Simulation of the Pyrolysis of Biomass Based on Ultimate and Proximate Characterizations

Knowledge of the qualitative and quantitative composition of biomass is essential for designing energy conversion processes such as pyrolysis or gasification. Among the various types of analyses used to characterize biomasses, the most important are the thermogravimetric analysis, scanning calorimetry, proximate analysis, ultimate analysis and biochemical analysis. Pyrolysis and gasification of biomass are processes that can be considered as flexible for a variety of biomasses. However, the type of biomass used significantly affects the overall composition of the syngas, char, tar and potential operational issues. In this sense, the proximate analysis categorizes biomasses based on the parameters of moisture content, volatile content, fixed carbon and ash content. One of the most important characterizations of the biomass is the ultimate analysis, which presents the main elements found in it, such as carbon, hydrogen and oxygen. This paper presents a simulation in Aspen PlusTM, based on the ultimate and proximate characterization of the biomass, was modeled a pyrolysis unit for fixed bed (FB) and fluidized bed (FDB) reactors. In the simulation at a temperature of 700 °C, gas yields of 63%, liquid yields of 21% and solids yields of 16% were found for the FDB, while in the case of the FB they were 42%, 30% and 28% respectively. The lowest yield of solid wastes found for FB at high temperatures found was 27%, while in FDB it was 15%. The simulation allows the finding of the main products of the pyrolysis, such as char, tar and gases, in addition to an ultimate and proximate characterization of tar and char.