Recovering lost power in natural gas pressure reduction stations using hybrid turbo expander and fuel cell systems

Abstract

As the world seeks a clean fuel source to power up engines, natural gas is one of the most important options. In order to use natural gas for residential/industrial purposes, the gas pressure needs to be reduced to more convenient pressure using Pressure Reduction Stations (PRS). Ordinary PRS using throttling valves achieve the required pressure drop dissipating lots of energy. The turbo expanders are used in parallel with throttling valves to recover lost energy. In this paper, hybrid single/dual turbo expanders and fuel cells will be utilized in order to capture lost energy in El-Mansoura PRS and produce electrical power that could be supplied to the grid. El-Mansoura PRS was selected specifically because of the high-pressure ratio and flow rate. The data used was provided by Egypt Gas Company through-out a year. After investigating some of the available turbo expander design flow ranges and fuel cell power it was found that the optimal efficiency for this PRS was achieved when using a 15000 m3/hr single turbo expander with a 300 kW fuel cell power.