Two Caterpillar power generators produce the heat energy of 45,000 GJ, and electrical energy of about 25,000 MWh. The total power of the new equipment is 4 MWEl. and will be used for the needs of the mine, thus allowing it to save PLN 7 million per year. The environmental effects of this investment are also significant, as the annual emissions of methane to the atmosphere will be reduced by 6.5 million of m3.
The combined production of electrical and heat energy allows the overall efficiency of the system to be obtained at a high level of 87%. The mine’s total demand for power amounts to about 24 MW, where 10.9 MWEl is obtained from methane derived from the process of demethylation.
The combined generation system has been installed in a light-structure free-standing building in the immediate vicinity of the demethylation station. The gas from demehtylation in the Krupiński mine is supplied directly through a pipeline to the gas-engine operated power generators which drive the electricity-producing generators at 6 kV voltage. This energy is fed through cables to the main switching station which powers the Krupiński mine. Through the proper exchangers, the heat produced in the engines (engine cooling system and hot combustion gases), is captured and supplied to the mine’s heat distribution network (temperature of 90/70oC), and subsequently used for the mine’s bath house and for heating the premises. About 41 million m3 of pure methane is captured annually by the demethylation station in the Krupiński mine, and the captured mixture of methane and air contains, on average, 50-60% of methane. This methane has so far been used in the mine’s flotation concentrate drying room, in two cogenerators, and in peak load boilers operated by Spółka Energetyczna Jastrzębie. The decision to install another cogeneration system with the power of 4.0 MWEl was made on the basis of the forecasts that the supply of this gas in the next years will be at a level of 40-55 million of m3 per year.
The contractor for the "turnkey" investment is the consortium of Controll Process and Eneria. The Jastrzębska Spółka Węglowa mines have some of the highest concentrations of methane in Poland, and so they are leaders in the economic application of this dangerous gas. Methane from the process of demethylation is a precious fuel obtained, so to say, additionally, during the process whose main purpose is to successfully fight the methane-related risks. In JSW it is used for production of electrical energy, heat and even coolness. As for the whole JSW, about 39% of the methane released during mining works goes through the process of demethylation, and 61% is released to the atmosphere through ventilation. The mixtures that are demethylated include 45-70% of methane, and are used economically in energy production systems. In 2010 the JSW mines captured 132 million m3 of methane, out of which 70% was used. Methane is used in cogeneration systems (production of electrical energy and heat), and in tri-generation systems, where "coolness" is additionally produced by the absorption refrigerators. The cogeneration systems are used in the "Budryk", Ruch "Borynia", "Krupiński" and 'Pniówek" mines, in the "Moszczenica" CHP plant, while the tri-generation system – in the "Pniówek" mine, for the mine’s central air-conditioning system. Until 2013, JSW will have been processing all gas captured in demethylation.
