Low-temperature methanation of fermentation gas with Ni-based catalysts in a multicomponent system.

A large amount of greenhouse gases, such as carbon dioxide and methane, are released during the production process of bioethanol and biogas. Converting CO into methane is a promising way of capturing CO and generating high-value gas. At present, CO methanation technology is still in the early stage. It requires high temperature (300-400 ℃) and pressure (> 1 MPa), leading to high cost and energy consumption. In this study, a new catalyst, Ni-Fe/Al-Ti, was developed. Compared with the activity of the common Ni/AlO catalyst, that of the new catalyst was increased by 1/3, and its activation temperature was reduced by 100℃. The selectivity of methane was increased to 99%. In the experiment using simulated fermentation gas, the catalyst showed good catalytic activity and durability at a low temperature and atmospheric pressure. Based on the characterization of catalysts and the study of reaction mechanisms, this article innovatively proposed a Ni-Fe/Al-Ti quaternary catalytic system. Catalytic process was realized through the synergism of Al-Ti composite support and Ni-Fe promotion. The oxygen vacancies on the surface of the composite carrier and the higher activity metals and alloys promoted by Fe accelerate the capture and reduction of CO. Compared with the existing catalysts, the new Ni-Fe/Al-Ti catalyst can significantly improve the methanation efficiency and has great practical application potential.