Design and operation of a CFB gasification and power generation system for rice husk

A circulating fluidized bed (CFB) biomass gasification & power generation system (BGPG) for rice husk was designed and installed to provide power for a rice mill with a capacity of 150 td−1. The project has been operating in Putian Huaguang Miye Ltd., located in Fujian Province of China since the August of 1998. The system consists of a CFB gasifier, a gas cleaner (including an inertial separator, a cyclone separator, a venturi and two water scrubbers), and power generation subsystem (containing five parallel gas engines rated 200 kW each), in addition to a wastewater treatment system. It is found that the system can be operated stably within the temperature from 700°C to 850°C, and its optimal condition was reached when the workload is increased above 800 kW. The main performance indices are: capacity: 1500 kgh−1, gasification efficiency: 65%, rice husk consumption: 1.7–1.9 kgkWh−1, total efficiency: about 17%. The reliability of the BGPG system has been proven through two years of operation (about 10,000 h). The total investment is 510 000 US$, the unit investment is 370 US$ kW−1, the operation cost is 0.032 US$ kW−1, and the payback period is not more than two years.