Co-firing of gas coal dust fine particles and synthetic peat gas. Part 1. Simulation of processes of steam-air gasification of peat in a fixed bed and combustion of dust and gas mix in a stream

Abstract

Purpose. To build a model of solid fuel gasification in a fixed bed taking into account the velocity of particles, which allows obtaining detailed information about the technological process. To develop an optimal technological scheme of co-firing of pulverized coal particles and peat gas in the TPP-210A boiler. To investigate the process of a binary mix burning. Methodology. The objects of research were pulverized coal of Ukrainian deposits and peat from Volyn region deposits. The developed model was used to calculate the peat gasification process. To study the process of burning a binary blend, ANSYS FLUENT package was used. Findings. A model of solid fuel gasification in a fixed bed has been developed, which differs from the existing models by taking into account the particle velocity and its change. With the aid of this model the detailed information on temperature and concentration fields of the two-phase environment is received. The process of burning binary mix in a TPP-210A boiler is investigated. Originality. It was found that in the time interval 2200 < < 3200 s a stable stationary process of thermochemical processing of peat with q4.1 = 0.130.3% is formed. The profile of the dispersed phase velocity distribution resembles a mirror reflection of the profile of the particle diameter dependence. Practical value. Using the constructed model, the process of thermochemical processing of 28939 kg/h of raw peat in three reactors with a fixed bed at a pressure of 1.5 MPa was numerically investigated. The composition of the generator gas at the reactor outlet was determined.