Institut za rudarstvo i metalurgiju Bor

COMMITTEE OF UNDERGROUND EXPLOITATION OF YU ISSN: 1451-0162
THE MINERAL DEPOSITS UDK: 622
UDK: 622.33:622.337(045)=20
Mirko Ivković*, Jovo Miljanović*
CALCULATION THE GAS CONCENTRATION IN THE UNDER-
GROUND COAL COMBUSTION
Abstract
Underground coal gasification (UCG) is a technology of gas extraction directly from a deposit
in the process of dry coal transformation. The composition of gas, its characteristics and productivity
depend on the coal type, the composition of blowing mixture and conditions of interposition
the coal layers. Depending on the use of excavated gas, an adjustment of concentrations of particular
components is carried out, and therefore it is necessary to calculate the composition of
gases in mixture.
Key words: exploitation, coal, oilshale, undergrond gas production
INTRODUCTION
An effective way of evaluating the offbalance
coal reserves as well as the balance
reserves in some cases is the underground
coal gasification (UCG). The technology
consists of drillhole preparation of underground
gas-generator in a deposit, the realization
of extracting process of gas obtained
in the channels of the coal seams by interaction
of coal and inflow of gasification medium
(air, water vapour, oxygen…). The
generation of coal arises after the coal seam
is ignited as the result of chemical, thermal
and mechanical effect on the coal seam. The
underground coal gasification is characterized
by total available quantity of coal for
UCG. Thermal efficiency of the process is
defined by the ratio of calorific power of
* PC for Underground Exploitation Resavica
the obtained gaseous mixture and calorific
power of coal, out of which the mixture
has resulted, reduced to the equivalent
proportion, what depends on a type of
gasification agent, its pressure and temperature,
the characteristics of coal subject
to the gasification, the depth of occurrence
and tectonic conditions.
The gas derived from the underground
coal gasification could be used as a power
fuel in thermal plants for electrical energy
production in boiler-rooms, drying in civil
engineering and chemical industry etc.
Figures 1 and 2 show the schematic
diagram of UCG generators and thermal
balance of this process.
No 1, 2010. 131
MINING ENGINEERING