AIR-STEAM GASIFICATION OF DAIRY BIOMASS USING SMALL SCALE FIXED BED GASIFIER

The composition of gases obtained from gasification of biomass fuels depends principally upon parameters like fuel and oxidizing medium supplied, equivalence ratio (Phi), steam-fuel ratio (S:F), pressure, reaction temperature, and residence time in the gasifier. Gasification with steam only is an endothermic process which produces rich mixtures of CO and H(2) while gasification with air-steam may not require heat input in order to produce H(2) rich mixtures of CO and CO(2). Furthermore, gases produced by gasification with-air-steam can be supplied to a shift reactor to produce mixtures of H(2), CO(2), and N(2). When pure O(2) is used instead of air, the H(2) separated from CO(2) can be used for in situ sustainable green power generation. The gasification process can handle low quality fuel and larger sized particles. While coal has higher fixed carbon (FC) providing more heat for gasification, the Dairy biomass (DB) selected in current study has lower FC and hence contributes less heat. While most of the past studies deal with gasification of coal, current study concentrates on DB as fuel. Expenmental results are presented for gasification of i) dairy biomass (DB) and ii) DB ash blends (DBAB) using a 10 KW fixed bed counter-flow gasifier and air-steam as oxidizing source. The results show that the reactor operates almost adiabatically. The effects of the Phi and S:F ratio on peak temperatures, gas composition, gross heating value of the products (HHV), and energy conversion efficiency (ECE) are investigated. A mass spectrometer has been used to analyze the composition of gases in real time continuously. Increasing Phi or S:F increases the production of H(2) and CO(2) but decreases the production of CO; thus, the reaction of CO+H(2)O -> CO(2)+H(2) seems to control the composition of gases. The operating parameters include 1.59<Phi<6.36 and 0.36<S F<0 8. Energy Conversion efficiencies (ECE) range from 0.26 to 0.80.