Influence of Pyrolysis Parameters and CaCl2 Catalyzer on Pyrolysis of Elephant Grass (Pennisetum purpureum Schum.)

Elephant grass is a fast growing and low nutrient demand plant with significant potential as a renewable energy source. In this work, the influence of heating temperatures, N
₂
sweeping gas flow rates and CaCl
₂
catalyzer weights on the yields of products and chemical composition of bio-gas was investigated by pyrolysis and catalytic pyrolysis of elephant grass in a fixed bed reactor. The results showed that as the heating temperature increased, the yield of charcoal decreased, while bio-gas and bio-oil increased. The concentration of CO
₂
decreased 20 vol.% at the heating temperature of 600°C than that at 350°C and the concentration of CO reached 25 vol.% in 600°C. With the flow rate of N
₂
sweeping gas risen, high yield of bio-oil, low yield of bio-gas and high concentration of CO
₂
were gained. CaCl
₂
had an obvious catalytic effect on elephant grass pyrolysis, and the low level of CaCl
₂
(less than 15.4 wt.%of grass weight) evolved high yield of charcoal. The high level of CaCl
₂
doping was helpful to evolve the degree of decomposition and improve the yield of bio-oil, but had a slight effect on the chemical composition of bio-gas.