Enhancing the efficiency of fuel gas consumption in a natural gas processing facility

Abstract

Today natural gas has been attracting significant attention by the world since its combustion release small amount of greenhouse gases compared to other fossil fuel. Natural gas is a mixture of heavy and light hydrocarbon with small amount of impurities but mainly composed by Methane. The separation of desirable product and byproduct take place in a gas processing plant or facility. During these activities not all processed gas is exported to the consumer rather a considerable amount of natural gas is typically consumed by natural gas processing plants in order to power gas turbines for the generation of electricity and mechanical power within the facility. Worldwide energy efficiency in industry plays key roles in improving energy security, environmental sustainability and economic performance. Hence, in this thesis the main aim was to enhance the efficiency fuel gas consumption through installation of a compressor booster to control the suction pressure of the low-pressure compressor and the study has been conducted based on a case study in a gas processing facility. A protype of gas compression at gas processing plant was built and its flowsheet model has been designed and simulate in Aspen HYSYS. The fuel gas consumption data for the gas plant main fuel gas user (LP and HP compressor and gas turbine generator) has been collected. Parametric studies were performed and variables like pressure, flowrate, work, pressure ratio and fuel gas quantity were analyzed on both sides (simulation and collected data). The collected data analysis results were shown that LP compressor unit was the main contributor to the total fuel gas consumption and excess total fuel gas consumption respectively where it is consuming ~ 9500GJ/day and ~ 3000GJ/day fuel gas respectively. The analysis of simulated results as well as of the collected ones have indicated that a high compression ratio above ~3 the driving force to excess of fuel gas consumption and the use of small compressor as a booster significantly enhance the efficient of fuel gas since it reduced the fuel gas flow rate 430.7 Kgmol/h up to 400.5kgmol/h.