Effect of Pyrolysis Temperature and Pyrolysis Pressure on Gasification Rate of Woody Biomass-derived Char

Abstract

This paper reports on the relationship between biomass char property and gasification reactivity. The gasification kinetics of biomass char has been revealed by measuring the rate of weight loss during reaction with CO₂, as a function of temperature. First-order kinetic rate constants are determined by fitting the weight loss data using a random pore model. The relationship between char structure and CO₂ gasification reactivity was investigated in the range of 873 to 1073K (pyrolysis temperature), and 0.1 to 3.0 Mpa (pyrolysis pressure) at 1073K. The experimental results indicate that the reactivity of the biomass char is determined by pyrolysis condition. The gasification rate of biomass char decreases with increasing pyrolysis temperature. This is due to promotions of carbonization and dehydrogenation of biomass char. The CO₂ gasification rates in char generated at 0.1 MPa exhibited approximately twice values compared to those at 3.0 MPa. This is because the uniformity of carbonaceous structure rises with increasing pyrolysis pressure. The uniformity of carbonaceous structures would affect the CO₂ gasification reactivity, and the decreasing uniformity would lead to the progression of cavities on the char surface during the CO₂ gasification process.