Methane gas contained in the coal seams is released during the underground mining of coal. To avoid explosions, the pits are constantly ventilated. The methane-containing waste air expelled by the ventilation system is generally discharged untreated into the atmosphere. Although this is still permissible today in most countries, methane emissions contribute around 21 times more to global warming than the same volume of CO2.
The VAM RTO technology developed by Dürr permits the methane to be dealt with sustainably and cost-effectively. The regenerative thermal oxidation process (VAM RTO), in which the gas is burned at approx. 1,000 degrees Celsius, significantly reduces emissions. If a steam turbine is connected, electricity can be generated for use in the mine or for feeding into the grid. In many countries proceeds can also be generated from emissions certificates.
In the province of Shanxi, the largest area of coal reserves in China, Dürr recently won a VAM RTO order to the value of more than € 10 million. Dürr is to install twelve RTO modules for the disposal of ventilation air methane in the Gao He mine by March 2013.
The company had already received a smaller order from the US last year. Dürr supplied three RTO modules for a coal mine in West Virginia which are enabling some 320,000 tonnes of CO2 equivalent to be scrubbed annually.
According to Ralph Heuwing, CFO and the member of the Dürr AG Board of Management with responsibility for the Clean Technology Systems division: "The increasing importance of environmental protection and energy efficiency is creating new markets for proven Dürr technologies. Our VAM RTOs mean that we can be part of this trend and generate further growth in the Clean Technology Systems division. In the next few years we anticipate a large number of new orders for VAM scrubbing systems".
The greatest potential exists in China where coal plays a substantial role in meeting the growing energy demand. At the same time, the country is increasingly intent on ensuring that its economic growth is sustainable. According to the current five-year plan, pollutant emissions are to be reduced by 16 to 17%. To achieve this, investment in sustainable technologies is being promoted more strongly.