Process and Network Level Optimization for High Salinity Brine Dewatering and Management

High salinity brine management is an essential and costly activity for several activities, including oil and gas production, inland brackish water desalination, and geologic carbon storage. Currently most of these brines are managed with a disposal centric strategy, where the brines are minimally treated and directly disposed of via deep well injection. This common brine management strategy has several consequences including increased seismic activity and high transportation costs, energy use, and air emissions. An alternative to this brine management strategy is to dewater the brines to reduce the waste volume for transport and disposal. However, technologies that can dewater high salinity brines are generally considered prohibitively costly and energy intensive. This thesis seeks to determine the potential of brine dewatering technologies and strategies to decrease the overall cost and environmental impact of high salinity brine management.
In this thesis, the efforts to assess brine dewatering technologies and management strategies are organized across three objectives that span different scales. The first objective is to develop module-scale models for membrane-based technologies to accurately assess their dewatering performance for high salinity brines. The second objective is to develop process-scale cost optimization models that determine the technoeconomic feasibility of emerging membrane-based brine dewatering technologies. The third objective is to develop network-scale supply chain optimization models and spatially resolved analyses that identify low cost and environmental impact brine management strategies across the U.S. A recurring theme in this thesis is that optimization modeling is a powerful tool for assessing the cost and performance of emerging dewatering technologies and strategies. Specifically, when optimization methods are paired with detailed process modeling and sensitivity analyses, it is easier to overcome common barriers of performing a technoeconomic assessment. These barriers include: accurately modeling the separation performance at full-scale deployment, specifying the design and operation of a technology or strategy without experience or heuristics, and handling high levels of uncertainty in process and financial parameters. Throughout this thesis, detailed cost optimization models are developed to comprehensively assess the cost and performance of two emerging membrane-based brine dewatering technologies (osmotically assisted reverse osmosis and membrane distillation) and several brine management strategies for two high salinity brine applications (wastewater from shale gas production and extracted brine from geologic carbon storage).