Coal mine methane (CMM) is methane released from coal and the surrounding rock strata during mining activities. The methane in mines poses a safety risk due to its explosive potential when mixed with air.
Ventilation Air Methane, or VAM, is methane contained in exhaust air of the ventilation system of an active, underground coal mine. These emissions originate across mine workings and are diluted to low concentrations by the circulation of outside air. VAM management and abatement is important for improved worker safety, mitigation of greenhouse gas emissions, and as a potential source of clean energy.
A Ventilation Air Methane Thermal Oxidizer or VAMTOX is a specialized type of the thermal oxidizer, designed to handle methane produced by mining.
Conifer Systems’ VAMTOX solutions consists of multiple RTOs based on the scale of the mine and its activities. The RTOs are highly efficient with a DRE between 95%-98% and typically have a combustion range of between 1400 ºF -1600ºF. Additionally, the systems operate at reduced fuel usage with waste recovery capabilities reaching 95%-97% heat recovery.
Thermal oxidation is the most widely accepted air pollution control technology and uses high heat to convert the process stream into a combination of water vapor, carbon dioxide, and thermal energy.
The RTO is brought up to combustion temperature using supplemental fuel such as natural gas, propane, diesel, or biofuel. During this start up period the RTO unit initially purges itself with fresh air and continues to process fresh air until it reaches combustion temperature equilibrium. To maximize heat recovery, the RTO will automatically cycle or alternate the inlet and outlet via a series of pneumatic, hydraulic, or electric valves in destroying the VAM emissions.
Ventilation air methane management allows for returns on investment through reduced OPEX and carbon offset. Carbon credit programs encourage VAM destruction rather than venting as a form of ROI. The goal is to allow market mechanisms to incentivize commercial and industrial processes to lower emissions
Carbon off-setters purchase credits from an investment fund or a carbon development company that has aggregated the credits from individual projects. Buyers and sellers can also use an exchange platform to trade, like the stock exchange. With methane emissions growing and carbon offset pricing rising, the VAM market potential through 2050 raises significant financial opportunities for mine owners committing to decarbonization initiatives.
Power generation options are also possible through CMM injection and waste heat recovery which leads to lower OPEX.