Determination of kinetic parameters of coal pyrolysis to simulate the process of underground coal gasification (UCG)

Purpose
The aim of the research presented in this paper was to determine the values of the kinetic parameters of coal pyrolysis from two areas of the planned experiment, UCG, i.e. the Barbara Experimental Mine of the Central Mining Institute and the Wieczorek Mine.
Methods
The thermal decomposition of coal analysis used the thermogravimetric technique. The test was carried out in a temperature range of 30–900°C in a nitrogen atmosphere for three fixed heating rates, β – 5, 10, and 15°C min–1. A selection of sample heating rates of coal and reaction environments were designed to reflect the conditions seen during the process of underground coal gasification. The kinetic parameters were determined by using modified Coats–Redfern, Kissinger and Mianowski-Radko methods.
Results
The values of the activation energy, E, and the pre-exponential factor, A, were determined for a given model of the first order decomposition reaction of coal. The study successfully compared kinetic parameters of the tested coals.
Practical implications
Designated kinetic parameters may be used to model the process of pyrolysis and – as preliminary data – for installation design of pilot underground coal gasification.
Originality/ value
The devolatilization of a homogenous lump of coal is a complex issue. Currently, the CFD technique (Computational Fluid Dynamics) is commonly used for the multi-dimensional and multiphase phenomena modelling. The mathematical models, describing the kinetics of the decomposition of coal, proposed in the article can, therefore, be an integral part of models based on numerical fluid mechanics.