Simulation and sensitivity analysis of a natural gas liquefaction cycle

Abstract

A sensitivity analysis of a Natural Gas (NG) Liquefaction Cycle with mixed refrigerant was done varying the operational conditions. It was used PROII/8.1® to simulate the process and in each case study the variation of the coefficient of performance (COP) and the refrigerant flow rate required for the total gas liquefaction was analyzed. The use of different pressure levels and the best intermediate pressure for the cycle were evaluated. The composition of the mixed refrigerant was varied in order to reduce the flow required for the liquefaction. The refrigerant flow rate was proportional to the inlet NG temperature. The most favorable intermediate pressure for the cycle was obtained from the geometric mean of the low and high pressure. The increment of propane in the studied mixed refrigerant improved the cycle performance coefficient. The feasibility to apply this technology of liquefaction in Venezuelan fields with different gas compositions was determined.

Keywords

• liquefaction
• liquefied natural gas
• refrigeration cycle
• mixed refrigerant