Keywords: natural gas pressure, pressure reduction stations, cogeneration, heat exchangers, turbo expanders, gas turbines, optimisation, Iran, exergy loss, power generation, power recovery, combined heat and power, CHP, simulation, energy saving, economic value, inlet air precooling
The effect of precooling inlet air on CHP efficiency in natural gas pressure reduction stations
Almost all pressure reduction stations in Iran use expansion valves to reduce the natural gas pressure, which leads to wasting large amount of exergy. In this paper, a system is proposed which includes the modification of a conventional pressure reduction station with the addition of a turbo expander and a gas turbine for power recovery and generation. The next step is investigating the effect of heat exchanger on proposed combined heat and power system. The objective of the simulation is first to investigate the effects of modifying components performance equations on system efficiency and performance at a set operating condition. Secondly, to conduct feasibility study of using a heat exchanger at gas pressure reduction station to boost station efficiency in terms of energy saving and economic value. The result demonstrates that by precooling inlet air of gas turbine, station efficiency increases specially when the turbine works at full load.