Development of biomass power generation in China

1 History of biomass power generation in China

China's biomass power generation started later than Europe and the United States, but after more than ten years of development, has basically mastered agricultural and forestry biomass power generation, urban waste power generation and other technologies.

Before 2005, large-scale grid-connected power generation projects using agricultural and forestry waste as raw materials were almost blank. In 2006, China approved more than 1 million kilowatts of direct-combustion power generation projects. The installed capacity of biomass power generation exceeds 2.2 million kilowatts, including 1.7 million kilowatts of bagasse power generation, 50,000 kilowatts of rice hulls power generation in rice mills, 400,000 kilowatts of municipal waste incineration power generation, in addition to some small-scale biomass gasification power generation demonstration projects. In 2006, the "renewable Energy Law" and the implementation of relevant supporting policies such as preferential on-grid electricity prices for biomass power generation have made China's biomass power generation industry begin to grow rapidly.

From 2006 to 2009, the installed capacity of straw direct combustion power generation increased at an average annual rate of more than 30%. At the end of 2009, China's total installed capacity of straw direct combustion power generation was 2.65 million kilowatts, accounting for 62% of all biomass power generation; The total installed capacity of waste incineration power generation is 1.25 million kWh, accounting for 29% of all biomass power generation; Other gasification power generation, biogas power generation, and mixed combustion power generation account for a small proportion, accounting for less than 10% in total.

According to the national renewable energy medium - and long-term project plan, biomass power generation will reach 30GW in 2020. At present, there are more than 10 biomass direct combustion power generation projects under construction in the country, with an installed capacity of more than 4 million kWh. However, to reach the 2020 development goals, there is still a need to solve the problem of resource fragmentation and raw material collection difficulties.

2 Status quo of biomass power generation technology in China

2.1 Direct combustion power generation

The domestic direct combustion power generation technology has matured, and the single-unit capacity can reach 15MW. According to the nature of the fuel can be divided into two categories: first, the combustion technology of woody biomass fuel in Europe and the United States. Bagasse and rice husk furnaces in early China belong to this category. The other kind is straw burning technology, China's biomass resources to straw as the main body, so the domestic biomass burning technology research mainly focuses on straw burning technology. Domestic boiler manufacturers according to the actual situation of biomass power generation in China to improve the introduction of Danish technology after manufacturing production. Domestic independent development of fuel pretreatment system, feed system and slag removal system. Many domestic scientific research institutions and boiler manufacturers have developed fluidized bed boilers with independent intellectual property rights, and the technology is relatively mature.

2.2 Hybrid fuel power generation

There are two main types of hybrid fuel power generation. One is biomass directly mixed with coal and then put into combustion, which has higher requirements for fuel processing and combustion equipment; One is the mixed combustion of gas and coal generated by biomass gasification, and the generated steam is sent to the turbine generator set. Hybrid fuel power generation is mainly modified by introducing Danish technology.

There is a precedent for the use of bagasse mixed combustion for power generation in south China. It is only necessary to slightly transform the furnace of the existing coal power plant boiler, and then add the feeding and bag-type dust removal device. The biomass that is less than 20% of the total calorific value is directly mixed in the traditional coal-fired boiler, which has been basically mature in technology.

2.3 Gasification power generation

Biomass gasification power generation refers to the conversion of biomass into gas fuel in the gasifier, and after purification, it is burned in the gas engine for power generation or into the fuel cell for power generation. The gasification technology applied to engineering in China is mainly the biomass circulating fluidized bed gasification technology developed by Guangzhou Energy Institute of the Chinese Academy of Sciences. Other domestic research institutions, such as the Shandong Energy Research Institute, are also carrying out relevant research. In 1998, the first 1MW biomass rice husk gasification power generation system was built in Putian, Fujian Province, followed by the construction of more than 20 biomass gasification power generation systems across the country.

The existing gas internal combustion engine has low efficiency, small installed capacity, and low power generation conversion efficiency (generally only 12 ~ 18%), which can not meet the needs of large-scale industrial applications. The calorific value of gas is low, the tar content in gasification gas is high, and the secondary pollution is serious. Therefore, it is necessary to further research and develop suitable large-scale equipment and technology.