Effects of temperature, hydrogen/carbon monoxide ratio and trace element addition on methane production performance from syngas biomethanation

Synthesis gas (Syngas) biomethanation is an environmentally friendly technology for fuel calorific value improvement. However, the slow mass transfer and poor product quality limit its development. In this study, the effects of temperature, hydrogen/carbon monoxide (H₂/CO) ratio and trace element addition on simulated syngas biomethanation were investigated in three batches of experiments. Results showed that (1) the temperature influenced little on the quality of produced biogas; (2) the methane content in the biogas production were 66.37 ± 4.04%, 70.61 ± 6.06% and 73.35 ± 2.39% respectively with the H₂/CO ratio of 3:1, 4:1 and 5:1; (3) after the addition of Fe, Co and Ni elements, the biogas quality was significantly improved (methane content was 79.76 ± 7.35%), but the microbial community structure did not change. This experiment provided a guidance for improving the biogas production performance of syngas biomethanation.