Design And Experimental Research Of Biomass Gasifier

Biomass gasifier is a core device of current biomass gasification central gas feed technology. Based on research of biomass materials, thermal chemical characteristics and combustion dynamics, this paper chooses fixed-bed downdraft gasifier type, researchs and designs differnt parts of biomass gasifier and gas cleaning system according to theories of gas combustion and heat transfer and fluid dynamics science. Fireproof material of inside body of biomass gasifier is aluminous material made by integral moulding technique, and middle body is ring-shaped gas channel, and outside body is recycle cooling water and bottom body is designed to deposit ashes. Gas cleaning system can efficiently remove fly ashes by an improved dedusting chamber, reduce gas temperature by a shell-tube heat exchanger, absorb wet content by triplicate desiccant devices, remove jar by a dry filter and send biomass gas to gas tank by a forced fan blower. Bedides, an improved water-seal is installed in front of the inlet of gas tank in order to avoid gas's returning to biomass gasifier. This paper tests main technical performances such as hearth temperature distribution, gas ingredient, net calorific value, impurity content, etc., and analyses influences on gasification effect of different biomass, gasification intensity, hearth temperature, coefficient of second air and other factors, which are very useful to find out the general design principles of biomass gasification equipment. In addition, the design principle of key technical indexes is offered. Better net calorific value and lower impurity content can be obtained when gasification intensity is about 200kg/m3·h and the quality of gas is better when coefficient of second air is 20-25% and reduction zone temperature is about 700℃. The experimental test results show that this biomass gasifier has better biomass adaptability and steady and reliable operation. Its index reaches the design requirements.