Biogas carbon sequestration hydrogen production simulation device based on biochar catalytic action and test method

Abstract

The invention discloses a biogas carbon sequestration hydrogen production simulation device based on biochar catalytic action and a test method. The biogas carbon sequestration hydrogen production simulation device comprises a gas preparation and conveying system, a reaction and temperature control system and a product treatment and analysis system which are connected in sequence, the gas preparation and conveying system comprises a CH4 gas cylinder, a first flow regulator and a mixed gas tank which are sequentially connected through a guide pipe, and a CO2 gas cylinder and a second flow regulator which are sequentially connected through a guide pipe and are connected with the mixed gas tank. According to the biogas carbon sequestration hydrogen production simulation device based on the biochar catalytic action and the test method, the biogas is converted into H2 and the carbon nanomaterial by utilizing a biogas chemical vapor deposition process, the H2 can be stored as clean energy, and the carbon nanomaterial is widely applied in multiple fields due to unique physical, chemical and mechanical energy, so that the biochar catalytic action-based biogas carbon sequestration hydrogen production simulation device can be widely applied to various fields. The problem of high emission of CO2 in the traditional anaerobic digestion and biogas treatment process is solved, meanwhile, carbon recycling is achieved, and high economic value is shown.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental engineering and sustainable technology, in particular to a biogas carbon sequestration hydrogen production simulation device based on the catalysis of biochar and a test method. BACKGROUND

[0002] In the process of sewage treatment, anaerobic digestion treatment technology is one of the most commonly used methods in sewage treatment because it can convert organic pollutants into biogas and has low equipment operation cost. In actual application, due to the high uncertainty of sewage quality, the energy density of biogas in sewage treatment plants is low, and it cannot be used as energy storage. At present, most sewage treatment plants will burn biogas through a flare to produce steam or hot water, which is used to maintain the temperature of the anaerobic digestion tank or to heat the plant area. The CO2 after combustion is not specially treated and is directly discharged into the atmosphere. However, the base number of sewage treatment plants in China is large, and the traditional biogas treatment method will result in a high CO2 emission, which will undoubtedly exacerbate the greenhouse effect. How to optimize the anaerobic digestion technology to reduce the carbon emission generated in the process of sewage treatment has become a problem to be solved.

[0003] Through catalytic reaction, biogas is converted into H2 (clean energy) and carbon nanomaterials (high value-added products), avoiding the problem of carbon emission while realizing "carbon resourceization", which is a feasible idea in the current research that conforms to the concept of circular economy. There are mainly two types of catalysts that can realize the conversion of biogas to H2 in the existing research: metal catalysts and carbon-based catalysts. Transition metals (Group VIII) usually use metal oxides as carriers to realize the decomposition of biogas, and are widely used. However, the carbon particles produced in the process of biogas conversion to H2 will adhere and accumulate on the surface of the metal catalyst, seriously affecting the activity of the metal catalyst and even leading to the complete deactivation of the catalyst. In the process of decomposing biogas, the metal catalyst under high temperature conditions is easy to sinter and deactivate, which cannot be recycled, greatly increasing the treatment cost. In addition, the metal catalyst has the potential risk of metal pollution to the carbon nanomaterials produced in the conversion process. In contrast, carbon-based catalysts have higher thermal stability and anti-inactivation ability, and have specific surface area, micropore volume, oxygen-containing functional groups (R-COOH, R-OH, R-OCO, R=O), fine and dispersed particle size structure, etc. as the advantages of catalyst materials. In the process of biogas conversion reaction, the produced carbon nanomaterials do not need to be separated from the carbon-based catalyst materials, and even it is beneficial to improve the purity of the produced carbon nanomaterials, avoiding the defects of metal catalysts.

[0004] At present, the research on biocarbon catalytic biogas decomposition is very limited, the mechanism of biocarbon hydrogen production is not clear, and the hydrogen production performance has high uncertainty. According to the previous research, the raw material properties and production method of carbon-based catalysts will affect their performance in the biogas conversion process, which limits the promotion and application of biocarbon catalytic biogas hydrogen production process in practice. Therefore, it is necessary to invent a device to study the influence of biocarbon catalysis on biogas carbon fixation and hydrogen production, to explore the influence mechanism of biocarbon raw material properties and preparation conditions on catalysis in the hydrogen production process, and to realize low-cost and large-scale green production of biogas hydrogen production. SUMMARY

[0005] The purpose of the present application is to provide a biogas carbon fixation and hydrogen production simulation device based on biocarbon catalysis, which solves the problem of optimizing biocarbon catalyst selection and hydrogen production process, realizing efficient and low-cost conversion of biogas to H2 and carbon nanomaterials, directly reducing CO2 emissions, and improving the economic efficiency and sustainable development ability of biogas utilization.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a biogas carbon fixation and hydrogen production simulation device based on biocarbon catalysis, comprising a gas preparation and delivery system, a reaction and temperature control system and a product processing and analysis system connected in sequence; The gas preparation and delivery system comprises a CH4 gas cylinder and a first flow regulator connected in sequence through a conduit and connected with a mixed gas tank, a CO2 gas cylinder and a second flow regulator connected in sequence through a conduit and connected with the mixed gas tank, and the outlet end of the mixed gas tank is connected with a third flow regulator through a conduit. The gas preparation and delivery system is used to prepare CH4 and CO2 mixed gas with a specific ratio and control its input flow; The reaction and temperature control system comprises a reaction furnace, a spiral pipe-shaped fluidized bed reactor arranged in the reaction furnace, and a temperature table for monitoring the temperature in the furnace. The spiral pipe-shaped fluidized bed reactor is filled with biocarbon catalyst, and its gas inlet is connected with the third flow regulator through a conduit; The product processing and analysis system comprises a dust filter, a three-way valve and a gas chromatograph connected in sequence through a conduit. The gas inlet of the dust filter is connected with the gas outlet of the reaction furnace, and the three-way valve is used to selectively guide the gas to the exhaust port or the gas chromatograph Preferably, the spiral pipe-shaped fluidized bed reactor is made of quartz material, with an inner diameter of 30mm and a vertical length of 800mm Preferably, the top or side wall of the reaction furnace is provided with an exhaust hole for balancing the internal pressure Preferably, the method comprises the following steps: Step 1: preparing biochar catalysts of different sources and pyrolysis conditions; Step 2: loading a predetermined mass of the biochar catalyst into the spiral tubular fluidized bed reactor, and heating the reaction furnace to a predetermined reaction temperature; Step 3: preparing a mixed gas of CH4 and CO2 with a predetermined volume ratio by the gas preparation and delivery system, and feeding it into the reaction and temperature control system at a predetermined flow rate; Step 4: in the reaction and temperature control system, the mixed gas is subjected to chemical vapor deposition reaction under the catalysis of the biochar catalyst to generate a gas product containing H2 and a solid-phase carbon material; Step 5: filtering and periodically analyzing the gas product by the product processing and analysis system, and ending a single test when the gas chromatograph detects that the concentration of the gas components is stable 5. The biocatalytic methane carbon sequestration hydrogen production simulation device and test method according to claim 1, wherein in the step of preparing biochar catalysts, the biomass raw material is selected from at least one of straw, sawdust, coconut shell and animal bone; and the biomass raw material is pyrolyzed at a temperature of 600℃, 700℃ or 800℃ for 3h, 5h or 8h after pretreatment to prepare biochar with different characteristics.

[0007] Preferably, the mass of the biochar catalyst is 5g, 10g or 15g.

[0008] Preferably, in the step of heating the reaction furnace, the predetermined reaction temperature is 600℃, 700℃ or 800℃.

[0009] Preferably, in the step of preparing a mixed gas, the volume ratio of CO2 is 30%, 40% or 50%.

[0010] Preferably, in the step of performing chemical vapor deposition reaction, the injection flow rate of the mixed gas is 50ml / min, and the gas product is sampled and analyzed by the gas chromatograph every 20 minutes.

[0011] Preferably, the test method further comprises: after completing the first chemical vapor deposition test, without replacing the biochar catalyst, performing a second chemical vapor deposition test under the same conditions to explore the effect of deposited carbon wrapping on the performance of the catalyst.

[0012] Compared with the prior art, the present application has the following advantages: 1. The biocarbon catalysis-based biogas carbon fixation hydrogen production simulation device and test method utilizes the biogas chemical weathering deposition process to convert biogas into H2 and carbon nanomaterials, wherein H2 can be used as clean energy reserves, and carbon nanomaterials are widely used in various fields due to their unique physical, chemical, and mechanical energy, solving the problem of high CO2 emission in traditional anaerobic digestion and biogas treatment processes, realizing carbon resourceization, and exhibiting high economic value; 2. The biocarbon catalysis-based biogas carbon fixation hydrogen production simulation device and test method introduces biocarbon into the biogas decomposition process, and the carbon-based catalyst has high thermal stability and anti-inactivation ability, overcoming the problems of traditional metal catalysts, such as easy sintering and easy sintering, and the biocarbon catalyst can be recycled, which has high economic benefits and avoids the potential metal pollution risk of metal catalysts to the generated carbon materials; 3. The biocarbon catalysis-based biogas carbon fixation hydrogen production simulation device and test method introduces biocarbon into the biogas decomposition process, and the biocarbon material can be obtained from waste biomass, which can realize waste treatment and recycling, and the synthesis method is simple, compared with most carbon material synthesis processes which are complex and require materials from fossil resources, biocarbon material can realize large-scale green production, which has high economic feasibility and great development prospects. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The structure of the biocarbon catalysis-based biogas carbon fixation hydrogen production simulation device of the present application is shown in the figure.

[0014] In the figure: A, gas preparation and delivery system; B, reaction and temperature control system; C, product treatment and analysis system; 1, CH4 gas cylinder; 2, first flow regulator; 3, CO2 gas cylinder; 4, second flow regulator; 5, mixed gas tank; 6, third flow regulator; 7, conduit; 8, reaction furnace; 9, spiral tube fluidized bed reactor; 10, temperature gauge; 11, dust filter; 12, three-way valve; 13, gas chromatograph. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] Please refer to Figure 1The application provides a technical scheme: a biogas carbon fixation and hydrogen production simulation device based on the catalysis of biochar, which comprises a gas preparation and delivery system A, a reaction and temperature control system B and a product processing and analysis system C connected in sequence. The gas preparation and delivery system A comprises a CH4 gas cylinder 1 and a first flow regulator 2 connected in sequence through a conduit 7 and connected with a mixed gas tank 5, a CO2 gas cylinder 3 and a second flow regulator 4 connected in sequence through a conduit 7 and connected with the mixed gas tank 5, and an outlet end of the mixed gas tank 5 connected with a third flow regulator 6 through a conduit 7, and the gas preparation and delivery system A is used for preparing CH4 and CO2 mixed gas with a specific ratio and controlling the input flow thereof. The reaction and temperature control system B comprises a reaction furnace 8, a spiral pipe-shaped fluidized bed reactor 9 arranged in the reaction furnace 8 and a thermometer 10 for monitoring the temperature in the furnace, the spiral pipe-shaped fluidized bed reactor 9 is filled with a biochar catalyst, the spiral pipe-shaped fluidized bed reactor 9 is made of quartz, has an inner diameter of 30 mm and a vertical length of 800 mm, and an air inlet thereof is connected with the third flow regulator 6 through a conduit 7. The product processing and analysis system C comprises a dust filter 11, a three-way valve 12 and a gas chromatograph 13 connected in sequence through a conduit 7, an air inlet of the dust filter 11 is connected with an air outlet of the reaction furnace 8, an exhaust hole for balancing the internal pressure is arranged at the top or the side wall of the reaction furnace 8, and the three-way valve 12 is used for selectively guiding the gas to the exhaust hole or the gas chromatograph 13.

[0017] A test method of a biogas carbon fixation and hydrogen production simulation device based on the catalysis of biochar, which explores the influence mechanism of biochar on the process of biogas carbon fixation and hydrogen production by controlling the type, quality, biogas composition, reaction temperature and other conditions of the biochar catalyst. The test device is composed of a gas preparation and delivery system, a reaction and temperature control system and a product processing and analysis system. The test method comprises the following steps: 1. Prepare biochar materials, select and pretreat raw materials: select four kinds of raw materials of straw, sawdust, coconut shell and animal bone. For plant raw materials (straw, sawdust and coconut shell), after being crushed and sieved, they are air-dried and ground into powder; for animal raw materials (animal bone), after being defatted and deproteinized, they are air-dried and ground into powder. All raw materials are ground to a particle size of 100-200 μm.

[0018] Pyrolysis preparation: the pretreated bio-solid material is placed in a muffle furnace to be pyrolyzed at high temperature to prepare biochar. Three groups of preparation temperatures (600℃, 700℃ and 800℃) are set, and for the same temperature, three groups of heating times (3h, 5h and 8h) are set. After heating, the biochar is naturally cooled to room temperature, collected and stored in a desiccator for subsequent test analysis and test. A total of 36 groups of different types of biochar are prepared.

[0019] Characterization analysis: The surface microstructure of biochar was characterized by scanning electron microscopy (SEM), microscopy, X-ray diffraction spectroscopy, Raman spectroscopy and other technical means. The surface morphology images, diffraction patterns and Raman spectra were recorded and analyzed to evaluate the surface particle distribution, pore structure, crystal phase composition, graphitization degree and carbon material order degree.

[0020] 2. Test preparation Device lapping: The lapping work of the gas preparation and delivery system, the reaction and temperature control system, and the product processing and analysis system was completed. Ensure that all the conduits are tightly connected and there is no leakage.

[0021] Biochar loading: A certain mass (5g, 10g or 15g) of pre-prepared biochar catalyst was loaded into a spiral pipe-shaped fluidized bed reactor (quartz material, inner diameter 30mm, vertical length 800mm). By setting different mass, the influence mechanism of biochar mass on biogas decomposition for hydrogen production was explored.

[0022] Air exclusion: The entire test device was filled with helium (He) to exclude air in the gas tank, conduit and reactor, avoiding interference with the reaction.

[0023] Temperature setting: Turn on the heating power of the reaction furnace and monitor the temperature in the furnace in real time. Set three different reaction temperatures (600℃, 700℃ and 800℃), heat the reaction furnace to the target temperature, and keep the temperature constant during the test to explore the influence of temperature on the catalytic performance of biochar.

[0024] 3. Preparation of artificial synthetic biogas, including gas ratio setting and gas mixing, where the gas ratio setting is: to explore the influence of biogas composition on the decomposition process for hydrogen production, and the influence of CH4 and CO2 volume ratio on the chemical reaction rate and H2 conversion efficiency, three CO2 ratios (30%, 40% and 50%) are set. Correspondingly, the CH4 ratio is 70%, 60% and 50% respectively. Gas mixing: connect the flow regulator power, set the target flow rate of CH4 and CO2 gas input on the control panel of the flow regulator. Open the CH4 cylinder and CO2 cylinder outlet valve, start the flow regulator, and make CH4 and CO2 input into the mixing gas tank through the conduit at the set flow rate, and mix well to form artificial synthetic biogas.

[0025] 4. Carry out the first biogas chemical vapor deposition test, including; Start the reaction: Set the biogas injection flow rate to 50ml / min in the flow regulator at the outlet of the mixing gas tank. Open the mixing gas tank outlet valve, start the flow regulator, and make the artificial synthetic biogas continuously inject into the spiral pipe-shaped fluidized bed reactor in the reaction furnace at the target flow rate.

[0026] Gas monitoring: The mixed gas was sampled and detected every 20 min interval by gas chromatograph, and the single sampling volume was 0.5 ml. During the detection, the three-way valve was adjusted to open to the side of the gas chromatograph, so that the mixed gas entered the gas chromatograph after being filtered by the dust filter. The H2, CH4 and CO2 concentration results output by the gas chromatograph were recorded. When the concentration of each component gas remained stable, the test was marked as the end. The catalytic performance of different biochar catalysts under different conditions was compared by the stable time.

[0027] Sampling and characterization: After the test, the heating power, gas cylinder valve and flow regulator were closed, and the device was naturally cooled to room temperature. The biochar material in the spiral pipe fluidized bed reactor was sampled in situ using a micro-sampler (the sampling position was selected at the center of the gas inlet cross section at the lower end of the fluidized bed reactor, and the single sampling mass was 0.2 g, which was less than 5% of the total mass). The surface microstructure of the biochar was characterized again by scanning electron microscopy, microscopy, X-ray diffraction spectrum analysis, Raman spectrum analysis and other technical means. The changes of the surface characteristics of the biochar before and after the first test were recorded and compared.

[0028] 5. The second methane chemical vapor deposition test was carried out, including the following steps; Repeat the test: The test device was filled with helium again to exclude the residual gas of the first test. The test conditions were set, including the mass of biochar, the composition of biogas, the reaction temperature, etc., and the operation process was consistent with the first test. The methane chemical vapor deposition test was repeated.

[0029] Gas monitoring and end condition: When the gas chromatograph detected that the H2, CH4 and CO2 concentration results remained stable, the test was ended. The results of the two tests were recorded and compared.

[0030] Sampling and characterization: The biochar material after the test was sampled, and the surface microstructure was characterized by scanning electron microscopy, microscopy, X-ray diffraction spectrum analysis, Raman spectrum analysis and other technical means. The changes of the surface characteristics of the biochar catalyst before and after the first test and after the second test were recorded and compared.

[0031] 6. Comparison and analysis of test results Data analysis: By comparing the stable time, CH4 and CO2 conversion rate, H2 yield and the change of gas concentration with time of the two tests, the order of CH4 and CO2 reaction in the process of biogas hydrogen production was analyzed.

[0032] Mechanism exploration: Based on the observation of surface microstructure, the catalytic performance of different types of biochar with different mass under different CO2 proportion and reaction temperature and the influence of deposition carbon wrapping were analyzed. The best CH4 and CO2 ratio combination of biogas conversion efficiency was identified, and the main control factors and mechanism of biochar catalysis were revealed, which provided the basis for optimizing the preparation process of biochar and the hydrogen production process of biogas.

[0033] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Modifications can be made by those skilled in the art, particularly in light of the foregoing teachings, without departing from the spirit of the present application. The present application is thus intended to cover all modifications and variations of this application which come within the scope of the following claims and their equivalents.

Claims

1. A biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar, characterized in that, The device comprises a gas preparation and delivery system (A), a reaction and temperature control system (B) and a product processing and analysis system (C) connected in sequence. The gas preparation and delivery system (A) comprises a CH4 cylinder (1) and a first flow regulator (2) connected in sequence through a conduit (7) and connected with a mixing gas tank (5), a CO2 cylinder (3) and a second flow regulator (4) connected in sequence through a conduit (7) and connected with the mixing gas tank (5), and an outlet end of the mixing gas tank (5) connected with a third flow regulator (6) through a conduit (7), and the gas preparation and delivery system (A) is used for preparing a CH4 and CO2 mixed gas with a specific ratio and controlling the input flow rate. The reaction and temperature control system (B) comprises a reaction furnace (8), a spiral pipe-shaped fluidized bed reactor (9) arranged in the reaction furnace (8), and a thermometer (10) for monitoring the temperature in the furnace, and the spiral pipe-shaped fluidized bed reactor (9) is filled with a biochar catalyst, and an air inlet of the spiral pipe-shaped fluidized bed reactor (9) is connected with the third flow regulator (6) through a conduit (7). The product processing and analysis system (C) comprises a dust filter (11), a three-way valve (12) and a gas chromatograph (13) connected in sequence through a conduit (7), an air inlet of the dust filter (11) is connected with an air outlet of the reaction furnace (8), and the three-way valve (12) is used for selectively guiding the gas to an exhaust port or the gas chromatograph (13).

2. The biogas hydrogen production and carbon sequestration simulation device based on catalysis of biochar according to claim 1, characterized in that, The spiral pipe-shaped fluidized bed reactor (9) is made of quartz, has an inner diameter of 30 mm and a vertical length of 800 mm.

3. The biogas hydrogen production and carbon sequestration simulation device based on catalysis of biochar according to claim 1, characterized in that, An exhaust hole for balancing the internal pressure is arranged on the top or the sidewall of the reaction furnace (8).

4. A test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar, characterized in that, The biogas carbon sequestration hydrogen production simulation device according to claims 1-3 comprises the following test steps: In a first step, biochar catalysts of different sources and pyrolysis conditions are prepared. In a second step, a predetermined mass of the biochar catalyst is loaded into the spiral pipe-shaped fluidized bed reactor (9), and the reaction furnace (8) is heated to a predetermined reaction temperature. In a third step, a CH4 and CO2 mixed gas with a predetermined volume ratio is prepared by the gas preparation and delivery system (A), and is introduced into the reaction and temperature control system (B) at a predetermined flow rate. In a fourth step, the mixed gas is subjected to a chemical vapor deposition reaction under the catalysis of the biochar catalyst in the reaction and temperature control system (B) to generate a gas product containing H2 and a solid-phase carbon material. In a fifth step, the gas product is filtered and periodically analyzed by the product processing and analysis system (C), and when the gas chromatograph (13) detects that the gas component concentration is stable, a single test is ended.

5. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, In the step of preparing the biochar catalyst, the biomass raw material is selected from at least one of straw, sawdust, coconut shell and animal bone, and after being pretreated, the biomass raw material is pyrolyzed at a temperature of 600℃, 700℃ or 800℃ for 3h, 5h or 8h to prepare biochar with different characteristics.

6. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, The mass of the biochar catalyst is 5g, 10g or 15g.

7. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, In the step of "heating the reaction furnace", the predetermined reaction temperature is 600℃, 700℃ or 800℃.

8. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, In the step of "preparing the mixed gas", the volume ratio of CO2 is 30%, 40% or 50%.

9. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, In the step of "carrying out the chemical vapor deposition reaction", the injection flow rate of the mixed gas is 50ml / min, and the gas products are sampled and analyzed every 20 minutes by using the gas chromatograph (13).

10. The test method of a biogas carbon sequestration hydrogen production simulation device based on catalysis of biochar according to claim 4, characterized in that, The test method further comprises: after completing the first chemical vapor deposition test, without replacing the biochar catalyst, carrying out a second chemical vapor deposition test under the same conditions to explore the influence of the deposited carbon coating on the performance of the catalyst.

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