Volume 25: Accelerated Energy Innovations and Emerging Technologies

Numerical Modelling of Fixed-Bed Co-gasification Process Through Multiple Thermally Thick Particle (MTTP) Model Linzheng Wang, Ruiqu Deng, Ruizhi Zhang

Abstract

Co-gasification technology provides a feasible solution for the energetic valorization of various types of biomass feedstocks, especially those not directly applicable for gasification owing to their low-calorific values or high ash content. Numerical modelling is a promising approach to evaluate the performance and analyze the conversion processes inside the gasifier, but the complexity of cogasification technology has put forward challenges to the model formulation. This paper established the Multiple Thermally Thick Particle (MTTP) model for simulating the co-gasification process. MTTP model could not only calculate the individual conversion processes of different fuels, but also simultaneously reflect the characteristics of thermally thick particles and the interactions between different fuels through sub-grid models for the solid phase. Experimental results of a downdraft fixed-bed co-gasification from literature were adopted for model validation. The modelling results from the MTTP model are in good agreement with the measured values of temperature and syngas composition upon changing the co-gasification ratio (CGR). Further analysis of the weight-loss process of different fuel particles and the corresponding intraparticle temperature distribution have confirmed the different conversion characteristics and interactions between different fuels during co-gasification process.

Keywords Co-gasification, Downdraft fixed-bed gasifier, Numerical modelling, Thermally-thick particle, Subgrid mode