Numerical studies on thermochemical processing of peat in a fixed layer

Abstract

Purpose. To investigate the gasification process of peat in gas generators with a fixed bed at a pressure of 1.5 MPa and create the initial conditions at the entrance to the waste burners required for combustion of the binary mixture. Methodology. The objects of research were peat granules of Volyn peat. To calculate the process of gasification of peat gas, the constructed model of thermochemical processing of solid fuel, described in the first part of the work by the authors was used. Findings. It is shown that in the area close to the upper boundary of the fixed bed, where the process of gasification of peat is stationary, there is a jump in the temperature of peat particles from 300 to 772C, in which the tar is practically not released, and thus the obtained pyrolysis gas contains CO2, H2O, H2 and CO. The structural and physicochemical characteristics of gas generators are obtained and the initial conditions at the entrance to the discharge burners of the chamber furnace of the steam generator TPP-210A are formed. Originality. It is shown that when the velocity of peat particles decreases, a slag bed is formed between the zone of maximum heat release and the grate, which consists of cooled ash particles, which protect the grate from overheating. With such an organization of the process it is possible to achieve the stationary process of gasification with mechanical incompletely burned material equal to zero. Practical value. It is shown that with the help of the model of thermochemical processing of solid fuels it is possible to adjust the height of the dry distillation zone by changing the velocity of the dispersed phase and the rate of heterogeneous and homogeneous chemical reactions by changing the proportion of O2 or H2O air enrichment.