A composite chlorine dioxide gas preparation device

Abstract

In order to overcome the problems of existing chlorine dioxide preparation scheme exists crystal block and conversion rate is insufficient, the utility model provides a kind of composite chlorine dioxide gas preparation equipment, including front reactor and main reactor;The front reactor is provided with front reaction cavity, and the front reaction cavity is used to accommodate the reaction liquid of sodium chlorate solution and hydrochloric acid, so that the sodium chlorate crystal deposited in reaction liquid is reacted and digested;The main reactor is used to continue reaction for the gas-liquid mixture without crystal precipitate exported by the front reactor.The composite chlorine dioxide gas preparation equipment provided by the utility model completely solves the problem that crystal precipitate deposits in the gap of main reactor filler and blocks the main reactor, greatly improves the raw material utilization, breaks through the bottleneck of low conversion rate (≤50%) of existing equipment, and reaches the final conversion rate of 90% or more.

Description

Technical Field

[0001] This utility model belongs to the field of composite chlorine dioxide gas preparation technology, specifically relating to a composite chlorine dioxide gas preparation device. Background Technology

[0002] Chlorine dioxide (ClO2) is an internationally recognized highly efficient and safe disinfectant with advantages such as good bactericidal effect, fast onset of action, low residue and no drug resistance. However, due to its unstable nature and tendency to explode, it needs to be prepared on-site by a chlorine dioxide generator in water purification applications.

[0003] The current mainstream equipment uses sodium chlorate solution and hydrochloric acid as raw materials, employing a negative pressure multi-stage reaction process. It consists of feeding, reaction, and absorption systems: metering pumps deliver raw materials to the reactor in proportion; the reaction is carried out under negative pressure at 55℃~65℃ to generate a gas-liquid mixture, which is absorbed by a water jet injector to form a disinfectant solution that is then introduced into the water to be treated. While this equipment is simple in structure and widely used, it has a key drawback: First, the conversion rate of chlorine dioxide is extremely low, not exceeding 50% under optimal conditions (verified by Guangzhou Water Purification Co., Ltd. in its "Analysis of Chlorine Dioxide Conversion Rate and Disinfection Dosage"). This only meets the current national standard "Chemical Compound Chlorine Dioxide Generator" (GB-T20621-2006) for qualified products (≥50%). The conversion rate of most drinking water equipment is at the qualified level, far from meeting the high efficiency requirements.

[0004] Secondly, raw material residues cause health and cost problems. Low conversion rates result in at least 50% sodium chlorate and a large amount of hydrogen chloride entering drinking water with the disinfectant. Sodium chlorate, as a disinfection byproduct, can oxidize heme in humans and animals, causing anemia and harming the circulatory and reproductive systems (as pointed out in "Generation and Control of Inorganic Disinfection Byproducts of Chlorine Dioxide in Drinking Water," the main reason for excessive chlorate levels in water plants is the lack of conversion of raw materials); at the same time, the waste of unreacted raw materials increases the production cost.

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

[0006] Furthermore, such as Figure 2As shown, in this type of chlorine dioxide preparation equipment, crystals are formed when sodium chlorate solution and hydrochloric acid are mixed. These crystals clog the packing and pipes in the reactor, thus affecting the chlorine dioxide conversion rate. This clogging problem is particularly pronounced when using high-concentration sodium chlorate solution and hydrochloric acid. However, existing research has not revealed the specific composition and causes of these crystals, and therefore, no effective solution to this technical problem has been proposed. The industry has attempted improvements, such as the method mentioned by Chen Tianwen et al. in "Current Status and Development Trend of Chemical Chlorine Dioxide Generators," which involves periodically emptying the residual liquid in the reaction chamber and rinsing the crystals with dilution water. However, this method results in significant raw material waste, fails to solve the low chlorine dioxide conversion rate problem, and generates a large amount of wastewater, also affecting production efficiency. Another invention patent application, CN118976455A, discloses a two-stage reaction system that attempts to solve the clogging problem and improve the conversion rate through a pre-reactor. However, this technology has a fundamental flaw: it mistakenly treats the crystals precipitated from the primary reactor as sodium chloride and directly discharges the crystals precipitated from the pre-reactor into the packed bed. In fact, this approach cannot fundamentally solve the problems of blockage and low conversion rate caused by crystallization. On the contrary, the crystals discharged into the packed bed from the primary reactor will cause deposition and blockage due to the low flow rate, which will also lead to blockage of the packed bed. Utility Model Content

[0007] To address the problems of crystal blockage and insufficient conversion rate in existing chlorine dioxide preparation methods, this invention provides a composite chlorine dioxide gas preparation device.

[0008] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: This utility model provides a composite chlorine dioxide gas preparation device, including 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.

[0009] Optionally, 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.

[0010] Optionally, 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.

[0011] Optionally, the pre-reactor further 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.

[0012] Optionally, the top of the side wall of the isolation cover is provided with a vent hole, the height of which 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 packing zone 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.

[0014] Optionally, the main reactor is further provided with a flow equalization plate, which is located below the overflow pipe and is perpendicular to the flow equalization plate.

[0015] Optionally, the main reactor is further 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.

[0016] Optionally, a hot carrier gas pipe is connected to the bottom of the side wall of the main reactor, and the hot carrier gas pipe is located below the packing zone.

[0017] Optionally, the bottom of the main reactor is connected to a residual liquid outlet pipe, and the residual liquid outlet pipe is equipped with a liquid seal structure.

[0018] Optionally, 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.

[0019] Optionally, 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.

[0020] This invention is based on overturning the industry's erroneous assumption that the crystals produced during the reaction process are NaCl, as described in invention patent CN118976455A, and in the article "Current Status and Development Trend of Chemical Chlorine Dioxide Generators" by Chen Tianwen et al. of the Central Laboratory of Fuzhou University. Due to the current industry's erroneous understanding of the blockage crystals, incorrect countermeasures have been implemented, increasing costs. To address the technical problem of blockage caused by crystals in the packed bed, the inventors first quantitatively proved that even if NaClO3 reacts completely with hydrogen chloride, the sodium chloride produced cannot reach dissolution saturation relative to the sodium chlorate solution, the water carried by hydrochloric acid, and the water produced in the reaction, thus proving that the assumption by those skilled in the art that the precipitated crystals are sodium chloride is incorrect. Next, the inventors conducted component analysis on the precipitated crystals and found that they are sodium chlorate. The proposed formation mechanism is: at a certain temperature, NaCl in the sodium chlorate solution... + ClO3 - It reacts with water molecules to form hydrated Na+ + With hydrated ClO3 - This forms a stable system; in a closed container, most of the HCl and H2O in hydrochloric acid (especially concentrated hydrochloric acid) exist in the form of HCl • nH2O, while a small portion of the HCl forms hydrated H+. + With hydrated Cl - A quasi-steady-state system is formed; when hydrochloric acid and sodium chlorate solution are mixed to form a reaction solution, due to H... + Cl - Its ability to compete for water molecules is far stronger than that of Na. + With ClO3 - The equilibrium between the two systems is disrupted, and some HCl • nH2O in the new system is released from the hydrated Na+. + With hydrated ClO3 - The process involves competing for H2O molecules to form hydrated H+. + With hydrated Cl - Na + With ClO3 - Sodium chlorate crystals precipitate out.

[0021] Based on the above findings, the inventors improved the composite chlorine dioxide gas preparation equipment by setting up a pre-reactor before the main reactor. Sodium chlorate solution and hydrochloric acid are mixed and reacted in the pre-reactor, and sodium chlorate crystals precipitate and are deposited at the bottom of the pre-reaction chamber under gravity. In the pre-reaction chamber, HCl in the reaction liquid continuously reacts with the generated sodium chlorate crystals. The precipitation and reaction digestion of sodium chlorate crystals occur simultaneously until the precipitation and consumption of sodium chlorate crystals reach an equilibrium state, ensuring that the gas-liquid mixture entering the main reactor has no crystal precipitates, avoiding blockage of the packing and pipes in the main reactor, ensuring stable operation of the equipment, and completely solving the problem of crystal precipitates depositing in the gaps of the main reactor packing and clogging the main reactor. This makes it possible to use high-concentration reactants. Because the sodium chlorate crystals are fully reacted and digested in the pre-reaction chamber, the amount of unreacted raw materials entering the subsequent stages is reduced. At the same time, the reaction liquid in the main reactor continues to react, greatly improving the raw material utilization rate and breaking through the bottleneck of low conversion rate (≤50%) of existing equipment, achieving a final conversion rate of 90% or higher. This reduces the risk of unreacted raw materials such as sodium chlorate entering drinking water with disinfectant, thus reducing health hazards (such as the effects of chlorate on the blood circulation and reproductive system) and lowering preparation costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the composite chlorine dioxide gas preparation equipment provided by this utility model; Figure 2 Photographs showing crystal blockage in the packed bed of an existing composite chlorine dioxide gas preparation device.

[0023] The reference numerals in the accompanying drawings are as follows: 1. Pre-reactor; 11. Pre-reaction chamber; 111. First deposition reaction zone; 112. Second deposition reaction zone; 12. Isolation hood; 121. Vent; 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. Insulation facilities; 3. Hydrochloric acid supply device; 31. Hydrochloric acid supply... 32. Hydrochloric acid metering pump; 4. Main reactor; 41. Packing zone; 42. Flow equalization 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 plate separation chamber; 511. Baffle plate; 52. Liquid collection hopper; 521. Splash barrier; 53. Separation orifice plate; 6. Liquid-laden gas inlet pipe; 7. Drain pipe; 8. Exhaust pipe; 9. Controller. Detailed Implementation

[0024] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0025] See Figure 1 As shown, this utility model provides a composite chlorine dioxide gas preparation device, including a pre-reactor 1 and a main reactor 4; The pre-reactor 1 is provided with a pre-reaction chamber 11, 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 4 is used to receive the gas-liquid mixture without crystal precipitates discharged from the pre-reactor 1 for further reaction.

[0026] To address the technical problem of clogging of packed beds caused by crystals, the inventors first proved through quantitative calculations that even if NaClO3 reacts completely with hydrogen chloride, the sodium chloride produced would not reach dissolution saturation relative to the sodium chlorate solution, the water carried by hydrochloric acid, and the water produced in the reaction, thus proving that the assumption by those skilled in the art that the precipitated crystals are sodium chloride is incorrect. Next, the inventors conducted compositional analysis on the precipitated crystals and found that they were sodium chlorate. The proposed formation mechanism is as follows: at a certain temperature, NaClO3 in the sodium chlorate solution... + ClO3 - It reacts with water molecules to form hydrated Na+ + With hydrated ClO3 - This forms a stable system; in a closed container, most of the HCl and H2O in hydrochloric acid (especially concentrated hydrochloric acid) exist in the form of HCl • nH2O, while a small portion of the HCl forms hydrated H+. + With hydrated Cl - A quasi-steady-state system is formed; when hydrochloric acid and sodium chlorate solution are mixed to form a reaction solution, due to H... + Cl - Its ability to compete for water molecules is far stronger than that of Na. + With ClO3 - The equilibrium between the two systems is disrupted, and some HCl • nH2O in the new system is released from the hydrated Na+. + With hydrated ClO3 - The process involves competing for H2O molecules to form hydrated H+. + With hydrated Cl - Na + With ClO3 - Sodium chlorate crystals precipitate out.

[0027] Based on the above findings, the inventors improved the composite chlorine dioxide gas preparation equipment by installing a pre-reactor 1 upstream of the main reactor 4. Sodium chlorate solution and hydrochloric acid are mixed and reacted in the pre-reactor 1, causing sodium chlorate crystals to precipitate and deposit at the bottom of the pre-reaction chamber 11 under gravity. In the pre-reaction chamber 11, HCl in the reaction solution continuously reacts with the precipitated sodium chlorate crystals. The precipitation and reaction digestion of sodium chlorate crystals occur simultaneously until an equilibrium is reached, ensuring gas-liquid mixing before entering the main reactor 4. The absence of crystal precipitates prevents blockage of the packing and pipes in the main reactor 4, ensuring stable equipment operation and completely resolving the problem of crystal precipitates depositing and clogging the main reactor 4. This makes it possible to use high-concentration reactants: because sodium chlorate crystals are fully reacted and dissolved in the pre-reaction chamber 11, unreacted raw materials are reduced from entering subsequent stages. Simultaneously, the main reactor 4 continues to react the gas-liquid mixture, significantly improving raw material utilization and overcoming the bottleneck of low conversion rates (≤50%) in existing equipment, achieving a final conversion rate of 90% or higher. This reduces the risk of unreacted raw materials such as sodium chlorate entering drinking water with the disinfectant, minimizing health hazards (such as the effects of chlorate on the circulatory and reproductive systems), while also reducing preparation costs.

[0028] In one embodiment, a sodium chlorate solution supply device 2 is also included. The sodium chlorate solution supply device 2 is connected to the pre-reactor 1 via a sodium chlorate solution supply pipeline 21. A sodium chlorate solution metering pump 22 is installed on the sodium chlorate solution supply pipeline 21. The sodium chlorate solution supply device 2 is equipped with a heating device 23 and a heat preservation facility 24.

[0029] The heating device 23 increases 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, in the composite chlorine dioxide gas preparation method provided by this utility model, a higher concentration of sodium chlorate solution (30%~67%) can be used as the reaction solution. As the concentration of reactants increases, the reaction rate accelerates. At the same time, increasing the concentration of reactants can directly reduce the amount of water in the residual liquid, reduce the amount of residual liquid discharged, and effectively increase the conversion rate of sodium chlorate and the yield of the products chlorine dioxide and chlorine gas.

[0030] The insulation facility 24 is used to maintain the temperature of the sodium chlorate solution in the sodium chlorate solution supply device 2, thereby reducing temperature fluctuations and heating energy consumption.

[0031] It should be noted that the increase in sodium chlorate solution concentration in this composite chlorine dioxide gas preparation method is a further improvement based on solving the bottleneck of crystallization by using pre-reactor 1. Existing preparation methods usually use relatively low-concentration sodium chlorate solution at room temperature. The main limiting factor is the crystallization problem. If the concentration of sodium chlorate solution is increased without solving the crystallization problem, the problem of crystallization blockage will be aggravated, and thus it cannot be implemented in practice.

[0032] In one embodiment, a hydrochloric acid supply device 3 is also included, which is connected to the pre-reactor 1 via a hydrochloric acid supply pipeline 31, and a hydrochloric acid metering pump 32 is provided on the hydrochloric acid supply pipeline 31.

[0033] In one embodiment, a controller 9 is also included, which is connected to the sodium chlorate solution metering pump 22 and the hydrochloric acid metering pump 32 respectively, to achieve precise control of the amount of hydrochloric acid and sodium chlorate solution added, to ensure that the two react fully, and to avoid problems such as intensified crystallization and insufficient reaction due to imbalance of addition.

[0034] In one 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, ensuring the supply of high-concentration sodium chlorate solution (avoiding concentration limitation due to low temperature), avoiding crystal precipitation due to excessively low temperature, and improving the reaction rate.

[0035] In one embodiment, the pre-reactor 1 is a cylindrical cavity that is closed at both ends.

[0036] In one embodiment, the pre-reactor 1 includes an overflow pipe 15, the top end of which is inserted into the pre-reaction chamber 11 to form an overflow port 151, and a deposition reaction zone for containing the reaction liquid and sodium chlorate crystals is formed between the overflow port 151 and the bottom of the pre-reaction chamber 11.

[0037] The overflow port 151 of the overflow pipe 15 is designed to control the liquid level and form a deposition reaction zone, so that sodium chlorate crystals are deposited 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, ensuring that the crystals are fully digested and further improving the conversion rate. Only the gas-liquid mixture without crystals enters the main reactor 4 through the overflow port 151, completely avoiding crystallization clogging the main reactor 4.

[0038] In one embodiment, the pre-reactor 1 further includes an isolation cover 12, which is located in the pre-reaction chamber 11. The top of the isolation cover 12 is connected to the top of the inner cavity of the pre-reaction chamber 11, and the bottom of the isolation cover 12 is suspended above the bottom surface of the inner cavity of the pre-reaction chamber 11. The isolation cover 12 is located on the outer periphery of the overflow pipe 15. The isolation cover 12 isolates the deposition reaction zone to form a first deposition reaction zone 111 located outside the isolation cover 12 and a second deposition reaction zone 112 located inside the isolation cover 12. The first deposition reaction zone 111 and the second deposition reaction zone 112 are connected at the bottom of the isolation cover 12. The pre-reactor 1 is provided with a sodium chlorate solution inlet 14 and a hydrochloric acid inlet 13 that connect to the first deposition reaction zone 111. The sodium chlorate solution inlet 14 and the hydrochloric acid inlet 13 are respectively located on the outer walls of the two sides of the pre-reactor 1.

[0039] The structural design of separating the first deposition reaction zone 111 and the second deposition reaction zone 112 by the isolation cover 12 ensures that the crystalline precipitate precipitated in the pre-reactor 1—sodium chlorate crystals—is deposited at the bottom of the pre-reactor 11 under the action of gravity, and continuously reacts with HCl in the flowing reaction liquid. The dual deposition reaction zone design increases the contact opportunity between sodium chlorate crystals and hydrochloric acid, completely dissolving the crystalline precipitate before entering 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.

[0040] In one embodiment, the pre-reactor 1, the isolation hood 12, and the overflow pipe 15 are all made of non-metallic materials that are resistant to acid and alkali corrosion, thus avoiding structural stability problems caused by corrosion from the reaction liquid and generated gas.

[0041] In one embodiment, a vent 121 is provided on the top of the side wall of the isolation cover 12, and the height of the vent 121 is higher than the sodium chlorate solution inlet 14, the hydrochloric acid inlet 13 and the overflow port 151.

[0042] The vent 121 at the top of the isolation cover 12 can balance the gas pressure of the first deposition reaction zone 111 and the second deposition reaction zone 112. The composite chlorine dioxide gas generated in the first deposition reaction zone 111 can directly enter the second deposition reaction zone 112 through the vent 121, and after forming a gas-liquid mixture, it enters the overflow port 151.

[0043] In one embodiment, the main reactor 4 is made of a non-metallic material that is resistant to acid and alkali corrosion.

[0044] In one embodiment, the main reactor 4 is provided with a packing zone 41, which is filled with polyhedral packing.

[0045] Setting up polyhedral packing can increase the contact area between the reaction liquid and the carrier gas. As the reaction liquid flows downward, it can form a liquid film with a high specific surface area through the polyhedral packing, allowing the unreacted raw materials to react fully. At the same time, it can allow the hot carrier gas to flow countercurrently through the pores in the middle, thereby reducing the flow rate of the reaction liquid, diluting and carrying away the gaseous products, and further improving the conversion rate of chlorine dioxide.

[0046] The pre-reactor 1 is located at the top of the main reactor 4, and the bottom of the overflow pipe 15 enters the main reactor 4 and extends above the packing zone 41.

[0047] The pre-reactor 1 is located at the top of the main reactor 4, and the overflow pipe 15 extends directly to the top of the packing zone 41. The integrated layout shortens the transport path of the gas-liquid mixture, facilitates equipment integration and maintenance, saves installation space, and ensures that the crystal-free gas-liquid mixture enters the packing zone 41 directly, preventing crystal deposition and clogging of the packing.

[0048] In one embodiment, the main reactor 4 is further provided with a flow equalization plate 42, which is located below the overflow pipe 15 and the overflow pipe 15 is arranged perpendicularly to the flow equalization plate 42. Its function is to make the reaction liquid flowing out of the overflow pipe 15 evenly distributed in a ring shape on the packing area 41 in the main reactor 4, forming a wedge-shaped downward flow to achieve the function of dispersing the reaction liquid.

[0049] In one embodiment, the flow equalization plate 42 is a circular flat plate.

[0050] In one embodiment, the main reactor 4 is further provided with at least one flow guide ring 43. The flow guide ring 43 is made of non-metallic material and is resistant to acid and alkali corrosion. The flow guide ring 43 is located in the packing zone 41, and the outer edge of the flow guide ring 43 abuts against the inner wall of the main reactor 4. When there are multiple flow guide rings 43, the multiple flow guide rings 43 are arranged at intervals from top to bottom in the packing zone 41.

[0051] The function of the guide ring 43 is to make the reaction liquid that flows along the inner wall of the main reactor 4 due to the wall flow effect return to the packing bed in a uniform manner and flow downward in a wedge shape again, so as to prevent it from flowing along the inner wall of the main reactor 4, thickening the liquid film, increasing the flow rate, and exceeding the liquid film on the surface of the polyhedral packing, thus forming residual liquid before it has fully reacted.

[0052] When the height-to-diameter ratio of the main reactor 4 is large, multiple spaced guide rings 43 need to be set. Multiple spaced guide rings 43 can correct the liquid film distribution multiple times to ensure that the liquid film of the reaction liquid in the entire packing zone 41 is uniform.

[0053] In one embodiment, a hot carrier gas pipe 46 is connected to the bottom of the side wall of the main reactor 4, and the hot carrier gas pipe 46 is located below the packing zone 41.

[0054] The hot carrier gas provides the temperature conditions for the reaction in the packed zone 41, promoting the forward reaction of sodium chlorate and hydrochloric acid and increasing the reaction rate. Simultaneously, in the packed zone 41, the upward flow of the hot carrier gas comes into countercurrent contact with the downward flowing liquid film, accelerating the escape of the composite chlorine dioxide gas from the liquid film, further promoting the forward reaction and increasing the conversion rate. Furthermore, the hot carrier gas can dilute the generated high-concentration composite chlorine dioxide gas, eliminating the risk of explosion, and efficiently remove the gas to subsequent processing stages.

[0055] In one embodiment, a fan 47 is provided on the hot carrier gas pipeline 46, and the controller 9 is connected to the fan 47 to control the supply rate of the hot carrier gas.

[0056] In one embodiment, the bottom of the main reactor 4 is connected to a residual liquid outlet pipe 44, and the residual liquid outlet pipe 44 is provided with a liquid seal structure 441.

[0057] The liquid seal structure 441 is a U-shaped tube structure. The liquid seal structure 441 can prevent outside air from entering the main reactor 4, and at the same time avoid leakage caused by the inclusion of compound chlorine dioxide gas when the residual liquid is discharged, thereby improving the safety of equipment operation.

[0058] In one embodiment, the residual liquid discharge pipeline 44 is connected to a residual liquid recovery tank 45.

[0059] In one embodiment, the system further includes a gas-liquid separator 5, a liquid-containing gas inlet pipe 6, an exhaust pipe 8, and a liquid drain pipe 7. The liquid-containing gas inlet pipe 6 is connected to the top of the packing zone 41 and the gas-liquid separator 5, respectively. The exhaust pipe 8 is connected to the gas-liquid separator 5 and is used to discharge the composite chlorine dioxide gas after gas-liquid separation. The liquid drain pipe 7 is connected to the gas-liquid separator 5 and the packing zone 41, respectively, and is used to guide the liquid after gas-liquid separation to the packing zone 41.

[0060] The gas-liquid separator 5 separates the liquid from the liquid-containing gas, ensuring that the discharged composite chlorine dioxide gas is dry and pure, facilitating subsequent absorption and utilization. The separated liquid is returned to the packing zone 41 through the drain pipe 7 to continue the reaction, reducing raw material waste caused by liquid entrainment, further improving the conversion rate, reducing raw material consumption costs, and simplifying the post-gas-liquid separation processing flow.

[0061] In one embodiment, the gas-liquid separator 5 includes a baffle plate separation chamber 51 and a liquid collection hopper 52. The baffle plate separation chamber 51 is located above the liquid collection hopper 52. The baffle plate separation chamber 51 is provided with a plurality of baffle plates 511 arranged at intervals. The bottom surface of the liquid collection hopper 52 is provided with a splash-proof layer 521. The liquid-laden gas inlet pipe 6 is connected to the top of the baffle plate separation chamber 51. The liquid outlet pipe 7 is connected to the bottom of the liquid collection hopper 52. The exhaust pipe 8 is connected to the side wall of the liquid collection hopper 52.

[0062] The baffle separation chamber 51 uses multiple baffles 511 to form multiple baffles, which allows the liquid in the liquid-laden gas to fully adhere to the baffles 511 and be separated.

[0063] The splash-proof layer 521 is made of acid and alkali resistant metal or acid and alkali resistant non-metallic material with many pores. It is evenly spread in the bucket-shaped structure at the bottom of the liquid collection hopper 52. Its function is to prevent the separated liquid from being entrained by gas again when it falls, thereby improving the separation effect.

[0064] In one embodiment, the gas-liquid separator 5 further includes a separation orifice plate 53, which is located in the liquid collection hopper 52 and is arranged around the bottom outer periphery of the baffle plate separation chamber 51, thereby further preventing the separated liquid from splashing out.

[0065] Another embodiment of this utility model provides a method for preparing composite chlorine dioxide gas, using the composite chlorine dioxide gas preparation equipment described above, and including the following operating steps: Sodium chlorate solution and hydrochloric acid are introduced into the pre-reaction chamber 11 and mixed to form a reaction solution; The reaction process in the reaction solution is as follows: 2NaClO3+4HCl=2ClO2↑+Cl2↑+2NaCl+2H2O A deposition reaction zone containing the reaction liquid is formed in the pre-reaction chamber 11. In the deposition reaction zone, sodium chlorate crystals precipitate from the reaction liquid, deposit in the reaction liquid, and react and dissolve. The gas-liquid mixture without crystal precipitates is introduced into the main reactor 4 to continue the reaction and generate composite chlorine dioxide gas.

[0066] This method for preparing composite chlorine dioxide gas achieves the digestion of sodium chlorate crystals in the deposition reaction zone of the pre-reactor 11. The pre-reactor 1 and the main reactor 4 react in succession, allowing the raw materials to be fully converted in two stages, preventing crystals from entering the main reactor 4. This fundamentally solves the clogging problem of existing equipment, eliminating the need for frequent shutdowns to flush crystallization (such as dilution water flushing in the background technology), reducing wastewater generation and raw material waste, improving the conversion rate of sodium chlorate, and overcoming the limitation of low conversion rate in existing processes.

[0067] In one embodiment, 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 and kept at a temperature of 25°C~100°C.

[0068] The heating temperature of the sodium chlorate solution is set according to the required concentration of sodium chlorate solution, so as to ensure that the sodium chlorate in the sodium chlorate solution is fully dissolved.

[0069] In conjunction with the design of the pre-reaction zone, the solubility of sodium chlorate solution is increased by heating it (25℃~100℃) to solve the crystallization blockage problem, which supports the use of high-concentration raw materials, accelerates the reaction rate, and improves the conversion rate of sodium chlorate.

[0070] In one embodiment, the pre-reaction chamber 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 interconnected. Sodium chlorate solution and hydrochloric acid are mixed and reacted in the first deposition reaction zone 111, causing sodium chlorate crystals to precipitate and deposit at the bottom of the first deposition reaction zone 111 and the bottom of the second deposition reaction zone 112 under gravity. The liquid portion flows from the bottom of the first deposition reaction zone 111 through the second deposition reaction zone 112, and the reaction continues during the flow. The composite chlorine dioxide gas generated in 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 discharged to the main reactor 4. In the deposition reaction zone, the precipitation and reaction digestion 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 of sodium chlorate crystals with HCl increases until the precipitation and consumption of sodium chlorate crystals reach an equilibrium state, and the amount of sodium chlorate crystals deposited remains unchanged. Finally, as the injection of the reaction liquid stops, the sodium chlorate crystals gradually decrease until they disintegrate and disappear.

[0071] By combining the design of the first deposition reaction zone 111 and the second deposition reaction zone 112, it is possible to ensure that the precipitated sodium chlorate crystals are fully deposited at the bottom of the first deposition reaction zone 111 and the second deposition reaction zone 112, maintaining the dynamic equilibrium process of "precipitation-deposition-dissolution" of sodium chlorate crystals. This allows the crystals to continuously react with hydrochloric acid in the flow until they are completely dissolved, ensuring that the crystals do not accumulate in the pre-reaction chamber 11 and do not enter the main reactor 4, maintaining the long-term stable operation of the equipment, and ensuring a stable amount of composite chlorine dioxide generated.

[0072] In one embodiment, the main reactor 4 further includes the following process: A gas-liquid mixture without crystal precipitates is introduced into the main reactor 4 through an overflow pipe 15. A flow equalization plate 42 is provided at the bottom of the overflow pipe 15. The gas-liquid mixture flows downward along the outer edge of the flow equalization plate 42 and contacts the polyhedral packing, forming a double-wedge-shaped uniform downward flow cross section on the central section of the main reactor 4.

[0073] The flow equalization plate 42 makes the reaction liquid form a double wedge-shaped uniform downward flow cross section. The uniform flow distribution makes the liquid film thickness on the packing surface consistent, ensuring that all parts of the packing zone 41 are in full contact with the reaction liquid, avoiding local reaction dead zones, stabilizing the reaction rate, and improving the overall conversion rate.

[0074] In one embodiment, the main reactor 4 further includes the following process: A gas-liquid mixture without crystal precipitates is introduced into the packing zone 41 from the top, and a hot carrier gas is introduced into the packing zone 41 from the bottom. The reaction liquid flows downward in sequence 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 sequence in the packing zone 41. 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 41.

[0075] The hot carrier gas continuously provides heat to maintain the reaction temperature in the packing zone 41, ensuring reaction activity. Furthermore, the hot carrier gas and the liquid film are in countercurrent contact, increasing their contact time and promoting the release of the composite chlorine dioxide gas from the liquid film, thus driving the reaction forward. In addition, the hot carrier gas can dilute the high concentration of composite chlorine dioxide gas, keeping it within a safe concentration range and eliminating the risk of explosion.

[0076] In one embodiment, the main reactor 4 further includes the following process: As the reaction liquid flows downward, it naturally accumulates on the inner wall of the main reactor 4. To prevent the liquid film on the inner wall of the main reactor 4 from thickening, reducing the reaction rate, and increasing the flow velocity to "overtake" the liquid film on the surface of the polyhedral packing, a guide ring 43 is provided on the inner wall of the main reactor 4. When the reaction liquid contacts the guide ring 43, the liquid film on the inner wall flows radially inward along the upper surface of the guide ring 43 and downward along the inner edge of the guide ring 43 to contact the polyhedral packing, thus forming a double-wedge-shaped uniform downward flow cross section on the central section of the main reactor 4.

[0077] After being guided by the flow guide ring 43, the liquid film on the inner wall can be redirected to the central region, forming a double wedge-shaped uniform flow cross section again, extending the contact time with the packing and improving the reaction conversion rate.

[0078] Depending on the size of the main reactor 4, the flow pattern can be adjusted by the number of guide rings 43 to ensure that the reaction efficiency is not affected by the size of the equipment.

[0079] In one embodiment, the following operations are also included: The liquid-containing gas is introduced into the gas-liquid separator 5 for gas-liquid separation. The liquid after gas-liquid separation is returned to the packing zone 41 to continue the reaction, so as to avoid the waste of unreacted sodium chlorate and hydrochloric acid in the liquid and further improve the conversion rate.

[0080] The present invention will be further described below through embodiments.

[0081] Example 1 This embodiment uses the composite chlorine dioxide gas preparation equipment and method described above, wherein: In the sodium chlorate solution supply device: 5 kg of sodium chlorate is added and 5 kg of water is added. The temperature of the sodium chlorate solution is controlled to be no lower than 30°C by a heating device. In the supply device: take 33% hydrochloric acid, and according to the molar ratio of NaClO3 to HCl of 1:2.2, take 103.29 mol of HCl, that is, 3.77 kg of HCl, and 7.65 kg of water. The total water content in the residual liquid is 5 kg + 7.65 kg + 0.85 kg = 13.5 kg. The measured ratio of sodium chlorate to water was approximately 3.5:100. After the reaction was carried out using the composite chlorine dioxide gas preparation equipment described above, the sodium chlorate content in the residual liquid was measured to be 0.473 kg, and 4.527 kg of sodium chlorate was converted, which is equivalent to a conversion rate of 90.54%.

[0082] Example 2 This embodiment uses the composite chlorine dioxide gas preparation equipment and method described above, wherein: In the sodium chlorate solution supply device: 6 kg of sodium chlorate is added and 4 kg of water is added. The temperature of the sodium chlorate solution is controlled to be no lower than 85°C by a heating device. In the supply device: take 33% hydrochloric acid, and according to the molar ratio of NaClO3 to HCl of 1:2.2, take 123.94 mol of HCl, that is, 4.524 kg of HCl, and 9.05 kg of water. The total water content in the residual liquid is 4 kg + 9.05 kg + 1.01 kg = 14.06 kg. The measured ratio of sodium chlorate to water was approximately 3.4:100. After the reaction was carried out using the composite chlorine dioxide gas preparation equipment described above, the sodium chlorate content in the residual liquid was measured to be 0.478 kg, and 5.522 kg of sodium chlorate was converted, which is equivalent to a conversion rate of 92.03%.

[0083] Based on 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.

[0084] As can be seen from the above, the composite chlorine dioxide gas preparation method provided by this utility model can achieve a sodium chlorate conversion rate of over 90%, completely changing the current situation where "a large amount of unreacted raw material is wasted, driving up preparation costs" in existing equipment, and significantly reducing the cost of raw material procurement and residual liquid treatment for enterprises. Furthermore, by completely solving the crystallization problem, increasing the concentration of the sodium chlorate solution further improves the sodium chlorate conversion rate, confirming the positive promoting effect of the synergistic design of "temperature control + pre-crystallization digestion" on reaction efficiency, providing a double guarantee for high conversion rates.

[0085] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

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.

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