(39a) Cogeneration Options in LNG Liquefaction

High thermal efficiency for LNG liquefaction plants is of importance due to the need to minimize feed usage and to reduce CO2 emissions. The need for high efficiency becomes very important in gas constrained situations where any savings in the fuel auto consumption of the plant for liquefaction chilling and power generation can be converted into LNG production. The application of aeroderivative engines allows a significantly lower CO2 footprint of about 30% compared to the use of simple cycle heavy duty engines. Aeroderivative engines offer very attractive efficiencies where steam systems are not viable or desired by the end customer. When steam systems are acceptable, a cogeneration type liquefaction facility can be attractive. This paper will cover concepts relating to cogeneration options for LNG facilities using both aeroderivative engines and heavy duty engines. Parametric analysis relating to different cogeneration options and schemes will be presented with varying levels of heat integration between the liquefaction block and also the powergeneration block. The paper will discuss the interaction of gas turbine driver parameters with cogen / combined cycles.