Kinetics of pyrolysis and gasification using thermogravimetric and thermovolumetric analysis

Abstract

The carbon dioxide gasification process of Miscanthus giganteus biomass was examined by using two methods. Firstly, isothermal thermovolumetric method was applied. The measurement was conducted at 950 °C and under the pressure of 0.1 MPa. Thermovolumetric method, based on the continuous analysis of different kind of gases, which are formed during the gasification process, allowed determination of yields and composition of resulting gas as well as constant rate of CO formation. Then, non-isothermal thermogravimetric methods was applied, which records the loss of weight of a sample as the function of temperature. During measurement, temperature was raised from ambient to 950 °C and pressure was 0.1 MPa. As a results, changes in carbon conversion degree was obtained. Moreover, TGA methods made it possible to distinguish the various stages of the gasification process such as primary pyrolysis, secondary pyrolysis and gasification, and determine kinetic parameters for each stages. The presented methods are different since they are based either on analysis of changes in the resulting product or analysis of changes in the supplied feedstock, but both can be successfully used to effective examination of  kinetics of the gasification process. In addition, an important advantage of both methods is possibility to carry out the gasification process for a variety of solid fuels as coal, biomass or solid waste in an atmosphere of a variety gasifying agents.