Study on simulation of pulverized coal gasification process in the GSP gasifier

Abstract

A model of entrained‐flow coal gasifier (1920 t/d and single nozzle) was established to simulate the gasification process of pulverized coal from Ningxia of China on the basis of ANSYS Fluent. In order to simulate the characteristics of the coal gasification process, the Lagrange model was adopted to obtain properties of particles, and the standard k‐ϵ turbulence model was applied to the gas phase flow. Meanwhile, the species transport model and modified eddy‐dissipation model (EDM) were used to simulate the species transport and gas phase reaction, respectively. Radiation heat transfer was modelled with the P1 model. The simulation results were in good agreement with the actual production data. In addition, the effects of the pressure, temperature, oxygen‐coal ratio, and steam‐coal ratio on the gasification process were studied using this model. It was found that increasing the gasification pressure had little effect on the composition of outlet gas. The concentration of CO and H2 increased with the increase of temperature. The best oxygen‐coal ratio range was 0.70–0.85 for this gasifier and coal sample. The steam‐coal ratio was decided by the actual operating conditions of the gasification. The simulation of the coal gasification process can predict the details of flow field, temperature field, velocity field, and concentration field in the gasifier. It is helpful to clearly understand coal gasification behaviour inside the gasifier so as to better understand the actual gasification process. Furthermore the simulation method is practicable in the gasifier design and structure optimization, and also supplies some useful data to assist the production operation.