144 at a mine site in Australia (Figure 7) and has been tested with actual VAM in 24/5 continuous operation for total 8 weeks. Figure 7. CataVAM pilot unit trialled at a mine site in Australia. As an example of trial tests, Figure 8 shows the self-sustaining operation with VAM at 0.19 vol% at various VA flow rates up to 1.3 Nm3/s. Once the reactor bed was preheated at around 550 °C, the preheating burner was shut off and the VAM was introduced to the pilot unit. When the VA flow rate was initially maintained at 1.0 Nm3/s, the central reactor bed temperature remained stable and the methane oxidation efficiency was around 98%. Subsequently, the VA flow rates were increased to 1.1, 1.2 and 1.3 Nm3/s as indicated in Steps 2, 3 and 4 in Figure 8. For three consecutive days of trials, the self-sustained oxidation of 0.19% VAM was achieved at stable operation with the average bed temperature at around 550 °C, and the methane oxidation efficiency stabilized at around 98%. The flue gas was sampled, and its methane concentration (exhaust methane content) was measured using a GHG analyzer capable of accurately detecting methane levels below 100 ppm. The exceptional methane destruction efficiency achieved from site trials indicated that, at high VA flow rates between 1.0 and 1.3 Nm³/s, the CataVAM exhibited a notably lower pressure drop, with values ranging from 2.4 to 3.2 kPa. Successful pilot trials at a coal mine in Australia showed approximately 98% methane destruction efficiency across ventilation air flow rates up to 1.3 Nm³/s and methane concentrations between 0.15-0.5%. Key features of CataVAM include: • Self-sustaining operation with <0.2% methane, tested down to 0.15%. • Higher VA throughput, indicating a smaller unit footprint and reduced capital expenditure. • Lower operating temperatures, enabling heat recovery from low concentration VAM
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