Upgradation of high co2-content natural gas by low-temperature distillation /

Abstract

High 2CO content in natural gas reduces the overall calorific value and creates handling and transportation problems. In the low-temperature distillation process for 2CO removal from natural gas, methane is recovered as the top product, whereas 2CO and heavy hydrocarbons are recovered from the bottoms of a series of distillation columns. The principle challenges in the design and operation of this process include the high energy requirements to meet liquid natural gas (LNG) feed specifications, minimizing the total utility requirements, and avoiding 2CO solidification. In this study, pinch analysis was performed for a 6-column, low-temperature distillation process to identify opportunities for heat integration in the process and to reduce energy consumption and utility requirements while maintaining methane recovery and purity. A comparison indicated that the heat-integrated process offers 19.8% reduction in total energy requirements, 16.9% reduction in greenhouse gas emissions due to utilities, 24.4% reduction in total heat-transfer area, and 9.9% cost savings relative to the reference process.