Cascade Utilization of Fuel Gas Energy in Gas to Liquids Plant

Abstract

This paper investigates on a gastoliquids (GTL) plant with ATR syngas production and proposes a new process to use a gas turbine and waste heat recovery gas/steam streams preheater to replace the fired heater. The new process features cascade utilization of fuel gas energy, as fuel gas is firstly used in a gas turbine (GT) at very high temperature and then lowertemperature GT exhaust gas is further used for preheating. Large exergy loss of heat transfer in the fired heater is eliminated. The improved process has an equivalent power generation efficiency of 80% which is significantly higher than conventional technology. Economic analysis indicates 129.8 M$ revenue would be produced over the lifetime if the extra power from a 15,000 bbl/d GTL plant can be exported to the grid at the price of cost of electricity for a conventional natural gas fired combined cycle plant.