Thermodynamic analysis of a comprehensive energy utilization system for natural gas pressure reduction stations based on Allam cycle

In order to effectively utilize the pressure energy and cold energy of the natural gas pressure reduction stations, this paper proposes a comprehensive energy utilization system for natural gas pressure reduction stations based on Allam cycle. The low-grade waste heat during the Allam cycle and ambient heat are used to heat the decompressed natural gas to the temperature required by the user. Based on the established mathematical model, the effects of turbine inlet temperature, turbine inlet pressure, turbine outlet pressure, isentropic efficiency of power equipment, and natural gas expansion stages on the performance of the proposed system are studied. The proposed system and the pre-heating system are compared and analyzed. The results show that when the combustor outlet temperature is 900celcius, the energy efficiency and incremental efficiency of the proposed system are 99.31% and 103.55%, respectively. Compared with pre-heating system based on gas turbine cycle, they have increased by 9.84 percentage points and 19.32 percentage points, respectively. Compared with the boiler-based post-heating system, the energy efficiency is increased by 3.5 percentage points.