Energy saving research of natural gas liquefaction plant based on waste heat utilization of gas turbine exhaust

Abstract

In this study, a series of novel natural gas liquefaction systems integrated with waste heat utilization of gas turbine exhaust are proposed to reduce the energy consumption of the liquefaction plants. The most widely used propane precooled mixed refrigerant (C3MR) and cascade natural gas liquefaction processes, are integrated with the waste heat utilization methods of adsorption refrigeration and organic Rankle cycle (ORC). The integrated systems are simulated and optimized with HYSYS software and genetic algorithm. The results show that, with ammonia water absorption refrigeration, the power consumption of C3MR process and cascade process is reduced by 16.23% and 14.62%, respectively, and the waste heat utilization exergy efficiency of the two integrated processes reaches 56.96% and 48.73%, respectively; With ORC, the power consumption is reduced by 20.59%, and the waste heat utilization exergy efficiency reaches 75.61%. In addition, for a liquefaction plant with an annual processing capacity of about 1.4 million tons, the waste heat utilization achieves CO2 emission reduction of about 4000–6000 t/a.