(144f) Process Integration and Economic Analysis of Gas-to-Liquid Process

Gas-to-liquid (GTL) processes convert natural gas to liquid fuels as well as other hydrocarbon products. A common GTL approach is based on Fischer-Tropsch (FT) technology. Notwithstanding the long history of this technology, the challenges to optimize and commercialize GTL process still exist. These are due to the complex nature of the synthesis process as well as the difficulty to control heat and mass transfer as well as kinetics within the FT process. In this work, we adopt a process integration approach to the synthesis and optimization of a GTL plant. In addition, a new strategy for advanced FT process is analyzed for alternative design. A framework is provided for evaluating and optimizing the performance of GTL plants. First, a base-case flowsheet is synthesized and developed with computer-aided process simulation tool ASPEN Plus for a GTL process. Next, process specifications and key design operations are determined from process performance. After that, integration analysis is carried out on mass and energy basis. It covers the following aspects: 1. thermal utilities analysis, 2. process cogeneration, 3. process water recycle, 4. tail-gas targeting, and 5. reactor solvent recovery. Finally, the economic impact of alternative designs is estimated and the various designs are compared.