Optimization of compressor networks in LNG operations

Abstract

Liquefied natural gas (LNG) is the most economic way of transporting natural gas (NG) over long distances. Although LNG is an attractive source of clean fossil fuel, it involves energy intensive liquefaction of NG using refrigeration. Often the compressors that run the refrigerant cycles in an LNG plant operate in suboptimal fashion, which results in higher fuel and energy consumption. To this end, we present a generalized model for the compressor operations in multiple interacting refrigerant cycles in LNG and other cryogenic applications. We determine the optimal load distribution between the cycles to minimize total power consumption of the system for a given plant capacity and operating conditions. We also show the applicability of our model using a case study on the AP-X™ LNG process, which includes three interacting cycles, each with single or multiple compressors. © 2009 Elsevier B.V. All rights reserved.