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A novel modification on preheating process of natural gas in pressure reduction stations to improve energy consumption, exergy destruction and CO2 emission: Preheating based on real demand

Olfati, Mohammad, Bahiraei, Mehdi, Veysi, Farzad
Energy 2019 v.173 pp. 598-609
carbon dioxide, exergy, gas hydrate, greenhouse gas emissions, temperature
One of the tools for optimizing energy systems is the design of the system output based on real (desired) demand. Thermodynamic performance of natural gas pressure reduction stations are functions of inlet conditions. In order to investigate the impacts of changes in inlet pressure and temperature on performance of a natural gas pressure reduction station, energy consumption and exergy destruction of a natural gas pressure reduction station of 10,000 SCMH are evaluated for different inlet conditions. In order to improve the station performance, a novel modification is proposed in the present research based on the real demand of preheating, wherein thermodynamic operation of the regulator is modeled and minimum pre-heating temperature of natural gas is calculated based on desirable temperature at the regulator outlet (natural gas hydrate formation temperature). Indeed, once the temperature at the heater outlet reaches the calculated minimum temperature, the heater is turned off. Compared to conventional stations, the modified station exhibits at least 33% and 15% reductions in energy consumption and exergy destruction, respectively. The results of investigating the performance of two sample stations also show that by implementing the proposed modification, CO2 emission can be reduced by up to 80% or even higher.