Biomass gasification power generation can use biomass materials such as agricultural and forestry waste, aquatic plants, oil plants, urban and industrial organic waste, and animal waste. The sources of raw materials are wide, the power generation equipment is diverse, and the scale of power generation varies, which has led to the diversification of gasification technology.
First、According to power generation scale
From the scale of power generation, biomass gasification power generation systems can be divided into small, medium and large.
1. The biomass required for small biomass gasification power generation system is small, simple and flexible, and more fixed bed gasification equipment is used. It is mainly used for rural lighting or as a self-supplied generator set for small and medium-sized enterprises. The power generation is generally less than 200KW. The fixed bed gasification equipment can be further divided into three types: upper suction type, lower suction type and happy layer type. The lower suction type is beneficial to reduce the tar content generated by pyrolysis in the furnace, and thus is widely used. The small biomass gasification power generation project designed and developed by Luoyang Building Material and Architectural Design and Research Institute uses rotary gasification equipment. The power of the conventional generator set is 200KW.
2.The medium-sized biomass gasification power generation system is mainly used as a self-supplied power station or a small-scale power station for large and medium-sized enterprises. It is the main mode of current biomass gasification power generation technology. The amount of biomass raw materials required is large and can be adapted to one type or a variety of different biomass materials, gasification mode is mainly fluidized bed gasification, the power is generally 500-3000KW. Fluidized bed gasification technology includes three types of bubbling bed gasification, circulating fluidized bed gasification and dual fluidized bed gasification. Among them, the most research and application is circulating fluidized bed gasification technology, which adapts to biomass raw materials. Strong in nature, it can also be mixed with traditional fuels such as coal and heavy oil. It has high production intensity and high gasification efficiency. The medium-sized biomass gasification power generation project designed and developed by Luoyang Building Material and Architectural Design and Research Institute uses rotary gasification equipment. The power of conventional generator sets is 500KW, 800KW and 1000KW.
3.Large-scale biomass gasification power generation system is mainly used as a power station. It adapts to a wide range of biomass and requires a large amount of biomass. It must be equipped with a dedicated biomass supply center and a pretreatment center. The system power is generally above 5000KW. Although it is still very small compared to conventional energy sources, it will be one of the main ways to replace conventional energy sources in the future as technology matures. In general, the larger the scale of power generation, the lower the cost required for unit power generation, and the more favorable it is to improve thermal efficiency and reduce secondary pollution.
Second、According to power generation equipment
Using different power generation equipment, biomass gasification power generation technology can be divided into the following three categories:
1.The gasification gas is directly burned as a fuel for a steam boiler, and the production of steam drives the steam turbine to generate electricity. In this way, when the gas composition and the heating value change, the stable combustion state can be maintained, the emissions are less polluted and the gas requirements are not strict, and the impurities and ash can be removed by the cyclone separator, and the cooling can be performed.
2.The gasification gas is burned in the gas turbine to drive the generator to generate electricity. The gas turbine must be modified accordingly to pressurize the gasification gas with a lower calorific value to between 9.8X104 and -29.4X105Pa, otherwise the power generation efficiency is lower. In addition, gas turbines have high requirements for gasification gas quality and must have a high level of automation control, so there are fewer biomass gasification power generation systems using gas turbines alone. The medium-sized biomass gasification equipment designed and developed by Luoyang Building Material and Architectural Design and Research Institute is equipped with gas turbine internal combustion to drive generators to generate electricity.
3.The gasification of the gas in the internal combustion engine drives the generator to generate electricity. The simple internal combustion engine group can be used with low calorific value gasification gas alone, gasification gas and oil, compact equipment and simple system, so it is widely used and has high efficiency. However, this method requires strict gas, and the gasification gas must be purified and cooled. The small biomass gasification equipment designed and developed by Luoyang Building Material and Architectural Design and Research Institute is equipped with gas turbine internal combustion to drive generators to generate electricity.
Some power plants use two kinds of power generation equipment to increase the steam boiler combined cycle on the basis of gas turbine power generation, make full use of waste heat and increase production intensity, which is called biomass integrated gasification combined cycle power generation system. The total efficiency of the system can reach more than 40%. It is a large-scale gasification power generation technology that is mainly researched in developed countries and has broad development prospects.
The biomass gasification power generation project designed and developed by Luoyang Building Material and Architectural Design and Research Institute is the core technology of rotary gasification equipment. Through the rotary gasification equipment, the combustible gas obtained by gasification is used for power generation and comprehensive energy supply, and the conventional generator set power is 200KW, 500KW, 800KW, 1000KW. The working principle of biomass gasification power generation project is to convert biomass and domestic garbage into high-temperature gas through gasification system. After heat exchange and purification, high-temperature gas drives the power generation equipment such as internal combustion engine and generator to produce electricity. The heat of the gas after heat exchange and the exhaust gas after combustion of the gas are passed through waste heat boiler, lithium bromide heat and cold unit and other equipment, to achieve cooling and heat supply, and finally achieve the purpose of cooling, heat and electricity. Through the use of energy cascades, energy efficiency is greatly improved, and energy use rate is >95%. Based on the products of cold, hot and electric triple supply (CCHP system), the project will increase the supply of two kinds of saleable commodities – gas and fertilizer, and develop electricity, gas, fertilizer, cold and heat supply (CCHP-5 ) System.