Investigation of Operational Scenarios to Mitigate CO2 Emission and Natural Gas Consumption in City Gate Stations (CGSs)

Abstract

City gate stations (CGSs) are the main pressure reduction stations of natural gas (NG) transmission lines where enormous decrease of NG pressure results in significant temperature drop. Therefore, high pressure gas is preheated by means of NG fuel water bath heaters (WBHs) to prevent downstream hydrate formation. In this research, the effect of different operational scenarios was investigated by means of process simulation to enhance the combustion efficiency of WBHs which consequently causes lower CO2 emission into the atmosphere. In this regard, WBH of Minudasht CGS in the north of Iran with nominal capacity of 30,000 m3/h was considered as a case study and process enhancement was carried out with the goal of lower CO2 emission and the NG fuel consumption. On the basis of obtained results, it was demonstrated that the NG preheating and air preheating by means of energy of hot stack gases are the most effective scenarios which can result in around 65 and 50 tons lower CO2 emission, respectively. In addition, these scenarios have the merit of saving more than 33,000 and 25,000 m3 lower NG fuel consumption annually, respectively.