Stepwise Analysis Of Gasification Reactions With Aspen Plus And Cpfd

Abstract

The energy from biomass can be utilized through the thermochemical conversion processes of pyrolysis and gasification. Biomass such as wood chips is heated in a gasification reactor to produce a synthesis gas containing CO, H2 and CH4. The gas can be further processed to bioproducts or fuels. The thermo-chemical process involves devolatilization of wood followed by steam gasification, CO2 gasification, methanation, water gas shift reactions and methane reforming. To optimize the performance of the reactor, it is important to study each of the reactions separately. The reactions are simulated individually using the chemical process optimization software Aspen Plus. The results are compared with simulations performed with the Computational Particle Fluid Dynamic (CPFD) software Barracuda VR 15. The CPFD methodology solves the fluid and particle equations in three dimensions with the transient flow and is time-consuming. Aspen Plus is one dimen- sional and solves the included reactions fast. The results of the Aspen Plus and CPFD simulations, given as product gas compositions (CO, CO2, CH4 and H2), show that each reaction contributes to the product gas composition differently. Comparison between Aspen Plus and CPFD simulations of individual gasification reactions show good agreement. However, when all reactions are included in the simulations, there is a deviation in the volume fraction of product gas composition.