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Pushing the Limits of SNG Process Intensification: High GHSV Operation at Pilot Scale

Abstract:

Process intensification leads to a substantially smaller process technology. In this work, we present a combination of an active microsize catalyst and an effective microstructured reactor technology for CO2 methanation. The product of the reaction is renewable synthetic natural gas which can be injected into the existing gas infrastructure. The designed process was evaluated at pilot scale (37 kW electrolyzer) in a relevant environment using sewage biogas and a CO2 waste stream as carbon sources. The desired gas quality was obtained in a 2-step synthesis process at moderate pressure using a decreasing temperature profile (T = 275-475 °C) and water sequestration. Temperature profiles were adjusted by vaporizing water, compressed air, and heating cartridges. It was observed that pressure, carbon feedstock, and GHSV had an impact on the product gas quality. At the minimum pressure (P = 5 bar·g) for direct gas grid injection purposes, the process worked successfully at 31â»500 h-1 using upgraded CO2 and 37â»500 h-1 using biogas. This represents a reduction of 4 times the volume of the commercial reference. Accordingly, the limits of CO2 methanation process intensification were clearly crossed by the combination of reactor and catalyst miniaturization.