Utilization system for tail gas in bamboo activated carbon production and bamboo activated carbon production system

Abstract

The utility model discloses a bamboo activated carbon production tail gas utilization system and a bamboo activated carbon production system. The utilization system comprises an electric fuel gas heat supply unit which comprises ignition equipment and an outer boiler for supplying heat to secondary carbonization treatment and activation treatment, and first tail gas is ignited and combusted by the ignition equipment after flowing into the outer boiler to generate combustion tail gas; the first purification unit is used for treating the first mixed gas and then outputting purified gas; the purified gas and methane react in the first reaction equipment to generate first reaction gas containing H2 and CO; the second purification unit is used for treating the activated tail gas and outputting second reaction gas; second mixed gas formed by the first reaction gas and the second reaction gas reacts in the second reaction equipment to generate first synthesis gas containing H2 and CO2; the separation equipment is used for recovering CO2 in the first synthesis gas by adopting a CO2 selective separation membrane and outputting third reaction gas; and the third reaction gas reacts in the third reaction equipment to generate synthesis gas containing methanol.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of bamboo quality activated carbon production, specifically, relate to the utilization system of bamboo quality activated carbon production tail gas and bamboo quality activated carbon production system. BACKGROUND

[0002] Biomass energy is the fourth largest energy after coal, oil and natural gas. Biomass energy is energy with biomass as carrier, usually from firewood, straw, livestock manure and municipal solid waste, etc. Modern technology usually converts these biomass into solid, liquid or gaseous fuel for use. Bamboo energy is an important form of biomass energy, with the advantages of low pollution, wide distribution, large reserves and renewable. China is the country with the most abundant bamboo resources in the world, and has favorable conditions and environment for developing bamboo energy.

[0003] At present, an important use of bamboo resources in China is to prepare bamboo activated carbon. The preparation process mainly includes carbonization process and activation process, and the carbonization process can be one or two times. Twice carbonization usually refers to grinding, kneading, granulating the once carbonized material into special shapes such as columnar, honeycomb and spherical, and then performing secondary carbonization to remove the adhesive used in granulation. In addition to the activation process which produces a large amount of tail gas, the once carbonization process and the twice carbonization also produce a lot of tail gas, and the composition of the tail gas produced by the two carbonizations is obviously different.

[0004] In addition to the protective gas and water vapor, the main components of the tail gas produced by the once carbonization are CO, CO2, H2, volatile organic compounds (such as alkanes, alkenes, aldehydes, etc.), organic vapor (such as terpenes, tannins, methanol, etc.), and acid gases (such as formic acid, phenol, acetic acid, H2S, SO2, NH3, nitrogen oxides, etc.).

[0005] The tail gas produced by twice carbonization is quite different depending on the type of adhesive. For example, the main components of the tail gas of traditional twice carbonization with pitch or coal tar as adhesive are protective gas, water vapor, CO, CO2, volatile organic compounds (such as benzene, toluene, xylene, methyl phenol, ethyl phenol, etc.) and acid gases (such as phenol, formic acid, acetic acid, aldehydes, nitrogen oxides, etc.), which have great toxicity. When using high molecular adhesive (such as starch, molasses, carboxymethyl cellulose, lignin, gelatin, chitosan, etc.), the content of volatile organic compounds and acid gases in the twice carbonization tail gas is significantly reduced, and the main components are protective gas, water vapor, CO and CO2.

[0006] During the activation process, the activator reacts with carbon elements, thereby causing the erosion of the pores to generate a large number of micropores. In addition to the protective gas and the activator (such as water vapor, CO2, and O2), the main components of the activation exhaust gas also include H2, CO, a small amount of volatile organic compounds (such as CH4, C2H4, and propylene), and acidic gases (such as phenol).

[0007] If the tail gas generated during the carbonization process and the activation process can be converted into clean energy, the utilization rate of bamboo resources can be significantly improved. Chinese invention patent CN116332128A discloses a system for preparing methanol and high-quality activated carbon from biomass and a preparation method thereof. In this method, the tail gas generated during the activation process is directly subjected to a water-gas shift reaction, and then a CO hydrogenation reaction is performed, and finally methanol is obtained. On the one hand, a large amount of tail gas generated during the carbonization process is not recycled and utilized, and on the other hand, directly synthesizing the activation tail gas can easily cause catalyst poisoning and result in low purity of methanol. Practical new type content

[0008] The technical problem to be solved by the present application is to provide a simple and efficient method and system for utilizing the tail gas generated during the production of bamboo activated carbon, and a production method and system for bamboo activated carbon.

[0009] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method and system for utilizing the tail gas generated during the production of bamboo activated carbon are provided, and the technical solution is as follows:

[0010] The method for utilizing the tail gas generated during the production of bamboo activated carbon includes a first tail gas generated by a primary carbonization process, a second tail gas generated by a secondary carbonization process, and a third tail gas generated by an activation process. The adhesive used for the secondary carbonization process is a high molecular adhesive, and the activator used for the activation process is water vapor. The utilization method includes the following steps:

[0011] The first tail gas is introduced into an external boiler used for the secondary carbonization process and the activation process, and then ignited and burned to obtain combustion tail gas;

[0012] The first mixed gas composed of the combustion tail gas and the second tail gas is subjected to purification treatment to obtain purified gas;

[0013] The purified gas and methane are introduced into a first reaction device loaded with a catalyst to perform a catalytic reaction, thereby generating a first reaction gas containing H2 and CO;

[0014] The activation tail gas is subjected to purification treatment to obtain a second reaction gas;

[0015] The second mixed gas composed of the first reaction gas and the second reaction gas is introduced into a second reaction device loaded with a catalyst to perform a catalytic reaction, thereby generating a first synthesis gas containing H2 and CO2.

[0016] CO2 is recovered from the first syngas to generate the third reaction gas;

[0017] The third reaction gas is introduced into a third reaction device containing a catalyst to carry out a catalytic reaction, generating a second synthesis gas containing methanol.

[0018] As a further improvement to the above-mentioned method for utilizing the exhaust gas from bamboo activated carbon production: the purification treatment of the first mixed gas includes sequential condensation treatment, deacidification treatment, dust removal treatment and adsorption treatment; the purification treatment of the activated exhaust gas includes sequential condensation treatment, dust removal treatment and adsorption treatment and deacidification treatment.

[0019] As a further improvement to the above-mentioned method for utilizing the exhaust gas from bamboo activated carbon production: the adsorption treatment employs activated carbon adsorption; the first mixed gas is deacidified using a dry deacidification method; and the activated exhaust gas is deacidified using a wet deacidification method.

[0020] As a further improvement to the above-mentioned method for utilizing the exhaust gas from bamboo activated carbon production: the purified gas has a water vapor volume fraction of 2-5%, a COD content of ≤5ppm, a volatile organic compound content of ≤3ppm, an acidic gas content of ≤2ppm, and a particulate matter content of ≤20mg / Nm³. 3 The second reaction gas contains 30-40% water vapor by volume, ≤5 ppm COD, ≤3 ppm volatile organic compounds, ≤2 ppm acidic gases, and ≤20 mg / Nm³ of particulate matter. 3 .

[0021] As a further improvement to the above-mentioned method for utilizing the tail gas from bamboo activated carbon production, it also includes recirculating CO2 recovered from the first synthesis gas back to the first reaction equipment to react with methane.

[0022] As a further improvement to the above-mentioned method for utilizing the tail gas from bamboo activated carbon production: CO2 in the first synthesis gas is recovered using a CO2 selective separation membrane.

[0023] As a further improvement to the above-mentioned method for utilizing the tail gas from bamboo activated carbon production: the catalyst in the first reaction device is a perovskite-type nickel-based composite catalyst. Preferably, the preparation method of the perovskite-type nickel-based composite catalyst includes the following steps:

[0024] dissolving the soluble cerium salt and the zirconium salt in deionized water; adding ammonia water dropwise into the solution under stirring until the pH is 9-10; then continuing to stir for 2 hours and aging at 70-90℃ for 2 hours; after collecting, washing and drying the solid, performing calcination treatment in air to obtain the CeO2-ZrO2 carrier; further preferably, the molar ratio of cerium ions to zirconium ions is 1; the calcination temperature is 500-700℃, and the calcination time is 3-5 hours;

[0025] The soluble lanthanum salt, the soluble strontium salt, the soluble nickel salt, the soluble trivalent iron salt and the soluble ruthenium salt are weighed according to the molar ratio of La: Sr: Ni: Fe: Ru being 0.8: 0.2: 0.7: 0.2: 0.1 and dissolved in deionized water; an appropriate amount of citric acid is added into the solution; the solution is stirred and evaporated at 70-90℃ until a gel is formed; the gel is dried at 110-130℃ for 12 hours to obtain the perovskite precursor; further preferably, the molar ratio of metal ions to citric acid is 1: (1.4-1.6);

[0026] The perovskite precursor and the CeO2-ZrO2 carrier are uniformly mixed by being dispersed in a small amount of ethanol; after the ethanol is evaporated by stirring at 70-90℃, the mixture is first dried at 100-120℃ and then calcination treatment is performed in air to form a perovskite structure, and finally reduction treatment is performed in a reducing atmosphere to obtain the perovskite-type nickel-based composite catalyst. Further preferably, the perovskite precursor and the CeO2-ZrO2 carrier are weighed according to the loading amount of the perovskite precursor being 15-25%; the calcination temperature is 800-1000℃, and the calcination time is 4-8 hours; the reduction temperature is 600-800℃, and the reduction time is 1-3 hours.

[0027] As a further improvement of the method for utilizing the tail gas produced in the production of the bamboo-based activated carbon, the catalyst in the second reaction device is a Cu-Zr catalyst. Preferably, the preparation method of the Cu-Zr catalyst comprises the following steps:

[0028] An aqueous solution comprising urea and a soluble zirconium salt is prepared, and the aqueous solution is subjected to hydrothermal treatment, and the generated first solid is collected, washed and dried; further preferably, the soluble zirconium salt is zirconium nitrate, and the molar ratio of urea to zirconium ions in the aqueous solution is 1.8-2.2; the hydrothermal reaction temperature is 140-160℃, and the hydrothermal reaction time is 18-30 hours;

[0029] The first solid is subjected to calcination treatment to obtain a zirconium precursor; further preferably, the calcination temperature for the calcination treatment of the first solid is 230-270℃, and the calcination time is 3-5 hours;

[0030] The zirconium precursor and the copper salt are mixed by grinding, and then dispersed in deionized water to form a dispersion liquid. An alkali solution is added to the dispersion liquid under water bath conditions. The second solid is collected, washed and dried. Further preferably, the copper salt is copper nitrate, the molar ratio of copper ions to zirconium ions is 0.1-0.15, the water bath temperature is 50-70℃, sodium hydroxide is used as the alkali solution, and the pH of the dispersion liquid is adjusted to 9 after stirring for 1-3 hours under water bath conditions.

[0031] The second solid is calcined to obtain the Cu-Zr catalyst. Further preferably, the calcination temperature for calcining the second solid is 350-450℃, and the calcination time is 3-5 hours.

[0032] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo-based activated carbon, the catalyst in the third reaction device has a multi-layer structure, the core is Fe3O4, the inner layer is CeO2, the middle layer is Cu-Zn alloy, the outer layer is ZrO2, and the surface layer is graphene quantum dots. Preferably, the preparation method of the multi-layer structure catalyst comprises the following steps: using a co-precipitation method to prepare the Fe3O4 core by reacting a soluble trivalent iron salt, a soluble divalent iron salt and ammonia; using a hydrothermal method to load the CeO2 inner layer on the surface of the Fe3O4 core by reacting a soluble cerium salt and urea; using a chemical reduction method to deposit the Cu-Zn alloy middle layer on the surface of the CeO2 inner layer by reacting a soluble copper salt, a soluble zinc salt and sodium borohydride; using a sol-gel method to load the ZrO2 outer layer on the surface of the Cu-Zn alloy middle layer by reacting n-butoxy zirconium, water and ethanol; using an impregnation method to load graphene quantum dots on the surface of the ZrO2 outer layer by impregnating a graphene quantum dot solution; and after loading the graphene quantum dots, performing calcination treatment and reduction treatment: the calcination treatment is performed in an air atmosphere at a temperature of 400-500℃ for 3-5 hours; and the reduction treatment is performed in a mixed gas of N2 and H2 at a temperature of 300-400℃ for 1-3 hours.

[0033] The utilization system of the tail gas produced in the production of bamboo activated carbon, the tail gas including the first tail gas produced in the primary carbonization treatment, the second tail gas produced in the secondary carbonization treatment and the third tail gas produced in the activation treatment, the adhesive used for the blank body subjected to the secondary carbonization treatment being a high molecular adhesive, and the activation agent used in the activation treatment being water vapor, the utilization system including: an electric gas heating unit, the electric gas heating unit including an ignition device and an outer boiler for heating the secondary carbonization treatment and the activation treatment, the first tail gas being ignited and combusted by the ignition device after flowing into the outer boiler to generate combustion tail gas; a first purification unit, including a first condensing device, a first deacidification device, a first dust removal device and a first adsorption device for sequentially performing condensing treatment, deacidification treatment, dust removal treatment and adsorption treatment on the first mixed gas composed of the combustion tail gas and the second tail gas; the first purification unit outputting purified gas after processing the first mixed gas; a first reaction device, the first reaction device being provided with a catalyst packing structure, the purified gas and the methane being catalytically reacted in the first reaction device to generate the first reaction gas containing H2 and CO; the gas inlet of the first reaction device being connected with the gas outlet of the first adsorption device and a methane conveying device; a second purification unit, including a second condensing device, a second dust removal device, a second adsorption device and a second deacidification device for sequentially performing condensing treatment, dust removal treatment, adsorption treatment and deacidification treatment on the activation tail gas; the second purification unit outputting the second reaction gas after processing the activation tail gas; a second reaction device, the second reaction device being provided with a catalyst packing structure, the second mixed gas composed of the first reaction gas and the second reaction gas being catalytically reacted in the second reaction device to generate the first synthesis gas containing H2 and CO2; the gas inlet of the second reaction device being connected with the gas outlets of the first reaction device and the second deacidification device; a separation device, the separation device adopting a CO2 selective separation membrane to recover the CO2 in the first synthesis gas and output the third reaction gas; the gas inlet of the separation device being connected with the gas outlet of the second separation device; a third reaction device, the third reaction device being provided with a catalyst packing structure, the third reaction gas being catalytically reacted in the third reaction device to generate the synthesis gas containing methanol; the gas inlet of the third reaction device being connected with the gas outlet of the separation device.

[0034] As a further improvement of the above-mentioned utilization system of the tail gas produced in the production of bamboo activated carbon: the first dust removal device and the second dust removal device are filters adopting porous metal filter cores.

[0035] As a further improvement of the above-mentioned utilization system of the tail gas produced in the production of bamboo activated carbon: the first deacidification device is a dry deacidification tower, and the second deacidification device is a spray tower.

[0036] As a further improvement of the above-mentioned utilization system of the tail gas produced in the production of bamboo activated carbon: the first adsorption device and the second adsorption device are provided with activated carbon packing structures.

[0037] As a further improvement of the above-mentioned utilization system of tail gas produced in bamboo activated carbon production, the application further comprises a reflux pipeline for refluxing the CO2 recovered by the separation device into the first reaction device.

[0038] As a further improvement of the above-mentioned utilization system of tail gas produced in bamboo activated carbon production, the application further comprises:

[0039] A third condensing device for condensing the second synthesis gas and outputting liquid methanol, wherein the gas inlet of the third condensing device is connected with the gas outlet of the third reaction device;

[0040] A rectifying device for rectifying the liquid methanol and outputting high-purity methanol, wherein the liquid inlet of the rectifying device is connected with the liquid outlet of the third condensing device.

[0041] To achieve the above-mentioned purpose, according to the second aspect of the application, the application provides a bamboo activated carbon production method and production system using the utilization method and utilization system of tail gas produced in bamboo activated carbon production according to the first aspect, and the technical scheme is as follows:

[0042] The bamboo activated carbon production method comprises primary carbonization treatment, secondary carbonization treatment and activation treatment on bamboo raw materials, and further comprises utilization of production tail gas by using the utilization method of tail gas produced in bamboo activated carbon production, wherein the production tail gas comprises first tail gas produced in primary carbonization treatment, second tail gas produced in secondary carbonization treatment and third tail gas produced in activation treatment.

[0043] The primary carbonization treatment comprises the following steps:

[0044] The dried bamboo raw materials are put into a carbonization furnace, the furnace temperature is increased from room temperature to 130-280 DEG C under inert atmosphere, and the temperature is kept for 0.5-1.5 hours;

[0045] The temperature is continuously increased to 300-400 DEG C, and the temperature is kept for 0.5-1.5 hours;

[0046] The temperature is continuously increased to 500-600 DEG C, and the temperature is kept for 0.5-1.5 hours, and then the primary carbonized material is obtained by cooling the furnace;

[0047] The secondary carbonization treatment comprises the following steps:

[0048] The primary carbonized material and the high-molecular adhesive are granulated into a green body, the green body is put into a carbonization furnace, the furnace temperature is increased from room temperature to 500-600 DEG C under inert atmosphere, the temperature is kept for 0.5-1.5 hours, and then the secondary carbonized material is obtained by cooling the furnace;

[0049] The activation treatment is that the secondary carbonized material is put into an activation furnace, water vapor is used as an activation agent under inert atmosphere, the temperature is kept for 2-4 hours at 800-1100 DEG C, and then the bamboo activated carbon is obtained by cooling the furnace.

[0050] The bamboo active carbon production system comprises a first carbonization furnace for primary carbonization treatment of bamboo raw materials, a second carbonization furnace for secondary carbonization treatment, and an activation furnace for activation treatment, the adhesive used for the blank body subjected to the secondary carbonization treatment is a high molecular adhesive, the activation agent used for the activation treatment is water vapor, and the bamboo active carbon production tail gas utilization system is further included.

[0051] The bamboo active carbon production system has the following advantages:

[0052] (1) The tail gas generated in the carbonization process and the activation process of the bamboo raw materials is effectively utilized, the tail gas is converted into synthesis gas including methanol through the catalytic reaction of CO and H2 (reaction equation: CO+2H2→CH3OH), and high-purity liquid methanol can be obtained through simple treatment (such as rectification), which not only reduces the environmental pollution caused by tail gas emission, but also has a wide range of uses, is an important chemical raw material and fuel, and can be used as a production raw material of formaldehyde, acetic acid, dimethyl ether and biodiesel, and can be used as fuel and fuel additive, and the methanol can be sold outside to increase economic benefits.

[0053] (2) The first tail gas is ignited and combusted, on one hand, heat generated by combustion is used for heat supply of the secondary carbonization treatment and the activation treatment, thereby reducing energy consumption, and on the other hand, most of the organic matters are combusted and converted into CO2 that can react with methane, thereby greatly reducing the processing difficulty of the organic matters.

[0054] (3) The combustion tail gas after combustion and the second tail gas have similar compositions, after purification treatment of the first mixed gas formed by the combustion tail gas and the second tail gas, a large amount of CO2 in the purified first mixed gas is converted into CO and H2 for methanol preparation through the reaction of CO2 and methane (reaction equation: CO2+2CH4→2CO+H2), so that the reaction gas obtained after purification is suitable for the reaction gas of the activated tail gas after purification, and the reaction efficiency of the subsequent catalytic reaction can be significantly improved.

[0055] (4) According to the particularity of the first mixed gas (formed by the combustion tail gas and the second tail gas) and the activated tail gas, the first mixed gas and the activated tail gas are respectively pretreated, so that water vapor, organic vapor, volatile organic compounds, acidic gases and particulate matter impurities are efficiently removed, and the catalytic reaction after the pretreatment is helpful to improve the activity of the catalyst and the catalytic reaction efficiency, and reduce the problems of catalyst poisoning and equipment blockage and wear.

[0056] (5) First, CO2+2CH4→2CO+H2 is used to increase the content of H2, and then CO+H2O→CO2+H2 is used to further increase the content of H2 and consume part of CO, so that the contents of CO and H2 in the final third reaction gas are adapted, and the methanol synthesis reaction can be carried out without supplementing or supplementing a small amount of H2, thereby effectively reducing H2 supplement and saving cost.

[0057] The embodiments of the application provided in the specification will be further described below in conjunction with the drawings and specific embodiments. Additional aspects and advantages of the embodiments of the application provided in the specification will be partially given in the following description, partially become obvious from the following description, or be understood by the practice of the embodiments of the application provided in the specification. BRIEF DESCRIPTION OF DRAWINGS

[0058] The drawings constituting part of the embodiments of the application provided in the specification serve to assist the understanding of the embodiments of the application provided in the specification, and the contents provided in the drawings and the description thereof related to the embodiments of the application provided in the specification can be used to explain the embodiments of the application provided in the specification, but do not constitute improper limitation on the embodiments of the application provided in the specification. In the drawings:

[0059] Figure 1 Structure schematic diagram of a first embodiment of a bamboo-based activated carbon production system and a utilization system for tail gas produced in the bamboo-based activated carbon production.

[0060] Figure 2 Structure schematic diagram of a second embodiment of a bamboo-based activated carbon production system and a utilization system for tail gas produced in the bamboo-based activated carbon production.

[0061] Figure 3 XRD pattern of Cu-Zr catalyst.

[0062] The relevant marks in the above drawings are:

[0063] 110-electricity and gas heating unit, 120-first purification unit, 130-first reaction device, 140-second purification unit, 150-second reaction device, 160-separation device, 170-third reaction device, 180-third condensation device, 190-distillation device. DETAILED DESCRIPTION

[0064] The embodiments of the application provided in the specification will be further described below in conjunction with the drawings and specific embodiments. Additional aspects and advantages of the embodiments of the application provided in the specification will be partially given in the following description, partially become obvious from the following description, or be understood by the practice of the embodiments of the application provided in the specification.

[0065] The technical solutions and technical features provided in the parts including the following description in the embodiments of the present application provided in the specification can be combined with each other without conflict.

[0066] In addition, the embodiments of the present application provided in the specification involved in the following description are generally only a part of the embodiments of the present application provided in the specification rather than all the embodiments, therefore, all the other embodiments obtained by the person skilled in the art based on the embodiments of the present application provided in the specification without creative labor should belong to the protection scope of the embodiments of the present application provided in the specification.

[0067] Regarding the terms and units in the embodiments of the present application provided in the specification: the terms "include", "contain", "have" and any variants thereof in the specification and claims of the embodiments of the present application provided in the specification and relevant parts are intended to cover non-exclusive inclusion. In addition, other related terms and units in the embodiments of the present application provided in the specification can be reasonably interpreted based on the relevant content of the embodiments of the present application provided in the specification.

[0068] The embodiment of the bamboo activated carbon production method of the present application comprises the following steps:

[0069] Drying treatment: put the fresh bamboo raw material into an oven and dry for 48 hours at 100 DEG C.

[0070] Primary carbonization treatment: put the dried bamboo raw material into a carbonization furnace, under inert atmosphere, raise the furnace temperature from room temperature to 200 DEG C, keep for 1 hour; continue to raise the temperature to 350 DEG C, keep for 1 hour; continue to raise the temperature to 550 DEG C, keep for 1 hour, and then cool down with the furnace to obtain carbonized material.

[0071] Secondary carbonization treatment: grind the primary carbonized material to a particle size of 325 mesh, then use molasses as an adhesive, water as an auxiliary agent, and granulate into a green body in a kneader according to the mass ratio of molasses to primary carbonized material of 0.5 and the addition of 30 mL of auxiliary agent per 100 g of primary carbonized material, put the green body into a carbonization furnace, under inert atmosphere, raise the furnace temperature from room temperature to 550 DEG C, keep for 1 hour, and then cool down with the furnace to obtain secondary carbonized material.

[0072] Activation treatment: put the secondary carbonized material into an activation furnace, under inert atmosphere, use water vapor as an activator, the volume of liquid water introduced per 100 g of green body per hour is 40 mL, keep for 3 hours at 1000 DEG C, and then cool down with the furnace to obtain bamboo activated carbon.

[0073] The utility model discloses a bamboo quality activated carbon production tail gas's utilization method for utilizing the production tail gas of bamboo quality activated carbon production method, the production tail gas includes the first tail gas of primary carbonization treatment, the second tail gas of secondary carbonization treatment and the third tail gas of activation treatment, and its first embodiment includes the following steps:

[0074] The first tail gas is introduced into the outer boiler for secondary carbonization treatment and activation treatment, and then ignition combustion is carried out to obtain combustion tail gas.

[0075] The first mixed gas formed by the combustion tail gas and the second tail gas is purified to obtain purified gas, and the purification treatment is condensation treatment, deacidification treatment, dust removal treatment and adsorption treatment in sequence, wherein the water vapor, organic vapor and low-boiling-point acid gas in the production tail gas can be removed through the condensation treatment; the deacidification treatment adopts dry deacidification, so that the residual acid gas in the first mixed gas can be removed through the deacidification treatment to obtain relatively dry low-acid gas, and the influence of the wet deacidification on the catalyst catalytic reaction in the first reaction equipment caused by introducing more water vapor is avoided; the dust removal treatment is preferably filtration dust removal, and the dust removal is arranged after the deacidification treatment, which can not only remove the particulate impurities in the first mixed gas, but also remove the deacidifying agent used in the deacidification treatment. Through the adsorption treatment, the volatile organic compounds in the first mixed gas can be adsorbed, and the activated carbon is preferably used as the adsorbent. Therefore, through the purification treatment, the particulate impurities, volatile organic compounds and residual acid gas in the first mixed gas can be removed, the volume fraction content of water vapor in the obtained purified gas is 2-5%, the COD content is less than or equal to 5ppm, the volatile organic compound content is less than or equal to 3ppm, the acid gas content is less than or equal to 2ppm, and the particulate content is less than or equal to 20mg / Nm 3 .

[0076] The purified gas and methane are introduced into the first reaction equipment loaded with catalyst to carry out catalytic reaction to generate the first reaction gas containing H2 and CO.

[0077] The activated tail gas is purified to obtain the second reaction gas. The purification treatment is a condensation treatment, a dust removal treatment, an adsorption treatment and an acid removal treatment in sequence. The water vapor, organic vapor and low-boiling acid gas in the production tail gas can be removed by the condensation treatment. The dust removal treatment is preferably filtration. The volatile organic compounds in the production tail gas can be adsorbed by the adsorption treatment, preferably using activated carbon as the adsorbent. The residual acid gas in the production tail gas can be removed by the acid removal treatment, preferably using a spray tower for wet acid removal. The acid removal treatment not only effectively removes the acid gas, but also increases the humidity of the reaction gas, making it more suitable for catalytic reaction in the second reaction equipment. Therefore, the first mixed gas and the activated tail gas after acid removal are subjected to adsorption treatment by activated carbon. The second reaction gas obtained has a water vapor volume fraction content of 30-40%, a COD content of ≤5 ppm, a volatile organic content of ≤3 ppm, an acid gas content of ≤2 ppm, and a particulate matter content of ≤20 mg / Nm 3 .

[0078] The second mixed gas composed of the first reaction gas and the second reaction gas is introduced into the second reaction equipment loaded with catalyst for catalytic reaction to generate the first synthesis gas containing H2 and CO2.

[0079] The CO2 in the first synthesis gas is recovered by using a CO2 selective separation membrane to generate the third reaction gas. A CO2 concentration detection device is provided at the gas inlet end of the first reaction equipment. When the CO2 content in the purified gas is low, the CO2 recovered by the separation equipment is returned to the first reaction equipment through a return pipeline. When the CO2 content in the purified gas is sufficient for reaction with methane, the CO2 recovered by the separation equipment can be directly discharged.

[0080] The third reaction gas is introduced into the third reaction equipment loaded with catalyst for catalytic reaction to generate the second synthesis gas containing methanol. When the volume of H2 is slightly higher than twice the volume of CO, it helps the methanol synthesis reaction to proceed. Therefore, in order to adjust the H2:CO volume ratio to (2.05-2.1):1, a CO concentration detection device and an H2 concentration detection device are provided at the gas inlet end of the third reaction equipment to detect the third reaction gas, and then H2 is introduced into the third reaction equipment according to the demand.

[0081] Figure 1 The structure of the first embodiment of the bamboo activated carbon production system and the utilization system of the bamboo activated carbon production tail gas is shown in the figure. Figure 1As shown, the bamboo active carbon production system includes a first carbonization furnace for primary carbonization treatment of bamboo raw materials, a second carbonization furnace for secondary carbonization treatment, an activation furnace for activation treatment after carbonization, and a utilization system of production tail gas, which includes first tail gas generated by primary carbonization treatment, second tail gas generated by secondary carbonization treatment, and third tail gas generated by activation treatment. The utilization system includes an electric gas heating unit 110, a first purification unit 120, a first reaction device 130, a second purification unit 140, a second reaction device 150, a separation device 160, and a third reaction device 170.

[0082] The electric gas heating unit 110 includes an ignition device and an outer boiler for heating secondary carbonization treatment and activation treatment, and the first tail gas flows into the outer boiler and is ignited and burned by the ignition device to generate combustion tail gas.

[0083] The first purification unit 120 includes a first condensing device, a first deacidification device, a first dust removal device, and a first adsorption device for sequentially performing condensation treatment, deacidification treatment, dust removal treatment, and adsorption treatment on the first mixed gas composed of combustion tail gas and second tail gas; the first purification unit 120 outputs purified gas after processing the first mixed gas.

[0084] The first reaction device 130 is provided with a catalyst packing structure, and the purified gas and methane are catalytically reacted in the first reaction device 130 to generate first reaction gas containing H2 and CO; the gas inlet of the first reaction device 130 is connected with the gas outlet of the first adsorption device and a methane conveying device.

[0085] The second purification unit 140 includes a second condensing device, a second dust removal device, a second adsorption device, and a second deacidification device for sequentially performing condensation treatment, dust removal treatment, adsorption treatment, and deacidification treatment on the activation tail gas; the second purification unit 140 outputs second reaction gas after processing the activation tail gas.

[0086] The second reaction device 150 is provided with a catalyst packing structure, and the second mixed gas composed of the first reaction gas and the second reaction gas is catalytically reacted in the second reaction device 150 to generate first synthesis gas containing H2 and CO2; the gas inlet of the second reaction device 150 is connected with the gas outlet of the first reaction device 130 and the second deacidification device.

[0087] The separation device 160 recovers CO2 in the first synthesis gas by using a CO2 selective separation membrane, and outputs a third reaction gas. The gas inlet of the separation device 160 is connected with the gas outlet of the second reaction device 150, and the gas outlet of the separation device 160 is connected with the gas inlet of the third reaction device 170. The CO2 selective separation membrane is any one of a polyetherimide membrane, a polyamide membrane, and a carbon membrane. A CO2 concentration detection device is arranged at the gas inlet end of the first reaction device 130. When the CO2 content in the purified gas is low, the recovered CO2 in the separation device 160 is returned to the first reaction device 130 through a return pipeline. When the CO2 content in the purified gas is sufficient to react with methane, the recovered CO2 in the separation device 160 can be directly discharged.

[0088] The third reaction device 170 is internally provided with a catalyst packing structure. The third reaction gas is catalytically reacted in the reaction device to generate a synthesis gas containing methanol. The gas inlet of the third reaction device 170 is connected with the gas outlet of the separation device 160.

[0089] The first and second dust removal devices are filters using porous metal filter cartridges. The first deacidification device is a dry deacidification tower, and the second deacidification device is a spray tower. The first and second adsorption devices are internally provided with active carbon packing structures.

[0090] Figure 2 It is a structural schematic diagram of a second embodiment of a bamboo active carbon production system and a utilization system of a bamboo active carbon production tail gas. As shown in Figure 2 Compared with the first embodiment, the utilization system of the second embodiment further includes a third condensation device 180 and a rectification device 190. The third condensation device 180 performs condensation treatment on the second synthesis gas, and outputs liquid methanol. The gas inlet of the third condensation device 180 is connected with the gas outlet of the third reaction device 170. The rectification device 190 performs rectification treatment on the liquid methanol, and outputs high-purity methanol. The liquid inlet of the rectification device 190 is connected with the liquid outlet of the third condensation device 180.

[0091] The catalyst in the first reaction device 130 is a perovskite type nickel-based composite catalyst. An embodiment of a preparation method of the catalyst includes the following steps:

[0092] A soluble cerium salt and a zirconium salt are dissolved in deionized water, and the molar ratio of cerium ions to zirconium ions is 1. Ammonia water is added dropwise to the solution under stirring until the pH is 9-10. Then, the solution is continuously stirred for 2 hours, and is aged at 80°C for 2 hours. After the solid is collected, washed, and dried, the solid is calcined at 600°C in air for 3-5 hours to obtain a CeO2-ZrO2 carrier.

[0093] The soluble lanthanum salt, the soluble strontium salt, the soluble nickel salt, the soluble ferric salt and the soluble ruthenium salt are weighed according to the molar ratio of La, Sr, Ni, Fe, Ru being 0.8:0.2:0.7:0.2:0.1 and dissolved in deionized water; the solution is added with an appropriate amount of citric acid according to the molar ratio of metal ions to citric acid being 1:1.5; the solution is stirred and evaporated at 80℃ until a gel is formed; the gel is dried at 120℃ for 12 hours to obtain the perovskite precursor;

[0094] The perovskite precursor and the CeO2-ZrO2 carrier are weighed according to the loading of the perovskite precursor being 20%, uniformly mixed by dispersing in a small amount of ethanol; after the ethanol is stirred and evaporated at 80℃, the perovskite structure is formed by first drying at 110℃ and then calcining in air at 900℃ for 6 hours, and finally reducing in a mixed atmosphere of H2 and Ar at 700℃ for 2 hours to obtain the perovskite-type nickel-based composite catalyst.

[0095] The perovskite-type nickel-based composite catalyst is used for catalyzing the purified gas (the volume percentage of one embodiment is: 5.41% CO, 75.24% CO2, 1.49% H2, 2.31% water vapor, and the balance is N2) and methane, the volume ratio of the purified gas to methane is (1.05-1.5):1, the reaction temperature is 700℃, the reaction pressure is 0.1 MPa, and the space velocity is 20000h-1. -1 The average CO2 conversion rate is 81%.

[0096] The catalyst in the second reaction device 150 is a Cu-Zr catalyst, and an embodiment of the preparation method thereof includes the following steps:

[0097] Zirconium nitrate and urea are dissolved in 150 mL of deionized water to form an aqueous solution, the molar ratio of urea to zirconium ions in the aqueous solution is 2, and the concentration of zirconium ions is 0.2 mol / L; the aqueous solution is subjected to hydrothermal treatment, the hydrothermal reaction temperature is 150℃, the hydrothermal reaction time is 24 hours, and the generated first solid is collected, washed and dried;

[0098] The first solid is subjected to calcination treatment, the calcination temperature is 250℃, the calcination time is 4 hours, and a zirconium precursor is obtained;

[0099] The zirconium precursor and copper nitrate are ground and mixed, the molar ratio of copper ions to zirconium ions (calculated according to zirconium nitrate) is 0.12; then the ground mixture is dispersed in 200 mL of deionized water to form a dispersion, stirred for 2 hours under the condition of a water bath temperature of 60℃, and sodium hydroxide is slowly added dropwise into the dispersion under the condition of a water bath until the pH of the dispersion is 9; the generated second solid is collected, washed and dried;

[0100] The second solid was calcined at 400℃ for 4 hours to obtain the Cu-Zr catalyst.

[0101] Figure 3 The image shows the XRD pattern of the Cu-Zr catalyst. Figure 3 As shown, the Cu-Zr catalyst exhibits good crystal structure, and its XRD pattern shows CuO. x The characteristic peaks of Cu and ZrO2 indicate that Cu was not embedded in the zirconium precursor (ZrO2) during the preparation process, but was uniformly attached to the ZrO2 surface as CuOx. Through the interaction between the two, a better catalytic effect was produced.

[0102] The specific surface area of ​​the zirconium precursor (ZrO2) was determined to be 37.35 m² / s² using N₂ adsorption-desorption experiments and the BET (Brunauer-Emmett-Teller) method. 2 / g, total pore volume is 0.22cm³ 3 / g, with an average pore size of 23.6nm, and a specific surface area of ​​56.48m² for the Cu-Zr catalyst. 2 / g, total pore volume is 0.30cm³ 3 / g, with an average pore size of 21.8nm, indicating that the supported CuO... x Subsequently, the specific surface area of ​​the Cu-Zr catalyst increased significantly, which played a decisive role in the adsorption and activation of the gas.

[0103] A mixture of gas with volume fractions of 15% CO, 40% H2, 35% N2, and 10% CO2 was mixed with water vapor and catalyzed using a Cu-Zr catalyst at 180–300 °C. The results showed that the CO conversion rate increased sharply with increasing catalytic temperature, and then gradually leveled off. The CO conversion rates at 180 °C, 210 °C, 240 °C, 270 °C, and 300 °C were 62%, 79%, 85%, 86%, and 87%, respectively.

[0104] The Cu-Zr catalyst was used to catalyze the reaction of a second gas mixture (in one embodiment, the volume fraction was: 31.62% CO, 1.25% CO2, 27.65% H2, 33.54% water vapor, with the balance being N2) at a reaction temperature of 270°C, a reaction pressure of 5 MPa, and a space velocity of 5000 h⁻¹. -1 The CO conversion rate is 83%.

[0105] The catalyst in the third reaction apparatus 170 has a multi-layer structure, with Fe3O4 as the core, CeO2 as the inner layer, Cu-Zn alloy as the middle layer, ZrO2 as the outer layer, and graphene quantum dots as the surface layer. An embodiment of its preparation method includes the following steps:

[0106] Preparation of Fe3O4 core by coprecipitation method: FeCl3·6H2O, FeCl2·4H2O and ammonia were used as raw materials. Equal volume of Fe 3+ solution and Fe 2+ solution were mixed, and Fe 3+ and Fe 2+ molar ratio was 2:1. The mixture was heated to 80°C, and ammonia was added to the mixture under stirring at 500 rpm until pH was 10-11. After 30 minutes of continuous reaction, magnetic separation was performed, and the collected solid was washed with deionized water and ethanol for 3 times, and vacuum dried at 60°C for 12 hours to obtain Fe3O4 core.

[0107] Preparation of CeO2 inner layer by hydrothermal method: Ce(NO3)3·6H2O and urea were dissolved in water, and the concentration of Ce 3+ was 0.05M, and the concentration of urea was 0.5M. 1g Fe3O4 core was dispersed in 150mL of the above solution, and transferred to a hydrothermal reactor, and reacted at 180°C for 12 hours. After cooling to room temperature, centrifugal separation was performed, and the collected solid was washed with water and ethanol for 3 times, and dried at 60°C for 12 hours, and then calcined at 350°C for 2 hours to obtain CeO2@Fe3O4, in which the CeO2 inner layer was coated on the surface of Fe3O4 core.

[0108] Preparation of Cu-Zn alloy middle layer by chemical reduction method: Cu(NO3)2·3H2O and Zn(NO3)2·6H2O were dissolved in water, and the concentration of Cu 2+ was 0.1M, and the concentration of Zn 2+ was 0.05M. 0.8g CeO2@Fe3O4 was dispersed in 100mL of the above solution, and ultrasonic treatment was performed for 30 minutes. Under stirring in an ice bath, NaBH4 solution (concentration was 0.2M) was slowly added dropwise until precipitation was formed. After stirring at room temperature for 2 hours, centrifugal separation was performed, and the collected solid was washed with water and ethanol for 3 times, and vacuum dried at 50°C for 8 hours to obtain Cu-Zn@CeO2@Fe3O4, in which the Cu-Zn alloy middle layer was deposited on the surface of CeO2 inner layer.

[0109] Preparation of ZrO2 outer layer by sol-gel method: Zr(OC4H9)4 was dissolved in ethanol, and the concentration of Zr(OC4H9)4 was 0.1M. 100mL of the above solution was added with a small amount of water (water / Zr molar ratio = 2) and 0.6g Cu-Zn@CeO2@Fe3O4, and stirred at room temperature for 4 hours. After refluxing at 60°C for 2 hours, centrifugal separation was performed, and dried at 80°C for 12 hours, and then calcined at 450°C for 3 hours to obtain ZrO2@Cu-Zn@CeO2@Fe3O4, in which the ZrO2 outer layer was coated on the surface of Cu-Zn alloy middle layer.

[0110] Graphene quantum dots (GQDs) were prepared by impregnation method: A 1 mg / mL aqueous solution of GQDs was prepared; then 0.5 g ZrO2@Cu-Zn@CeO2@Fe3O4 was dispersed in 100 mL of GQDs aqueous solution; the solution was sonicated for 30 minutes, stirred at room temperature for 4 hours, centrifuged, and vacuum dried at 50 °C for 12 hours, thus loading graphene quantum dots onto the outer surface of ZrO2 to obtain GQDs@ZrO2@Cu-Zn@CeO2@Fe3O4.

[0111] Calcination treatment: GQDs@ZrO2@Cu-Zn@CeO2@Fe3O4 was calcined in air at 450℃ for 4 hours to obtain the precursor.

[0112] Reduction treatment: The precursor was reduced at 350°C for 2 hours in a mixed atmosphere of N2 and H2 to obtain the multilayer catalyst.

[0113] This multilayer catalyst was used to catalyze the third reaction gas (in one embodiment, the volume composition is: 28.56% CO, 10.36% CO2, 52.24% H2, 2.28% water vapor, with the balance being N2). The volume ratio of the third reaction gas to the supplementary H2 was (20.05–20.5):1, the reaction temperature was 240℃ (220–300℃ is acceptable), the reaction pressure was 4 MPa (3–10 MPa is acceptable), and the space velocity was 6000 h⁻¹. -1 (3000~10000h -1 (Both are acceptable), with a space-time yield of 0.6–1.2 kg methanol / (L catalyst·h). It is estimated that 6.98 tons of methanol can be produced as a byproduct for every ton of bamboo activated carbon produced, and the purity of the liquid methanol is over 95%.

[0114] The wet deacidification method refers to deacidification by spraying liquid absorbent; the dry deacidification method refers to deacidification by spraying solid absorbent.

[0115] The embodiments of the invention provided in this specification have been described above. Those skilled in the art will be able to implement the embodiments of the invention provided in this specification based on these descriptions. All other preferred embodiments and implementations obtained by those skilled in the art based on the above description of the embodiments of the invention provided in this specification without inventive effort should fall within the protection scope of the embodiments of the invention provided in this specification.

Claims

1. A system for utilizing exhaust gas from bamboo activated carbon production, wherein the exhaust gas includes a first exhaust gas generated from a primary carbonization process, a second exhaust gas generated from a secondary carbonization process, and a third exhaust gas generated from an activation process, wherein the binder used in the secondary carbonization process is a polymer binder, and the activator used in the activation process is water vapor, characterized in that: The system includes: Electric gas heating unit (110), the electric gas heating unit (110) includes an ignition device and an external boiler for heating the secondary carbonization and activation treatments. The first tail gas flows into the external boiler and is ignited and burned by the ignition device to generate combustion tail gas. The first purification unit (120) includes a first condensing device, a first deacidifying device, a first dust removal device, and a first adsorption device that sequentially perform condensation treatment, deacidification treatment, dust removal treatment, and adsorption treatment on a first mixture of combustion exhaust gas and second exhaust gas; the first purification unit (120) outputs purified gas after processing the first mixture. The first reaction device (130) is equipped with a catalyst packing structure. The purified gas and methane react with the catalyst in the first reaction device (130) to generate a first reaction gas containing H2 and CO. The gas inlet of the first reaction device (130) is connected to the gas outlet of the first adsorption device and the methane conveying device. The second purification unit (140) includes a second condensation device, a second dust removal device, a second adsorption device, and a second deacidification device that sequentially perform condensation treatment, dust removal treatment, adsorption treatment, and deacidification treatment on the activated tail gas; the second purification unit (140) outputs a second reaction gas after processing the activated tail gas. The second reaction device (150) is equipped with a catalyst packing structure. The second mixture of the first reaction gas and the second reaction gas is catalyzed by the catalyst in the second reaction device (150) to generate a first synthesis gas containing H2 and CO2. The gas inlet of the second reaction device (150) is connected to the gas outlet of the first reaction device (130) and the second deacidification device. A separation device (160) is provided, wherein the separation device (160) uses a CO2 selective separation membrane to recover CO2 from the first synthesis gas and outputs a third reaction gas; the inlet of the separation device (160) is connected to the outlet of the second separation device (160); The third reaction device (170) is equipped with a catalyst packing structure. The third reaction gas is catalyzed by the catalyst in the reaction device to generate synthesis gas containing methanol. The gas inlet of the third reaction device (170) is connected to the gas outlet of the separation device (160).

2. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The first dust removal device and the second dust removal device are filters using porous metal filter elements.

3. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The first deacidification device is a dry deacidification tower; the second deacidification device is a spray tower.

4. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The first and second adsorption devices are equipped with activated carbon packing structures.

5. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: It also includes a reflux pipe for returning CO2 recovered by the separation device (160) to the first reaction device (130).

6. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: Also includes: The third condensation unit (180) condenses the second synthesis gas and outputs liquid methanol. The air inlet of the third condensing device (180) is connected to the air outlet of the third reaction device (170); A distillation apparatus (190) is used to distill liquid methanol to output high-purity methanol; the inlet of the distillation apparatus (190) is connected to the outlet of the third condenser (180).

7. A bamboo activated carbon production system, comprising a first carbonization furnace for primary carbonization of bamboo raw materials, a second carbonization furnace for secondary carbonization, and an activation furnace for activation treatment, wherein the binder used for the green body subjected to secondary carbonization is a polymer binder, and the activator used for activation treatment is water vapor, characterized in that: It also includes a system for utilizing the exhaust gas from the production of bamboo activated carbon as described in any one of claims 1-6, wherein the exhaust gas includes a first exhaust gas generated by a primary carbonization process, a second exhaust gas generated by a secondary carbonization process, and a third exhaust gas generated by an activation process.

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