Low-Grade Syngas Biomethanation in Continuous Reactors with Respect to Gas–Liquid Mass Transfer and Reactor Start-Up Strategy

In order to utilize a wider range of low-grade syngas, the syngas biomethanation was studied in this work with respect gas–liquid mass transfer and reactor start-up strategy. Two reactors, continuous stirred tank (CSTR) bubble column gas recirculation (BCR-C), were used experiment by feeding an artificial 20% H2, 50% CO, 30% CO2 into reactors at 55 °C. The results showed that CH4 productivity slightly increased reducing retention time (GRT), but significantly improved increasing stirring speed CSTR circulation rate BCR-C. best performance 22.20 mmol·Lr?1·day?1 yield 49.01% achieved GRT 0.833 h 300 rpm, while for BCR-C, 61.96 87.57% 0.625 40 L·Lr?1·h?1. capability provided is far superior mechanical stirring, leading much better Feeding H2/CO2 during startup stage can effectively stimulate growth metabolism microorganisms, create metabolic environment subsequent biomethanation. addition, thermophilic Methanothermobacter dominant genus.