138 abatement is technically complex due to high airflow, low methane concentrations (< 1% CH4), and the presence of moisture and airborne contaminants. CSIRO commenced the VAM abatement research in 2000. Through over 30 research projects that range from fundamental studies including theoretical analysis and laboratory scale experiments, through to mine site sampling and pilot scale prototype unit development and site trials, the CSIRO team has developed the following four VAM abatement technologies that have achieved technology readiness levels 6-7. • VAMCAT: A novel catalytic gas turbine system capable of operating with methane concentrations as low as 0.8% for power generation • VAMMIT: A compact flow reversal reactor featuring a novel regenerative bed for selfsustaining destruction of ≥ 0.3% methane • VAMCAP: A VAM capture system employing CSIRO-developed carbon composite adsorbents and a two-stage temperature and vacuum swing adsorption (TVSA) process for methane enrichment over 25% methane • CataVAMTM: A catalytic flow reversal reactor with a high-performance catalytic regenerative bed designed for self-sustaining destruction of as low as 0.1% methane, optimised for the 0.2-0.4% methane range typical of Australian VAM conditions CSIRO has also been developing emerging technologies for methane emissions abatement involving photocatalytic oxidation and novel catalyst materials for thermal catalytic oxidation. Photocatalytic oxidation is targeting ultra-low level and diffuse methane emissions, which is promising for abating open cut fugitive emissions or offset by destructing atmospheric methane with solar energy. Developing novel catalysts with high activity and durability and low cost is to accelerate wide implementation of catalytic VAM mitigation. 2. HIGH TECHNOLOGY READINESS LEVELS VAM ABATEMENT TECHNOLOGIES VAMCAT Lean-burn gas turbines are being developed worldwide. CSIRO designed a 1% methane catalytic combustion gas turbine system based on methane catalytic combustion experimental data and the design criteria for a turbine system. A 1% methane turbine can use a greater proportion of ventilation air compared with a 1.5% or 2% methane gas turbine unit. Thermodynamic analysis indicates that lean-burn turbines can be operated at lower methane concentrations to 0.8%, depending on heat recovery effectiveness. A 25 kWe prototype VAMCAT unit was designed, constructed and tested at CSIRO laboratories in 2009, followed by trials conducted at coal mines in China and Australia. Field trials at Appin Coal mine were carried out to test the 25kWe VAMCAT prototype unit for the first time under real VAM conditions in Australia (Figure 1). In November 2017, a series of planned site trials of the VAMCAT unit were undertaken by using actual VAM at full speed. CNG was used to replace drainage gas that had stopped being produced in April 2016. Results from these site trials demonstrates that the unit is capable of stable operation with 0.8% methane, generating
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