Abstract
This paper examines the viability of using low cost techniques to increase the performance (COP) of the overall natural gas liquefaction processes. Mixing propane with ammonia, sulfur dioxide or carbon dioxide and their effect on the compressor's required work is studied. The simulation results show that propane-ammonia and propane-sulfur dioxide mixtures enhance the COP by a maximum value of 7% and 9%, respectively. The COP enhancement in these blends is due to the closeness of their boiling temperatures with the operating temperature. However, the addition of carbon dioxide to the propane refrigerant reduces the COPof the cycle. This reduction is due to the poor energy absorption capabilities of carbon dioxide at the cycle operating temperature. The goal of this study is to investigate the feasibility of enhancing the COP using mixed refrigerants consisting of a hydrocarbon (propane) and natural fluids (ammonia, sulfur dioxide and carbon dioxide).
