Heating Value Reduction of LNG (Liquefied Natural Gas) by Recovering Heavy Hydrocarbons: Technoeconomic Analyses Using Simulation-Based Optimization

LNG is expected to play a major role in global natural gas trade. Implementing a heating value adjustment unit within regasification terminal allows importing of LNG from diverse sources around the world, thus increasing the energy security of the importing country. In this study, we focus on heavy hydrocarbons removal (HHR) as a strategy to reduce heating value of LNG to meet desired specifications. We have developed a superstructure for the HHR process, which is optimized using a particle swarm optimization algorithm to maximize profitability of the HHR process. The optimal process configuration not only meets heating value specification but also utilizes LNG’s cold energy to liquefy the methane-rich stream before pumping to send out pressure and produces ethane and LPG as co-products. Our technoeconomic analyses show that at the current prices of co-products, the HHR process configuration yields 7–10% profit depending on the heating value of the LNG feed.