Technical and economic assessment of processes for the LNG production in cycles with expander and refrigeration

Optimized liquefied natural gas (LNG) process can be helpful for better energy and cost saving for gas transportation and storage. In this study, different layouts of LNG units are examined technically and economically so that with the specific and combined refrigerants, the least amount of energy can be consumed in the LNG unit. Two optimized LNG production processes were selected and compared. In Case 1, the expander is used for preventing energy loss in joule Thomson phenomena, and in Case 2, precooling was performed for better integration of heat. The study used Aspen HYSYS software to simulate the process and Aspen Capital Cost Estimator (Icarus) for economic analysis. According to the economic analysis of the energy and the process of these two cases, Case 2 is better in economic terms and energy consumption. This simulation is for an LNG unit with a capacity of 1000 tons per day. Total costs (including direct and indirect) in Case 1 and 2 are 152 and 130 USD/Tone, respectively. This issue is related to use of the compressors and turbo-expanders in Case 1.

Automated summary

Optimized LNG process can save energy and cost. Two optimized LNG production processes were compared, and it was found that Case 2 is better in economic terms and energy consumption.