128 / 2021-10-04 14:12:06

Methane capture to ensure safety of mining works and electricity production – A case study

hard coal mine,methane capture,methane hazard,mining safety,electricity production

Methane is captured from the mines to ensure the operational safety of the mine and the continuity of mining operations. Capturing and using methane gained increasing interest in the past number of years. Many factors affect methane capture and its concentration in the air-methane mixture. The quality of the gas is important for the possibility of use and durability of the installation. At the same time, hard coal deposits are one of the largest sources of anthropogenic methane emissions. Methane emissions increase in the case of active mining activities. Methane is a significant greenhouses gas with a global warming potential (GWP) 28 times larger than carbon dioxide over 100 years. Therefore, methane capture becomes an important challenge. The average methane drainage efficiency in 2020 in Polish mines was 36.95%, with only one of the active mines having a methane drainage efficiency of more than 50%. The average efficiency of the included methane management in 2020 was approximately 62.1%. This accounts for a decrease of 0.7% compared to 2019. This means that because of mining activities, only in 2020, nearly 632 million m3 of methane was emitted into the atmosphere (WUG, 2021). Importantly, in addition to the ecological benefits of capturing methane, it is also possible to achieve economic benefits. There are many potential utilization methods of coal mine methane. These include using methane as vehicle fuel or fuel in steel furnaces, boilers, and industrial burners. Captured methane could also be injected into natural gas pipelines or used as fuel in internal combustion (IC) engines or turbines for power generation. The available technologies could optimize the use of methane and significantly reduce emissions from underground coal mining. (UNECE, 2016). An interesting solution that allows increasing the efficiency of methane use is cogeneration systems (CHP). Cogeneration systems can use internal combustion engines or turbines to generate electricity, and the waste heat is used to heat and/or cool mine facilities. Conventional power generation systems operate at an efficiency of 25-45%. Cogeneration can increase this to over 80%, depending on the thermal energy consumption (Sloss, 2006). The use of the captured methane depends on the quantity and quality of the gas produced. Therefore, to increase the efficiency and safety of methane capture, it is necessary to control and measure the concentration of methane in the captured mixture.

The subject of the paper is capturing methane to ensure the safety of mining works in conditions of methane hazard. Additionally, captured methane from the coal seams drainage is used for electricity production. The article analyzes the possibility of producing electricity using gas engines fueled with methane captured from the active hard coal mine Budryk in Poland.