Definition of biomass in a broad sense includes all solar energy converted and fixed by photosynthesis of plants. Biomass has many definitions as a carrier of biomass energy. The US Department of Energy defines biomass as: organic matter derived from plants and animals. Types of biomass: Biomass commonly used for energy conversion can be divided into four categories: wood residues (including all materials derived from wood and wood products, mainly including: firewood, charcoal, waste wood and forest residues), agricultural waste Articles (all waste) are related to planting and crop processing.

For example: rice husk, straw and animal manure, energy crops (crops dedicated to energy production, such as sugar cane stalks and cassava) and municipal solid waste (MSW). Biomass boiler detailed description of biomass fuel characteristics: According to the biomass pellet standards of Sweden and the EU, biomass pellets should have the following characteristics.

The diameter is usually 8 mm, and the length is 4-5 times the diameter; the breakage rate is ≤1.5%-2.0%; the dry base moisture content is ≤10%-15%; the ash content is ≤1.5%; the sulfur content and chlorine content ≤0.07%, nitrogen Content ≤0.5%; calorific value: EU has no clear requirements, Sweden requires ≥16.9MJ. Utilization and conversion of biomass: There are three main ways to use biomass for conversion: thermochemical method, biochemical method and extraction method.

The thermochemical method refers to the conversion technology that converts biomass into other forms of energy at high temperature. It mainly includes four methods of direct combustion (biomass directly burns to directly release heat); gasification (partial oxidation of biomass and conversion into gaseous fuel with the participation of gaseous media such as oxygen, air, or steam.