CA2946017A1 - A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator - Google Patents
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator Download PDFInfo
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- CA2946017A1 CA2946017A1 CA2946017A CA2946017A CA2946017A1 CA 2946017 A1 CA2946017 A1 CA 2946017A1 CA 2946017 A CA2946017 A CA 2946017A CA 2946017 A CA2946017 A CA 2946017A CA 2946017 A1 CA2946017 A1 CA 2946017A1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B11/00—Oxides or oxyacids of halogens; Salts thereof
- C01B11/02—Oxides of chlorine
- C01B11/022—Chlorine dioxide (ClO2)
- C01B11/023—Preparation from chlorites or chlorates
- C01B11/026—Preparation from chlorites or chlorates from chlorate ions in the presence of a peroxidic compound, e.g. hydrogen peroxide, ozone, peroxysulfates
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Abstract
A method for hydrogen peroxide based chlorine dioxide production process with a single vessel vertical generator is disclosed. The process involves mixing a sodium chlorate solution (600-700g/l) and a hydrogen peroxide solution (27wt%-60wt%) in sodium chlorate feed pipes, feeding into the generator circulation system from lower circulation pipe of the generator; and further feeding a concentrated sulfuric acid (93wt%-98wt%) solution into the generator circulation system through the nozzle of the reboiler after being diluted with deionized water and reducing the concentration down to 60wt%-65wt%, for complete and thorough reaction by application of a circulation pump. The process generates a stream of highly purified chlorine dioxide solution with a low byproduct concentration of chlorine of 0.01 ¨0.08g-Cl2/l-ClO2, by controlling multiple parameters in the generator, e.g. liquor acidity between 2-5N, gauge pressure at -72~-85kPa, temperature at 60-80 degree C, liquor density at 1.4~1.8g/cm3, and sodium chlorate concentration at 1.8~3.3mol/l. The process does not emit waste acid into the environment, while generates neutral salt cake as byproducts.
Description
A METHOD FOR HYDROGEN PEROXIDE BASED CHLORINE DIOXIDE
PRODUCTION PROCESS WITH A VERTICAL GENERATOR
Description Field This invention relates to a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator.
Background Chlorine dioxide (C102) is a strong oxidizing agent that has been applicable in medical care, sterilization, and pulp bleaching and water treatment. Production process for chlorine dioxide can be categorized into electrolytic process and chemical process. The electrolytic process has certain advantages in environmental discharge, and low raw material consumption, yet requiring high investment for a complex system and maintenance, sophisticated requirement of operation and high energy consumption, which limits its application.
Therefore, the chemical process dominants in the industry today. After years of development and research, the chemical process has been fully developed for dozens of derivative methods.
The most applied method ¨ a methanol based process has multiple advantages regarding the product purity, low capital investment and convenient production. However, various byproducts are produced in the process e.g. methanol, formaldehyde and formic acid, which are toxic and bring drawbacks to the applications. For instance, chlorinated organics can be formed in bleaching process; or, carcinogens e.g. trichloromethane can be formed in drinking water treatment process. Another widely applied method is the hydrochloric acid based process. During this process, 1 mol of chlorine dioxide generated 0.5 mol chlorine gas will simultaneously be produced which requires further treatment. On the contrary, the hydrogen peroxide based process possesses an incomparable improvement that can generate high quality chlorine dioxide without chlorine and other hazardous gases or with small amount of chorine. Due to multiple advantages of the hydrogen peroxide based process, e.g. raw material, cost, and efficiency etc., the process shows bright prospects for the future.
However, the hydrogen peroxide based process generally use a multistage aeration generator which gives rise to a large amount of waste discharge and leads to environmental issues during the chlorine dioxide production.
Therefore, it becomes an urgent problem for eliminating or reducing contaminative discharges during the chlorine dioxide production process.
Summary of Invention The technical issue to be solved by the current invention is to provide a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, which discharges no waste acid while producing high purity chlorine dioxide, with neutral salt cake and oxygen as the by-products, being clean and environmental-friendly.
This invention presents approaches to above technical issues as follows:
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, characterized by consisting of a chlorine dioxide generation section constituted of a reboiler (3), an upper circulation piping (5), a generator (21), a lower circulation piping (22), a generator exhaust gas pipe (10), a generator circulation pump (23), an indirect cooler (19), an absorber (18), a generator vacuum pump (13) and the related piping;
a salt cake filtration section constituted of a filter (7), a hydrocyclone (8), a gas-liquid separation tank (9), a filter vacuum pump (11), a salt cake feed pump (20) and the related piping; and a tail gas treatment section constituted of a tail gas scrubber (14), a tail gas blower (15) and the related piping.
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, also characterized by the following process procedures:
1. Mix hydrogen peroxide and sodium chlorate solution in the piping before feed into the generator through a straight pipe in the header below the reboiler.
Concentrated sulfuric acid flows to a throat in the outlet on the top of the reboiler and is diluted to 60wt%-65wt%
PRODUCTION PROCESS WITH A VERTICAL GENERATOR
Description Field This invention relates to a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator.
Background Chlorine dioxide (C102) is a strong oxidizing agent that has been applicable in medical care, sterilization, and pulp bleaching and water treatment. Production process for chlorine dioxide can be categorized into electrolytic process and chemical process. The electrolytic process has certain advantages in environmental discharge, and low raw material consumption, yet requiring high investment for a complex system and maintenance, sophisticated requirement of operation and high energy consumption, which limits its application.
Therefore, the chemical process dominants in the industry today. After years of development and research, the chemical process has been fully developed for dozens of derivative methods.
The most applied method ¨ a methanol based process has multiple advantages regarding the product purity, low capital investment and convenient production. However, various byproducts are produced in the process e.g. methanol, formaldehyde and formic acid, which are toxic and bring drawbacks to the applications. For instance, chlorinated organics can be formed in bleaching process; or, carcinogens e.g. trichloromethane can be formed in drinking water treatment process. Another widely applied method is the hydrochloric acid based process. During this process, 1 mol of chlorine dioxide generated 0.5 mol chlorine gas will simultaneously be produced which requires further treatment. On the contrary, the hydrogen peroxide based process possesses an incomparable improvement that can generate high quality chlorine dioxide without chlorine and other hazardous gases or with small amount of chorine. Due to multiple advantages of the hydrogen peroxide based process, e.g. raw material, cost, and efficiency etc., the process shows bright prospects for the future.
However, the hydrogen peroxide based process generally use a multistage aeration generator which gives rise to a large amount of waste discharge and leads to environmental issues during the chlorine dioxide production.
Therefore, it becomes an urgent problem for eliminating or reducing contaminative discharges during the chlorine dioxide production process.
Summary of Invention The technical issue to be solved by the current invention is to provide a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, which discharges no waste acid while producing high purity chlorine dioxide, with neutral salt cake and oxygen as the by-products, being clean and environmental-friendly.
This invention presents approaches to above technical issues as follows:
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, characterized by consisting of a chlorine dioxide generation section constituted of a reboiler (3), an upper circulation piping (5), a generator (21), a lower circulation piping (22), a generator exhaust gas pipe (10), a generator circulation pump (23), an indirect cooler (19), an absorber (18), a generator vacuum pump (13) and the related piping;
a salt cake filtration section constituted of a filter (7), a hydrocyclone (8), a gas-liquid separation tank (9), a filter vacuum pump (11), a salt cake feed pump (20) and the related piping; and a tail gas treatment section constituted of a tail gas scrubber (14), a tail gas blower (15) and the related piping.
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, also characterized by the following process procedures:
1. Mix hydrogen peroxide and sodium chlorate solution in the piping before feed into the generator through a straight pipe in the header below the reboiler.
Concentrated sulfuric acid flows to a throat in the outlet on the top of the reboiler and is diluted to 60wt%-65wt%
2 concentration with deionized water before being injected into generator circulation system.
Under the force of the generator circulation pump, the chemical raw materials are mixed and react sufficiently, producing chlorine dioxide, water, oxygen and neutral salt cake under a controlled low mother liquor acidity in the vertical generator as well as the generator pressure, the temperature and other process parameters maintained within a certain range. The produced C102 gas is released, while the remaining liquor and by-product settle to the bottom of the generator as generator liquor, which is circulated between the reboiler and the generator continuously by the circulation pump to mix and react with a continuous feed of hydrogen peroxide, NaC103 mixture and concentrated sulfuric acid, producing C102 gas continuously.
The C102 gas produced in the generator is diluted by a large amount of water vapors and oxygen produced from the reactions, becoming gas mixture. The gas mixture exits from the generator exhaust pipe, passes through the intercooler, and then enters the absorber to be absorbed by chilled water and form C102 aqueous solution for delivery. The reaction is as below:
2NaC103+H2SO4 + 14202 ¨> 2C102 + 02+ 2H20+Na2SO4 2. With a continuous feeding of hydrogen peroxide and sodium chlorate mixture and concentrated sulfuric acid, reactions take place continuously. Along with the continuous generation of C102, there is a continuous crystallization of salt cake, the by-product, inside the generator. The salt cake feed pump (20) takes out part of the mother liquor containing salt cake crystals from the lower circulation piping (22) of the generator and transfers them to the hydrocyclone (8) to separate solids and liquid. Mother liquor that has gone through the separation, after joining with washing liquid from the filter (7) and the gas-liquid separation tank (9), flows to the lower circulation piping (22) of the generator, while the filtrated neutral salt cake crystals are transferred out of the system for utilization.
Under the force of the generator circulation pump, the chemical raw materials are mixed and react sufficiently, producing chlorine dioxide, water, oxygen and neutral salt cake under a controlled low mother liquor acidity in the vertical generator as well as the generator pressure, the temperature and other process parameters maintained within a certain range. The produced C102 gas is released, while the remaining liquor and by-product settle to the bottom of the generator as generator liquor, which is circulated between the reboiler and the generator continuously by the circulation pump to mix and react with a continuous feed of hydrogen peroxide, NaC103 mixture and concentrated sulfuric acid, producing C102 gas continuously.
The C102 gas produced in the generator is diluted by a large amount of water vapors and oxygen produced from the reactions, becoming gas mixture. The gas mixture exits from the generator exhaust pipe, passes through the intercooler, and then enters the absorber to be absorbed by chilled water and form C102 aqueous solution for delivery. The reaction is as below:
2NaC103+H2SO4 + 14202 ¨> 2C102 + 02+ 2H20+Na2SO4 2. With a continuous feeding of hydrogen peroxide and sodium chlorate mixture and concentrated sulfuric acid, reactions take place continuously. Along with the continuous generation of C102, there is a continuous crystallization of salt cake, the by-product, inside the generator. The salt cake feed pump (20) takes out part of the mother liquor containing salt cake crystals from the lower circulation piping (22) of the generator and transfers them to the hydrocyclone (8) to separate solids and liquid. Mother liquor that has gone through the separation, after joining with washing liquid from the filter (7) and the gas-liquid separation tank (9), flows to the lower circulation piping (22) of the generator, while the filtrated neutral salt cake crystals are transferred out of the system for utilization.
3. Tail gas from the system enters the tail gas scrubber (14) to be scrubbed by chilled water. Dilute chlorine dioxide solution obtained from this process returns to the absorber (18), and tail gas is discharged by the tail gas blower (15).
It is preferred that the generator be a vertical generator.
It is preferred that hydrogen peroxide and sodium chlorate mix in pipeline before being introduced to generator circulation system through a straight pipe in the header below the boiler.
It is preferred that sulfuric acid be diluted to 60wt%-65wt% concentration by deionized water before being injected into the generator circulation system.
It is preferred that acidity of the mother liquor within the generator be maintained at 2-5N.
It is preferred that temperature inside the generator be 60-80 C, maintaining vacuum conditions at a gauge pressure of -72 to -85kPa.
It is preferred that the mother liquor density inside the generator be 1.4 to 1.8g/cm3.
It is preferred that the sodium chlorate concentration inside the generator be 1.8 to 3 .3mo1/1.
Advantages and effects of the invention:
1. Hydrogen peroxide and sodium chlorate mix in the pipeline before being introduced to the generator circulation system to decrease the concentration of hydrogen peroxide, which prevents the situation where chlorine dioxide decomposes due to violent reactions caused by high concentration of hydrogen peroxide fed to the generator, improving reaction efficiency and safety.
2. High purity chlorine dioxide, with a chlorine content of 0.01 to 0.08 g/1 C102.
It is preferred that the generator be a vertical generator.
It is preferred that hydrogen peroxide and sodium chlorate mix in pipeline before being introduced to generator circulation system through a straight pipe in the header below the boiler.
It is preferred that sulfuric acid be diluted to 60wt%-65wt% concentration by deionized water before being injected into the generator circulation system.
It is preferred that acidity of the mother liquor within the generator be maintained at 2-5N.
It is preferred that temperature inside the generator be 60-80 C, maintaining vacuum conditions at a gauge pressure of -72 to -85kPa.
It is preferred that the mother liquor density inside the generator be 1.4 to 1.8g/cm3.
It is preferred that the sodium chlorate concentration inside the generator be 1.8 to 3 .3mo1/1.
Advantages and effects of the invention:
1. Hydrogen peroxide and sodium chlorate mix in the pipeline before being introduced to the generator circulation system to decrease the concentration of hydrogen peroxide, which prevents the situation where chlorine dioxide decomposes due to violent reactions caused by high concentration of hydrogen peroxide fed to the generator, improving reaction efficiency and safety.
2. High purity chlorine dioxide, with a chlorine content of 0.01 to 0.08 g/1 C102.
4 3. No waste acid discharge from the chlorine dioxide production process.
4. By-product of the chlorine dioxide production process is a neutral salt cake.
Description of the drawings Fig. 1 shows the process flow diagram of the invention.
Where:
1. Sodium chlorate feed pipe; 2. Hydrogen peroxide feed pipe; 3. Reboiler; 4.
Sulfuric acid feed pipe; 5. Upper circulation piping of the generator; 6. Salt cake outlet;
7. Filter; 8.
Hydrocyclone; 9. Gas-liquid separation tank; 10. Generator exhaust gas pipe;
11. Filter vacuum pump; 12. Absorber chilled water feed pipe; 13. Generator vacuum pump;
14. Tail gas scrubber; 15. Tail gas blower; 16. Scrubber chilled water feed pipe; 17.
Chlorine dioxide transfer pipe; 18. Absorber; 19. Intercooler; 20. Salt cake feed pump; 21.
Generator; 22 Lower circulation piping of the generator; 23. Generator circulation pump Detailed description of embodiments A further description of the method for hydrogen peroxide based chlorine dioxide production process with a vertical generator that this invention relates to is given through the examples below. The following examples are prescribed for illustrating the technical framework and characteristics of this invention with the intention to make the details of the invention understandable to those unfamiliar with it, while not meant to limit the protection scope of the invention. The protection scope shall cover any equivalent transformation of or embellishment to the spirit of this invention.
Example 1:
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, characterized by the following: a chlorine dioxide generation section, a salt cake filtration section and a tail gas treatment section.
The operation procedures of the invention are shown as follows:
1) Sodium chlorate from sodium chlorate feed pipe (1) at 600g/1 concentration mixes with hydrogen peroxide from hydrogen peroxide feed pipe (2) at 60wt% concentration in the sodium chlorate feed pipe (1), before introduced to the generator circulation system through a straight pipe in the header below the reboiler (3). Concentrated sulfuric acid from sulfuric acid feed pipe (4) at 98wt% concentration flows to a throat in the outlet on the top of the reboiler (3) and is diluted to 60wt%-65wt% concentration with deionized water before being injected into the generator circulation system. Under the force of the generator circulation pump (23), the chemical raw materials are mixed and react sufficiently, producing chlorine dioxide, water, oxygen and neutral salt cake under controlled conditions inside the vertical generator (21) with a mother liquor acidity of 2 - 5N, a gauge pressure of -72 to -85kPa, a temperature of 60 C - 80 C, a mother liquor density of 1.4 - 1.8g/cm3 and a sodium chlorate solution concentration of 1.8 - 3.3mo1/1. The produced C102 gas is released, while the remaining liquor and by-product settle to the bottom of the generator (21) as generator liquor, which is circulated between the reboiler (3) and the generator (21) continuously by the circulation pump (23) to mix and react with constant feed of hydrogen peroxide, sodium chlorate mixture and concentrated sulfuric acid, producing C102 gas continuously. The C102 gas produced in the generator (21) is diluted inside the generator (21) by a large amount of steam evaporated and oxygen produced from the reactions, becoming gas mixture. The gas mixture exits from the generator exhaust pipe (10), passes through the indirect cooler (19), and then enters the absorber (18) to be absorbed by chilled water from absorber chilled water feed pipe (12) and form C102 aqueous solution for delivery via chlorine dioxide transfer pipe (17). While generating vacuum in the generator (21), generator vacuum pump (13) also pumps tail gas in the absorber (18) to the tail gas scrubber (14).
2) With the continuous feeding of hydrogen peroxide and sodium chlorate mixture and concentrated sulfuric acid, reactions take place ceaselessly. Along with the continuous generation of C102, there is a continuous crystallization of salt cake, the by-product, inside the generator (21). The salt cake feed pump (20) takes out part of the mother liquor containing salt cake crystals from the lower circulation piping (22) of the generator and transfers them to the hydrocyclone (8) to separate solids and liquid. Mother liquor passes through the separation, after joining with washing liquid from the filter (7) and the gas-liquid separation tank (9), flowing to the lower circulation piping (22) of the generator, while the filtrated neutral salt cake crystals are transferred out of the system from salt cake outlet (6) for utilization. While generating vacuum inside the filter (7), the filter vacuum pump (11) also pumps tail gas in the salt cake treatment section to the tail gas scrubber (14).
3) Tail gas from the system enters the tail gas scrubber (14) to be scrubbed by 5 C - 7 C
chilled water from scrubber chilled water feed pipe (16). Dilute chlorine dioxide solution obtained from this process returns to the absorber (18), and tail gas is discharged by the tail gas blower (15).
Example 2:
It is a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator. The feature is that the process is consisted of chlorine dioxide generation, salt cake filtration and tail gas treatment.
The process of the invention is as following.
1) The 650g/1 concentration sodium chlorate solution from chlorate feed pipe (1) and the 50wt% concentration hydrogen peroxide solution from hydrogen peroxide feed pipe (2) are mixed in the chlorate feed pipe (1). Then the mixed liquor flows into the generator circulation system from the pipe header of the bottom reboiler (3). The 96wt%
concentration sulfuric acid from sulfuric acid feed pipe (4) flows to the nozzle at the top of the reboiler (3). The sulfuric acid is diluted to 60wt%-65wt% with deionized water and then injected into the generator circulation system. The chemical raw material is mixed by the generator circulation pump (23) and reacts in the process, acidity of mother liquor is 2-5N, vacuum degree is -72 - -85kPa, temperature is 60 C-80 C, the density of the mother liquor is 1.4-1.8g/cm3 and the concentration of sodium chlorate is 1.8-3.3mol/L in the vertical generator (21). The reaction outcome is chlorine dioxide, water, oxygen and neutral salt cake. The chlorine dioxide is generated, the reaction remains in liquid and the by-product is precipitated down to the bottom of generator (21) and becomes the generator solution. The solution is circulated between the reboiler (3) and the generator (21). The liquid continuously mixes with the fed hydrogen peroxide, sodium chlorate and sulfuric acid, which generates chlorine dioxide gas.
The chlorine dioxide from the generator (21) is diluted by the steam and oxygen gas produced in the generator (21), the mixed gas is exhausted from the generator exhaust pipe (10). After indirect cooler (19) the exhaust gas then enters absorber (18), is absorbed by chilled water from the chilled water feed pipe (12). The chlorine dioxide solution is produced. The solution is sent out from chlorine dioxide transfer pipe (17). The generator vacuum pump (13) generates vacuum in the generator (21) and pumps the tail gas from the absorber (18) to the scrubber (14).
2) The hydrogen peroxide and sodium chlorate mixed while sulfuric acid is continuously added. The chlorine dioxide generated with by-product salt cake is crystallizing in the generator (21), the salt cake feed pump (20) sucks out the salt cake from the generator lower circulation pipe (22) and sends it to the hydrocyclone separator (8) for solid-liquid separation.
The separated mother liquor and the liquid from the filter (7) and washing liquid from gas-liquid separation tank (9) are mixed before flow back to the generator lower circulation pipe (22). The filtered neutral salt cake crystal is discharged from the salt cake outlet (6) and sent to other plants. The filter vacuum pump (11) generates vacuum in the filter (7) and sucks out the tail gas in the salt cake treatment process to the tail gas scrubber (14).
3) The system produced tail gas enters the tail gas scrubber (14) and scrubbed by 5 C -7 C chilled water from scrubber chilled water dosing pipe (16). The obtained diluted chlorine dioxide solution flows back to the absorber (18), the tail gas is pumped out by the tail gas blower (15).
Example 3:
It is a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator. The feature is that the process is consisted of chlorine dioxide generation, salt cake filtration and tail gas treatment.
The process of the invention is as following.
1) 700g/1 concentration sodium chlorate solution from the chlorate feed pipe (1) and the 27.5wt% concentration hydrogen peroxide solution from the hydrogen peroxide feed pipe (2) is mixed in the chlorate feed pipe (1). Then the mixed liquid flows into the generator circulation system from the pipe header of bottom reboiler (3). The 93wt%
concentration sulfuric acid from sulfuric acid feed pipe (4) flows to the nozzle at the top of the reboiler (3).
The sulfuric acid is diluted to 60wt%-65t% with deionized water and injected into the generator circulation system. The chemical raw material is mixed by the generator circulation pump (23) and reaction occurs. The acidity of the mother liquor is 2-5N, vacuum degree is -72 - -85kPa, temperature is 60 C -80 C, the density of the mother liquor is 1.4-1.8g/cm3 and the sodium chlorate concentration is 1.8-3.3mol/L in the vertical generator (21).The reaction outcome is chlorine dioxide, water, oxygen and neutral salt cake. Chlorine dioxide is generated, the reaction remained in liquid and the by-product is precipitated down to the bottom of the generator (21) and become the generator solution. The solution is circulated between the reboiler (3) and the generator (21). The liquid is continuously mixed with the fed hydrogen peroxide, sodium chlorate and sulfuric acid, which generates chlorine dioxide gas.
The chlorine dioxide gas from the generator (21) is diluted by the steam and oxygen gas produced in the generator (21), and the mixed gas is exhausted from the generator exhaust pipe (10). After indirect cooler (19), the mixed gas enters the absorber (18), absorbed by chilled water from the chilled water dosing pipe (12) and produced a chlorine dioxide solution.
The solution is sent out from the chlorine dioxide transfer pipe (17). The generator vacuum pump (13) generates vacuum in the generator (21) and pumps the tail gas from the absorber (18) to the tail gas scrubber (14).
2) Hydrogen peroxide and sodium chlorate are mixed while the sulfuric acid is continuously added in the process. As chlorine dioxide is generated in the system, a by-product salt cake is crystallized in the generator (21), the salt cake feed pump (20) sucks out the salt cake from the generator lower circulation pipe (22) and send to the hydrocyclone separator (8) for solid-liquid separation. The separated mother liquor and the liquid from the filter (7) and the washing liquid from the gas-liquid separation tank (9) are mixed and flow back to the generator lower circulation pipe (22). The filtered neutral salt cake crystal is discharged from the salt cake outlet (6) and is sent to other plants. The filter vacuum pump (11) generates vacuum in the filter (7) and pumps out the tail gas in salt cake treatment process to the tail gas scrubber (14).
3) Tail gas from the system enters the tail gas scrubber (14), is processed with 5-7 C
chilled water from the chilled water feed pipe (16) of the scrubber, forms a dilute chlorine dioxide solution which flows back to the absorber (18), while the remaining tail gas is blown out by the tail gas blower (15).
4. By-product of the chlorine dioxide production process is a neutral salt cake.
Description of the drawings Fig. 1 shows the process flow diagram of the invention.
Where:
1. Sodium chlorate feed pipe; 2. Hydrogen peroxide feed pipe; 3. Reboiler; 4.
Sulfuric acid feed pipe; 5. Upper circulation piping of the generator; 6. Salt cake outlet;
7. Filter; 8.
Hydrocyclone; 9. Gas-liquid separation tank; 10. Generator exhaust gas pipe;
11. Filter vacuum pump; 12. Absorber chilled water feed pipe; 13. Generator vacuum pump;
14. Tail gas scrubber; 15. Tail gas blower; 16. Scrubber chilled water feed pipe; 17.
Chlorine dioxide transfer pipe; 18. Absorber; 19. Intercooler; 20. Salt cake feed pump; 21.
Generator; 22 Lower circulation piping of the generator; 23. Generator circulation pump Detailed description of embodiments A further description of the method for hydrogen peroxide based chlorine dioxide production process with a vertical generator that this invention relates to is given through the examples below. The following examples are prescribed for illustrating the technical framework and characteristics of this invention with the intention to make the details of the invention understandable to those unfamiliar with it, while not meant to limit the protection scope of the invention. The protection scope shall cover any equivalent transformation of or embellishment to the spirit of this invention.
Example 1:
A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, characterized by the following: a chlorine dioxide generation section, a salt cake filtration section and a tail gas treatment section.
The operation procedures of the invention are shown as follows:
1) Sodium chlorate from sodium chlorate feed pipe (1) at 600g/1 concentration mixes with hydrogen peroxide from hydrogen peroxide feed pipe (2) at 60wt% concentration in the sodium chlorate feed pipe (1), before introduced to the generator circulation system through a straight pipe in the header below the reboiler (3). Concentrated sulfuric acid from sulfuric acid feed pipe (4) at 98wt% concentration flows to a throat in the outlet on the top of the reboiler (3) and is diluted to 60wt%-65wt% concentration with deionized water before being injected into the generator circulation system. Under the force of the generator circulation pump (23), the chemical raw materials are mixed and react sufficiently, producing chlorine dioxide, water, oxygen and neutral salt cake under controlled conditions inside the vertical generator (21) with a mother liquor acidity of 2 - 5N, a gauge pressure of -72 to -85kPa, a temperature of 60 C - 80 C, a mother liquor density of 1.4 - 1.8g/cm3 and a sodium chlorate solution concentration of 1.8 - 3.3mo1/1. The produced C102 gas is released, while the remaining liquor and by-product settle to the bottom of the generator (21) as generator liquor, which is circulated between the reboiler (3) and the generator (21) continuously by the circulation pump (23) to mix and react with constant feed of hydrogen peroxide, sodium chlorate mixture and concentrated sulfuric acid, producing C102 gas continuously. The C102 gas produced in the generator (21) is diluted inside the generator (21) by a large amount of steam evaporated and oxygen produced from the reactions, becoming gas mixture. The gas mixture exits from the generator exhaust pipe (10), passes through the indirect cooler (19), and then enters the absorber (18) to be absorbed by chilled water from absorber chilled water feed pipe (12) and form C102 aqueous solution for delivery via chlorine dioxide transfer pipe (17). While generating vacuum in the generator (21), generator vacuum pump (13) also pumps tail gas in the absorber (18) to the tail gas scrubber (14).
2) With the continuous feeding of hydrogen peroxide and sodium chlorate mixture and concentrated sulfuric acid, reactions take place ceaselessly. Along with the continuous generation of C102, there is a continuous crystallization of salt cake, the by-product, inside the generator (21). The salt cake feed pump (20) takes out part of the mother liquor containing salt cake crystals from the lower circulation piping (22) of the generator and transfers them to the hydrocyclone (8) to separate solids and liquid. Mother liquor passes through the separation, after joining with washing liquid from the filter (7) and the gas-liquid separation tank (9), flowing to the lower circulation piping (22) of the generator, while the filtrated neutral salt cake crystals are transferred out of the system from salt cake outlet (6) for utilization. While generating vacuum inside the filter (7), the filter vacuum pump (11) also pumps tail gas in the salt cake treatment section to the tail gas scrubber (14).
3) Tail gas from the system enters the tail gas scrubber (14) to be scrubbed by 5 C - 7 C
chilled water from scrubber chilled water feed pipe (16). Dilute chlorine dioxide solution obtained from this process returns to the absorber (18), and tail gas is discharged by the tail gas blower (15).
Example 2:
It is a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator. The feature is that the process is consisted of chlorine dioxide generation, salt cake filtration and tail gas treatment.
The process of the invention is as following.
1) The 650g/1 concentration sodium chlorate solution from chlorate feed pipe (1) and the 50wt% concentration hydrogen peroxide solution from hydrogen peroxide feed pipe (2) are mixed in the chlorate feed pipe (1). Then the mixed liquor flows into the generator circulation system from the pipe header of the bottom reboiler (3). The 96wt%
concentration sulfuric acid from sulfuric acid feed pipe (4) flows to the nozzle at the top of the reboiler (3). The sulfuric acid is diluted to 60wt%-65wt% with deionized water and then injected into the generator circulation system. The chemical raw material is mixed by the generator circulation pump (23) and reacts in the process, acidity of mother liquor is 2-5N, vacuum degree is -72 - -85kPa, temperature is 60 C-80 C, the density of the mother liquor is 1.4-1.8g/cm3 and the concentration of sodium chlorate is 1.8-3.3mol/L in the vertical generator (21). The reaction outcome is chlorine dioxide, water, oxygen and neutral salt cake. The chlorine dioxide is generated, the reaction remains in liquid and the by-product is precipitated down to the bottom of generator (21) and becomes the generator solution. The solution is circulated between the reboiler (3) and the generator (21). The liquid continuously mixes with the fed hydrogen peroxide, sodium chlorate and sulfuric acid, which generates chlorine dioxide gas.
The chlorine dioxide from the generator (21) is diluted by the steam and oxygen gas produced in the generator (21), the mixed gas is exhausted from the generator exhaust pipe (10). After indirect cooler (19) the exhaust gas then enters absorber (18), is absorbed by chilled water from the chilled water feed pipe (12). The chlorine dioxide solution is produced. The solution is sent out from chlorine dioxide transfer pipe (17). The generator vacuum pump (13) generates vacuum in the generator (21) and pumps the tail gas from the absorber (18) to the scrubber (14).
2) The hydrogen peroxide and sodium chlorate mixed while sulfuric acid is continuously added. The chlorine dioxide generated with by-product salt cake is crystallizing in the generator (21), the salt cake feed pump (20) sucks out the salt cake from the generator lower circulation pipe (22) and sends it to the hydrocyclone separator (8) for solid-liquid separation.
The separated mother liquor and the liquid from the filter (7) and washing liquid from gas-liquid separation tank (9) are mixed before flow back to the generator lower circulation pipe (22). The filtered neutral salt cake crystal is discharged from the salt cake outlet (6) and sent to other plants. The filter vacuum pump (11) generates vacuum in the filter (7) and sucks out the tail gas in the salt cake treatment process to the tail gas scrubber (14).
3) The system produced tail gas enters the tail gas scrubber (14) and scrubbed by 5 C -7 C chilled water from scrubber chilled water dosing pipe (16). The obtained diluted chlorine dioxide solution flows back to the absorber (18), the tail gas is pumped out by the tail gas blower (15).
Example 3:
It is a method for hydrogen peroxide based chlorine dioxide production process with a vertical generator. The feature is that the process is consisted of chlorine dioxide generation, salt cake filtration and tail gas treatment.
The process of the invention is as following.
1) 700g/1 concentration sodium chlorate solution from the chlorate feed pipe (1) and the 27.5wt% concentration hydrogen peroxide solution from the hydrogen peroxide feed pipe (2) is mixed in the chlorate feed pipe (1). Then the mixed liquid flows into the generator circulation system from the pipe header of bottom reboiler (3). The 93wt%
concentration sulfuric acid from sulfuric acid feed pipe (4) flows to the nozzle at the top of the reboiler (3).
The sulfuric acid is diluted to 60wt%-65t% with deionized water and injected into the generator circulation system. The chemical raw material is mixed by the generator circulation pump (23) and reaction occurs. The acidity of the mother liquor is 2-5N, vacuum degree is -72 - -85kPa, temperature is 60 C -80 C, the density of the mother liquor is 1.4-1.8g/cm3 and the sodium chlorate concentration is 1.8-3.3mol/L in the vertical generator (21).The reaction outcome is chlorine dioxide, water, oxygen and neutral salt cake. Chlorine dioxide is generated, the reaction remained in liquid and the by-product is precipitated down to the bottom of the generator (21) and become the generator solution. The solution is circulated between the reboiler (3) and the generator (21). The liquid is continuously mixed with the fed hydrogen peroxide, sodium chlorate and sulfuric acid, which generates chlorine dioxide gas.
The chlorine dioxide gas from the generator (21) is diluted by the steam and oxygen gas produced in the generator (21), and the mixed gas is exhausted from the generator exhaust pipe (10). After indirect cooler (19), the mixed gas enters the absorber (18), absorbed by chilled water from the chilled water dosing pipe (12) and produced a chlorine dioxide solution.
The solution is sent out from the chlorine dioxide transfer pipe (17). The generator vacuum pump (13) generates vacuum in the generator (21) and pumps the tail gas from the absorber (18) to the tail gas scrubber (14).
2) Hydrogen peroxide and sodium chlorate are mixed while the sulfuric acid is continuously added in the process. As chlorine dioxide is generated in the system, a by-product salt cake is crystallized in the generator (21), the salt cake feed pump (20) sucks out the salt cake from the generator lower circulation pipe (22) and send to the hydrocyclone separator (8) for solid-liquid separation. The separated mother liquor and the liquid from the filter (7) and the washing liquid from the gas-liquid separation tank (9) are mixed and flow back to the generator lower circulation pipe (22). The filtered neutral salt cake crystal is discharged from the salt cake outlet (6) and is sent to other plants. The filter vacuum pump (11) generates vacuum in the filter (7) and pumps out the tail gas in salt cake treatment process to the tail gas scrubber (14).
3) Tail gas from the system enters the tail gas scrubber (14), is processed with 5-7 C
chilled water from the chilled water feed pipe (16) of the scrubber, forms a dilute chlorine dioxide solution which flows back to the absorber (18), while the remaining tail gas is blown out by the tail gas blower (15).
Claims (10)
1. A method for hydrogen peroxide based chlorine dioxide production process in a vertical generator, wherein the said process consists of the following characteristics:
the chlorine dioxide production system comprised a reboiler (3), a generator upper circulation pipe (5), a generator (21), a generator lower circulation pipe (22), a generator exhaust pipe (10), a generator circulation pump (23), an intercooler (19), an absorber (18), a generator vacuum pump (13) and the corresponding pipelines; and the salt cake filtration system comprised a filter (7), a hydrocyclone separator (8), a gas-liquid separator (9), a filter vacuum pump (11), a salt cake feed pump (20) and the corresponding pipelines; and the exhaust gas treatment system comprised a scrubber (14), a blower (15) and the corresponding pipelines.
the chlorine dioxide production system comprised a reboiler (3), a generator upper circulation pipe (5), a generator (21), a generator lower circulation pipe (22), a generator exhaust pipe (10), a generator circulation pump (23), an intercooler (19), an absorber (18), a generator vacuum pump (13) and the corresponding pipelines; and the salt cake filtration system comprised a filter (7), a hydrocyclone separator (8), a gas-liquid separator (9), a filter vacuum pump (11), a salt cake feed pump (20) and the corresponding pipelines; and the exhaust gas treatment system comprised a scrubber (14), a blower (15) and the corresponding pipelines.
2. A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator, wherein its characteristics are presented in the following processes.
a) Sodium chlorate solution (600-700g/l) is fed through a sodium chlorate feed pipe (1), mixed with hydrogen peroxide (27wt%-60wt%) from a hydrogen peroxide feed pipe (2), and then enters the generator circulation system via the straight pipes of the lower header of reboiler (3). Concentrated sulfuric acid (93wt%-98wt%) flows through a sulfuric acid feed pipe (4) towards a nozzle of the top outlet of reboiler (3), injecting into the generator circulation system after dilution with deionized water to form 60wt%-65wt% of solution, for complete and thorough reaction by application of a circulation pump (23). The process generates a stream of highly purified chlorine dioxide solution with a low byproduct concentration of chlorine of 0.01 ~
0.08g-Cl2/l-ClO2, by controlling multiple parameters in the vertical generator (21), e.g. liquor acidity between 2-5N, gauge pressure at -72~ -85kPa, temperature at 60-80 degree C, liquor density at 1.4~1.8g/cm3, and sodium chlorate concentration at 1.8~3.3mol/l. The process generates product streams containing chlorine dioxide, water, oxygen and neutral salt cakes. Reaction liquor remains while byproducts settling downwards to the bottom of the generator (21), circulating between the reboiler (3) and the generator (21) by application of the circulation pump (23) while the mixed solution of hydrogen peroxide, sodium chlorate and concentrated sulfuric acid is added to form chlorine dioxide gas. Chlorine dioxide gas generated within the generator (21) mixes with water vapors and oxygen, passing intercooler (19) through the exhaust pipe (10), entering the absorber (18) to form chlorine dioxide solution by adding chilled water from chilled water feed pipe (12), with the solution later transferred out for application via the transfer pipe (17). The generator vacuum pump (13) is designed to produce vacuum in the generator (21) and pumps out tail gases in the absorber (18) towards tail gas scrubber (14).
b) The process is continuously carrying out as hydrogen peroxide, sodium chlorate and concentrated sulfuric acid continuously being added into the system. While generating chlorine dioxide, byproduct salt cakes are crystallized in the generator, part of which is pumped into the hydrocyclone separator (8), along with the liquor, by salt cake feed pump (20). Liquor separated mixes with scrubbing solution from the filter (7) and the gas-liquid separator (9), flowing to the lower circulation pipe (22) of the generator, while salt cake filtered is pumped out for applications.
c) Tail gas from the system is treated with chilled water in the scrubber (14), generating diluted chlorine dioxide solution and returning back to the absorber (18).
Residual gas is pumped out by the blower (15).
a) Sodium chlorate solution (600-700g/l) is fed through a sodium chlorate feed pipe (1), mixed with hydrogen peroxide (27wt%-60wt%) from a hydrogen peroxide feed pipe (2), and then enters the generator circulation system via the straight pipes of the lower header of reboiler (3). Concentrated sulfuric acid (93wt%-98wt%) flows through a sulfuric acid feed pipe (4) towards a nozzle of the top outlet of reboiler (3), injecting into the generator circulation system after dilution with deionized water to form 60wt%-65wt% of solution, for complete and thorough reaction by application of a circulation pump (23). The process generates a stream of highly purified chlorine dioxide solution with a low byproduct concentration of chlorine of 0.01 ~
0.08g-Cl2/l-ClO2, by controlling multiple parameters in the vertical generator (21), e.g. liquor acidity between 2-5N, gauge pressure at -72~ -85kPa, temperature at 60-80 degree C, liquor density at 1.4~1.8g/cm3, and sodium chlorate concentration at 1.8~3.3mol/l. The process generates product streams containing chlorine dioxide, water, oxygen and neutral salt cakes. Reaction liquor remains while byproducts settling downwards to the bottom of the generator (21), circulating between the reboiler (3) and the generator (21) by application of the circulation pump (23) while the mixed solution of hydrogen peroxide, sodium chlorate and concentrated sulfuric acid is added to form chlorine dioxide gas. Chlorine dioxide gas generated within the generator (21) mixes with water vapors and oxygen, passing intercooler (19) through the exhaust pipe (10), entering the absorber (18) to form chlorine dioxide solution by adding chilled water from chilled water feed pipe (12), with the solution later transferred out for application via the transfer pipe (17). The generator vacuum pump (13) is designed to produce vacuum in the generator (21) and pumps out tail gases in the absorber (18) towards tail gas scrubber (14).
b) The process is continuously carrying out as hydrogen peroxide, sodium chlorate and concentrated sulfuric acid continuously being added into the system. While generating chlorine dioxide, byproduct salt cakes are crystallized in the generator, part of which is pumped into the hydrocyclone separator (8), along with the liquor, by salt cake feed pump (20). Liquor separated mixes with scrubbing solution from the filter (7) and the gas-liquid separator (9), flowing to the lower circulation pipe (22) of the generator, while salt cake filtered is pumped out for applications.
c) Tail gas from the system is treated with chilled water in the scrubber (14), generating diluted chlorine dioxide solution and returning back to the absorber (18).
Residual gas is pumped out by the blower (15).
3. The process in claim 1 wherein the said generator is a vertical generator.
4. The process in claim 2 wherein the said hydrogen peroxide mixes with sodium chlorate in pipes, entering the generator circulation system through the straight pipes of the lower head of the reboiler.
5. The process in claim 2 wherein the said concentrated sulfuric acid is diluted with deionized water to form 60wt%-65wt% of solution prior to entering the generator circulation system.
6. The process in claim 2 wherein the said chlorine dioxide gas, generated by reaction of sodium chlorate, hydrogen peroxide and sulfuric acid, forms a mixed gas with water vapor and oxygen.
7. The process in claim 2 wherein the said acidity of liquor shall be maintained at 2-5N.
8. The process in claim 2 wherein the said temperature in the generator shall be 60-80 degree C, and the gauge pressure shall be controlled at -72~-85kPa.
9. The process in claim 2 wherein the said liquor density in the generator shall be 1.4~
1. 8g/cm3.
1. 8g/cm3.
10. The process in claim 2 wherein the said sodium chlorate solution concentration in the generator shall be 1.8~3.3mol/l.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2946017A CA2946017A1 (en) | 2016-10-14 | 2016-10-14 | A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2946017A CA2946017A1 (en) | 2016-10-14 | 2016-10-14 | A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator |
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| CA2946017A1 true CA2946017A1 (en) | 2017-01-26 |
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|---|---|---|---|
| CA2946017A Abandoned CA2946017A1 (en) | 2016-10-14 | 2016-10-14 | A method for hydrogen peroxide based chlorine dioxide production process with a vertical generator |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108636323A (en) * | 2018-06-06 | 2018-10-12 | 南京曙光精细化工有限公司 | Polysulfide silanes coupling agent process units |
| CN110040689A (en) * | 2019-04-25 | 2019-07-23 | 兰州泰邦化工科技有限公司 | A kind of big production capacity and sodium chlorite production equipment and its production method without spent acid discharge |
-
2016
- 2016-10-14 CA CA2946017A patent/CA2946017A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108636323A (en) * | 2018-06-06 | 2018-10-12 | 南京曙光精细化工有限公司 | Polysulfide silanes coupling agent process units |
| CN108636323B (en) * | 2018-06-06 | 2024-02-20 | 南京曙光新材料有限公司 | Polysulfide silane coupling agent production device |
| CN110040689A (en) * | 2019-04-25 | 2019-07-23 | 兰州泰邦化工科技有限公司 | A kind of big production capacity and sodium chlorite production equipment and its production method without spent acid discharge |
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