Scheme Design and Analysis on Biogas Liquefaction System

The biogas has important practical significance in solving the energy crisis as a kind of clean, renewable biological energy of ground. As the large-scale concentratedness of the biogas is produced, the liquefaction of the biogas is extremely urgent in technical research in China. According to the characteristic of the biogas, on the basis of mature natural gas purification and liquefaction technology, this paper discussed the small-scale biogas liquefaction system of the double purposes to purification, liquefaction and recovery of liquefied CO2. This paper provides the liquefaction biogas plant process chart, and system analysis, and the effects on the key parameters. Furthermore, the thermal parameters of the liquefaction cycle are presented. Finally, the economic investment of 5000Nm3•d small-scale biogas liquefaction cycle is emphatically analyzed, and the conclusion is that the payback period of the investment on the biogas liquefaction equipments is only 2.63 years. The result provides guidelines for the project feasibility analysis and design of the small-scale biogas liquefaction device.