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: a first condensing device for condensing a first tail gas to obtain a first non-condensable gas and a condensate; the second condensing equipment is used for condensing the second tail gas and the third tail gas to obtain second non-condensable gas; the deacidification equipment is used for deacidifying mixed gas formed by the first non-condensable gas and the second non-condensable gas to obtain low-acid gas; a gas inlet of the deacidification equipment is connected with gas outlets of the first condensing equipment and the second condensing equipment; the dust removal equipment is used for carrying out dust removal treatment on the low-acid gas to obtain low-dust gas; a gas inlet of the dust removal equipment is connected with a gas outlet of the deacidification equipment; the adsorption equipment is used for carrying out adsorption treatment on the low-dust gas to obtain reaction gas; and the reaction equipment is internally provided with a catalyst filling structure, and the reaction gas is subjected to a catalytic reaction in the reaction equipment through a catalyst to obtain the methanol-containing synthesis gas.

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, causing the erosion of the pore channels 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 contain 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, followed by a CO hydrogenation reaction, 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. SUMMARY

[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] 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, the production tail gas 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 adhesive used for the blank body subjected to the secondary carbonization treatment is a high molecular adhesive, and the activator used for the activation treatment is water vapor. The utilization method includes the following steps:

[0011] The first tail gas is subjected to condensation treatment to obtain first non-condensable gas and condensate;

[0012] The second tail gas and the third tail gas are subjected to condensation treatment to obtain second non-condensable gas;

[0013] The mixed gas composed of the first non-condensable gas and the second non-condensable gas is subjected to purification treatment to obtain reaction gas;

[0014] The reaction gas is introduced into a reaction device loaded with a catalyst to perform catalytic reaction, and synthesis gas containing methanol is generated.

[0015] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the water vapor content in the reaction gas obtained through purification treatment is 2-5%, the COD content is ≤5 ppm, the volatile organic compound content is ≤3 ppm, the acid gas content is ≤2 ppm, and the particulate matter content is ≤20 mg / Nm 3 .

[0016] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the purification treatment includes sequentially performing deacidification treatment, dust removal treatment, and adsorption treatment on the mixed gas; and the deacidification treatment adopts dry deacidification.

[0017] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the method further includes removing CO2 in the production tail gas by using a CO2 selective separation membrane before catalytic reaction.

[0018] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the method further includes introducing H2 into the reaction equipment.

[0019] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the method further includes purifying the condensate obtained through condensation treatment to obtain biomass oil.

[0020] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the catalyst 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.

[0021] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon, the preparation method of the catalyst includes the following steps:

[0022] Fe3O4 core is prepared by a coprecipitation method through reaction of a soluble trivalent iron salt, a soluble divalent iron salt, and ammonia water;

[0023] CeO2 inner layer is loaded on the surface of the Fe3O4 core through reaction of a soluble cerium salt and urea by a hydrothermal method;

[0024] Cu-Zn alloy middle layer is deposited on the surface of the CeO2 inner layer through reaction of a soluble copper salt, a soluble zinc salt, and sodium borohydride by a chemical reduction method;

[0025] ZrO2 outer layer is loaded on the surface of the Cu-Zn alloy middle layer through reaction of n-butoxy zirconium, water, and ethanol by a sol-gel method;

[0026] Graphene quantum dots are loaded on the surface of the ZrO2 outer layer by impregnating a graphene quantum dot solution by an impregnation method.

[0027] As a further improvement of the method for utilizing the tail gas produced in the production of bamboo activated carbon: it further comprises calcination treatment and reduction treatment after loading graphene quantum dots; the atmosphere of the calcination treatment is air, the temperature is 400-500 DEG C, and the duration is 3-5 hours; the atmosphere of the reduction treatment is a mixture of N2 and H2, the temperature is 300-400 DEG C, and the duration is 1-3 hours.

[0028] The utilization system of the tail gas produced in the production of bamboo activated carbon, the production tail gas includes the first tail gas produced by the first carbonization treatment, the second tail gas produced by the second carbonization treatment, and the third tail gas produced by the activation treatment, the adhesive used for the blank body subjected to the second carbonization treatment is a high molecular adhesive, and the activation agent used for the activation treatment is water vapor, the utilization system comprises: a first condensing device, which condenses the first tail gas to obtain first non-condensable gas and condensate; a second condensing device, which condenses the second tail gas and the third tail gas to obtain second non-condensable gas; a deacidification device, which deacidifies the mixed gas composed of the first non-condensable gas and the second non-condensable gas to obtain low-acid gas; the gas inlet of the deacidification device is connected with the gas outlets of the first condensing device and the second condensing device; a dust removal device, which removes dust from the low-acid gas to obtain low-dust gas; the gas inlet of the dust removal device is connected with the gas outlet of the deacidification device; an adsorption device, which adsorbs the low-dust gas to obtain reaction gas; the gas inlet of the adsorption device is connected with the gas outlet of the dust removal device; and a reaction device, which is provided with a catalyst packing structure, and the reaction gas is catalyzed by the catalyst in the reaction device to obtain synthesis gas containing methanol; the gas inlet of the reaction device is connected with the gas outlet of the adsorption device.

[0029] As a further improvement of the utilization system of the tail gas produced in the production of bamboo activated carbon: the dust removal device is a filter with a porous metal filter core.

[0030] As a further improvement of the utilization system of the tail gas produced in the production of bamboo activated carbon: the deacidification device is a dry deacidification tower.

[0031] As a further improvement of the utilization system of the tail gas produced in the production of bamboo activated carbon: the adsorption device is provided with an activated carbon packing structure.

[0032] As a further improvement of the utilization system of the tail gas produced in the production of bamboo activated carbon: it further comprises a separation device for removing CO2 in the reaction gas, the gas inlet of the separation device is connected with the gas outlet of the adsorption device, and the gas outlet of the separation device is connected with the gas inlet of the reaction device.

[0033] As a further improvement of the above-mentioned bamboo activated carbon production tail gas utilization system: the separation device is a membrane separation device loaded with a CO2 selective separation membrane, which is any one of a polyetherimide membrane, a polyamide membrane, and a carbon membrane.

[0034] As a further improvement of the above-mentioned bamboo activated carbon production tail gas utilization system: further comprising a hydrogen delivery device for inputting H2 into the reaction device.

[0035] As a further improvement of the above-mentioned bamboo activated carbon production tail gas utilization system: further comprising:

[0036] A third condensing device for condensing the synthesis gas and outputting liquid methanol; the gas inlet of the third condensing device is connected to the gas outlet of the reaction device;

[0037] A rectification device for rectifying the liquid methanol and outputting high-purity methanol; the liquid inlet of the rectification device is connected to the liquid outlet of the third condensing device.

[0038] To achieve the above-mentioned purpose, according to the second aspect of the present application, a bamboo activated carbon production method and production system are provided, which adopt the bamboo activated carbon production tail gas utilization method and utilization system of the first aspect, and the technical solution is as follows:

[0039] The bamboo activated carbon production method comprises primary carbonization treatment, secondary carbonization treatment, and activation treatment of bamboo raw materials, and further comprises utilization of production tail gas by the bamboo activated carbon production tail gas utilization method, wherein the production tail gas comprises first tail gas generated by primary carbonization treatment, second tail gas generated by secondary carbonization treatment, and third tail gas generated by activation treatment.

[0040] The primary carbonization treatment comprises the following steps:

[0041] The dried bamboo raw material is placed in a carbonization furnace, and the furnace temperature is raised from room temperature to 130-280℃ under an inert atmosphere, and the temperature is maintained for 0.5-1.5 hours;

[0042] Continue to raise the temperature to 300-400℃, and maintain the temperature for 0.5-1.5 hours;

[0043] Continue to raise the temperature to 500-600℃, and maintain the temperature for 0.5-1.5 hours, and then cool down with the furnace to obtain the primary carbonized material;

[0044] The secondary carbonization treatment comprises the following steps:

[0045] The primary carbonization material and the high polymer adhesive are granulated into a blank, the blank is put into a carbonization furnace, the furnace temperature is raised from room temperature to 500-600 DEG C under inert atmosphere, and the blank is cooled with the furnace after being kept for 0.5-1.5 hours, so that the secondary carbonization material is obtained;

[0046] The activation treatment is that the secondary carbonization material is put into an activation furnace, water vapor is used as the activation agent under inert atmosphere, and the secondary carbonization material is kept for 2-4 hours at 800-1100 DEG C, and then the bamboo activated carbon is obtained after being cooled with the furnace.

[0047] The bamboo activated 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 after carbonization, the adhesive used for the blank subjected to the secondary carbonization treatment is a high polymer adhesive, the activation agent used for the activation treatment is water vapor, and the system further comprises the utilization system of the production tail gas of the bamboo activated carbon provided in the application, and the production tail gas comprises first tail gas generated in the primary carbonization treatment, second tail gas generated in the secondary carbonization treatment, and third tail gas generated in the activation treatment.

[0048] The bamboo activated carbon production system has the following advantages:

[0049] (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 (reaction equation: CO+2H2→CH3OH) including methanol through the catalytic reaction of CO and H2, and high-purity liquid methanol can be obtained through simple treatment (such as rectification), which not only reduces the environmental pollution caused by the tail gas emission, but also has a wide range of uses, is an important chemical raw material and fuel, and can be used as the production raw material of formaldehyde, acetic acid, dimethyl ether and bio-diesel, and can be used as fuel and fuel additive, so that the economic benefits of enterprises can be increased by selling the methanol.

[0050] (2) According to the particularity of the three kinds of tail gas, the tail gas is pretreated and then mixed and purified, so that the purification efficiency can be significantly improved, the water vapor, organic vapor, volatile organic compounds, acidic gas and particulate impurities can be efficiently removed, the catalytic reaction after the purification can help to improve the activity and catalytic reaction efficiency of the catalyst, reduce the catalyst poisoning and equipment blockage and wear problems, and the purity of the methanol can be significantly improved. The condensate obtained after the condensation of the primary carbonization tail gas (i.e. the first tail gas) contains a large amount of organic compounds, and the organic compounds can be condensed into bio-oil with high calorific value, so that the enterprises can further generate income.

[0051] The embodiments of the application provided in the specification will be further described below in combination with the drawings and specific embodiments. The 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 known by the practice of the embodiments of the application provided in the specification. Attached Figure Description

[0052] The accompanying drawings, which form part of the embodiments of the invention provided in this specification, are used to aid in understanding the embodiments of the invention provided in this specification. The content provided in the drawings and the related descriptions in the embodiments of the invention provided in this specification can be used to explain the embodiments of the invention provided in this specification, but do not constitute an undue limitation on the embodiments of the invention provided in this specification. In the drawings:

[0053] Figure 1 This is a schematic diagram of the structure of a first embodiment of a bamboo activated carbon production system and a bamboo activated carbon production tail gas utilization system.

[0054] Figure 2 This is a schematic diagram of the second embodiment of the bamboo activated carbon production system and the bamboo activated carbon production tail gas utilization system.

[0055] Figure 3 This is a schematic diagram of the third embodiment of the bamboo activated carbon production system and the bamboo activated carbon production tail gas utilization system.

[0056] The relevant markings in the above figures are:

[0057] 210 - First condensing unit, 220 - Second condensing unit, 230 - Deacidification unit, 240 - Dust removal unit, 250 - Adsorption unit, 260 - Reaction unit, 270 - Third condensing unit, 280 - Distillation unit, 290 - Separation unit. Detailed Implementation

[0058] The embodiments of the invention provided in this specification will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the embodiments of the invention provided in this specification based on these descriptions. Before describing the embodiments of the invention provided in this specification in conjunction with the accompanying drawings, it should be particularly noted that:

[0059] The technical solutions and features provided in the embodiments of the invention provided in this specification, including the following description, can be combined with each other without conflict.

[0060] Furthermore, the embodiments of the inventions provided in this specification mentioned below are generally only a portion of the embodiments of the inventions provided in this specification, and not all of them. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the inventions provided in this specification without creative effort should fall within the scope of protection of the embodiments of the inventions provided in this specification.

[0061] Terms and units in the embodiments of the application provided in the specification: the terms "include", "contain", "have" and any variants thereof in the specification and claims and related parts of the embodiments of the application provided in the specification are intended to cover non-exclusive inclusion. In addition, other related terms and units in the embodiments of the application provided in the specification can be reasonably interpreted based on the related content of the embodiments of the application provided in the specification.

[0062] The embodiment of the bamboo activated carbon production method of the utility model discloses a step comprising:

[0063] Drying treatment: put the fresh bamboo raw material into the oven and dry for 48 hours at 100 DEG C.

[0064] First carbonization treatment: put the dried bamboo raw material into the carbonization furnace, under inert atmosphere, the furnace temperature is raised from room temperature to 200 DEG C, and the temperature is kept for 1 hour;Continue to heat to 350 DEG C, keep for 1 hour;Continue to heat to 550 DEG C, keep for 1 hour, and then cool down with the furnace to obtain carbonized material.

[0065] Second carbonization treatment: grind the first carbonized material to a particle size of 325 mesh, then use molasses as adhesive, water as auxiliary agent, and the mass ratio of molasses to first carbonized material is 0.5, and 30ml of auxiliary agent is added for every 100g of first carbonized material, and the mixture is granulated into green body in the kneader, and then the green body is put into the carbonization furnace, under inert atmosphere, the furnace temperature is raised from room temperature to 550 DEG C, and the temperature is kept for 1 hour, and then cooled down with the furnace to obtain second carbonized material.

[0066] Activation treatment: put the second carbonized material into the activation furnace, under inert atmosphere, use water vapor as activator, the volume of liquid water per 100g of green body per hour is 40ml, and then cool down with the furnace after keeping at 1000 DEG C for 3 hours to obtain bamboo activated carbon.

[0067] In the carbonization tail gas, the yield of H2 is less than that of CO, usually, the volume fraction of CO is about 10-30%, the volume fraction of H2 is about 1.5-8%, and the volume fraction of CO2 is about 10-25%. But in the activation process, water vapor reacts with carbon to generate H2 and CO, and CO can further react with water vapor to generate CO2 and H2, so in the activation tail gas, CO2 and H2 are the main components, and the content of CO is relatively small. Therefore, the carbonization tail gas and the activation tail gas can be used together, which can reduce the yield difference of CO and H2, and make CO and H2 more suitable for reaction to generate methanol.

[0068] The utilization method of the bamboo activated carbon production tail gas is used for utilizing the production tail gas generated by the bamboo activated carbon production method, and the production tail gas 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.

[0069] The first embodiment of the utilization method of the bamboo activated carbon production tail gas includes the following steps:

[0070] The first tail gas is subjected to condensation treatment to obtain first non-condensable gas and condensate. The second tail gas and the third tail gas are subjected to condensation treatment to obtain second non-condensable gas. Through the condensation treatment, water vapor, organic vapor and some low-boiling-point acidic gases are mainly removed. The condensation of the first tail gas alone can enrich the organic vapor in the first tail gas at a high concentration, which is helpful for the recovery and preparation of biomass oil.

[0071] The mixed gas composed of the first non-condensable gas and the second non-condensable gas is subjected to purification treatment to obtain reaction gas; the purification treatment includes deacidification treatment, dust removal treatment and adsorption treatment in sequence; wherein the deacidification treatment adopts dry deacidification, that is, spraying solid absorbent for deacidification, so that the residual acidic gas in the mixed gas can be removed through the deacidification treatment and dry low-acid gas can be obtained, avoiding the influence of wet deacidification on the methanol synthesis reaction caused by introducing more water vapor; 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 mixed gas, but also remove the deacidification agent used in the deacidification treatment. Through the adsorption treatment, the volatile organic compounds in the mixed gas can be adsorbed, and the activated carbon is preferably used as the adsorbent. Thus, through the purification treatment, the particulate impurities, volatile organic compounds and residual acidic gas can be removed, and the reaction gas obtained after the purification treatment of the mixed gas is mainly composed of CO2, CO and H2O, the volume fraction content of water vapor is 2-5%, the COD content is ≤5ppm, the volatile organic compound content is ≤3ppm, the acidic gas content is ≤2ppm, and the particulate matter content is ≤20mg / Nm 3 .

[0072] The reaction gas is introduced into the reaction equipment loaded with the catalyst to perform catalytic reaction to generate synthesis gas containing methanol.

[0073] The second embodiment of the utilization method of the bamboo activated carbon production tail gas is that, on the basis of the first embodiment, H2 is further introduced into the reaction equipment.

[0074] The third embodiment of the utilization method of the bamboo activated carbon production tail gas is that, on the basis of the second embodiment, CO2 is removed from the production tail gas (reaction gas) by using a CO2 selective separation membrane before the catalytic reaction.

[0075] Figure 1Structure diagram of the first embodiment of the bamboo activated carbon production system and the utilization system of the bamboo activated carbon production tail gas. As shown in Figure 1 The bamboo activated 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.

[0076] The first embodiment of the utilization system of the bamboo activated carbon production tail gas includes a first condensing device 210, a second condensing device 220, a deacidification device 230, a dust removal device 240, an adsorption device 250, and a reaction device 260.

[0077] The first condensing device 210 condenses the first tail gas to obtain first non-condensable gas and condensate. The second condensing device 220 condenses the second tail gas and the third tail gas to obtain second non-condensable gas. The deacidification device 230 deacidifies the mixed gas composed of the first non-condensable gas and the second non-condensable gas to obtain low-acid gas; the gas inlet of the deacidification device 230 is connected with the gas outlets of the first condensing device 210 and the second condensing device 220, and the deacidification device 230 is a dry deacidification tower. The dust removal device 240 removes dust from the low-acid gas to obtain low-dust gas; the gas inlet of the dust removal device 240 is connected with the gas outlet of the deacidification device 230, and the dust removal device 240 is a filter with a porous metal filter core. The adsorption device 250 adsorbs the low-dust gas to obtain reaction gas; the gas inlet of the adsorption device 250 is connected with the gas outlet of the dust removal device 240, and the adsorption device 250 is provided with an activated carbon packing structure. The reaction device 260 is provided with a catalyst packing structure, and the reaction gas and H2 react in the reaction device 260 to obtain synthesis gas containing methanol after being catalyzed by the catalyst; the gas inlet of the reaction device 260 is connected with the gas outlet of the adsorption device 250 and a hydrogen gas conveying device.

[0078] The volume fraction of H2 is slightly higher than twice the volume fraction of CO, which will facilitate the methanol synthesis reaction, so by supplementing H2 in the reaction gas treated by the adsorption device 250, the synthesis reaction can be promoted to generate methanol.

[0079] Figure 2 Structure diagram of the second embodiment of the bamboo activated carbon production system and the utilization system of the bamboo activated carbon production tail gas. As shown in Figure 2As shown, compared to the first embodiment, the system in the second embodiment further includes a third condensation device 270 and a distillation device 280. The third condensation device 270 condenses the synthesis gas to output liquid methanol, and its inlet is connected to the outlet of the reaction device 260. The distillation device 280 distills the liquid methanol to output high-purity methanol, and its inlet is connected to the outlet of the third condensation device 270.

[0080] Figure 3 This is a schematic diagram of the third embodiment of a bamboo activated carbon production system and a bamboo activated carbon production tail gas utilization system. Figure 3 As shown, compared with the first embodiment, the third embodiment further includes a separation device 290 for removing CO2 from the reaction gas. The inlet of the separation device 290 is connected to the outlet of the adsorption device 250, and the outlet of the separation device 290 is connected to the inlet of the reaction device 260. The separation device 290 is a membrane separation device loaded with a CO2 selective separation membrane, which is any one of a polyetherimide membrane, a polyamide membrane, or a carbon membrane.

[0081] A suitable amount of CO2 helps maintain catalyst activity, but too much will reduce methanol selectivity. Therefore, removing some of the CO2 from the reaction gas using separation equipment 290, so that the volume fraction of CO2 in the treated reaction gas is 2-8%, can effectively promote the methanol synthesis reaction.

[0082] The catalyst in the reaction apparatus has a multilayer 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. Its preparation method includes the following steps:

[0083] Preparation of Fe3O4 core by coprecipitation: Using FeCl3·6H2O, FeCl2·4H2O and ammonia as raw materials, under nitrogen protection, equal volumes of Fe... 3+ Solution and Fe 2+ Solution mixing, Fe 3+ and Fe 2+ The molar ratio was 2:1; the mixture was heated to 80°C, and ammonia was added to the mixture at a stirring speed of 500 rpm until the pH was 10-11; after continuing the reaction for 30 minutes, magnetic separation was performed, and the collected solid was washed three times with deionized water and ethanol, and then vacuum dried at 60°C for 12 hours to obtain the Fe3O4 core.

[0084] Hydrothermal preparation of CeO2 inner layer: Ce(NO3)3·6H2O and urea are dissolved in water, Ce... 3+The concentration of Fe3O4 was 0.05M, and the concentration of urea was 0.5M. 1g of Fe3O4 core was dispersed in 150mL of the above solution, transferred to a hydrothermal reactor, and reacted at 180℃ for 12 hours. After cooling to room temperature, it was centrifuged. The collected solid was washed three times with water and ethanol, dried at 60℃ for 12 hours, and then calcined at 350℃ for 2 hours, that is, CeO2 inner layer was coated on the surface of Fe3O4 core to obtain CeO2@Fe3O4.

[0085] Preparation of Cu-Zn alloy interlayer by chemical reduction method: Cu(NO3)2·3H2O and Zn(NO3)2·6H2O are dissolved in water, Cu 2+ The concentration is 0.1M, Zn 2+ The concentration was 0.05M; 0.8g CeO2@Fe3O4 was dispersed in 100mL of the above solution and sonicated for 30 minutes; NaBH4 solution (concentration 0.2M) was slowly added dropwise in an ice bath until a precipitate was formed; then, after stirring at room temperature for 2 hours, the solid was centrifuged and the collected solid was washed three times with water and ethanol and dried under vacuum at 50℃ for 8 hours, that is, a Cu-Zn alloy intermediate layer was deposited on the surface of the CeO2 inner layer to obtain Cu-Zn@CeO2@Fe3O4.

[0086] 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; a small amount of water (water / Zr molar ratio = 2) and 0.6g Cu-Zn@CeO2@Fe3O4 were added to 100mL of the above solution and stirred at room temperature for 4 hours; then refluxed at 60℃ for 2 hours and centrifuged, dried at 80℃ for 12 hours, and then calcined at 450℃ for 3 hours, that is, a ZrO2 outer layer was coated on the surface of the Cu-Zn alloy intermediate layer to obtain ZrO2@Cu-Zn@CeO2@Fe3O4.

[0087] 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.

[0088] Calcination treatment: GQDs@ZrO2@Cu-Zn@CeO2@Fe3O4 was calcined in air at 450℃ for 4 hours to obtain the precursor.

[0089] Reduction treatment: the precursor is reduced at 350℃ for 2 hours in a mixed gas atmosphere of N2 and H2 (volume fraction of H2 is 10%), to obtain the catalyst.

[0090] The prepared catalyst has a multi-layer structure and each structural layer has excellent performance. The Fe3O4 core facilitates magnetic separation and recovery of the catalyst, the CeO2 inner layer can provide high oxygen storage capacity and oxygen vacancies to promote the reaction, the Cu-Zn alloy intermediate layer provides the main catalytic active site, the ZrO2 outer layer can enhance the stability and sintering resistance of the catalyst, and the graphene quantum dot surface layer can enhance electron transfer and improve catalytic activity. Through the synergistic effect of each structural layer, the catalyst has high catalytic activity and can promote the reaction of CO and H2 at a lower temperature, thereby improving the catalytic reaction efficiency. The preparation method is simple, and the reaction activity and stability of the obtained catalyst are strong, which helps to improve the stability of the synthesis gas production process and reduce the update frequency of the catalyst, thereby saving long-term operating costs. The effective conversion of the tail gas produced in the production of bamboo activated carbon by catalytic reaction technology is an innovative green chemical process, which meets the global trend of promoting green production and reducing carbon emissions, and has a significant promotional effect on the development and application of bamboo resources.

[0091] The multi-layer structure catalyst is used for catalysis of the reaction gas (one embodiment data: 25.41% CO, 3.05% CO2, 26.21% H2, 2.45% steam, and the balance is N2) treated by the separation device 290. The volume ratio of the reaction gas to the supplemented H2 is (4.05-4.5):1, the reaction temperature is 240℃ (220-300℃ are all available), the reaction pressure is 4MPa (3-10MPa are all available), the space velocity is 6000h-1 (3000-10000h-1 are all available), and the space time yield of liquid methanol is 0.2-0.6 kg / (L catalyst·h), and the purity of the liquid methanol is more than 95%. -1 (3000-10000h -1 are all available), and the space time yield of liquid methanol is 0.2-0.6 kg / (L catalyst·h), and the purity of the liquid methanol is more than 95%.

[0092] The condensate obtained after condensation of the carbonization tail gas contains a large amount of organic matter, which can be condensed into bio-oil with high calorific value. In order to deeply recover the valuable resources of the production tail gas, the utilization method of the bamboo activated carbon production tail gas of the utility model further utilizes the condensate recovered by the condensation device. Based on the third embodiment, the fourth embodiment further includes the following steps:

[0093] The condensate obtained by condensing the first tail gas is subjected to solid-liquid separation treatment to obtain a permeate. The solid-liquid separation treatment is filtration treatment or centrifugal separation treatment, so that the particulate impurities captured by liquid droplets in the condensation process can be removed.

[0094] The permeate is subjected to membrane separation treatment by using a nanofiltration membrane to obtain an oily liquid; preferably, the membrane separation treatment is vacuum filtration treatment of the permeate, the vacuum degree is 100 mmHg, the temperature is 40°C, and the pore size of the nanofiltration membrane is 5 nm. In this way, the nanofiltration membrane can make water pass through, while most of the organic matter is effectively intercepted, so that most of the organic matter is enriched in the oily liquid.

[0095] The oily liquid is subjected to extraction treatment by using an extractant to obtain an extractant-soluble liquid; preferably, the extractant is ethanol and / or acetone; and the volume of the extractant is 2 times the volume of the condensed liquid.

[0096] The extractant-soluble liquid is subjected to vacuum distillation treatment at 50°C and 16 kPa to obtain a biomass oil. Through the vacuum distillation treatment, the extractant can be evaporated and condensed, and the condensate obtained by the vacuum distillation treatment can be repeatedly used for the extraction treatment of the oily liquid, so that the utilization rate of the extractant can be improved.

[0097] Different from the fourth embodiment, the fifth embodiment of the method for utilizing the tail gas produced in the production of bamboo activated carbon is as follows:

[0098] The condensate obtained by condensing the first tail gas is subjected to solid-liquid separation treatment to obtain a permeate; the solid-liquid separation treatment is filtration treatment or centrifugal separation treatment, so that the particulate impurities captured by liquid droplets in the condensation process can be removed.

[0099] The permeate is subjected to extraction treatment by using an extractant to obtain a first extractant-soluble liquid.

[0100] The first extractant-soluble liquid is subjected to vacuum distillation treatment at 35°C and 16 kPa to obtain a distillate; through the vacuum distillation treatment, the extractant can be evaporated and condensed, and the condensate obtained by the vacuum distillation treatment can be repeatedly used for the extraction treatment of the permeate, so that the utilization rate of the extractant can be improved.

[0101] The distillate is subjected to extraction treatment by using an extractant and water to obtain a second extractant-soluble liquid; preferably, in specific implementation, stirring is maintained, the extractant is first added dropwise, stirring is maintained for 15 minutes after the addition of the extractant is completed, then water is added dropwise, stirring is continued for 30 minutes after the addition of the water is completed, then the system is sealed and left standing for 48 hours, and finally the second extractant-soluble liquid is obtained through phase separation.

[0102] The second extractant-soluble liquid is subjected to vacuum distillation treatment at 35°C and 16 kPa to obtain a biomass oil. Through the vacuum distillation treatment, the extractant can be evaporated and condensed, and the condensate obtained by the vacuum distillation treatment can be repeatedly used for the extraction treatment of the permeate, so that the utilization rate of the extractant can be improved.

[0103] The extraction agent is dichloromethane; preferably, the volume of the extraction agent is 2 times the volume of the permeate or the first biomass oil; the volume of water is 1.5 times the volume of the first biomass oil.

[0104] The second embodiment of the method for utilizing the tail gas produced in the production of bamboo activated carbon is: on the basis of the first embodiment, the biomass oil is distilled into a solid at 200-250°C (preferably 235°C) under normal pressure, and the method further comprises crushing, grinding and vacuum drying the solid, thereby obtaining a solid biomass oil.

[0105] In the fourth and fifth embodiments, the biomass oil can be further distilled into a solid or a concentrated liquid at 200-250°C under normal pressure. For the solid, the solid is crushed, ground and vacuum dried, thereby obtaining a solid biomass oil; for the concentrated liquid, the concentrated liquid is hydrotreated, comprising the steps of: preparing a reaction solution according to the mass ratio of biomass oil:methanol: catalyst = 20:25:1, hydrothermally reacting at 190°C under 1 MPa hydrogen pressure for 3h, thereby obtaining a refined biomass oil; using an activated carbon-based Ni / BC catalyst, the preparation method of which is: dispersing 0.5g of nickel nitrate and 1g of activated carbon in ethanol, stirring for 5h; after rotary evaporation at 80°C until the ethanol solvent is completely removed, drying in a vacuum oven; using 20% H2-Ar as a reducing atmosphere, calcining at 550°C for 2h, thereby obtaining the activated carbon-based Ni / BC catalyst.

[0106] The above describes the relevant content of the embodiments of the invention provided in the specification. A person of ordinary skill in the art will be able to implement the embodiments of the invention provided in the specification based on these descriptions. Based on the above content of the embodiments of the invention provided in the specification, all other preferred embodiments and examples obtained by a person of ordinary skill in the art without creative labor shall belong to the scope of protection of the embodiments of the invention provided in the 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: The first condensation device (210) condenses the first tail gas to obtain the first non-condensable gas and condensate. The second condensing device (220) condenses the second tail gas and the third tail gas to obtain the second non-condensable gas; A deacidification device (230) is used to deacidify a mixture of a first non-condensable gas and a second non-condensable gas to obtain low-acid gas; the inlet of the deacidification device (230) is connected to the outlet of a first condensing device (210) and a second condensing device (220). A dust removal device (240) is used to remove dust from low-acid gas to obtain low-dust gas; the inlet of the dust removal device (240) is connected to the outlet of the deacidification device (230); An adsorption device (250) is used to adsorb low-dust gas to obtain a reaction gas; the inlet of the adsorption device (250) is connected to the outlet of the dust removal device (240). The reaction device (260) is equipped with a catalyst packing structure. The reaction gas is catalyzed by the catalyst in the reaction device (260) to obtain synthesis gas containing methanol. The gas inlet of the reaction device (260) is connected to the gas outlet of the adsorption device (250).

2. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The dust removal equipment (240) is a filter that uses a porous metal filter element.

3. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The deacidification equipment (230) is a dry deacidification tower.

4. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: The adsorption device (250) is equipped with an activated carbon packing structure.

5. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: It also includes a separation device (290) for removing CO2 from the reaction gas, the inlet of which is connected to the outlet of the adsorption device (250), and the outlet of which is connected to the inlet of the reaction device (260).

6. The system for utilizing tail gas from bamboo activated carbon production as described in claim 5, characterized in that: The separation device (290) is a membrane separation device (290) loaded with a CO2 selective separation membrane, wherein the CO2 selective separation membrane is any one of polyetherimide membrane, polyamide membrane, and carbon membrane.

7. The system for utilizing exhaust gas from bamboo activated carbon production as described in claim 1, characterized in that: It also includes a hydrogen delivery device for feeding H2 into the reaction apparatus (260).

8. The system for utilizing tail gas from bamboo activated carbon production as described in claim 1, characterized in that: Also includes: The third condensing device (270) condenses the synthesis gas and outputs liquid methanol; the inlet of the third condensing device (270) is connected to the outlet of the reaction device (260). A distillation apparatus (280) is used to distill liquid methanol to output high-purity methanol; the inlet of the distillation apparatus (280) is connected to the outlet of the third condenser (270).

9. 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 after carbonization, 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 1-8, 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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