The operating mine conditions test of the underground coal gasification (UCG) process began in the belonging to the Katowicki Holding Węglowy (KHW) Wieczorek Coal Mine on the 24th March 2014. Pilot installation has been constructed jointly by GIG and KHW at Wieczorek Coal Mine site referring to the realization of the research task “Elaboration of the coal gasification technology for highly effective fuels and electric energy production”. GIG is the leading unit in the range of UCG works.
It has to be underlined that this test has research character and it was conducted not only to check the technological assumptions but also to answer the questions connected with the definition of the process impact on the environment and its safe conduction. The experiment is also to show that the process is possible to control and stop at any stage.
Pilot installation
The installation consists of 2 basic parts:
- underground part located 400 meters under the surface and its essential element is a gasification georeactor at 501 seam with the thickness of 5m
- surface part located at the Wschodni (East) shaft consisting of the georeactor media supplying elements and gas collection, purification and utilization elements.
The basic goals of the pilot installation are:
- verification of the possibility of underground coal gasification process conduction in the conditions of operating coal mine
- data obtainment for elaboration of technological project and preliminary feasibility study of UCG demonstration installation
- data obtainment for elaborated technology multi-parameter eco-effectiveness assessment
Supply of the gasification factors and reception of the reaction products from the gasification area at the seam is realized by 2 V-shaped holes bored diagonally from the excavation made about 2-2,5m above the seam. The pipeline of the products at its initial part is cooled diaphragmatically with water filling the part of the excavation after its shotcrete method sealing. Gasification factors are supplied from the surface by the pipelines system located in the shaft and in excavations:
- air – from air compressor
- oxygen – from liquid oxygen container with evaporating basin
Because of safety considerations the gasification area is also supplied with backfill and nitrogen pipelines.
Pre-emission of the pitch substances will take place in the separators located in underground excavations. Gaseous products of the temperature up to 400 oC are transported to the surface by isolated pipeline in the shaft and there they are cooled and purified. Purified gas is directed to the torch.
Process parameters
Complex process parameters of the pilot installation are as follows:
- coal gasification rate from 100 up to maximally 600 kg/h
- amount of the gasified coal parcel – about 200m2, the amount of gasified coal during the test – about 1200 tons
- gasification factors supply rate:
- only air – up to 1200 Nm3/h
- oxygen – 200-300 Nm3/h
- amount of produced gas – max 1500 Nm3/h
- expected composition of the produced gas is heat value of 3,5 – 5 MJ/Nm3
nitrogen – 53%, carbon dioxide – 16% carbon oxide – 12%, methane – 3%, hydrogen – 15%
The above experiment is realized within the frame of scientific research and development works strategic program “Advanced technologies of energy sourcing” financed by National Centre of Research and Development. Apart from coal gasification in Poland strategy elaboration the main utilitarian goal of the task in the range of UCG is to elaborate technological project and preliminary feasibility study of the UCG demonstration installation at the scale of 20 MW. Basic sources of the data in this range are the results of multi-day test at pilot scale at the 501 seam at Wieczorek Coal Mine.
Installation construction at the conditions of operating mine is an unparalleled enterprise in Polish mining practice which caused the necessity of solving of series of formal-legal problems connected with the meeting of the requirements of Geological and Mining Law. State Mining Authority and Katowice Mining Office took part in these activities.
Underground coal gasification despite of the researches conducted in many countries since many years has not been commercially used as far (the exception is the installation in Angren in Uzbekistan). Intense works on this technology are conducted in Australia, China, Canada and Republic of Southern Africa.
The aim of the researches conducted by GIG and KHW is to elaborate own technology of underground coal gasification verified in pilot scale. The researches conducted at GIG are partially oriented to shaft underground coal gasification method technology elaboration. This method uses existing mine infrastructure for ‘usage of the desiduous deposits of coal.
Central Mining Institute (GIG) has been taking part in UCG process researches since 2007 by coordinating the realization of 2 big projects HUGE and HUGE2, co-financed by RFCS.
Underground coal gasification consists of supplying of the gasification factor to the coal seam and collecting of the produced gas of industrial value at the surface. The condition of the positive process course is competent dosing of the gasification factor to obtain the temperature allowing for determined composition gases production. Coal gasification originated gas can have many applications. It can be used for heat and electricity production in energy industry, can replace natural gas in chemistry, it can be also used for liquid fuel production processes.
Underground coal gasification can be conducted with air, oxygen, steam or the mixtures of the above as gasification factors. For energy-related usage gas is usually produced with air or oxygen application. Gained product differs in its heat value. Gas produced with the usage of oxygen has about 8MJ/m3, air – 3,5-4,5 MJ/m3. Unlike the surface gasification UCG technology and installation size are determined by the seam conditions.
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