Euler-Lagrange Modeling of Entrained Flow Gasification of Coke-Biomass Slurry Mixture

Abstract

An Euler-Lagrange CFD method for co-gasification simulation of slurry mixture of pulverized petroleum coke and up to 20% biomass (wheat straw) in a pressurized entrained flow gasifier is proposed to increase the biomass contribution to green electricity generation. The gas phase is modeled as a continuum and the solid phase is modeled by a Discrete Phase Modeling (DPM) using a soft sphere approach for the particle collision dynamic. The model takes into account detailed gas phase chemistry, modeling of the pyrolysis and gasification of each individual particle, particle shrinkage, and heat and mass-transfer between the gas phase and the dispersed phase. The coke was blended with 5–20% wheat straw on mass basis. The effect of the percentage of biomass blended with coke on the flow field, gas and temperature distribution, syngas composition and particles trajectories are presented. Most important result is the quality and quantity of syngas produced when blended up to 20% biomass is similar to that of coke gasification. Additional observation is that the reactivity of coke was greatly improved by the presence of biomass. The overall conclusion of this his study is that co-gasification is possible provided that operation is properly adapted.