1. Analysis of characteristics of biomass centralized gas supply system
The application prospects of biomass energy in rural areas are mainly to promote biomass gasification gas supply technology, so that the biomass gas produced by gasifiers can be supplied to corresponding supporting equipment to provide cooking gas for residents. At present, biomass gasification gas supply is mainly divided into two types: centralized gas supply and individual gas supply. Biomass gasification centralized gas supply has developed rapidly in recent years. It establishes a biomass gasification station in a village or group in the countryside, stores the biomass gas in a gas storage cabinet, and centrally provides domestic gas to residents through the gas pipeline network.
At present, there are hundreds of centralized gas supply systems built across the country, which have played a certain role in efficiently utilizing surplus rural straw and mitigating environmental problems caused by farmers burning excess straw. After the biomass centralized gas supply system was promoted and applied in some rural areas, it was found that it faced the following problems:
1) The total investment of the project is relatively large, usually at least one million yuan, with an average investment of more than 4,000 yuan per household. In some economically underdeveloped areas, it is difficult for users to pay;
2) The project requires overall contiguous promotion, which is difficult to adapt to the current situation of rural residence in my country that is not concentrated enough;
3) The calorific value of biomass gas is low, but the capacity of the gas cabinet is limited and the gas supply time is required to be uniform, so users often find it inconvenient to use, resulting in serious arrears in many gasification projects, the number of households that cannot meet the design requirements, and the utilization rate of gasification equipment is reduced;
4) The overall gasification technology is not mature enough. After long-term operation, tar, fly ash, etc. are prone to clogging pipelines or stoves, resulting in the project being forced to be decommissioned after a period of operation.
2. Current application status of biomass separate gas supply technology
The characteristic of this technology is that rural residents directly use small gasifiers as a family unit, and the gas produced is connected to nearby stoves for use. The gasification system has the characteristics of small size and low investment, and is more suitable for rural users with relatively backward economies and scattered residences [2]. At present, small household biomass gasification technology has developed to a certain extent. For example, the household gasifier produced by Hunan Zhangjiajie Sanmu Energy Development Co., Ltd. adopts a fixed bed suction furnace type. It has the characteristics of simple gasifier equipment and low investment. A set of biomass gasifier sells for only more than 700 yuan, and has entered some rural markets. Existing household gasification devices in China still have problems of uneven quality and unstable performance. Developing small or household biomass gasification devices with less investment, low tar content and mature technology as soon as possible is the key to the current promotion and application of biomass utilization technology in rural areas.
