Biomass gasification high-temperature fuel gas heat recovery device and recovery method

Abstract

The invention belongs to the technical field of energy, and particularly relates to a biomass gasification high-temperature fuel gas heat recovery device and method. The device comprises a biomass circulating fluidized bed gasifier, a high-pressure heater, a heat exchanger and a boiler, a fuel gas outlet of the biomass circulating fluidized bed gasifier is communicated with a hot medium inlet of the heat exchanger; a water outlet of the high-pressure heater is communicated with a cold medium inlet of the heat exchanger; a hot medium outlet of the heat exchanger is communicated with the boiler, and a cold medium outlet of the heat exchanger is communicated with the boiler economizer. The device has the beneficial effects that high-temperature fuel gas generated by gasification of the gasification furnace and high-pressure feed water flowing out of the high-pressure heater are subjected to heat exchange, so that the heat of the high-temperature fuel gas is fully utilized, and the high-pressure feed water is heated by using the high-temperature fuel gas, so that the operation cost of the system is reduced; according to the device, gradient utilization of energy is achieved, stable electric power and heat supply can be provided, and environmental pollution is reduced.

Description

Technical Field

[0001] This application belongs to the field of energy technology, specifically relating to a biomass gasification high-temperature gas heat recovery device and recovery method. Background Technology

[0002] With increasing energy demand and growing environmental awareness, biomass energy, as a renewable and clean energy source, is receiving increasing attention. Biomass circulating fluidized bed gasifiers are highly efficient biomass conversion devices that can convert biomass into high-temperature fuel gas. However, a significant amount of sensible heat is wasted during subsequent processing of this high-temperature fuel gas, which not only reduces energy efficiency but may also cause thermal pollution to the environment.

[0003] On the other hand, power plants require a large amount of high-pressure feedwater during operation, which typically consumes significant energy for heating. If the heat from the high-temperature fuel gas in a biomass circulating fluidized bed gasifier can be effectively recovered and used to heat the high-pressure feedwater in the power plant, it will achieve cascaded energy utilization, improve the overall system's energy efficiency, and yield significant economic and environmental benefits. Currently, although some heat recovery technologies exist, the technology for recovering heat from the high-temperature fuel gas in a biomass circulating fluidized bed gasifier still needs improvement, and problems such as low recovery efficiency and poor system compatibility remain. Summary of the Invention

[0004] This application provides a biomass gasification high-temperature gas heat recovery device and method, aiming to solve the problems of low utilization efficiency, environmental pollution, and poor system matching when heating high-pressure feedwater in existing biomass circulating fluidized bed gasification high-temperature gas heat recovery devices.

[0005] The first aspect of this application provides a biomass gasification high-temperature gas heat recovery device, including a biomass circulating fluidized bed gasifier, a high-pressure heater, a heat exchanger, and a boiler;

[0006] The gas outlet of the biomass circulating fluidized bed gasifier is connected to the heat medium inlet of the heat exchanger, and the water outlet of the high-pressure heater is connected to the cold medium inlet of the heat exchanger.

[0007] The heat exchanger's hot medium outlet is connected to the boiler, and the heat exchanger's cold medium outlet is connected to the boiler's economizer.

[0008] According to some embodiments of the biomass gasification high-temperature gas heat recovery device described in this application, a booster pump is also included; the booster pump is installed on the pipeline connecting the high-pressure heater and the heat exchanger, and is used to pressurize the water flowing into the heat exchanger.

[0009] According to some embodiments of the biomass gasification high-temperature gas heat recovery device described in this application, a booster fan is also included; the booster fan is installed on the pipeline connecting the heat exchanger and the boiler, and is used to pressurize the gas flowing into the boiler.

[0010] The second aspect of this application provides a method for recovering the heat from high-temperature gas generated during biomass gasification, using the high-temperature gas generated during biomass gasification heat recovery device described in the first aspect of this application.

[0011] According to some embodiments of the biomass gasification high-temperature fuel gas heat recovery method described in this application, the method includes the following steps: the high-temperature fuel gas generated by biomass gasification is transported to the heat exchanger through the heat medium inlet; at the same time, water flowing out of the high-pressure heater flows into the heat exchanger through the cold medium inlet; the high-temperature fuel gas and water exchange heat in the heat exchanger, the cooled high-temperature fuel gas is transported to the boiler through the heat medium outlet of the heat exchanger, and the heated water flows into the boiler economizer through the cold medium outlet of the heat exchanger.

[0012] According to some embodiments of the biomass gasification high-temperature gas heat recovery method described in this application, the biomass includes rice straw and / or agricultural and forestry waste.

[0013] According to some embodiments of the biomass gasification high-temperature combustion heat recovery method described in this application, the gasification agent used in the gasification includes air; as a preferred embodiment, the amount of air used is 0.2-0.3 of the amount of air required for the complete combustion of the biomass.

[0014] According to some embodiments of the biomass gasification high-temperature gas heat recovery method described in this application, the gasification temperature is 750-850℃ and the gasification time is 5-300s.

[0015] According to some embodiments of the biomass gasification high-temperature gas heat recovery method described in this application, the temperature of the high-temperature gas is 700-750°C.

[0016] According to some embodiments of the biomass gasification high-temperature gas heat recovery method described in this application, the flow rate of the high-temperature gas delivered to the heat exchanger is 45000 Nm³. 3 / h-55000Nm 3 / h.

[0017] According to some embodiments of the biomass gasification high-temperature fuel gas heat recovery method described in this application, the temperature of the water flowing out of the high-pressure heater is 200-250°C.

[0018] According to some embodiments of the biomass gasification high-temperature fuel heat recovery method described in this application, the flow rate of water flowing into the heat exchanger is 80-100 t / h, and the pressure of water flowing into the heat exchanger is 15-17 MPa.

[0019] According to some embodiments of the biomass gasification high-temperature gas heat recovery method described in this application, the temperature of the high-temperature gas flowing out of the heat medium outlet of the heat exchanger is 400-450°C.

[0020] According to some embodiments of the biomass gasification high-temperature fuel gas heat recovery method described in this application, the temperature of the water flowing out of the cold medium outlet of the heat exchanger is 280-300℃.

[0021] The beneficial effects of this application include: the device described in this application exchanges heat between the high-temperature gas generated by the gasification of the gasifier and the high-pressure feedwater flowing out of the high-pressure heater, so that the heat of the high-temperature gas is fully utilized, and the use of high-temperature gas to heat the high-pressure feedwater reduces the operating cost of the system; the device described in this application realizes energy cascade utilization, can provide a stable power and heat supply, and reduce environmental pollution. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the biomass gasification high-temperature gas heat recovery device described in this application. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] This application provides a biomass gasification high-temperature gas heat recovery device, including a biomass circulating fluidized bed gasifier, a high-pressure heater, a heat exchanger, and a boiler;

[0026] The gas outlet of the biomass circulating fluidized bed gasifier is connected to the heat medium inlet of the heat exchanger, and the water outlet of the high-pressure heater is connected to the cold medium inlet of the heat exchanger.

[0027] The heat exchanger's hot medium outlet is connected to the boiler, and the heat exchanger's cold medium outlet is connected to the boiler's economizer.

[0028] When using the apparatus described in this application, the high-temperature fuel gas generated by the biomass gasification process in the biomass circulating fluidized bed gasifier and the high-pressure feedwater flowing out of the high-pressure heater flow into a heat exchanger for heat exchange. In the heat exchanger, the heat from the high-temperature fuel gas is transferred to the high-pressure feedwater, and the cooled high-temperature fuel gas is returned to the boiler to improve its utilization rate; the heated water flows into the boiler economizer.

[0029] The biomass gasification high-temperature gas heat recovery device described in this application exchanges heat between the high-temperature gas generated by the gasification furnace and the high-pressure feedwater flowing out of the high-pressure heater, thus fully utilizing the heat of the high-temperature gas. Furthermore, using the high-temperature gas to heat the high-pressure feedwater reduces the system's operating costs. This device achieves cascaded energy utilization, provides a stable supply of electricity and heat, reduces environmental pollution, and aligns with the direction of green and environmentally friendly energy development.

[0030] In some embodiments of this application, a booster pump is also included; the booster pump is installed on the pipe connecting the high-pressure heater and the heat exchanger, and is used to pressurize the water flowing into the heat exchanger.

[0031] In some embodiments of this application, a booster fan is also included; the booster fan is installed on the pipe connecting the heat exchanger and the boiler, and is used to pressurize the gas flowing into the boiler.

[0032] This application also provides a method for recovering heat from high-temperature gas generated during biomass gasification, using the biomass gasification high-temperature gas heat recovery device described in the first aspect of this application.

[0033] In some embodiments of this application, the following steps are included: high-temperature gas generated from biomass gasification is transported to the heat exchanger through the heat medium inlet; simultaneously, water flowing out of the high-pressure heater flows into the heat exchanger through the cold medium inlet; the high-temperature gas and water exchange heat in the heat exchanger, the cooled high-temperature gas is transported to the boiler through the heat medium outlet of the heat exchanger, and the heated water flows into the boiler economizer through the cold medium outlet of the heat exchanger.

[0034] The method for recovering heat from high-temperature flue gas in biomass gasification described in this application reduces system operating costs, achieves cascaded energy utilization, reduces environmental pollution, and aligns with the direction of green and environmentally friendly energy development.

[0035] In some embodiments of this application, the biomass includes rice straw and / or agricultural and forestry waste.

[0036] In some embodiments of this application, the gasification agent used in the gasification includes air. Using air as a gasification agent improves the gasification efficiency and cleanliness of biomass, and gives the fuel gas a higher calorific value.

[0037] In some embodiments of this application, the amount of air used is 0.2-0.3 of the amount of air required for the complete combustion of the biomass; for example, 0.2, 0.25, 0.3, etc.

[0038] In some embodiments of this application, the vaporization temperature is 750-850℃, such as 750℃, 780℃, 800℃, 820℃, 850℃, etc., and the vaporization time is 5-300s, such as 5s, 10s, 50s, 80s, 120s, 160s, 210s, 250s, 300s, etc.

[0039] In some embodiments of this application, the temperature of the high-temperature gas is 700-750°C; for example, 700°C, 720°C, 730°C, 750°C, etc. The composition of the high-temperature gas is generally approximately 20% CO, approximately 10% H2, CH4, and C. m H n Approximately 3%, with the remainder consisting of nitrogen, carbon dioxide, water, and other gases.

[0040] In some embodiments of this application, the flow rate of the high-temperature gas delivered to the heat exchanger is 45000 Nm³. 3 / h-55000Nm 3 / h, for example 45000Nm 3 / h, 48000Nm 3 / h, 50000Nm 3 / h, 52000Nm 3 / h, 55000Nm 3 / h etc.

[0041] In some embodiments of this application, the temperature of the water flowing out of the high-pressure heater is 200-250°C; for example, 200°C, 220°C, 230°C, 250°C, etc.

[0042] In some embodiments of this application, the flow rate of water flowing into the heat exchanger is 80-100 t / h, such as 80 t / h, 85 t / h, 88 t / h, 90 t / h, 95 t / h, 100 t / h, etc., and the pressure of water flowing into the heat exchanger is 15-17 MPa, such as 15 MPa, 16 MPa, 17 MPa, etc.

[0043] In some embodiments of this application, the temperature of the high-temperature gas flowing out of the heat medium outlet of the heat exchanger is 400-450°C, for example, 400°C, 410°C, 425°C, 430°C, 450°C, etc.

[0044] In some embodiments of this application, the temperature of the water flowing out of the cold medium outlet of the heat exchanger is 280-300°C, such as 280°C, 292°C, 290°C, 300°C, etc.

[0045] The technical solution of this application will be further described below with reference to specific embodiments.

[0046] Example 1

[0047] A biomass gasification high-temperature fuel gas heat recovery device includes a biomass circulating fluidized bed gasifier, a high-pressure heater, a heat exchanger, and a boiler. The fuel gas outlet of the biomass circulating fluidized bed gasifier is connected to the heat medium inlet of the heat exchanger, and the water outlet of the high-pressure heater is connected to the cold medium inlet of the heat exchanger. The high-temperature fuel gas generated by the biomass circulating fluidized bed gasifier and the high-pressure feedwater flowing out of the high-pressure heater exchange heat in the heat exchanger, transferring the energy of the high-temperature fuel gas to the high-pressure feedwater. The cooled high-temperature fuel gas flows into the boiler from the heat medium outlet of the heat exchanger for reuse, improving its utilization value; the heated high-pressure feedwater flows into the boiler economizer from the cold medium outlet of the heat exchanger.

[0048] To increase the pressure of the water flowing into the heat exchanger, a booster water pump is installed on the pipeline connecting the high-pressure heater and the heat exchanger; to increase the pressure of the gas flowing into the boiler, a booster fan is installed on the pipeline connecting the heat exchanger and the boiler.

[0049] Example 2

[0050] A method for recovering heat from high-temperature fuel gas generated during biomass gasification includes the following steps:

[0051] Rice straw and air are gasified in a biomass circulating fluidized bed gasifier (the amount of air used is 0.2 times the amount required for complete combustion of biomass). After gasification at 800℃ for 60 seconds, the resulting high-temperature fuel gas (temperature of 700℃) is emitted at a rate of 50,000 Nm³. 3 A flow rate of 100t / h is fed into the heat exchanger. Simultaneously, water (200℃) from the high-pressure heater flows into the heat exchanger at a flow rate of 100t / h under the action of a booster pump, bringing the pressure of the water entering the heat exchanger to 16MPa. High-temperature fuel gas and water exchange heat in the heat exchanger. The high-temperature fuel gas transfers heat to the water, raising the water temperature to 290℃, while the temperature of the high-temperature fuel gas drops to 410℃. The cooled high-temperature fuel gas flows out of the heat exchanger's hot medium outlet, is pressurized by a booster fan, and then transported to the boiler for reuse. The heated water flows out of the heat exchanger's cold medium outlet into the boiler's economizer for reuse.

[0052] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A biomass gasification high-temperature fuel gas heat recovery device, characterized in that, This includes biomass circulating fluidized bed gasifiers, high-pressure heaters, heat exchangers, and boilers; The gas outlet of the biomass circulating fluidized bed gasifier is connected to the heat medium inlet of the heat exchanger, and the water outlet of the high-pressure heater is connected to the cold medium inlet of the heat exchanger. The heat exchanger's hot medium outlet is connected to the boiler, and the heat exchanger's cold medium outlet is connected to the boiler's economizer.

2. The biomass gasification high-temperature fuel gas heat recovery device according to claim 1, characterized in that, It also includes booster pumps; The booster pump is installed on the pipeline connecting the high-pressure heater and the heat exchanger, and is used to boost the water flow into the heat exchanger.

3. The biomass gasification high-temperature fuel gas heat recovery device according to claim 1, characterized in that, It also includes booster fans; The booster fan is installed on the pipe connecting the heat exchanger and the boiler, and is used to pressurize the gas flowing into the boiler.

4. A method for recovering heat from high-temperature fuel gas generated during biomass gasification, characterized in that, The biomass gasification high-temperature fuel gas heat recovery device described in any one of claims 1-3 is used for heat recovery.

5. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 4, characterized in that, Includes the following steps: The high-temperature gas generated from biomass gasification is transported to the heat exchanger through the heat medium inlet; at the same time, water flowing out of the high-pressure heater flows into the heat exchanger through the cold medium inlet; the high-temperature gas and water exchange heat in the heat exchanger, the cooled high-temperature gas is transported to the boiler through the heat medium outlet of the heat exchanger, and the heated water flows into the boiler economizer through the cold medium outlet of the heat exchanger.

6. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 5, characterized in that, The biomass includes rice straw and / or agricultural and forestry waste products; And / or, the gasifying agent used in the gasification includes air; preferably, the amount of air used is 0.2-0.3 of the amount of air required for the complete combustion of the biomass; And / or, the vaporization temperature is 750-850°C, and the vaporization time is 5-300 seconds.

7. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 5, characterized in that, The temperature of the high-temperature gas is 700-750℃; And / or, the flow rate of the high-temperature gas delivered to the heat exchanger is 45000 Nm³. 3 / h-55000Nm 3 / h.

8. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 5, characterized in that, The temperature of the water flowing out of the high-pressure heater is 200-250℃; And / or, the flow rate of water flowing into the heat exchanger is 80-100 t / h, and the pressure of water flowing into the heat exchanger is 15-17 MPa.

9. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 5, characterized in that, The temperature of the high-temperature gas flowing out of the heat medium outlet of the heat exchanger is 400-450℃.

10. The method for recovering heat from high-temperature fuel gas from biomass gasification according to claim 5, characterized in that, The temperature of the water flowing out of the cold medium outlet of the heat exchanger is 280-300℃.

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