Gasification system of oxygen-enriched biomass circulating fluidized-bed

Abstract

The invention relates to a gasification system of an oxygen-enriched biomass circulating fluidized-bed. Biomass is fed from the middle-lower part of a gasification furnace, oxygen-enriched air preheated by a preheater and overheated water steam are fed from the bottom of the gasification furnace, the biomass is rapidly fluidized under the assistant action of a bed material to generate pyrolysis and gasification reactions, generated high-temperature fuel gas is subjected to gas-solid separation by using a cyclone separator, carbon residues in the fuel gas and the bed material are fed to the gasification furnace from the lower part of the gasification furnace by a material return device to continuously react, and the high-temperature fuel gas passes through a cyclone dust collector, a superheater, a waste heat boiler and the preheater in sequence and is then separated from the system. According to the gasification system, the volume fraction as well as the dust and tar concentration in the fuel gas can be effectively reduced, the heat value of the fuel gas is increased, and the high-quality clean fuel gas is obtained.

Description

technical field [0001] The invention relates to the field of biomass thermochemical conversion, in particular to an oxygen-enriched biomass circulating fluidized bed gasification system. Background technique [0002] my country is rich in biomass fuel resources, and vigorously developing biomass fuel resources will help improve my country's fossil fuel-based energy structure, which can not only reduce the emission of sulfide and nitrogen oxides, but also alleviate the greenhouse effect. Biomass gasification technology realizes the transformation of low-grade biomass into high-quality gas, which can replace petrochemical energy such as oil and natural gas in many fields. However, in the existing biomass technology, the nitrogen content in the biomass gas is too high, which makes the calorific value of the gas low, which limits the application of biomass gasification technology. Therefore, the use of oxygen-enriched gasification can reduce the nitrogen content in the gas and i...

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Problems solved by technology

This method and device have high requirements on the moisture content and particle size of the biomass raw material, and the biomass raw material needs to be dried and pulverized, the operating cost is high, and the economy is poor, so it is difficult to be really applied in actual production

[0004] The Chinese invention patent with the authorized publication number CN101164866A discloses a method and device for preparing synthesis gas by stepwise oxygen-enriched oxidation of biomass. Biomass raw materials are pyrolyzed at low temperature in the absence of air, and all products are sent together to the downdraft The fixed-bed gasification furnace reacts with high-temperature oxygen-enriched gas to form a high-temperature oxidation zone at 950-1300°C to obtain biomass gas with high calorific value and low tar. This method can indeed reduce the tar content in the gas, but due to oxidation The temperature in the zone is already higher than the slagging temperature of the biomass, and the system cannot operate continuously and stably; the gasification intensity of the downdraft fixed-bed gasifier is low, and it is difficult to meet the needs of large-scale industrial applications

[0005] The existing biomass oxygen-enriched oxidation technology is difficult to achieve large-scale industrial application, and needs to be improved and developed

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