Metal porous filter membrane based on biological fermentation as well as preparation method and application of metal porous filter membrane

Abstract

The invention discloses a metal porous filter membrane based on biological fermentation and a preparation method and application thereof, and belongs to the technical field of flue gas purification. The method comprises the following steps: mixing an adhesive, metal powder and dilute sulphuric acid to prepare metal slurry; blade-coating the metal slurry on the front surface of the metal wire mesh, and performing vacuum drying to obtain a film carrier; mixing higher fatty acid and sulfate reducing bacteria to prepare an activating solution; spraying the activating solution on the reverse side of the film carrier in a sterile environment to obtain an inoculated film carrier; the inoculated film carrier is subjected to biological fermentation in a sterile environment, and the metal porous filter membrane is prepared. The metal porous filter membrane prepared by the invention has excellent high temperature resistance and corrosion resistance, and can stably operate for a long time in a severe smoke environment, and the service life of the filter membrane is effectively prolonged. The filtering precision is extremely high, and the production cost is low.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flue gas purification, and relates to a metal porous filter membrane based on biological fermentation and a preparation method and application thereof. BACKGROUND

[0002] At present, the steel industry is an important source of air pollution, In the traditional converter wet method once dust removal (OG method for short) system, the 1400-1600℃ high-temperature flue gas generated by converter steelmaking is cooled to about 900℃ by vaporization cooling flue; the dust-containing flue gas at the outlet of the flue is sequentially introduced into an overflow venturi, a gravity dehydrator, an RD adjustable throat venturi, a 90° elbow dehydrator and a wet spin dehydrator to remove most of the dust in the flue gas; finally, it is extracted by a fan, and the flue gas without recycling conditions is ignited and discharged by a diffuser chimney, and the coal gas with recycling conditions is sent into a gas tank after a rotating water seal check valve. A large amount of water is sprayed in the wet dust removal process, which consumes a large amount of water resources, and sludge is generated.

[0003] In the traditional converter dry method once dust removal (LT method for short) system, the 1400-1600℃ high-temperature flue gas generated by the converter is captured by a movable smoke hood, and the flue gas is first cooled and cooled to 800-1000℃ by a vaporization cooling flue, and heat energy can also be recovered at the same time. After the flue gas reaches the evaporative cooler, the flue gas is cooled by evaporation. In order to meet the temperature requirements of the electric dust collector, the flue gas temperature at the outlet of the cooler is controlled at 170-250℃. At the same time, the cooler captures coarse particle dust, and the dust is treated to make the specific resistance of the dust more conducive to the capture of dust by the subsequent electric dust collector. The electrostatic precipitator performs fine dust removal, which is also a key link to meet the ultra-low emission requirement. After the ID fan frequency conversion adjustment, the flue gas enters the three-way switching valve, and the flue gas that does not meet the recycling conditions is ignited and discharged by the diffuser cup valve and the diffuser chimney; when the flue gas meets the recycling conditions, the diffuser cup valve is closed and the recycling cup valve is opened, the flue gas is cooled and dusted by the coal gas cooler and then enters the coal gas tank. In order to prevent the explosion of converter coal gas, the coal gas is directly sprayed with water or sprayed with a mist, and only a part of the waste heat of the coal gas (1000℃ or below) can be recovered. On the other hand, the electrostatic precipitator in the current dry dust removal technology (LT method) has an explosion hazard, although it can avoid equipment damage by explosion relief, but explosion relief will affect normal production operation. In summary, the converter coal gas full heat recovery and purification technology not only meets the deep needs of enterprise energy saving and emission reduction, but also solves the problem of dust removal. A high-temperature resistant metal membrane dust collector is proposed to replace the traditional electrostatic dust removal system, and waste heat recovery is increased, which can achieve less or no water spraying while achieving dust removal.

[0004] The Chinese invention patent CN103397244B relates to a preparation method of a sintered Fe-Al-based alloy porous material resistant to high-temperature oxidation. The steps include: 1) mixing powder preparation; 2) granulation, drying and molding; 3) sintering: placing the above-mentioned compact in a sintering furnace for sintering, and performing different high-temperature calcination in four stages to obtain the sintered Fe-Al-based alloy porous material. The calcination process consumes a large amount of energy, and the preparation cost is high, which is not suitable for large-scale promotion.

[0005] The Chinese invention patent CN117225081B discloses a coated metal fiber felt, which is a flexible structure and relates to the technical field of industrial high-temperature dust removal. The felt comprises a metal wire mesh, and the left and right ends of the metal wire mesh are fixedly installed with adhering blocks. The advantages of the felt are as follows: after the device is sintered at high temperature, the manufacturing of the coated metal fiber felt is completed, and then the metal wire mesh is fixedly connected with the adhering blocks on the left and right sides. When adhering, the metal fiber felt is installed on the adhering filter material in sequence from top to bottom. The metal fiber felt cancels the superfine fiber filter layer in the metal fiber felt, and the coating is superfine metal powder, which has relatively low cost. When pores appear on the metal film, the metal fiber can still ensure that the metal fiber felt has good filtering precision, so that the fiber felt can meet the ultra-low emission requirement. Due to the porosity characteristics of the metal fiber felt, the dust removal is not complete, and the phenomenon of hiding dirt and dust occurs. Long-term use can cause the metal fiber gap to be blocked, resulting in problems such as failure of converter gas filtration and blockage, and safety.

[0006] The Chinese invention patent CN113817977A relates to a preparation method of plasma sprayed Al Fe intermetallic compound powder. The steps include: soaking nano-alumina powder in dilute hydrochloric acid for pretreatment, adding a certain amount of surfactant into an iron salt solution, ultrasonic mixing, hydrolysis reaction, spray drying, calcination and the like. In the preparation process, plasma spraying, CO or H2 reducing atmosphere high-temperature sintering and the like are used, the process is complex, the cost is high, and the prepared product is rigid and cannot be used in the converter primary flue gas dust removal system. SUMMARY

[0007] The present application aims to provide a metal porous filter film based on biological fermentation and a preparation method and application thereof, so as to solve the technical problems of low filtering precision, complex preparation process, low economy and environmental protection of the metal porous filter film in the prior art.

[0008] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application: In a first aspect, the present application provides a preparation method of a metal porous filter film based on biological fermentation, comprising the following steps: Mixing an adhesive, metal powder and dilute sulfuric acid to prepare a metal slurry; The metal slurry is scraped and coated on the front surface of the metal wire mesh, and a thin film carrier is obtained after vacuum drying; Mixing and preparing the high-grade fatty acid and sulfate-reducing bacteria to obtain an activation solution; Spraying the activation solution on the reverse side of the film carrier in a sterile environment to obtain a film carrier inoculated. Carrying out biological fermentation on the film carrier inoculated in a sterile environment to obtain a metal porous filter film.

[0009] Further, the mass ratio of the binder, the metal powder and the dilute sulfuric acid is (80-82):(15-18):(3-5); the mass concentration of the dilute sulfuric acid is 50%; and the viscosity of the metal slurry is 3000 Pa·s-4000 m Pa·s.

[0010] Further, the specification of the metal wire mesh is 50 mesh, and the doctor blade coating thickness is 0.28 mm-0.32 mm; the temperature of the vacuum drying is 90℃, and the drying time is 30 min.

[0011] Further, the metal powder is a mixture of any two or three of iron, nickel, chromium and molybdenum; and the binder is one or a mixture of two of potassium silicate, sodium silicate and aluminum dihydrogen phosphate.

[0012] Further, the sulfate-reducing bacteria account for 1%-1.5% of the mass of the activation solution, and the MPN of the sulfate-reducing bacteria is 2.5×10 7 MPN / L-3.0×10 7 MPN / L.

[0013] Further, the high-grade fatty acid is one or a mixture of two of coconut oil acid, palm oil acid and oleic acid.

[0014] Further, in the step of spraying the activation solution on the reverse side of the film carrier in a sterile environment, a particle atomization sprayer is used for spraying, and the atomization particle fineness is 55 μm-65 μm.

[0015] Further, the step of carrying out biological fermentation on the film carrier inoculated in a sterile environment specifically comprises: placing the metal slurry coating layer of the film carrier inoculated upwards in a sterile environment for biological fermentation, the standard cleanliness is 10000, the fermentation temperature is 28℃-30℃, the relative humidity is 80%-90%, and the fermentation time is 14-16 days.

[0016] In a second aspect, the application provides a metal porous filter film based on biological fermentation, which is prepared according to the preparation method of the metal porous filter film based on biological fermentation.

[0017] In a third aspect, the application provides an application of the metal porous filter film based on biological fermentation in smoke recovery and dust removal.

[0018] Compared with the prior art, the present application has the following beneficial effects: The application discloses a metal porous filter membrane based on biological fermentation and a preparation method and application thereof. Metal slurry prepared from a binder, metal powder and dilute sulfuric acid is coated on the front surface of a metal wire mesh, and then activated liquid containing sulfate-reducing bacteria is sprayed on the back surface of the membrane carrier. Because the corrosion rates of the sulfate-reducing bacteria on different metals are different, especially the corrosion of the sulfate-reducing bacteria on iron is relatively strong, the proportion of iron elements is different, and the concentration of the activated liquid of the sulfate-reducing bacteria is different, the activated liquid is uniformly sprayed on the surface of the dried membrane carrier by spraying, fermentation is carried out under certain temperature and humidity by controlling the fermentation process, and thus the high-temperature-resistant and corrosion-resistant metal filter membrane is prepared. The metal filter membrane has a uniform micro-porous structure and controllable pore size. The micro-porous structure is mainly caused by the corrosion of the sulfate-reducing bacteria on iron compounds. Meanwhile, hydrogen sulfide generated in the corrosion process of the sulfate-reducing bacteria is removed in the process of preparing the metal filter membrane. The metal filter membrane is used for the primary flue gas dust removal system of a converter and has the characteristics of high-temperature resistance, corrosion resistance, high filtration precision and high cost performance.

[0019] Further, the metal porous filter membrane has very strong high-temperature resistance and completely meets the extreme high-temperature environment of 800 DEG C of the primary flue gas of the converter. The coating layer adopts high-temperature-resistant inorganic silicate. The sulfate-reducing bacteria multiply under anaerobic conditions in the fermentation process and generate mucous substances, which have the effect of infiltration on the porous filter membrane. The joint action of the organic substances and the inorganic silicate guarantees the high-temperature resistance and necessary machinability of the metal porous filter membrane.

[0020] Further, the metal porous filter membrane has very strong corrosion resistance. Different from traditional materials, the metal porous filter membrane mentioned in the application is doped with the corrosion-resistant elements nickel and chromium in the formula of the membrane carrier to achieve the first layer of protection. After the fermentation process of the sulfate-reducing bacteria, the uniform micro-porous structure caused by the corrosion of the sulfate-reducing bacteria has stronger biological inertia in the actual use process. Meanwhile, the metal porous filter membrane has strong corrosion resistance and stronger corrosion resistance due to the large amount of reproduction of the sulfate-reducing bacteria and the fermentation process. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0022] Figure 1A flow chart of a method for preparing a metal porous filter based on biological fermentation. DETAILED DESCRIPTION

[0023] To enable persons skilled in the art to have a better understanding of the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have the usual meanings understood by those skilled in the art of the present application, and in the event of a conflict, the definitions in the specification shall prevail.

[0024] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting on the scope of the present application, that is, the present application can be practiced without regard to any particular theory or mechanism.

[0025] Herein, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Therefore, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0026] Herein, unless otherwise specified, "comprise", "include", "contain", "have", or similar words encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0027] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of the technical features, each technical feature in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope disclosed in the specification.

[0028] The present application will be described in further detail below with reference to the accompanying drawings: Reference Figure 1 The present application discloses a method for preparing a metal porous filter based on biological fermentation, comprising the following steps: S1, mixing the binder, metal powder and dilute sulfuric acid to prepare a metal slurry; The mass ratio of the adhesive, the metal powder and the dilute sulfuric acid is (80-82):(15-18):(3-5); the mass concentration of the dilute sulfuric acid is 50%; the metal powder is a mixture of any two or three of iron, nickel, chromium and molybdenum, the preparation process is electrolysis, the particle morphology is dendritic, and the particle size is 25um-48um; the adhesive is one or a mixture of two of potassium silicate, sodium silicate and aluminum dihydrogen phosphate, the solid content of the adhesive is 40%-50%, and the modulus is 3.8-4.0. The viscosity of the metal slurry obtained by controlling the preparation time to be 25-30 minutes is 3000 Pa·s-4000 m Pa·s.

[0029] S2, the metal slurry is scraped on the front side of the metal wire mesh to obtain a thin film carrier after vacuum drying; The specification of the metal wire mesh is 50 mesh, and the scraping thickness is 0.28 mm-0.32 mm; the temperature of the vacuum drying is 90℃, and the drying time is 30 min. Since the metal elements such as iron in the metal powder will react with the dilute sulfuric acid during the preparation process to generate iron sulfate, ferrous sulfate, chromium sulfate, nickel sulfate and molybdenum sulfate, etc., the generated sulfate is deposited in the metal powder, and a uniform thin film carrier is formed by scraping to provide a growth carrier for sulfate-reducing bacteria. The content of the iron powder in the metal powder and the content of the dilute sulfuric acid in the slurry preparation, and the preparation time have a significant influence on the content of the generated iron sulfate and ferrous sulfate, and have a great influence on the subsequent fermentation process. Meanwhile, the thickness of the scraping on the surface of the metal wire mesh also has a significant influence on the fermentation process and the microporous structure. The adhesive is an inorganic binder, which has strong adhesion and corrosion resistance.

[0030] S3, a senior fatty acid and sulfate-reducing bacteria are mixed to prepare an activation liquid; The senior fatty acid is one or a mixture of two of coconut oil acid, palm oil acid and oleic acid. The sulfate-reducing bacteria account for 1%-1.5% of the mass of the activation liquid, the maximum possible number (MPN) of the bacterial population of the sulfate-reducing bacteria is 2.5×10 7 MPN / L-3.0×10 7 MPN / L. The maximum possible number of colonies has a close relationship with the number of microporous structures generated in the fermentation process, and can make the bacterial population uniformly dispersed in the activation liquid, S4, the activation liquid is sprayed on the back side of the thin film carrier in a sterile environment to obtain an inoculated thin film carrier; In this step, a particle atomization sprayer is used for spraying to realize inoculation, and the atomization particle fineness is 55um-65um.

[0031] S5, the inoculated thin film carrier is subjected to biological fermentation in a sterile environment to prepare a metal porous filter membrane.

[0032] The metal slurry coating surface of the inoculated film carrier is placed upwards, and biological fermentation is carried out in a sterile environment with a standard cleanliness of 10,000, a fermentation temperature of 28-30 DEG C, and a relative humidity of 80-90%; the growth rate of the sulfate-reducing bacteria is accelerated from the initial aerobic environment to the weak oxygen and anaerobic environment in the fermentation process, the high fatty acids on the surface of the film carrier are absorbed as nutrients, and the sulfate ions in the film carrier coating are reduced to hydrogen sulfide, and corrosion micropores are generated; by accurately controlling the fermentation process, a porous filter membrane with uniform pore size and controllable pore size can be realized; the high-speed fermentation process of the sulfate-reducing bacteria has high biological inertness and corrosion resistance to the porous metal filter membrane, so that corrosion resistance is realized; the adhesive used in the process is an inorganic high-temperature adhesive with high-temperature resistance, which can be used for subsequent mechanical processing; the whole process does not use high-temperature calcination process, and the production energy consumption is low, which achieves the purpose of reducing carbon and energy consumption, so that a metal filter membrane with corrosion resistance, high temperature resistance and high filtration precision suitable for the first converter flue gas is prepared.

[0033] The embodiment of the present application discloses a kind of based on biological fermentation of metal porous filter membrane, according to the preparation method of one kind based on biological fermentation of metal porous filter membrane described above is prepared.This embodiment obtained metal porous filter membrane has high temperature resistance and corrosion resistance, completely meet the limit high temperature environment 800 DEG C of the first converter flue gas, since coating uses high-temperature type inorganic silicate, under anaerobic condition in the fermentation process of sulfate-reducing bacteria, a large number of reproduction is generated, and the mucus material plays the role of infiltration to porous filter membrane, the common effect of the organic matter and inorganic silicate guarantees the high temperature resistance and necessary machinability of metal porous filter membrane.And by doping, corrosion resistance elements nickel and chromium can be improved, to achieve the first layer of protective effect, after the fermentation process of sulfate-reducing bacteria, due to the uniform microporous structure generated by the corrosion of sulfate-reducing bacteria, there is stronger biological inertness in actual use process, and at the same time, due to the large number of reproduction and fermentation process of sulfate-reducing bacteria, porous metal filter membrane has strong corrosion resistance, and has stronger corrosion resistance.

[0034] The application discloses an application of the metal porous filter membrane based on biological fermentation in flue gas recovery and dust removal.

[0035] The application will be further described in connection with specific examples. It should be understood that the examples are only used for illustrating the application but not for limiting the scope of the application. Furthermore, it should be understood that after reading the content taught in the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0036] The following examples use the conventional instruments and equipment in the art. The experimental methods not specified in the following examples are usually carried out according to the conventional conditions or the conditions suggested by the manufacturers. The various raw materials used in the following examples are conventional commercially available products, and the specifications thereof are conventional specifications in the art, unless otherwise specified. In the specification of the application and the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.

[0037] Example 1 S101: 4 grams of 50% concentrated dilute sulfuric acid, 60 grams of dendritic iron powder prepared by electrolysis, 10 grams of nickel powder and 10 grams of molybdenum powder were mixed for 28 minutes; 16 grams of potassium silicate were randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; a metal slurry coating layer with a thickness of 0.32 mm was scraped on a 50-mesh metal base net; and a thin film carrier was obtained after drying in a vacuum drying box at 90°C for 30 minutes.

[0038] S102: 98.8 grams of high-grade fatty acid and 1.2 grams of sulfate-reducing bacteria were accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population satisfies 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the thin film carrier prepared in S101 was inoculated by a particle atomization sprayer, and the atomization particle fineness was adjusted to 60 um.

[0039] S103: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S102 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is dried in a 90-degree oven to be completed, to obtain a metal porous filter film, and test the relevant indexes of the material.

[0040] Example 2 S201: 4 grams of 50% concentrated dilute sulfuric acid, 40 grams of dendritic iron powder prepared by electrolysis, 20 grams of nickel powder, and 20 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate is randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; a 0.32 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0041] S202: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S201 is inoculated by a particle atomization sprayer to adjust the atomization particle fineness to 60um.

[0042] S203: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S202 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is dried in a 90-degree oven to be completed, to obtain a metal porous filter film, and test the relevant indexes of the material.

[0043] Example 3 S301: 4 grams of 50% concentrated dilute sulfuric acid, 70 grams of dendritic iron powder prepared by electrolysis, and 10 grams of nickel powder are mixed for 28 minutes; 16 grams of potassium silicate is randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; a 0.32 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0044] S302: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S301 is inoculated by a particle atomization sprayer to adjust the atomization particle fineness to 60um.

[0045] S303: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S302 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is dried in a 90-degree oven to be completed, to obtain a metal porous filter film, and test the relevant indexes of the material.

[0046] Example 4 S401: 4 grams of 50% concentrated dilute sulfuric acid, 60 grams of dendritic iron powder prepared by electrolysis, 10 grams of nickel powder, and 10 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate are randomly added and mixed for 2 minutes to prepare a slurry of 3500 mPa s; a 0.30 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0047] S402: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation liquid, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S401 is inoculated by a particle atomization sprayer with a particle fineness of 60um.

[0048] S403: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S402 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is dried in a 90-degree oven to be completed, to obtain a metal porous filter film, and test the relevant indexes of the material.

[0049] Example 5 S501: 4 grams of 50% concentrated dilute sulfuric acid, 60 grams of dendritic iron powder prepared by electrolysis, 10 grams of nickel powder, and 10 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate are randomly added and mixed for 2 minutes to prepare a slurry of 3500 mPa s; a 0.32 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0050] S502: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation liquid, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 3.0X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S501 is inoculated by a particle atomization sprayer with a particle fineness of 60um.

[0051] S503: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S502 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is completed after drying in the 90-degree oven to obtain the metal porous filter membrane and test the relevant indexes of the material.

[0052] Example 6 S601: 4 grams of 50% concentrated dilute sulfuric acid, 60 grams of dendritic iron powder prepared by electrolysis, 10 grams of nickel powder, and 10 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate are randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; a 0.32 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0053] S602: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S601 is inoculated by a particle atomization sprayer to adjust the atomization particle fineness to 65 um.

[0054] S603: In the standard cleanliness of 10000 level, the inoculation completed film carrier of S602 is fermented for 15 days with the metal slurry coating facing up under the condition of the fermentation temperature of 28°C and the relative humidity of 85%, and is completed after drying in the 90-degree oven to obtain the metal porous filter membrane and test the relevant indexes of the material.

[0055] Example 7 S701: 4 grams of 50% concentrated dilute sulfuric acid, 60 grams of dendritic iron powder prepared by electrolysis, 10 grams of nickel powder, and 10 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate are randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; a 0.32 mm thick metal slurry coating is scraped on a 50 mesh metal mesh; and a film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0056] S702: 98.8 grams of a senior fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population meets 2.8X10 7 MPN / L. In a sterile environment, the reverse side of the film carrier prepared in S701 is inoculated by a particle atomization sprayer to adjust the atomization particle fineness to 60 um.

[0057] S703: In the standard cleanliness of 10000 level, the inoculated film carrier of S702 is fermented for 15 days with the metal slurry coating facing down at a fermentation temperature of 28°C and a relative humidity of 85%, and is dried in a 90-degree oven to complete the preparation of the metal porous filter film, and the relevant indicators of the material are tested.

[0058] Example 8 S801: 4 grams of 50% concentrated sulfuric acid, 40 grams of dendritic iron powder prepared by electrolysis, 20 grams of nickel powder, and 20 grams of molybdenum powder are mixed for 28 minutes; 16 grams of potassium silicate is randomly added and mixed for 2 minutes to prepare a slurry with a viscosity of 3500 mPa s; the metal slurry coating is coated on a 50-mesh metal mesh to a thickness of 0.32 mm; and the film carrier is obtained after drying in a vacuum drying oven at 90°C for 30 minutes.

[0059] S802: 98.8 grams of high-grade fatty acid and 1.2 grams of sulfate-reducing bacteria are accurately weighed to prepare an activation solution, wherein the maximum possible number (MPN) of the sulfate-reducing bacteria population satisfies 2.5X10 7 MPN / L. The reverse side of the film carrier prepared in S801 is inoculated by a particle atomization sprayer in a sterile environment to achieve inoculation, and the atomization particle fineness is adjusted to 60um.

[0060] S803: In the standard cleanliness of 10000 level, the inoculated film carrier of S802 is fermented for 15 days with the metal slurry coating facing up at a fermentation temperature of 28°C and a relative humidity of 85%, and is dried in a 90-degree oven to complete the preparation of the metal porous filter film, and the relevant indicators of the material are tested.

[0061] The high-temperature-resistant and corrosion-resistant metal porous filter film prepared by the biological fermentation method can be welded into a shape, a stainless steel framework structure is added to the bottom, and the relevant indicators of the metal porous filter bag are tested, and the test results are shown in Table 1.

[0062] Air permeability: Air permeability indicates the ease of gas passing through the filter bag. The higher the air permeability, the greater the ventilation. The air permeability is tested according to GB / T 24218.15 Textiles - Test methods for nonwovens - Part 15: Determination of air permeability. Filtering accuracy: The filtering accuracy indicates the minimum particle size that can be intercepted by the filter bag. The filtering accuracy is expressed by the maximum particle size value that is blocked when the filtering efficiency is 95%. The range is from a few tenths of a micrometer to several tens of micrometers.

[0063] Transverse and longitudinal breaking strength: The transverse and longitudinal breaking strength of the porous metal filter film is tested using a tensile tester, and the average value is taken.

[0064] Transverse and longitudinal elongation: The transverse and longitudinal breaking strength of the porous metal filter film is tested using a tensile tester, and the average value is taken.

[0065] Bubble point pressure: the test method refers to the provisions in GB / T5249.

[0066] Emission concentration: the metal porous filter bag simulates dust gas filtration, tests the dust concentration in the filtered gas, and obtains the emission concentration after filtration.

[0067] Table 1

[0068] The dust removal of the converter primary flue gas The converter steelmaking is intermittent production, and the generation of the converter flue gas is also intermittent. In addition, the converter flue gas has the characteristics of high temperature, toxicity, flammability and explosion, and high dust content, so that the flue gas treatment system becomes very complex. The converter flue gas treatment system is an auxiliary part of the converter smelting, and cannot cause the converter to be shut down due to the failure of the flue gas treatment system, and affect the converter production. The metal porous filter membrane prepared by the biological fermentation method process proposed in the application realizes the hot spots of high temperature resistance, corrosion resistance, environmental protection and energy saving in the production process, high bubble point pressure, high uniformity and high filtration precision, which are not possessed by the traditional market metal sintered filter membrane. The related data is obviously better than the method of the patent, and has very high large-scale popularization value.

[0069] The above is only a preferred embodiment of the application and is not used to limit the application. For those skilled in the art, the application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A method for preparing a metal porous filter membrane based on bio-fermentation, characterized in that, Includes the following steps: A metal slurry is prepared by mixing a binder, metal powder, and dilute sulfuric acid. Metal paste is coated onto the front side of a metal wire mesh and then vacuum dried to obtain a thin film carrier. An activation solution was prepared by mixing higher fatty acids and sulfate-reducing bacteria. The activation solution was sprayed onto the reverse side of the film carrier under sterile conditions to obtain the inoculated film carrier. The inoculated membrane carrier was subjected to bio-fermentation in a sterile environment to prepare a metal porous filter membrane.

2. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The mass ratio of the adhesive, metal powder, and dilute sulfuric acid is (80~82):(15~18):(3~5); the mass concentration of the dilute sulfuric acid is 50%; and the viscosity of the metal slurry is 3000 Pa·s~4000 mPa·s.

3. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The metal wire mesh has a specification of 50 mesh and a coating thickness of 0.28 mm to 0.32 mm; the vacuum drying temperature is 90°C and the drying time is 30 min.

4. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The metal powder is a mixture of any two or three of iron, nickel, chromium and molybdenum; the binder is a mixture of one or two of potassium silicate, sodium silicate and aluminum dihydrogen phosphate.

5. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The sulfate-reducing bacteria comprise 1% to 1.5% of the activation solution by mass, and the MPN of the sulfate-reducing bacteria is 2.5 × 10⁻⁶. 7 MPN / L ~3.0×10 7 MPN / L.

6. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The higher fatty acids are one or a mixture of two of coconut oil acid, palm oil acid and oleic acid.

7. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, In the step of spraying the activation solution onto the reverse side of the film carrier under sterile conditions, a particle atomizing sprayer is used for spraying, and the fineness of the atomized particles is 55μm to 65μm.

8. The method for preparing a metal porous filter membrane based on bio-fermentation according to claim 1, characterized in that, The step of carrying out biological fermentation of the inoculated film carrier in a sterile environment specifically includes: placing the metal slurry coating side of the inoculated film carrier upwards and carrying out biological fermentation in a sterile environment with a standard cleanliness level of 10,000, a fermentation temperature of 28℃~30℃, a relative humidity of 80%~90%, and fermentation for 14~16 days.

9. A porous metal filter membrane based on bio-fermentation, characterized in that, The metal porous filter membrane based on bio-fermentation is prepared according to any one of claims 1 to 8.

10. The application of the bio-fermentation-based metal porous filter membrane as described in claim 9 in flue gas recovery and dust removal.

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