PERFORMANCE OPTIMIZATION OF PROPANE PRE-COOLED MIXED REFRIGERANT (C3MR) PROCESS FOR NATURAL GAS LIQUEFACTION

Abstract

The global population surge and economic development project a substantial increase in energy demand. By 2030, NG is expected to contribute 25% of the global energy demand to meet this growth. LNG technology, particularly the Mixed Refrigerant LNG Process (C3MR), has demonstrated efficiency and emerged as a distinctive dual-refrigerant technology widely used in liquefaction processes. Despite its energy-intensive nature, researchers aimed to optimize C3MR cryogenic processes, which is the main goal of the present thesis research study. This study achieved a 14.6% reduction in Specific Energy Consumption (SEC) by refining pressure streams, adjusting mass flow rates, and optimizing MR composition using knowledge-based and constrained Bayesian optimization approaches. The achieved SEC of 0.2649 kWh/kg LNG, on a large-scale plant with a natural gas flow rate of 120 kg/s, results in an 18 MW compression power decrease, saving approximately 17.42 million QAR per year for each C3MR process. Moreover, the Coefficient of Performance (COP) of the cryogenic cooling process was improved by about 15%, and the CO2 emissions were reduced by 17% compared to the base case, indicating potential advancements in largescale LNG liquefaction processes.