A decoupled biomass gasification power generation system

Abstract

The utility model belongs to the field of biomass energy power generation technology especially relates to a decoupling type biomass gasification power generation system, including vertical multi -segment decoupling gasification furnace, gas treatment unit, flue gas waste heat utilization unit, the vertical multi -segment decoupling gasification furnace's furnace is by the perforated baffle from top to bottom and is divided into pyrolysis zone, oxidation zone, catalytic reduction zone, is equipped with the decoupling reactor in the reduction zone, the gas treatment unit includes the heat exchanger, filter one, steam -water condensation separator, roots blower, filter two that connect gradually, vertical multi -segment decoupling gasification furnace is connected with heat exchanger, and heat exchanger is used for reducing the gas temperature that vertical multi -segment decoupling gasification furnace produces, and the outlet of roots blower is connected with the internal combustion engine of flue gas waste heat utilization unit. Advantages are: the present application can realize tar in situ high temperature catalytic cracking, efficient utilization of waste heat and stable operation of system, improve power generation efficiency, reduce equipment cost simultaneously.

Description

Technical Field

[0001] This utility model belongs to the field of biomass energy power generation technology, and in particular relates to a decoupled biomass gasification power generation system. Background Technology

[0002] Biomass gasification power generation is a clean energy technology that utilizes biomass resources (such as crop straw, wood waste, and urban organic waste) to convert them into combustible gases through a gasification reaction, thereby driving power generation equipment to produce electricity. Biomass gasification is a thermochemical conversion process that decomposes biomass under partial oxidation conditions, converting it into combustible gases (mainly composed of hydrogen (H2), carbon monoxide (CO), and methane (CH4)). The gasification process typically takes place in a high-temperature (700℃~1000℃) and limited (or anaerobic) environment. The organic matter in the biomass is decomposed into gaseous products, while small amounts of solid residues (such as carbon black) and liquid products (such as tar) are produced. Compared to traditional direct combustion of biomass, gasification power generation produces fewer pollutants, and emissions can be further reduced through purification systems, meeting environmental protection requirements. However, with the application of biomass gasification power generation systems, some technical shortcomings have also been identified:

[0003] 1. Low biomass gasification efficiency: Traditional single gasification agent (oxidant) has low gasification efficiency and low calorific value of biomass gas.

[0004] 2. High energy consumption in tar treatment: Tar produced during gasification is a complex organic mixture that easily deposits in equipment, leading to blockages and corrosion, and affecting the stable operation of the system. Existing tar treatment methods rely on water washing or electrostatic precipitator units, accounting for 15% to 20% of the total system energy consumption, and are prone to generating secondary pollution. This also increases operating costs and capital investment in gas purification.

[0005] 3. Large fluctuations in gas quality: Open-loop control causes fluctuations in H2 / CO concentration in gasified gas of up to ±30%, affecting the stability of power generation.

[0006] 4. Low waste heat utilization rate: The waste heat recovery rate of traditional flue gas is less than 40%, the utilization is singular, and the overall power generation efficiency is less than 25%. Utility Model Content

[0007] To overcome the shortcomings of existing technologies, the purpose of this utility model is to provide a decoupled biomass gasification power generation system that enables in-situ high-temperature catalytic cracking of tar, efficient utilization of waste heat, and ensures stable system operation.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] A decoupled biomass gasification power generation system includes a vertical multi-stage decoupled gasifier, a gas processing unit, and a flue gas waste heat utilization unit.

[0010] The vertical multi-stage decoupled gasifier is divided into a pyrolysis zone, an oxidation zone, and a catalytic reduction zone from top to bottom by a perforated partition plate; the reduction zone is equipped with a decoupled reactor.

[0011] The gas processing unit includes a heat exchanger, filter one, a steam-water condenser separator, a Roots blower, and filter two connected in sequence. A vertical multi-stage decoupled gasifier is connected to the heat exchanger, which is used to reduce the temperature of the gas produced by the vertical multi-stage decoupled gasifier. The outlet of the Roots blower is connected to the internal combustion engine of the flue gas waste heat utilization unit.

[0012] The flue gas waste heat utilization unit includes an internal combustion engine, an exhaust turbocharger, and a compressed air generator. The flue gas processed by the gas treatment unit is input into the internal combustion engine. The exhaust turbocharger uses the gas discharged from the internal combustion engine to drive the compressed air generator. The compressed gasifying agent output by the compressed air generator is delivered to the vertical multi-stage decoupled gasifier.

[0013] A temperature sensor is connected to the oxidation zone, and a pressure transmitter is connected to the pyrolysis zone.

[0014] The vertical multi-stage decoupled gasifier is also connected to a spray pipe inside the furnace, and a high-temperature spray valve is connected to the spray pipe.

[0015] The outlet of the vertical multi-stage decoupled gasifier is connected to a flow meter.

[0016] The outlet of the vertical multi-stage decoupled gasifier is connected to a gas analyzer.

[0017] The decoupling reactor is filled with a supported nickel-based catalyst.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] This invention achieves in-situ high-temperature catalytic cracking of tar, efficient utilization of waste heat, and stable system operation through structural optimization, thereby improving power generation efficiency and reducing equipment costs. Specific advantages:

[0020] 1. Reduced Tar Content: The vertical multi-stage decoupled gasifier uses perforated partition plates to divide the gasifier into multiple sections, forming a downdraft positive pressure structure. Combined with a supported nickel-based catalyst, this improves operational stability and resistance to carbon buildup, effectively cracking tar and converting it into smaller molecule gases. It is easy to operate, has low energy consumption, does not produce secondary pollution, and extends the equipment's lifespan. Compared to the original power generation system, it eliminates the traditional water washing / electrostatic tar removal unit, optimizing the tar treatment process.

[0021] 2. Improve power generation efficiency: By using decoupled gasifier technology, the biomass gasification rate is increased and the calorific value of the mixed gas is increased, thereby improving power generation efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a decoupled biomass gasification power generation system.

[0023] Figure 2 It is a logic block diagram of multi-parameter collaborative control.

[0024] Figure 3 This is a graph showing the tar content of a traditional gasifier and a vertical multi-stage decoupled gasifier.

[0025] In the diagram: 1-Decoupled gasifier; 101-Perforated baffle plate; 102-Pyrolysis zone; 103-Oxidation zone; 104-Catalytic reduction zone; 105-Decoupled reactor; 201-Internal combustion engine; 202-Exhaust turbocharger; 211-Internal combustion engine flue gas; 212-Gasifying agent;

[0026] 3-Control system; 301-Temperature sensor; 302-Pressure transmitter; 303-High-temperature spray valve; 304-Gas flow meter; 305-Gas analyzer; 306-Air vaporizing agent flow meter;

[0027] 4-Gas processing unit; 401-Heat exchanger; 402-Filter 1; 403-Steam-water condenser separator; 404-Roots blower. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0029] See Figure 1 A decoupled biomass gasification power generation system includes a vertical multi-stage decoupled gasifier 1, a gas processing unit 4, and a flue gas waste heat utilization unit.

[0030] The vertical multi-stage decoupled gasifier 1 is divided into a pyrolysis zone 102, an oxidation zone 103, and a catalytic reduction zone 104 from top to bottom by a perforated partition plate 101. A decoupled reactor 105 is installed in the reduction zone. The pyrolysis zone 102 is used for the preliminary decomposition of biomass feedstock, generating volatiles and fixed carbon. The perforated partition plate 101 between the pyrolysis zone 102 and the oxidation zone 103 has a pore size of 1-3 cm. A gasifying agent is introduced into the oxidation zone 103 to ensure sufficient oxygen supply, promoting complete combustion of volatiles and releasing a large amount of heat. The perforated partition plate 101 between the oxidation zone 103 and the catalytic reduction zone 104 has a pore size of 0.5-1 cm, which helps reduce the gas flow rate in the catalytic reduction zone 104, prolonging the contact time between the gas and the catalyst, thereby improving the efficiency of the reduction reaction and generating a high-quality biomass mixed gas. Furthermore, a temperature sensor 301 is connected to the oxidation zone 103 to collect temperature data. A pressure transmitter 302 is connected to the pyrolysis zone 102 to monitor pressure changes within the furnace, preventing excessively high or low pressure from affecting gasification efficiency and safety. A spray pipe is also connected inside the furnace, with a high-temperature spray valve 303 connected to it. The spray volume is calculated based on the detected temperature and pressure values, and the spray volume is adjusted in real-time by regulating the opening of the high-temperature spray valve 303 to maintain the system's temperature and pressure within a preset safe range. Real-time monitoring and regulation are achieved through a temperature sensor 301, pressure transmitter 302, high-temperature spray valve 303, a gas analyzer 305 connected to the outlet of the decoupled gasifier 1, and the control system to ensure the stability and efficiency of the gasification process, reducing energy consumption and emissions. Furthermore, the control system is equipped with a self-diagnostic function, which can immediately activate protective measures (alarm and load reduction when exceeding set values, and shutdown in severe cases) when abnormalities in temperature, pressure, or gas composition are detected, preventing equipment damage or safety accidents.

[0031] The decoupling reactor 105 is filled with a supported nickel-based catalyst. The supported nickel-based catalyst is a nickel-based rare earth element catalyst with a loading of 20%–25%. The nickel-based rare earth element catalyst, by weight percentage, includes: Ni: 20%–25%; Al₂O₃: 65%–70%; MgO: 3%–5%; SiO₂: 2%–4%; rare earth elements: 2%–5%. The main rare earth element is Ce, with the remainder being La, Nd, Y, or Z.

[0032] The multi-stage decoupled gasifier 1 is a fixed, downdraft, positive pressure system. Biomass feedstock enters the furnace from the top, and a gasifying agent 212 at approximately 250°C is uniformly injected through the oxidation zone 103, raising the gasification temperature to over 900°C. Combustion and pyrolysis of the biomass feedstock occur simultaneously. The resulting high-temperature gas passes through the incandescent carbon layer catalytic reduction zone 104, where its main components are reduced to H2 and CO. The downdraft gasifier's product gas has a low tar content, and with the secondary action of the supported nickel-based catalyst, tar is almost completely removed.

[0033] The gas processing unit 4 includes a heat exchanger 401, a first filter 402, a steam-water condenser separator 403, a Roots blower 404, and a second filter connected in sequence. A vertical multi-stage decoupled gasifier 1 is connected to the heat exchanger 401, which is used to reduce the temperature of the gas produced by the vertical multi-stage decoupled gasifier 1; a gas-water heat exchanger can be used. The outlet of the Roots blower 404 is connected to the internal combustion engine 201 of the flue gas waste heat utilization unit. A gas analyzer 305 is connected to the outlet of the vertical multi-stage decoupled gasifier 1. The response speed of the temperature sensor 301, pressure transmitter 302, high-temperature spray valve 303, and gas analyzer 305 is <0.5s.

[0034] The flue gas waste heat utilization unit includes an internal combustion engine 201, an exhaust turbocharger 202, and a compressed air generator. The flue gas processed by the gas treatment unit 4 is input into the internal combustion engine 201. The exhaust turbocharger 202 uses the gas discharged from the internal combustion engine 201 to drive the compressed air generator. The compressed gasifying agent 212 output by the compressed air generator is delivered to the vertical multi-stage decoupled gasifier 1.

[0035] See Figure 2 Power generation methods utilizing decoupled biomass gasification power generation systems include:

[0036] 1) Biomass gasification treatment: Biomass feedstock is fed into vertical multi-stage decoupled gasifier 1 for gasification. Gasifying agent 212 and steam are introduced into the vertical multi-stage decoupled gasifier 1. By adjusting the amount of gasifying agent 212 and steam introduced, the temperature of the reduction zone is controlled at 700~900℃; the air-fuel ratio of the oxidation zone 103 is controlled at 0.25~0.35; and the residence time in the reduction zone is >10s.

[0037] The gasifying agent used is a composite gasifying agent: air and water vapor. During the gasification of biomass, these two gasifying agents are used simultaneously or alternately. Air acts as the oxidant, providing the necessary oxygen, while water vapor participates in the reaction as the gasifying agent. Their synergistic effect significantly improves gasification efficiency. By adjusting the ratio of air to water vapor, the H2 and CO content in the syngas is controlled. Furthermore, the addition of water vapor helps regulate the temperature distribution within the gasifier, preventing localized overheating and ensuring the stability of the gasification process. The participation of water vapor in the gasification reaction also effectively reduces tar formation, improves syngas quality, and reduces coking within the furnace.

[0038] Catalytic cracking can easily degrade relatively stable tar to a large extent. The combustible gas containing tar that enters the catalytic reduction zone 104 from the oxidation zone 103 is fed into the decoupled reactor 105 filled with a supported nickel-based catalyst. The reaction temperature is controlled at 800~950℃ by spraying water vapor, which increases the gas yield to 20% (volume percentage) and increases the calorific value. The mixed gas leaves the gasifier at a temperature of 800~950℃, realizing in-situ tar cracking (CnHm→CO+H2) and CH4 reforming.

[0039] Depend on Figure 3 It is known that the tar washing system of a traditional gasifier fails after 36 hours of operation, leading to secondary pollution and a sharp increase in tar content. In contrast, the vertical multi-stage decoupled gasifier 1, with its multi-parameter closed-loop control response starting from 36 hours of operation, can almost completely remove tar.

[0040] 2) Flue Gas Treatment: Before entering the gas-fired internal combustion engine 201, the biomass mixture needs to pass through a filter to remove most of the dust, and then undergoes dehumidification and cooling, condensation and dehydration, pressurization and dust removal processes. The gasification products of the vertical multi-stage decoupled gasifier 1 are cooled by heat exchanger 401 (heat exchanger 401 can be a gas-water heat exchanger), then filtered once by filter 402, and moisture is removed by steam-water condenser separator 403. The gas is then pressurized by Roots blower 404, filtered twice by filter 2, and sent to internal combustion engine 201 for power generation. The intake air temperature is stabilized at 35~50℃.

[0041] 3) Waste heat utilization of flue gas: The gas discharged from the internal combustion engine 201 is pressurized by the exhaust turbocharger 202, and then compressed by the compressed air generator before being sent to the vertical multi-stage decoupled gasifier 1 as a gasifying agent 212. Gas flow meters 304 are installed on the outlet of the decoupled gasifier, the inlet of the internal combustion engine, and other pipelines to monitor flow data in real time and provide control reference data. This effectively utilizes unused exhaust energy, especially by using the flowing energy for gasification and power generation, reducing external energy consumption.

[0042] In the initial startup phase of the decoupled biomass gasification power generation system, air is used as the main gasifying agent to rapidly raise the furnace temperature to the operating temperature. After stabilizing the operating temperature, the system enters a stable operation phase, where the ratio of air to steam is adjusted according to the target syngas composition. During the load regulation phase, the gasifying agent ratio is changed to adapt to changes in feedstock characteristics or load.

[0043] This utility model's vertical multi-stage decoupled gasifier uses perforated partition plates to divide the gasifier into multiple sections, forming a downdraft positive pressure structure. Combined with a supported nickel-based catalyst, it improves operational stability and resistance to carbon buildup, effectively cracking tar and converting it into smaller molecule gases. It is easy to operate, has low energy consumption, does not produce secondary pollution, and extends the equipment's service life. Compared to the original power generation system, it eliminates the traditional water washing / electrostatic tar removal unit, optimizing the tar treatment process.

[0044] Through the above specific embodiments, those skilled in the art can easily implement this utility model. However, it should be understood that this utility model is not limited to the specific embodiments described above. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions. Due to space limitations and for the sake of brevity, not all of these combined solutions have been described. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A decoupled biomass gasification power generation system, characterized by, It includes a vertical multi-stage decoupled gasifier, a gas processing unit, and a flue gas waste heat utilization unit; The vertical multi-stage decoupled gasifier is divided into a pyrolysis zone, an oxidation zone, and a catalytic reduction zone from top to bottom by a perforated partition plate; the reduction zone is equipped with a decoupled reactor. The gas processing unit includes a heat exchanger, filter one, a steam-water condenser separator, a Roots blower, and filter two connected in sequence. A vertical multi-stage decoupled gasifier is connected to the heat exchanger, which is used to reduce the temperature of the gas produced by the vertical multi-stage decoupled gasifier. The outlet of the Roots blower is connected to the internal combustion engine of the flue gas waste heat utilization unit.

2. The decoupled biomass gasification power generation system of claim 1, wherein, The flue gas waste heat utilization unit includes an internal combustion engine, an exhaust turbocharger, and a compressed air generator. The flue gas processed by the gas treatment unit is input into the internal combustion engine. The exhaust turbocharger uses the gas discharged from the internal combustion engine to drive the compressed air generator. The compressed gasifying agent output by the compressed air generator is delivered to the vertical multi-stage decoupled gasifier.

3. The decoupled biomass gasification power generation system according to claim 1, characterized in that, A temperature sensor is connected to the oxidation zone, and a pressure transmitter is connected to the pyrolysis zone.

4. The decoupled biomass gasification power generation system according to claim 1, characterized in that, The vertical multi-stage decoupled gasifier is also connected to a spray pipe inside the furnace, and a high-temperature spray valve is connected to the spray pipe.

5. A decoupled biomass gasification power generation system according to claim 1, characterized in that, The outlet of the vertical multi-stage decoupled gasifier is connected to a flow meter.

6. A decoupled biomass gasification power generation system according to claim 1, characterized in that, The outlet of the vertical multi-stage decoupled gasifier is connected to a gas analyzer.

7. A decoupled biomass gasification power generation system according to claim 6, characterized in that, The decoupling reactor is filled with a supported nickel-based catalyst.

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