24 April 2012

From Waste Heat to Cooling using Absorption Chillers: A Showcase Natural Gas Liquefaction Facility with CO2 Capturing Plant

Lique?ed natural gas (LNG) facilities are increasing in number due to the growing demand for natural gas (NG).
However, LNG facilities are energy-intensive because NG is liquefied at –160 °C. Since LNG facilities emit large
quantities of CO2, they are also suitable for CO2 capturing. Waste heat from LNG facility power plants can be
used to reduce the power consumption in the liquefaction process through the use of absorption chillers. Absorption
chillers are heat-driven devices, which utilize any type of heat input. They can therefore provide useful cooling by
utilizing the waste heat. This article explores the power-savings potential of using the absorption chillers in a NG
liquefaction process as well as CO2 liquefaction process for CO2 sequestration, and inlet-air cooling to a gas turbine powering the LNG facility. The resulting power savings in a 110 MW LNG plant were found to be as much as 14 %.