511, which makes the liquid in the liquid-carrying gas fully adhere to the baffles 511 and separate.

[0070] The splash-proof layer 521 is an acid and alkali corrosion resistant metal material or an acid and alkali corrosion resistant non-metal material with many pores, which is uniformly laid in the hopper-shaped structure at the lower part of the liquid collecting hopper 52, and its function is to prevent the separated liquid from being carried by gas again when falling, thereby improving the separation effect.

[0071] In an embodiment, the gas-liquid separator 5 further comprises a separation hole plate 53, which is located in the liquid collecting hopper 52 and surrounds the outer periphery of the bottom end of the baffle separation chamber 51, and its function is to further prevent the separated liquid from splashing out.

[0072] Another embodiment of the present application provides a composite chlorine dioxide gas preparation method, which adopts the composite chlorine dioxide gas preparation equipment as described above, and comprises the following operation steps: The sodium chlorate solution and hydrochloric acid are introduced into the pre-reaction cavity 11 to mix and form a reaction liquid; The reaction process in the reaction liquid is as follows: 2NaClO3+4HCl=2ClO2↑+Cl2↑+2NaCl+2H2O The pre-reaction cavity 11 forms a deposition reaction zone for accommodating the reaction liquid, and in the deposition reaction zone, the sodium chlorate crystals in the reaction liquid are precipitated and deposited in the reaction liquid and react and decompose; The gas-liquid mixture without crystal precipitate is introduced into the main reactor 4 for further reaction to generate composite chlorine dioxide gas.

[0073] The present composite chlorine dioxide gas preparation method realizes the digestion of sodium chlorate crystals in the front reaction cavity by the deposition reaction zone of the front reaction cavity 11, and the front reactor 1 and the main reactor 4 relay react, so that the raw materials are fully converted in two stages, the crystals are prevented from entering the main reactor 4, the blockage problem of the existing equipment is solved from the root, frequent shutdown for washing crystals (such as dilute water washing in the background art) is not needed, waste water generation and raw material waste are reduced, the conversion rate of sodium chlorate is improved, and the limitation of low conversion rate of the existing process is broken through.

[0074] In an embodiment, the sodium chlorate solution and hydrochloric acid are introduced in a molar ratio of sodium chlorate to HCl of 1: (2.0-2.2); the mass concentration of the hydrochloric acid is 31%-40%, and the mass concentration of sodium chlorate in the sodium chlorate solution is 30%-67%; the sodium chlorate solution is heated and kept warm, so that the temperature of the sodium chlorate solution is 25°C-100°C.

[0075] The heating temperature of the sodium chlorate solution is set according to the required concentration of the sodium chlorate solution, so that the sodium chlorate in the sodium chlorate solution can be fully dissolved.

[0076] In combination with the design of the front reaction zone, on the basis of solving the problem of crystal blockage, the solubility of the sodium chlorate solution is improved by heating (25°C-100°C), high-concentration raw materials are supported, the reaction speed is accelerated, and the conversion rate of sodium chlorate is improved.

[0077] In an embodiment, the front reaction cavity 11 includes the following reaction process: The deposition reaction zone includes a second deposition reaction zone 112 and a first deposition reaction zone 111 surrounding the outside of the second deposition reaction zone 112, the bottom of the first deposition reaction zone 111 and the bottom of the second deposition reaction zone 112 are in communication with each other, the sodium chlorate solution and hydrochloric acid are mixed and reacted in the first deposition reaction zone 111, sodium chlorate crystals are precipitated and deposited at the bottom of the first deposition reaction zone 111 and the bottom of the second deposition reaction zone 112 under the action of gravity; the liquid part flows through the second deposition reaction zone 112 through the bottom of the first deposition reaction zone 111, and continuously reacts during the flowing process; the composite chlorine dioxide gas generated by the first deposition reaction zone 111 and the second deposition reaction zone 112 forms a gas-liquid mixture with the reaction liquid flowing through the second deposition reaction zone 112 and is led out to the main reactor 4; in the deposition reaction zone, the precipitation and reaction digestion of sodium chlorate crystals occur at the same time; first, as the reaction liquid starts to be injected, the deposition amount of sodium chlorate crystals increases, then the reaction rate of sodium chlorate crystals with HCl increases, until the precipitation and consumption of sodium chlorate crystals reach a balance state, the deposition amount of sodium chlorate crystals remains unchanged, and finally, as the injection of the reaction liquid stops, the sodium chlorate crystals gradually decrease and disappear.

[0078] Through the combined design of the first deposition reaction zone 111 and the second deposition reaction zone 112, the precipitated sodium chlorate crystals can be fully deposited at the bottom of the first deposition reaction zone 111 and the second deposition reaction zone 112, the dynamic balance process of “precipitation-deposition-dissolution” of the sodium chlorate crystals is maintained, the crystals continuously react with hydrochloric acid in the flow until complete dissolution, the accumulation of crystals in the front reaction chamber 11 is avoided, the crystals do not enter the main reactor 4, the long-term stable operation of the equipment is maintained, and the generation amount of the composite chlorine dioxide is stable.

[0079] In an embodiment, the main reactor 4 further includes the following process: The gas-liquid mixture without crystal precipitates is introduced into the main reactor 4 through the overflow pipe 15, and a flow uniformizing plate 42 is arranged at the bottom of the overflow pipe 15. The gas-liquid mixture contacts the polyhedral packing along the outer edge of the flow uniformizing plate 42, and forms a double-wedge-shaped uniform downward flow section on the central section of the main reactor 4.

[0080] The flow uniformizing plate 42 makes the reaction liquid form a double-wedge-shaped uniform downward flow section, and the uniform flow state distribution makes the liquid film thickness on the surface of the packing consistent, ensures that each part of the packing zone 41 contacts the reaction liquid sufficiently, avoids local reaction dead angles, stabilizes the reaction rate, and improves the overall conversion rate.

[0081] In an embodiment, the main reactor 4 further includes the following process: The gas-liquid mixture without crystal precipitates is introduced into the packing zone 41 from the top of the packing zone 41, and the hot carrier gas is introduced at the bottom of the packing zone 41. The reaction liquid flows downward on the surface of the polyhedral packing in the packing zone 41 to form a liquid film, and the hot carrier gas flows upward in the packing zone 41. The reaction liquid in the liquid film continuously reacts to generate composite chlorine dioxide gas and enters the hot carrier gas, and the hot carrier gas dilutes the liquid-containing gas to form a liquid-containing gas that is discharged from the packing zone 41.

[0082] The hot carrier gas continuously provides heat to maintain the reaction temperature of the packing zone 41 and ensure the reaction activity. The hot carrier gas and the liquid film are countercurrently contacted, the contact time of the two is increased, the release of the composite chlorine dioxide gas from the liquid film is promoted, and the forward reaction is promoted. In addition, the hot carrier gas can dilute the high-concentration composite chlorine dioxide gas to a safe concentration range, and eliminate the explosion hazard.

[0083] In an embodiment, the main reactor 4 further includes the following process: The reaction liquid naturally gathers on the inner wall of the main reactor 4 during downward flow. To avoid thickening of the liquid film on the inner wall of the main reactor 4, the reaction rate is reduced, and the flow rate is accelerated to overtake the liquid film on the surface of the polyhedral packing. A flow guide ring 43 is arranged on the inner wall of the main reactor 4. When the reaction liquid contacts the flow guide ring 43, the liquid film on the inner wall flows radially inward along the upper surface of the flow guide ring 43, contacts the polyhedral packing downward along the inner surface of the flow guide ring 43, and again forms a double-wedge-shaped uniform flow section downward on the central cross section of the main reactor 4.

[0084] After being guided by the flow guide ring 43, the liquid film on the inner wall can be re-directed to the central area to form a double-wedge-shaped uniform flow section again, prolong the contact time with the packing, and improve the reaction conversion rate.

[0085] According to different sizes of the main reactor 4, the flow state can be adjusted by the number of flow guide rings 43 to ensure that the reaction efficiency is not affected by the size of the equipment.

[0086] In an embodiment, the following operations are further included: The gas-liquid separation is performed on the gas-liquid separator 5, and the liquid after gas-liquid separation is guided back to the packing zone 41 for continuous reaction, so as to avoid waste of unreacted sodium chlorate and hydrochloric acid in the liquid, and further improve the conversion rate.

[0087] The application is further described through the following examples.

[0088] Example 1 In this embodiment, the composite chlorine dioxide gas preparation equipment and the composite chlorine dioxide gas preparation method described above are used, wherein: In the sodium chlorate solution supply device: 5Kg of sodium chlorate is added, 5Kg of water is added, and the temperature of the sodium chlorate solution is controlled by the heating device to be not lower than 30℃; In the supply device: 33% concentrated hydrochloric acid is taken, and the molar ratio of NaClO3 to HCl is 1:2.2, so that 103.29mol of HCl, i.e. 3.77Kg of HCl, and 7.65Kg of water contained therein are taken; The total water content in the residual liquid is 5Kg+7.65Kg+0.85Kg=13.5Kg The measured ratio of sodium chlorate to water is about 3.5:100 After reaction by using the composite chlorine dioxide gas preparation equipment described above, the sodium chlorate content in the residual liquid is measured to be 0.473Kg, and the converted sodium chlorate is 4.527Kg, which is equivalent to a conversion rate of 90.54%.

[0089] Example 2 In this embodiment, the composite chlorine dioxide gas preparation equipment and the composite chlorine dioxide gas preparation method described above are used, wherein: The sodium chlorate solution supply device: add sodium chlorate 6Kg, add water 4Kg, control the temperature of sodium chlorate solution by heating device not less than 85℃; The supply device: take 33% concentration hydrochloric acid, according to the molar ratio of NaClO3 and HCl is 1:2.2, take HCl 123.94mol, i.e. HCl 4.524Kg, containing water 9.05Kg; The total water content in the residual liquid is 4Kg+9.05Kg+1.01Kg=14.06Kg The measured ratio of sodium chlorate to water is about 3.4:100 After the reaction of the composite chlorine dioxide gas preparation equipment as described above, the sodium chlorate content in the residual liquid is measured to be 0.478Kg, and the converted sodium chlorate is 5.522Kg, which is equivalent to a conversion rate of 92.03%.

[0090] From the above examples, two conclusions can be drawn: 1. Increasing the concentration of sodium chlorate solution can improve its conversion rate; 2. Increasing the concentration of sodium chlorate solution can reduce the concentration of sodium chlorate in the residual liquid.

[0091] As can be seen from the above, the composite chlorine dioxide gas preparation method provided by the present application can achieve a conversion rate of sodium chlorate of more than 90%, completely changing the current situation of "waste of a large amount of unreacted raw materials increasing the preparation cost" of existing equipment, significantly reducing the cost of raw material procurement and residual liquid treatment of enterprises. At the same time, on the basis of completely solving the crystallization problem, with the increase of the concentration of sodium chlorate solution used, it is beneficial to further improve the conversion rate of sodium chlorate, which confirms the positive promoting effect of the synergistic design of "temperature regulation + pre-crystallization digestion" on the reaction efficiency, and provides double protection for high conversion rate.

[0092] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite chlorine dioxide gas preparation device, characterized in that, Includes a pre-reactor and a main reactor; The pre-reactor is provided with a pre-reaction chamber, which is used to contain the reaction solution of sodium chlorate solution and hydrochloric acid, so that the precipitated sodium chlorate crystals are deposited in the reaction solution and reacted and dissolved. The main reactor is used to receive the gas-liquid mixture without crystal precipitates discharged from the pre-reactor for further reaction.

2. The composite chlorine dioxide gas preparation equipment according to claim 1, characterized in that, It also includes a sodium chlorate solution supply device and a hydrochloric acid supply device, wherein the sodium chlorate solution supply device is connected to the pre-reactor and is equipped with a heating device and a heat preservation device.

3. The composite chlorine dioxide gas preparation equipment according to claim 1, characterized in that, The pre-reactor includes an overflow pipe, the top end of which is inserted into the pre-reaction chamber to form an overflow port, and a deposition reaction zone for containing the reaction liquid and sodium chlorate crystals is formed between the overflow port and the bottom of the pre-reaction chamber.

4. The composite chlorine dioxide gas preparation equipment according to claim 3, characterized in that, The pre-reactor also includes an isolation hood located in the pre-reaction chamber and on the outer periphery of the overflow pipe. The isolation hood isolates the deposition reaction zone, forming a first deposition reaction zone located outside the isolation hood and a second deposition reaction zone located inside the isolation hood. The first deposition reaction zone and the second deposition reaction zone are connected by the bottom of the isolation hood. The pre-reactor is provided with a sodium chlorate solution inlet and a hydrochloric acid inlet that connect the first deposition reaction zone.

5. The composite chlorine dioxide gas preparation equipment according to claim 4, characterized in that, The top of the side wall of the isolation cover is provided with a vent hole, and the height of the vent hole is higher than the sodium chlorate solution inlet, the hydrochloric acid inlet and the overflow port.

6. The composite chlorine dioxide gas preparation equipment according to claim 3, characterized in that, The main reactor is provided with a packing zone, which is filled with polyhedral packing. The pre-reactor is located at the top of the main reactor, and the bottom of the overflow pipe enters the main reactor and extends above the packing zone.

7. The composite chlorine dioxide gas preparation equipment according to claim 6, characterized in that, The main reactor is also equipped with a flow equalization plate, which is located below the overflow pipe and is perpendicular to the flow equalization plate.

8. The composite chlorine dioxide gas preparation equipment according to claim 6, characterized in that, The main reactor is also provided with at least one flow guide ring, which is located in the packing zone and the outer edge of the flow guide ring abuts against the inner wall of the packing zone; when there are multiple flow guide rings, the multiple flow guide rings are arranged at intervals from top to bottom in the packing zone.

9. The composite chlorine dioxide gas preparation equipment according to claim 6, characterized in that, A hot carrier gas pipeline is connected to the bottom of the side wall of the main reactor, and the hot carrier gas pipeline is located below the packing zone.

10. The composite chlorine dioxide gas preparation equipment according to claim 6, characterized in that, The bottom of the main reactor is connected to a residual liquid discharge pipe, which is equipped with a liquid seal structure.

11. The composite chlorine dioxide gas preparation equipment according to claim 6, characterized in that, It also includes a gas-liquid separator, a liquid-containing gas inlet pipe, an exhaust pipe, and a liquid drain pipe. The liquid-containing gas inlet pipe is connected to the top of the packing area and the gas-liquid separator, respectively. The exhaust pipe is connected to the gas-liquid separator and is used to discharge the composite chlorine dioxide gas after gas-liquid separation. The liquid drain pipe is connected to the gas-liquid separator and the packing area, respectively, and is used to guide the liquid after gas-liquid separation to the packing area.

12. The composite chlorine dioxide gas preparation equipment according to claim 11, characterized in that, The gas-liquid separator includes a baffle plate separation chamber and a liquid collection hopper. The baffle plate separation chamber is located above the liquid collection hopper. The baffle plate separation chamber is provided with multiple baffle plates arranged at intervals. The bottom surface of the liquid collection hopper is provided with a splash-proof layer. The liquid-laden gas inlet pipe is connected to the top of the baffle plate separation chamber. The liquid outlet pipe is connected to the bottom of the liquid collection hopper. The exhaust pipe is connected to the side wall of the liquid collection hopper.

13. A method for preparing composite chlorine dioxide gas, characterized in that, The following steps are included: Sodium chlorate solution and hydrochloric acid are introduced into the pre-reaction chamber and mixed to form a reaction solution. A deposition reaction zone containing the reaction solution is formed in the pre-reaction chamber. In the deposition reaction zone, sodium chlorate crystals precipitate from the reaction solution and are deposited in the reaction solution and reacted and dissolved. The gas-liquid mixture without crystal precipitates is introduced into the main reactor to continue the reaction, generating composite chlorine dioxide gas.

14. The method for preparing composite chlorine dioxide gas according to claim 13, characterized in that, Sodium chlorate and hydrochloric acid are introduced into a sodium chlorate solution and hydrochloric acid at a molar ratio of 1:(2.0~2.2); the mass concentration of the hydrochloric acid is 31%~40%, and the mass concentration of sodium chlorate in the sodium chlorate solution is 30%~67%; the sodium chlorate solution is heated to a temperature of 25℃~100℃.

15. The method for preparing composite chlorine dioxide gas according to claim 13, characterized in that, The pre-reaction chamber includes the following reaction processes: The deposition reaction zone includes a second deposition reaction zone and a first deposition reaction zone surrounding the outside of the second deposition reaction zone. The bottom of the first deposition reaction zone and the bottom of the second deposition reaction zone are connected to each other. Sodium chlorate solution and hydrochloric acid are mixed and reacted in the first deposition reaction zone. Sodium chlorate crystals precipitate and are deposited at the bottom of the first deposition reaction zone and the bottom of the second deposition reaction zone under the action of gravity. The liquid portion flows from the bottom of the first deposition reaction zone into the second deposition reaction zone, and continues to react during the flow; The composite chlorine dioxide gas generated in the first and second deposition reaction zones forms a gas-liquid mixture with the reaction liquid flowing through the second deposition reaction zone and is then discharged to the main reactor. In the deposition reaction zone, the precipitation and reaction disintegration of sodium chlorate crystals occur simultaneously. First, as the reaction liquid is injected, the amount of sodium chlorate crystals deposited increases. Then, the reaction rate between sodium chlorate crystals and HCl increases until the precipitation and consumption of sodium chlorate crystals reach equilibrium, at which point the amount of sodium chlorate crystals deposited remains constant. Finally, as the injection of the reaction liquid stops, the amount of sodium chlorate crystals gradually decreases until they disintegrate and disappear.

16. The method for preparing composite chlorine dioxide gas according to claim 13, characterized in that, In the main reactor, there is also The process includes the following: A gas-liquid mixture without crystal precipitates is introduced into the main reactor through an overflow pipe. A flow equalization plate is installed at the bottom of the overflow pipe. The gas-liquid mixture flows downward along the outer edge of the flow equalization plate and contacts the polyhedral packing, forming a double-wedge-shaped uniform downward flow cross section on the central section of the main reactor.

17. The method for preparing composite chlorine dioxide gas according to claim 13, characterized in that, The main reactor also includes the following processes: A gas-liquid mixture without crystal precipitates is introduced into the packing zone from the top, and a hot carrier gas is introduced into the packing zone from the bottom. The reaction liquid flows downward in sequence on the polyhedral packing surface of the packing zone to form a liquid film, while the hot carrier gas flows upward in sequence in the packing zone. The reaction liquid in the liquid film continues to react to generate composite chlorine dioxide gas, which enters the hot carrier gas and is diluted by the hot carrier gas to form a liquid-containing gas that is discharged from the packing zone.

18. The method for preparing composite chlorine dioxide gas according to claim 13, characterized in that, In the main reactor, there is also The process includes the following: As the reaction liquid flows downward, it naturally accumulates on the inner wall of the main reactor, thickening the liquid film on the inner wall. This reduces the reaction rate and increases the flow velocity. A guide ring is provided on the inner wall of the main reactor. When the reaction liquid contacts the guide ring, the liquid film on the inner wall flows radially inward along the upper surface of the guide ring and downward along the inner edge of the guide ring to contact the polyhedral packing, thus forming a double-wedge-shaped uniform downward flow cross section on the central section of the main reactor.

19. The method for preparing composite chlorine dioxide gas according to claim 17, characterized in that, This also includes the following operations: The liquid-containing gas is introduced into the gas-liquid separator for gas-liquid separation, and the separated liquid is returned to the packing zone to continue the reaction.

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