(756e) Water-Energy Nexus in Gas-to-Liquid Processes: Assessment and Integration for Different Gas-Reforming Alternatives

The substantial discoveries of shale gas are leading to an increasing attention towards gas-to-liquid (GTL) processes using Fischer-Tropsch (FT) chemistry. These processes involve major energy and water issues. Traditionally, focus has been given to the reaction schemes while energy and water matters have been handled subsequently. This work analyzes energy and water generation and management options for three primary alternatives for the production of syngas: Steam reforming (SR), Partial oxidation (POx), and Autothermal reforming (ATR). Process simulation is used to identify the generation and consumption of water and thermal energy throughout the process for the three reforming scenarios. Process integration is used to induce heat integration and direct water recycle within the process. Additionally, the interaction between the water and energy profiles is analyzed to determine opportunities for resource conservation and cost savings. Power generation is also considered to improve the overall energy efficiency of the process. Finally, surplus heat and cogenerated power are used to produce water utilizing existing process technologies. The produced fresh water can then be used as an indirect commodity to export the surplus energy of the process. A case study is demonstrated for the work with Qatar’s current GTL plants forming the basis for water and energy conservation.