Ceramic fiber filter tube for removing chlorine and preparation method thereof, and gas-phase white carbon black tail gas dry method recovery system

Abstract

The application discloses a ceramic fiber filter tube for removing chlorine and a preparation method thereof and a fumed white carbon black tail gas dry method recovery system. The ceramic fiber filter tube for removing chlorine comprises a ceramic fiber filter tube, a first active layer arranged on the surface of ceramic fibers in the ceramic fiber filter tube, and a second active layer arranged outside the first active layer on the inner wall surface of the ceramic fiber filter tube. The first active layer comprises a first active species, and the first active species comprises at least one of manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, molybdenum nitrate, sodium chloropalladate and silver nitrate. The second active layer comprises a second active species and a carrier, and the second active species comprises at least one of manganese hydroxide, ferric chloride, ferric sulfate, iron hydroxide, nickel chloride and niobium pentoxide. The ceramic fiber filter tube is used as a main dust removal structure, has an excellent effect on the separation of nanoscale silicon dioxide dust in fumed white carbon black tail gas, and realizes selective catalytic conversion of chlorine gas.

Description

Technical Field

[0001] This invention belongs to the field of chlorine removal and dust removal technology for fumed silica tail gas, specifically relating to a ceramic fiber filter tube for chlorine removal and its preparation method, and a dry recovery system for fumed silica tail gas. Background Technology

[0002] The gas-phase method for producing precipitated silica involves synthesizing micro-nano-sized silica particles through a high-temperature hydrolysis reaction of hydrogen, air, and silicon tetrachloride. The gas-solid mixture output from the reactor undergoes gas-solid separation. The solids are further processed to obtain the precipitated silica product, while the dust-laden gas containing silica, hydrogen chloride, chlorine, water vapor, oxygen, and nitrogen enters the tail gas treatment system. To treat the silica micropowder and the two harmful gases, hydrogen chloride and chlorine, present in the tail gas, a traditional wet treatment process is typically employed. For example, a dual falling film tower is first used in series to absorb hydrogen chloride and produce concentrated hydrochloric acid, followed by washing with an alkaline scrubbing tower to remove chlorine and residual hydrogen chloride. The wet process is relatively mature and easy to operate, but there are several problems: (1) The white carbon black in the tail gas is easy to clog the falling film tower tubes and the absorber packing holes, affecting normal production; (2) The hydrochloric acid produced is yellow, viscous and contains impurities, with low industrial added value. Many enterprises can only concentrate the hydrochloric acid and then precipitate hydrogen chloride gas for use; (3) Using alkaline solution to treat chlorine and residual hydrogen chloride consumes a lot of alkaline solution, resulting in resource waste.

[0003] The above problems are caused by the composition of the fumed silica tail gas and the defects of the wet treatment process: (1) Some nano-sized silica dust (particle size is mostly below 10 nanometers) escapes from the gas-solid separation process and enters the tail gas treatment process. It can be absorbed into the aqueous solution to remove dust through a simple and mature wet treatment process; (2) In the wet treatment process, chlorine can only be treated with a solution containing alkali or reducing agent. If chlorine and hydrogen chloride enter the solution together, it will cause serious waste of hydrogen chloride. Therefore, in order to maximize the benefits, hydrogen chloride can be absorbed first to produce acid, and then chlorine can be absorbed with alkali.

[0004] Currently, the wet treatment process for fumed silica tail gas has a series of problems: fumed silica powder is difficult to separate from the gas, and solid powder flows into downstream processes, thus clogging the packed tower; the quality of hydrochloric acid produced by wet recovery of hydrogen chloride is poor, and the equipment is easily corroded; the wet recovery process has large alkali and chlorine consumption, resulting in high production costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a ceramic fiber filter tube for dechlorination and its preparation method, as well as a dry recovery system for fumed silica tail gas, which has an excellent effect on separating nano-sized silica dust in fumed silica tail gas, while simultaneously removing chlorine and dust.

[0006] The technical solution adopted to solve the technical problem of the present invention is to provide a ceramic fiber filter tube for chlorine removal, comprising: a ceramic fiber filter tube, a first active layer disposed on the surface of ceramic fibers in the ceramic fiber filter tube, and a second active layer disposed outside the first active layer on the inner wall surface of the ceramic fiber filter tube, wherein,

[0007] The first active layer includes: a first active species, which includes at least one of manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, molybdenum nitrate, sodium chloropalladium, silver nitrate, chloroplatinic acid, and chloroauric acid;

[0008] The second active layer includes: a second active species and a carrier. The second active species includes at least one of manganese hydroxide, ferric chloride, ferric sulfate, ferric hydroxide, nickel chloride, nickel sulfate, nickel hydroxide, niobium pentoxide, molybdenum dioxide, palladium chloride, silver chloride, lanthanum oxide, sodium bismuthate, and bismuth trioxide.

[0009] Preferably, the carrier includes at least one of activated carbon, aluminum oxide, silicon dioxide, silicon carbide, and titanium dioxide.

[0010] Preferably, the weight ratio of the second active species to the carrier is (0.2-5):(5-30).

[0011] Preferably, the thickness of the first active layer is less than 2 nm; and the thickness of the second active layer is 50–800 nm.

[0012] The present invention also provides a method for preparing the above-mentioned ceramic fiber filter tube for chlorine removal, comprising the following steps:

[0013] 1) The ceramic fiber filter tube is impregnated with an impregnation solution and then dried to form a first active layer on the surface of the ceramic fiber in the ceramic fiber filter tube. The impregnation solution includes a first active species and water.

[0014] 2) The inner wall of the ceramic fiber filter tube is sprayed with a coating solution and then dried to form a second active layer on the surface of the inner wall of the ceramic fiber filter tube. The coating solution includes a second active species, a carrier, and water.

[0015] 3) The ceramic fiber filter tube is subjected to reduction calcination treatment to obtain a ceramic fiber filter tube for dechlorination.

[0016] Preferably, the metal content in the impregnation solution is 0.2 wt% to 5 wt%.

[0017] Preferably, the impregnation solution also includes an additive, which is at least one of methanol, ethanol, ethylene glycol, and ascorbic acid.

[0018] Preferably, the additive content in the impregnation solution is 5 wt% to 30 wt%.

[0019] Preferably, the content of the second active species in the application solution is 0.5 wt% to 5 wt%, and the content of the carrier is 5 wt% to 45 wt%.

[0020] Preferably, the drying temperature in step 1) is 50–120°C and the processing time is 6–48 h.

[0021] Preferably, the drying temperature in step 2) is 50–120°C and the processing time is 6–48 h.

[0022] Preferably, the reduction roasting atmosphere in step 3) is hydrogen or a mixture of hydrogen and nitrogen.

[0023] Preferably, the temperature of the reduction roasting treatment in step 3) is 150-300°C and the time is 1-3 hours.

[0024] The present invention also provides a dry recovery system for fumed silica tail gas, comprising:

[0025] Cooling device for cooling gas-solid mixtures of fumed silica;

[0026] A gas-solid separation device is connected to a cooling device. The gas-solid separation device is used to separate the gas-solid mixture of gaseous silica to obtain the first tail gas.

[0027] The integrated ceramic fiber dechlorination and dust removal device is connected to the gas-solid separation device. The integrated ceramic fiber dechlorination and dust removal device is loaded with the aforementioned ceramic fiber filter tube for dechlorination. The integrated ceramic fiber dechlorination and dust removal device is used to dechlorinate and remove dust from the first tail gas to obtain the second tail gas.

[0028] The drying device is connected to the integrated ceramic fiber dechlorination and dust removal device. The drying device is used to remove water from the second tail gas to obtain the third tail gas.

[0029] The hydrogen chloride recovery unit is connected to the drying unit. The hydrogen chloride recovery unit is used to remove hydrogen chloride from the third tail gas to obtain the fourth tail gas.

[0030] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this invention have the following beneficial effects:

[0031] (1) The present invention loads catalytic dechlorination active components on ceramic fiber filter tubes by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0032] (2) The present invention uses ceramic fiber filter tube as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0033] (3) The present invention can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0035] Example 1

[0036] This embodiment provides a ceramic fiber filter tube for chlorine removal, comprising: a ceramic fiber filter tube, a first active layer disposed on the surface of ceramic fibers in the ceramic fiber filter tube, and a second active layer disposed outside the first active layer on the inner wall surface of the ceramic fiber filter tube, wherein...

[0037] The first active layer includes: a first active species, which includes at least one of manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, molybdenum nitrate, sodium chloropalladium, silver nitrate, chloroplatinic acid, and chloroauric acid;

[0038] The second active layer includes: a second active species and a carrier. The second active species includes at least one of manganese hydroxide, ferric chloride, ferric sulfate, ferric hydroxide, nickel chloride, nickel sulfate, nickel hydroxide, niobium pentoxide, molybdenum dioxide, palladium chloride, silver chloride, lanthanum oxide, sodium bismuthate, and bismuth trioxide.

[0039] This embodiment also provides a method for preparing the above-mentioned ceramic fiber filter tube for chlorine removal, including the following steps:

[0040] 1) The ceramic fiber filter tube is impregnated with an impregnation solution and then dried to form a first active layer on the surface of the ceramic fiber in the ceramic fiber filter tube. The impregnation solution includes a first active species and water.

[0041] 2) The inner wall of the ceramic fiber filter tube is sprayed with a coating solution and then dried to form a second active layer on the surface of the inner wall of the ceramic fiber filter tube. The coating solution includes a second active species, a carrier, and water.

[0042] 3) The ceramic fiber filter tube is subjected to reduction calcination treatment to obtain a ceramic fiber filter tube for dechlorination.

[0043] This embodiment also provides a dry recovery system for fumed silica tail gas, including:

[0044] Cooling device for cooling gas-solid mixtures of fumed silica;

[0045] A gas-solid separation device is connected to a cooling device. The gas-solid separation device is used to separate the gas-solid mixture of gaseous silica to obtain the first tail gas.

[0046] The integrated ceramic fiber dechlorination and dust removal device is connected to the gas-solid separation device. The integrated ceramic fiber dechlorination and dust removal device is loaded with the aforementioned ceramic fiber filter tube for dechlorination. The integrated ceramic fiber dechlorination and dust removal device is used to dechlorinate and remove dust from the first tail gas to obtain the second tail gas.

[0047] The drying device is connected to the integrated ceramic fiber dechlorination and dust removal device. The drying device is used to remove water from the second tail gas to obtain the third tail gas.

[0048] The hydrogen chloride recovery unit is connected to the drying unit. The hydrogen chloride recovery unit is used to remove hydrogen chloride from the third tail gas to obtain the fourth tail gas.

[0049] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0050] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0051] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0052] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0053] Example 2

[0054] This embodiment provides a ceramic fiber filter tube for chlorine removal, comprising: a ceramic fiber filter tube, a first active layer disposed on the surface of ceramic fibers in the ceramic fiber filter tube, and a second active layer disposed outside the first active layer on the inner wall surface of the ceramic fiber filter tube, wherein...

[0055] The first active layer includes: a first active species, which includes at least one of manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, molybdenum nitrate, sodium chloropalladium, silver nitrate, chloroplatinic acid, and chloroauric acid;

[0056] The second active layer includes: a second active species and a carrier. The second active species includes at least one of manganese hydroxide, ferric chloride, ferric sulfate, ferric hydroxide, nickel chloride, nickel sulfate, nickel hydroxide, niobium pentoxide, molybdenum dioxide, palladium chloride, silver chloride, lanthanum oxide, sodium bismuthate, and bismuth trioxide.

[0057] Preferably, the carrier includes at least one of activated carbon, aluminum oxide, silicon dioxide, silicon carbide, and titanium dioxide.

[0058] Preferably, the weight ratio of the second active species to the carrier is (0.2-5):(5-30).

[0059] The thickness of the first active layer is less than 2 nm; the thickness of the second active layer is 50–800 nm.

[0060] This embodiment also provides a method for preparing the above-mentioned ceramic fiber filter tube for chlorine removal, including the following steps:

[0061] 1) The ceramic fiber filter tube is impregnated with an impregnation solution and then dried to form a first active layer on the surface of the ceramic fiber in the ceramic fiber filter tube. The impregnation solution includes a first active species and water.

[0062] 2) The inner wall of the ceramic fiber filter tube is sprayed with a coating solution and then dried to form a second active layer on the surface of the inner wall of the ceramic fiber filter tube. The coating solution includes a second active species, a carrier, and water.

[0063] 3) The ceramic fiber filter tube is subjected to reduction calcination treatment to obtain a ceramic fiber filter tube for dechlorination.

[0064] Preferably, the metal content in the impregnation solution is 0.2 wt% to 5 wt%.

[0065] Preferably, the impregnation solution also includes an additive, which is at least one of methanol, ethanol, ethylene glycol, and ascorbic acid.

[0066] Preferably, the additive content in the impregnation solution is 5 wt% to 30 wt%.

[0067] Preferably, the content of the second active species in the application solution is 0.5 wt% to 5 wt%, and the content of the carrier is 5 wt% to 45 wt%.

[0068] Preferably, the drying temperature in step 1) is 50–120°C and the processing time is 6–48 h.

[0069] Preferably, the drying temperature in step 2) is 50–120°C and the processing time is 6–48 h.

[0070] Preferably, the reduction roasting atmosphere in step 3) is hydrogen or a mixture of hydrogen and nitrogen.

[0071] Preferably, the temperature of the reduction roasting treatment in step 3) is 150-300°C and the time is 1-3 hours.

[0072] Specifically, this embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0073] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing nickel nitrate (2wt% metal content), sodium chloropalladium (0.5wt% metal content), silver nitrate (1wt% metal content), chloroplatinic acid (1wt% metal content), chloroauric acid (0.5wt% metal content), and ascorbic acid (20wt%). After impregnation, remove the tubes and dry them at 120℃ for 12 hours.

[0074] 2) A coating solution containing nickel hydroxide (1 wt%), molybdenum dioxide (1 wt%), niobium pentoxide (0.5 wt%), palladium chloride (0.5 wt%), silver chloride (1 wt%), bismuth oxide (1 wt%), and silicon carbide (30 wt%) was sprayed onto the inner wall of the ceramic fiber filter tube and dried at 120°C for 6 hours.

[0075] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 200℃ for 3 hours to obtain a dechlorination ceramic fiber filter tube.

[0076] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 400 nm.

[0077] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0078] The dechlorination ceramic fiber filter tube was installed in the integrated ceramic fiber dechlorination and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 98.1% and the dechlorination efficiency was 97.4%.

[0079] This embodiment also provides a dry recovery system for fumed silica tail gas, including:

[0080] Cooling device for cooling gas-solid mixtures of fumed silica;

[0081] A gas-solid separation device is connected to a cooling device. The gas-solid separation device is used to separate the gas-solid mixture of gaseous silica to obtain the first tail gas.

[0082] The integrated ceramic fiber dechlorination and dust removal device is connected to the gas-solid separation device. The integrated ceramic fiber dechlorination and dust removal device is loaded with the aforementioned ceramic fiber filter tube for dechlorination. The integrated ceramic fiber dechlorination and dust removal device is used to dechlorinate and remove dust from the first tail gas to obtain the second tail gas.

[0083] The drying device is connected to the integrated ceramic fiber dechlorination and dust removal device. The drying device is used to remove water from the second tail gas to obtain the third tail gas.

[0084] The hydrogen chloride recovery unit is connected to the drying unit. The hydrogen chloride recovery unit is used to remove hydrogen chloride from the third tail gas to obtain the fourth tail gas.

[0085] The integrated ceramic fiber dechlorination and dust removal device includes components such as a silo, ash hopper, new catalytic dechlorination ceramic fiber filter tube, heating system, tail gasification device, pulse backflushing system, compressed air source, and fan.

[0086] The specific process flow for the dry recovery of fumed silica tail gas using the above-mentioned dry recovery system for fumed silica tail gas includes the following steps:

[0087] P1: The gas-solid two-phase flow flue gas generated by the hydrolysis furnace used for the production of fumed silica is cooled and then preliminarily separated in the gas-solid separation device to obtain the first tail gas. The first tail gas enters the ceramic fiber dechlorination and dust removal integrated device.

[0088] P2: Due to the pore structure inside the ceramic fiber filter tube wall of the integrated ceramic fiber dechlorination and dust removal device, the gaseous silica powder in the first tail gas is intercepted outside the tube wall. The gas passes through the ceramic fiber filter tube wall from the outside to the inside. The chlorine and water vapor in the gas react and are converted into hydrogen chloride under the action of the first active layer and the second active layer loaded on the ceramic fiber filter tube.

[0089] P3: The second tail gas after dust and chlorine removal is discharged harmlessly after passing through a drying device and a hydrogen chloride recovery device.

[0090] The dry recovery system for fumed silica tail gas treats the gas first by separating silica dust particles to facilitate subsequent gas processing. Then, under the action of a catalyst, chlorine reacts with a large amount of water vapor in the tail gas to convert it into hydrogen chloride. After further dehydration, the hydrogen chloride gas is separated and purified. This dry recovery process not only reduces subsequent processing steps and energy consumption, avoiding resource waste, but also recovers hydrogen chloride gas, allowing it to be directly used in other production processes instead of producing low-value, low-quality hydrochloric acid. Therefore, developing efficient dry recovery technology for fumed silica tail gas is an important direction for enterprises to reduce costs and increase efficiency, aiming to comprehensively improve the recovery and utilization value of hydrogen chloride and chlorine in fumed silica tail gas and reduce chlorine and alkali consumption in the production process.

[0091] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0092] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0093] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0094] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0095] Example 3

[0096] This embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0097] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing copper nitrate (1wt%), molybdenum nitrate (0.5wt%), silver nitrate (1wt%), chloroauric acid (1wt%), and ascorbic acid (30wt%). After impregnation, remove the tubes and dry them at 120℃ for 48 hours.

[0098] 2) Spray a coating solution containing manganese hydroxide (1 wt%), nickel chloride (1 wt%), silver chloride (1 wt%), bismuth oxide (1 wt%), and titanium dioxide (45 wt%) onto the inner wall of the ceramic fiber filter tube and dry it at 120°C for 6 hours.

[0099] 3) The ceramic fiber filter tube was calcined at 300℃ in a mixed atmosphere of hydrogen and nitrogen for 3 hours to obtain a chlorine-removing ceramic fiber filter tube. The chlorine-removing ceramic fiber filter tube was installed in an integrated ceramic fiber chlorine removal and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 97.7% and the chlorine removal efficiency was 96.5%.

[0100] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 50 nm.

[0101] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0102] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0103] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0104] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0105] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0106] Example 4

[0107] This embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0108] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing chloroplatinic acid (metal content 0.2wt%) and ascorbic acid (content 5wt%), remove them after impregnation, and dry them at 50℃ for 12h.

[0109] 2) Spray a coating solution containing palladium chloride (0.5 wt%) and activated carbon (5 wt%) onto the inner wall of the ceramic fiber filter tube and dry it at 50°C for 48 hours.

[0110] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 150℃ for 1 hour to obtain a chlorine-removing ceramic fiber filter tube. The chlorine-removing ceramic fiber filter tube was installed in an integrated ceramic fiber chlorine removal and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 92.9% and the chlorine removal efficiency was 94.1%.

[0111] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 800 nm.

[0112] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0113] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0114] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0115] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0116] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0117] Example 5

[0118] This embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0119] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing cobalt nitrate (metal content 2wt%), zinc nitrate (metal content 1wt%), chloroplatinic acid (metal content 1wt%) and ethylene glycol (content 20wt%). After impregnation, remove the tubes and dry them at 120℃ for 12h.

[0120] 2) A coating solution containing manganese hydroxide (1 wt%), ferric chloride (0.5 wt%), nickel sulfate (0.5 wt%), molybdenum dioxide (1 wt%), silver chloride (1 wt%), and aluminum oxide (35 wt%) was sprayed onto the inner wall of the ceramic fiber filter tube and dried at 120°C for 8 hours.

[0121] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 200℃ for 2 hours to obtain a dechlorination ceramic fiber filter tube. The dechlorination ceramic fiber filter tube was installed in an integrated ceramic fiber dechlorination and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 95.5% and the dechlorination efficiency was 96.0%.

[0122] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 100 nm.

[0123] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0124] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0125] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0126] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0127] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0128] Example 6

[0129] Specifically, this embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0130] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing ferric nitrate (metal content 2wt%), sodium chloropalladium (metal content 1.5wt%), silver nitrate (metal content 1.5wt%) and ethanol (content 30wt%). After impregnation, remove the tubes and dry them at 120℃ for 6 hours.

[0131] 2) Spray a coating solution containing ferric hydroxide (1wt%), nickel hydroxide (1wt%), silver chloride (2wt%), sodium bismuthate (1wt%), and silica (30wt%) onto the inner wall of the ceramic fiber filter tube and dry it at 60°C for 24 hours.

[0132] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 200℃ for 2 hours to obtain a dechlorination ceramic fiber filter tube. The dechlorination ceramic fiber filter tube was installed in an integrated ceramic fiber dechlorination and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 95.3% and the dechlorination efficiency was 96.3%.

[0133] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 600 nm.

[0134] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0135] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0136] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0137] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0138] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0139] Example 7

[0140] Specifically, this embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0141] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing manganese nitrate (1wt%), nickel nitrate (2wt%), chloroplatinic acid (1wt%), chloroauric acid (1wt%) and methanol (30wt%). After impregnation, remove the tubes and dry them at 120℃ for 18h.

[0142] 2) A coating solution containing ferric sulfate (0.5 wt%), nickel hydroxide (1 wt%), palladium chloride (0.5 wt%), lanthanum oxide (1 wt%), and silicon carbide (30 wt%) was sprayed onto the inner wall of the ceramic fiber filter tube and dried at 80°C for 30 hours.

[0143] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 200℃ for 2 hours to obtain a dechlorination ceramic fiber filter tube. The dechlorination ceramic fiber filter tube was installed in an integrated ceramic fiber dechlorination and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 96.7% and the dechlorination efficiency was 95.7%.

[0144] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 500 nm.

[0145] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0146] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0147] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0148] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0149] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0150] Example 8

[0151] Specifically, this embodiment provides a method for preparing a ceramic fiber filter tube for chlorine removal, including the following steps:

[0152] 1) Place the pre-washed and dried ceramic fiber filter tubes into an impregnation solution containing nickel nitrate (0.5wt%), copper nitrate (2.5wt%), zinc nitrate (0.5wt%), silver nitrate (0.5wt%), chloroplatinic acid (0.5wt%), chloroauric acid (0.5wt%), and ascorbic acid (20wt%). After impregnation, remove the tubes and dry them at 100℃ for 16 hours.

[0153] 2) Spray a coating solution containing manganese hydroxide (1 wt%), iron hydroxide (1 wt%), nickel hydroxide (1 wt%), silver chloride (2 wt%), and titanium dioxide (30 wt%) onto the inner wall of the ceramic fiber filter tube and dry it at 100°C for 12 hours.

[0154] 3) The ceramic fiber filter tube was calcined in a hydrogen atmosphere at 250℃ for 3 hours to obtain a dechlorination ceramic fiber filter tube. The dechlorination ceramic fiber filter tube was installed in an integrated ceramic fiber dechlorination and dust removal device and applied to the actual treatment of fumed silica tail gas of a company. The dust removal efficiency was 93.2% and the dechlorination efficiency was 97.1%.

[0155] Specifically, in this embodiment, the thickness of the first active layer is less than 2 nm, and the thickness of the second active layer is 300 nm.

[0156] Specifically, this embodiment provides a chlorine-removing ceramic fiber filter tube, which is obtained by the above preparation method.

[0157] Compared with the prior art, the ceramic fiber filter tube for chlorine removal and its preparation method in this embodiment have the following beneficial effects:

[0158] (1) In this embodiment, catalytic dechlorination active components are loaded onto the ceramic fiber filter tube by impregnation and coating, which can effectively achieve selective catalytic conversion of chlorine gas and achieve a dechlorination efficiency of over 94%.

[0159] (2) In this embodiment, ceramic fiber filter tube is used as the main dust removal structure, which has an excellent effect on the separation of nano-sized silica dust in fumed silica tail gas, with a dust removal efficiency of over 92%.

[0160] (3) This embodiment can realize the integrated operation of dechlorination and dust removal in one set of equipment. The equipment is simple, occupies little space, has a simple process flow, and low system energy consumption.

[0161] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A ceramic fiber filter tube for chlorine removal, characterized in that, include: The ceramic fiber filter tube comprises a first active layer disposed on the surface of the ceramic fibers within the ceramic fiber filter tube, and a second active layer disposed outside the first active layer on the inner wall surface of the ceramic fiber filter tube. The first active layer includes: the first active species after reduction calcination treatment; The second active layer includes: a second active species after reduction calcination treatment and a carrier; The reduction calcination treatment is carried out at a temperature of 150~300℃ for 1~3 h. The first active species and the second active species are selected from one of the following: (1) The first active species include nickel nitrate, sodium chloropalladium, silver nitrate, chloroplatinic acid, and chloroauric acid; the second active species include nickel hydroxide, molybdenum dioxide, niobium pentoxide, palladium chloride, silver chloride, and bismuth oxide. (2) The first active species include copper nitrate, molybdenum nitrate, silver nitrate, and chloroauric acid; the second active species include manganese hydroxide, nickel chloride, silver chloride, and bismuth oxide. (3) The first active species includes chloroplatinic acid, and the second active species includes palladium chloride; (4) The first active species include cobalt nitrate, zinc nitrate, and chloroplatinic acid; the second active species include manganese hydroxide, ferric chloride, nickel sulfate, molybdenum dioxide, and silver chloride. (5) The first active species include ferric nitrate, sodium chloropalladium, and silver nitrate; the second active species include ferric hydroxide, nickel hydroxide, silver chloride, and sodium bismuthate. (6) The first active species include manganese nitrate, nickel nitrate, chloroplatinic acid, and chloroauric acid; the second active species include ferric sulfate, nickel hydroxide, palladium chloride, and lanthanum oxide. (7) The first active species include nickel nitrate, copper nitrate, zinc nitrate, silver nitrate, chloroplatinic acid, and chloroauric acid, and the second active species include manganese hydroxide, iron hydroxide, nickel hydroxide, and silver chloride.

2. The ceramic fiber filter tube for chlorine removal according to claim 1, characterized in that, The carrier includes at least one of activated carbon, aluminum oxide, silicon dioxide, silicon carbide, and titanium dioxide.

3. The ceramic fiber filter tube for chlorine removal according to claim 1 or 2, characterized in that, The weight ratio of the second active species to the carrier is (0.2~5):(5~30).

4. The ceramic fiber filter tube for chlorine removal according to claim 1, characterized in that, The thickness of the first active layer is less than 2 nm; the thickness of the second active layer is 50~800 nm.

5. A method for preparing a ceramic fiber filter tube for chlorine removal as described in any one of claims 1 to 4, characterized in that, Includes the following steps: 1) The ceramic fiber filter tube is impregnated with an impregnation solution and then dried to form a first active layer on the surface of the ceramic fiber in the ceramic fiber filter tube. The impregnation solution includes a first active species and water. 2) The inner wall of the ceramic fiber filter tube is sprayed with a coating solution and then dried to form a second active layer on the surface of the inner wall of the ceramic fiber filter tube. The coating solution includes a second active species, a carrier, and water. 3) The ceramic fiber filter tube is subjected to reduction calcination treatment to obtain a ceramic fiber filter tube for dechlorination.

6. The method for preparing the ceramic fiber filter tube for chlorine removal according to claim 5, characterized in that, The metal content in the impregnation solution is 0.2 wt% to 5 wt%.

7. The method for preparing the ceramic fiber filter tube for chlorine removal according to claim 5, characterized in that, The impregnation solution also includes additives, which are at least one of methanol, ethanol, ethylene glycol, and ascorbic acid.

8. The method for preparing a ceramic fiber filter tube for chlorine removal according to claim 7, characterized in that, The additive content in the impregnation solution is 5 wt% to 30 wt%.

9. The method for preparing a ceramic fiber filter tube for chlorine removal according to claim 5, characterized in that, The content of the second active species in the application solution is 0.5 wt%~5 wt%, and the content of the carrier is 5 wt%~45 wt%.

10. The method for preparing a ceramic fiber filter tube for chlorine removal according to any one of claims 5 to 9, characterized in that, The drying temperature in step 1) is 50~120℃, and the processing time is 6~48h.

11. The method for preparing a ceramic fiber filter tube for chlorine removal according to any one of claims 5 to 9, characterized in that, The drying temperature in step 2) is 50~120℃, and the processing time is 6~48h.

12. The method for preparing a ceramic fiber filter tube for chlorine removal according to any one of claims 5 to 9, characterized in that, In step 3), the atmosphere for the reduction roasting process is hydrogen or a mixture of hydrogen and nitrogen.

13. The method for preparing a ceramic fiber filter tube for chlorine removal according to any one of claims 5 to 9, characterized in that, The reduction calcination treatment in step 3) is carried out at a temperature of 150~300℃ for 1~3h.

14. A dry recovery system for fumed silica tail gas, characterized in that, include: Cooling device for cooling gas-solid mixtures of fumed silica; A gas-solid separation device is connected to a cooling device. The gas-solid separation device is used to separate the gas-solid mixture of gaseous silica to obtain the first tail gas. A ceramic fiber dechlorination and dust removal integrated device is connected to a gas-solid separation device. The ceramic fiber dechlorination and dust removal integrated device is loaded with a ceramic fiber filter tube for dechlorination as described in any one of claims 1 to 4. The ceramic fiber dechlorination and dust removal integrated device is used to dechlorinate and remove dust from the first tail gas to obtain the second tail gas. The drying device is connected to the integrated ceramic fiber dechlorination and dust removal device. The drying device is used to remove water from the second tail gas to obtain the third tail gas. The hydrogen chloride recovery unit is connected to the drying unit. The hydrogen chloride recovery unit is used to remove hydrogen chloride from the third tail gas to obtain the fourth tail gas.