Low-tar black particle process

Abstract

The invention discloses a low-tar black particle process, and particularly relates to the field of low-tar black particle preparation, and the specific process steps are as follows: step 1, raw material preparation; step 2, pretreatment; 3, setting a material layer and adjusting the air volume; step 4, temperature control and pyrolysis; step 5, tar conversion; step 6, mixing and particle preparation; and step 10, cost and environmental influence analysis. The three material layers including the pyrolysis area, the baking area and the adsorption area are arranged in the internal heating vertical moving bed, raw materials in the baking area are preliminarily pyrolyzed through carried heat, volatile components in steam stay in the adsorption area along with temperature reduction to form tar-containing straw, tar is directly converted into a binder needed in the granulation stage, internal recycling is achieved, and energy consumption is reduced. The produced tar does not need to be discharged and is directly reused inside, tar, smoke and pyrolytic carbon produced by straw pyrolysis / baking are reasonably utilized, and the quality improvement and utilization cost of by-products and pollution caused by transportation are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of low-tar black particle preparation, and more specifically, to a low-tar black particle process. Background Art

[0002] The low-tar black particle process is mainly based on biomass pyrolysis and carbonization technologies. Under anoxic or micro-oxic conditions, biomass raw materials (such as crop straws, wood wastes, etc.) are pyrolyzed to decompose them into gaseous, liquid, and solid products. Among them, the solid product is further carbonized to form a black particle fuel with a low tar content.

[0003] With the continuous growth of global energy demand and the increasing awareness of environmental protection, the low-tar black particle process, as a clean and efficient biomass energy conversion technology, has broad development prospects. In the prior art, tar is often transported and processed outside the furnace as a by-product, which not only increases the processing cost but also may cause environmental pollution. Tar is not effectively recycled, resulting in waste of resources. Summary of the Invention

[0004] To overcome the above defects of the prior art, the present invention provides a low-tar black particle process.

[0005] To achieve the above object, the present invention provides the following technical solution: A low-tar black particle process, and the specific process steps are as follows:

[0006] Step 1: Raw material preparation, collect and screen suitable straw raw materials;

[0007] Step 2: Pretreatment, use a crusher to crush the screened straw;

[0008] Step 3: Set the material layer and adjust the air volume, set three material layers in the pyrolysis equipment, namely a pyrolysis zone, a baking zone, and an adsorption zone, and adjust the upper and lower air suction volumes so that the steam is collected in situ by the straw in the adsorption zone and moves upward;

[0009] Step 4: Temperature control and pyrolysis, by changing the temperature of the pyrolysis zone and adjusting the lengths of the three material layers, the heat carried will preliminarily pyrolyze the raw materials in the baking zone to form tar-containing steam;

[0010] Step 5: Tar conversion, as the temperature decreases, the volatile components in the steam stay in the adsorption zone and condense into tar, which adheres to the surface of the straw to form tar-containing straw. The tar is directly converted into the binder required for the granulation stage to achieve internal recycling;

[0011] Step 6: Mixing and particle preparation, mix the straw charcoal, baked straw, and tar-containing straw produced in different regions of the internally heated moving bed pyrolysis equipment, and then use a granulation device to granulate;

[0012] Step 7: Granulation process debugging;

[0013] Step 8: Product analysis and optimization;

[0014] Step 9: Establish an evaluation model, and establish an economic and environmental impact evaluation model including technologies such as granulating straw first and then carbonizing, carbonizing straw first and then granulating, and low-tar self-heating straw baking pellet fuel;

[0015] Step 10: Cost and environmental impact analysis, compare different tar and flue gas post-treatment technologies, and quantify key indicators such as the preparation cost and carbon emission intensity of low-tar self-heating straw baking pellet fuel.

[0016] As a further improvement of the technical solution of the present invention, in Step 1, straw with moderate maturity, no pests and diseases, and no pollution is selected as the raw material, and impurities, soil, and unqualified parts are removed by manual selection or mechanical screening, and the qualified straw is retained.

[0017] As a further improvement of the technical solution of the present invention, before the straw is crushed in Step 2, the selected straw raw material needs to be cleaned, and after cleaning, it is air-dried at room temperature, and then crushed. The fineness after crushing does not exceed 1 cm.

[0018] As a further improvement of the technical solution of the present invention, in Step 4, the temperature range of the pyrolysis zone is 300°C - 500°C, the temperature range of the baking zone is 200°C - 350°C, and the temperature range of the adsorption zone is 100°C - 250°C.

[0019] As a further improvement of the technical solution of the present invention, in Step 6, the forming pressure of the granulation equipment for granulation is 10 MPa - 50 MPa, and the forming temperature is 80°C - 150°C.

[0020] As a further improvement of the technical solution of the present invention, in Step 7, the granulation process debugging is carried out under different forming temperatures and pressures to determine the optimal granulation conditions. The debugging ranges of the forming temperature and the forming pressure are 80°C - 150°C and 10 MPa - 50 MPa respectively.

[0021] As a further improvement of the technical solution of the present invention, in Step 8, product analysis and optimization is to analyze the mechanical durability, gross calorific value, energy density, water resistance, apparent morphology, proximate analysis, and combustion weight loss characteristics of the pellet fuel, and comprehensively optimize the production process parameters to ensure that the product meets the quality standards and usage requirements.

[0022] As a further improvement of the technical solution of the present invention, the steps for establishing the evaluation model in Step 9 are as follows:

[0023] S1. Clearly define the evaluation objectives. First, clearly define the objectives of the evaluation model, that is, to compare the economic efficiency and environmental impacts of different straw treatment technologies. This includes evaluations in aspects such as costs, revenues, carbon emissions, and energy efficiency;

[0024] S2. Determine the evaluation indicators. According to the evaluation objectives, determine specific evaluation indicators. Among them, the economic indicators include investment costs, operating costs, revenues, payback periods, and cost-benefit ratios; the environmental impact indicators include carbon emission intensities, energy consumption, pollutant emissions, and resource utilization efficiencies;

[0025] S3. Collect data and information. Through methods such as literature review, field research, and expert consultation, collect relevant data and information on technologies and the market. This data should include the process flows, equipment investments, raw material costs, energy consumption, carbon emission factors, etc. of various straw treatment technologies;

[0026] S4. Establish an evaluation model, including an economic model and an environmental impact model;

[0027] S5. Model operation and result analysis. Input the collected data and information into the evaluation model for operation and analysis, compare the economic efficiency and environmental impacts of different technologies, and identify the superior technologies and existing problems;

[0028] S6. Model optimization and verification. Optimize and adjust the evaluation model based on the operation results and analysis.

[0029] Among them, in the economic model, the investment costs consider expenses such as equipment purchase, installation and commissioning, land leasing or purchase, and infrastructure construction; the operating costs include raw material costs, energy consumption, labor costs, maintenance costs, etc.; the revenue is calculated based on the market price and sales volume of the product; the payback period and cost-benefit ratio are calculated based on the investment costs, operating costs, and revenue.

[0030] Among them, in the environmental impact model, the carbon emission intensity is calculated based on the carbon emission factors and energy consumption of various technologies; the energy consumption considers the energy demands of various technologies, including electricity, fuel, etc.; the pollutant emissions analyze the pollutants that may be generated by various technologies, such as waste gas, waste water, solid waste, etc., and calculate their emission amounts; the resource utilization efficiency evaluates the utilization efficiency of straw resources by various technologies, including raw material conversion rates, product output rates, etc.

[0031] Advantages of the present invention:

[0032] The internally heated low-tar straw pyrolysis / baking process designed by the present invention sets three material layers, namely a pyrolysis zone, a baking zone, and an adsorption zone, in an internally heated vertical moving bed to reduce the out-of-furnace transfer of tar. By adjusting the upper and lower air intake volumes, the steam is in-situ collected by the straw in the adsorption zone and moves upward. By changing the temperature of the pyrolysis zone, the lengths of the three material layers are adjusted. Due to the heat carried, the raw materials in the baking zone are preliminarily pyrolyzed, and as the temperature decreases, the volatile components in the steam stay in the adsorption zone to form tar-containing straw. The tar is directly converted into the binder required in the granulation stage, realizing internal recycling, that is, the generated tar does not need to come out and is directly reused internally. Furthermore, the development of a low-pollution and low-energy-consumption straw pyrolysis / baking technology is achieved, rationally utilizing the tar, flue gas, and pyrolysis carbon generated by straw pyrolysis / baking, and reducing the upgrading utilization cost of by-products and the pollution caused by transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a process flow diagram of the present invention.

[0034] Figure 2 It is a schematic diagram of the upper and lower air intake in the pyrolysis equipment of the present invention.

[0035] Figure 3 It is a schematic diagram of the straw pyrolysis and baking process of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] As shown in the Figures 1-3 low-tar black particle process shown, the specific process steps are as follows:

[0038] Step 1: Raw material preparation, collect and screen suitable straw raw materials;

[0039] Step 2: Pretreatment, use a crusher to crush the screened straw;

[0040] Step 3: Set the material layer and adjust the air volume, set three material layers, namely a pyrolysis zone, a baking zone, and an adsorption zone, in the pyrolysis equipment, and adjust the upper and lower air intake volumes so that the steam is in-situ collected by the straw in the adsorption zone and moves upward;

[0041] Step 4: Temperature control and pyrolysis, by changing the temperature of the pyrolysis zone, adjust the lengths of the three material layers, and the heat carried pyrolyzes the raw materials in the baking zone preliminarily to form tar-containing steam;

[0042] Step 5. Tar conversion: As the temperature decreases, the volatile components in the steam stay in the adsorption zone and condense into tar, which adheres to the surface of the straw to form tar-containing straw. The tar is directly converted into the binder required in the granulation stage to achieve internal recycling.

[0043] Step 6. Mixing and pellet preparation: Mix the straw charcoal, baked straw, and tar-containing straw generated in different regions of the internally heated moving bed pyrolysis equipment, and then use pelletizing equipment to pelletize.

[0044] Step 7. Pelletizing process debugging.

[0045] Step 8. Product analysis and optimization.

[0046] Step 9. Establish an evaluation model: Establish an economic and environmental impact evaluation model including technologies such as pelletizing straw first and then carbonizing, carbonizing straw first and then pelletizing, and low-tar self-heating straw baked pellet fuel.

[0047] Step 10. Cost and environmental impact analysis: Compare different tar and flue gas post-treatment technologies, and quantify key indicators such as the preparation cost and carbon emission intensity of low-tar self-heating straw baked pellet fuel.

[0048] Preferably, in Step 1, select straw with moderate maturity, no pests and diseases, and no pollution as raw materials. Remove impurities, soil, and unqualified parts through manual selection or mechanical screening, and retain the qualified straw.

[0049] Preferably, before crushing the straw in Step 2, the selected straw raw materials need to be cleaned. After cleaning, air-dry at room temperature, and then perform the crushing operation. The fineness after crushing does not exceed 1 cm.

[0050] Preferably, in Step 4, the temperature range of the pyrolysis zone is 300°C - 500°C, the temperature range of the baking zone is 200°C - 350°C, and the temperature range of the adsorption zone is 100°C - 250°C.

[0051] Preferably, in Step 6, the forming pressure of the pelletizing equipment for pelletizing is 10 MPa - 50 MPa, and the forming temperature is 80°C - 150°C.

[0052] Preferably, in Step 7, the pelletizing process debugging is carried out under different forming temperatures and pressures to determine the optimal pelletizing conditions. The debugging ranges of the forming temperature and forming pressure are 80°C - 150°C and 10 MPa - 50 MPa respectively.

[0053] Preferably, in Step 8, product analysis and optimization are to comprehensively optimize the production process parameters by analyzing the mechanical durability, gross calorific value, energy density, water resistance, apparent morphology, proximate analysis, and combustion weight loss characteristics of the pellet fuel to ensure that the product meets the quality standards and usage requirements.

[0054] Preferably, the steps for establishing the evaluation model in Step Nine are as follows:

[0055] S1. Define the evaluation objectives. First, clarify the objectives of the evaluation model, that is, to compare the economic efficiency and environmental impacts of different straw treatment technologies. This includes evaluations in aspects such as cost, revenue, carbon emissions, energy efficiency, etc.;

[0056] S2. Determine the evaluation indicators. According to the evaluation objectives, determine specific evaluation indicators. Among them, the economic indicators include investment cost, operation cost, revenue, payback period of investment, and cost-benefit ratio; the environmental impact indicators include carbon emission intensity, energy consumption, pollutant emissions, and resource utilization efficiency;

[0057] S3. Collect data and information. Through methods such as literature review, on-site investigation, and expert consultation, collect relevant data and information on technologies and the market. These data should include the process flow, equipment investment, raw material cost, energy consumption, carbon emission factors, etc. of various straw treatment technologies;

[0058] S4. Establish the evaluation model, including the economic model and the environmental impact model. In the economic model, the investment cost considers expenses such as equipment purchase, installation and commissioning, land lease or purchase, and infrastructure construction; the operation cost includes raw material cost, energy consumption, labor cost, maintenance cost, etc.; the revenue is calculated based on the market price and sales volume of the product; the payback period of investment and the cost-benefit ratio are calculated based on the investment cost, operation cost, and revenue; in the environmental impact model, the carbon emission intensity is calculated based on the carbon emission factors and energy consumption of various technologies; the energy consumption considers the energy demands of various technologies, including electricity, fuel, etc.; the pollutant emissions are to analyze the pollutants that may be generated by various technologies, such as waste gas, waste water, solid waste, etc., and calculate their emission amounts; the resource utilization efficiency is to evaluate the utilization efficiency of various technologies for straw resources, including raw material conversion rate, product output rate, etc.

[0059] S5. Model operation and result analysis. Input the collected data and information into the evaluation model for operation and analysis, compare the economic efficiency and environmental impacts of different technologies, and find out the advantageous technologies and existing problems;

[0060] S6. Model optimization and verification. Optimize and adjust the evaluation model according to the operation results and analysis.

[0061] Working principle: The present invention designs a low-tar black pellet process. During operation, first, suitable straw raw materials are collected and screened. Straw with moderate maturity, no pests and diseases, and no pollution is selected as the raw material. Through manual selection or mechanical screening, impurities, soil, and unqualified parts are removed, and the qualified straw is retained. The screened straw is crushed by a crusher. Before crushing the straw, the screened straw raw material needs to be cleaned. After cleaning, it is air-dried at room temperature and then crushed. The fineness after crushing does not exceed 1 cm.

[0062] Then, three material layers, namely a pyrolysis zone, a baking zone, and an adsorption zone, are set in the pyrolysis equipment. The upper and lower air intake volumes are adjusted so that steam is collected in situ by the straw in the adsorption zone and moves upward. By changing the temperature of the pyrolysis zone and adjusting the lengths of the three material layers, the heat carried pyrolyzes the raw materials in the baking zone initially to form tar-containing steam. As the temperature decreases, the volatile components in the steam stay in the adsorption zone and condense into tar, which adheres to the surface of the straw to form tar-containing straw. The tar is directly converted into the binder required in the granulation stage, realizing internal recycling.

[0063] Furthermore, the straw charcoal, baked straw, and tar-containing straw generated in different regions of the internally heated moving bed pyrolysis equipment are mixed, and then granulated using granulation equipment. Parameters for debugging the granulation process are provided to determine the optimal parameters. By analyzing the mechanical durability, gross calorific value, energy density, water resistance, apparent morphology, proximate analysis, and combustion weight loss characteristics of the pellet fuel, the production process parameters are comprehensively optimized to ensure that the product meets the quality standards and usage requirements.

[0064] Finally, an economic and environmental impact assessment model including technologies such as pre-granulation and post-carbonization of straw, pre-carbonization and post-granulation of straw, and low-tar self-heating straw baked pellet fuel is established. Different tar and flue gas post-treatment technologies are compared, and key indicators such as the preparation cost and carbon emission intensity of the low-tar self-heating straw baked pellet fuel are quantified.

[0065] In summary, for the internally heated low-tar straw pyrolysis / baking process designed by the present invention, in order to reduce the out-of-furnace transfer of tar, three material layers, namely a pyrolysis zone, a baking zone, and an adsorption zone, are provided in the internally heated vertical moving bed. By adjusting the upper and lower air suction amounts, the steam is collected in situ by the straw in the adsorption zone and the pyrolysis steam moves upward. By changing the temperature of the pyrolysis zone, the lengths of the three material layers are adjusted. Due to the heat carried, the raw materials in the baking zone are preliminarily pyrolyzed. As the temperature decreases, the volatile components in the steam stay in the adsorption zone to form tar-containing straw, and the tar is directly converted into the binder required in the granulation stage, realizing internal recycling, that is, the generated tar does not need to come out and is directly reused internally. Then, granulation is carried out using the straw charcoal, baked straw, and tar-containing straw generated in different regions of the internally heated moving bed pyrolysis equipment, thereby realizing the development of a low-pollution and low-energy-consumption straw pyrolysis / baking technology, reasonably utilizing the tar, flue gas, and pyrolysis carbon generated by straw pyrolysis / baking, and reducing the upgrading utilization cost of by-products and the pollution caused by transfer.

[0066] The foregoing are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Low tar black particle process, characterized in that: The specific process steps are as follows: Step 1: Raw material preparation: collecting and selecting suitable straw raw materials; Step 2: pre-treatment, using a crusher to crush the screened straw; Step 3: Set the material layer and adjust the air volume. Set three material layers in the pyrolysis equipment, namely, the pyrolysis zone, the baking zone, and the adsorption zone. Adjust the upper and lower suction volumes so that the steam is collected in situ by the straw in the adsorption zone and moves upward. Step 4: temperature control and pyrolysis. By changing the temperature of the pyrolysis zone and adjusting the lengths of the three material layers, the heat carried will initially pyrolyze the raw materials in the baking zone to form tar-containing vapor; Step 5: Tar conversion: as the temperature decreases, the volatile components in the steam stay in the adsorption zone and condense into tar, which adheres to the surface of the straw to form tar-containing straw. The tar is directly converted into the binder required for the pelletizing stage. Step 6: Mixing and pellet preparation: mixing the straw charcoal, roasted straw and tar-containing straw produced in different areas of the internally heated moving bed pyrolysis equipment, and then pelletizing them using a pelletizing equipment; Step seven, granulation process debugging; Step 8: Product analysis and optimization; Step 9: Establish an evaluation model; Step 10: Cost and environmental impact analysis.

2. The low-tar black particle process according to claim 1, characterized in that: In the step 1, straw with moderate maturity, no pests or diseases, and no pollution is selected as raw material, and impurities, soil and unqualified parts are removed by manual selection or mechanical screening to retain straw that meets the requirements.

3. The low-tar black particle process according to claim 1, characterized in that: Before the straw is crushed in step 2, the screened straw raw material needs to be cleaned, and then air-dried at room temperature. After air-drying, the crushing operation is performed, and the fineness after crushing does not exceed 1 cm.

4. The low-tar black particle process according to claim 1, characterized in that: In the step 4, the temperature range of the pyrolysis zone is 300°C-500°C, the temperature range of the baking zone is 200°C-350°C, and the temperature range of the adsorption zone is 100°C-250°C.

5. The low tar black particle process according to claim 1, characterized in that: In the step six, the granulation pressure of the granulation equipment is 10MPa-50MPa, and the molding temperature is 80°C-150°C.

6. The low tar black particle process according to claim 1, characterized in that: The granulation process debugging in step seven is to debug the granulation process at different molding temperatures and pressures to determine the optimal granulation conditions. The debugging ranges of the molding temperature and the molding pressure are 80° C.-150° C. and 10 MPa-50 MPa, respectively.

7. The low-tar black particle process according to claim 1, characterized in that: The product analysis and optimization in step eight is to comprehensively optimize the production process parameters by analyzing the mechanical durability, high calorific value, energy density, water resistance, surface morphology, industrial analysis and combustion weight loss characteristics of the pellet fuel to ensure that the product meets the quality standards and usage requirements.

8. The low tar black particle process according to claim 1, characterized in that: The steps for establishing the evaluation model in step nine are as follows: S1. Clarify the evaluation objectives. First, the evaluation model objectives should be clarified, that is, to compare the economic and environmental impacts of different straw treatment technologies, including the evaluation of costs, benefits, carbon emissions, and energy efficiency. S2. Determine the evaluation indicators. According to the evaluation objectives, determine the specific evaluation indicators, among which the economic indicators include investment cost, operating cost, income, investment payback period and cost-benefit ratio; the environmental impact indicators include carbon emission intensity, energy consumption, pollutant emissions and resource utilization efficiency; S3. Collect data and information. By consulting literature, conducting field research, and consulting experts, collect data and information on relevant technologies and markets. These data include the process flow, equipment investment, raw material cost, energy consumption, and carbon emission factors of various straw processing technologies. S4. Establish an assessment model, including an economic model and an environmental impact model; S5. Model operation and result analysis: input the collected data and information into the evaluation model, perform operation and analysis, compare the economic and environmental impacts of different technologies, and identify the advantages and problems; S6. Model optimization and verification: optimize and adjust the evaluation model based on the calculation results and analysis.

9. The low tar black particle process according to claim 8, characterized in that: In the economic model, the investment cost takes into account equipment purchase, installation and commissioning, land lease or purchase, and infrastructure construction costs; the operating costs include raw material costs, energy consumption, labor costs, and maintenance costs; the income is calculated based on the market price and sales volume of the product; the investment payback period and cost-benefit ratio are calculated based on the investment cost, operating cost, and income.

10. The low-tar black particle process according to claim 8, characterized in that: The carbon emission intensity in the environmental impact model is calculated based on the carbon emission factors and energy consumption of various technologies; energy consumption takes into account the energy requirements of various technologies, including electricity and fuel; pollutant emissions analyze the pollutants that may be generated by various technologies, including waste gas, wastewater and solid waste, and calculate their emissions; resource utilization efficiency evaluates the utilization efficiency of straw resources by various technologies, including raw material conversion rate and product output rate.

Images