Safer Operational Conditions for Natural Gas Processing in Transmission Line to LNG Plants

Abstract

Carbon dioxide must be removed from natural gas before liquefying the gas because it freezes in pipelines and corrodes process equipment. There are several processes that can be used to remove CO2 from natural gas. The most common processes are chemical and physical absorption. Implementation of other processes such as adsorption, membrane separations and cryogenic distillations are also found all over the world. However, only chemical absorption and physical absorption processes meet the specification of COv2 to be less than the required specification in the United States for preventing corrosion in transmission lines. Therefore, the current study focuses on these two processes. In each process, there are various ways to operate. The objective of this work is to find the optimal process and operating conditions, which cost us the least between the two given where the specification of the natural gas is achieved. Aspen HYSYS was used to simulate all the processes mentioned and Aspen Economic Evaluation was used to calculate the expenses of the processes. Corrosion rate and pipeline cost were evaluated using the NORSOK corrosion model. The process operational cost and pipeline cost have been evaluated and compared to find the suitable COv2 removal process and optimal condition for various pipeline distance.