Pyrolysis Characteristics and Kinetic Analysis of Sediment from the Dianchi Lake in China

Abstract

Pyrolysis properties and kinetic analysis of lake sediment, as well as evolution characteristics of the gaseous products at 5°C/min, 10°C/min, and 20°C/min, were investigated by TG-FTIR. Comparison to the TG and DTG curves at different heating rates, the pyrolysis process at 10°C/min could describe the sediment pyrolysis characteristics better than at 5°C/min and 20°C/min; thus the process of sediment pyrolysis could be considered as four stages. From the kinetics analysis, the nth-order chemical reaction model was suitable to describe the sediment pyrolysis reaction well. The values of n were within 2.55-3.42 and activation energy E was ranged from 15.83 KJ/mol to 57.92 KJ/mol at different heating rates. The gaseous products of H2O, CO2, CO, CH4, and SO2 and several functional groups (C-H, C=O, and C-O) could be found from the IR spectrum. From the evolution characteristics with the temperature, there were two evolution peaks for CO2 and one peak for CH4 and SO2. However, the evolution of CO always increased. Besides, the evolution peak for CO2, CH4, and SO2 all shifted to the low temperature region with the decrease of heating rate. The results could provide theoretical basis for harmless treatment and resource utilization of lake sediment.