Palys, Matthew2021-10-252021-10-252021-08https://hdl.handle.net/11299/225098University of Minnesota Ph.D. dissertation.August 2021. Major: Chemical Engineering. Advisor: Prodromos Daoutidis. 1 computer file (PDF); xiii, 171 pages.Synthetic ammonia (NH3) used as fertilizer is essential for modern agriculture, but its production at present is fossil energy and emissions intensive. A more sustainable NH3 production alternative is to use renewable-derived electricity to obtain its precursors, specifically hydrogen (H2) from water electrolysis and nitrogen (N2) separated from air. The transformative impact of renewable NH3 is not limited to agriculture alone. Energy storage costs using NH3 are considerably lower than with H2or batteries, making it an ideal candidate for the high capacity, long duration seasonal energy storage necessitated by high fractions of renewables in the power generation mix. Internal combustion technologies which are well-developed for fossil fuel feedstocks can be easily modified to be fueled with NH3, allowing its use for controllable power generation or as a carbon neutral liquid fuel. Despite its promise, a number of challenges remain in realizing the full potential of this alternative paradigm. This thesis aims to collectively address some of these challenges through the use of mathematical optimization. The economics of small-scale renewable NH3 production for agriculture are analyzed and optimized at both the synthesis process and supply chain level. A flowsheet model is developed for optimal design and technoeconomic analysis of an absorbent-enhanced NH3 synthesis process which can reduce pressure and increase separation temperature, the main drivers of capital cost in traditional condenser-based synthesis process. Absorbent-enhanced process design optimization gives 30% lower capital costs and comparable energy efficiencies to the condenser-based process at production scales smaller than conventional by one to two orders of magnitude. Optimal deployment of this absorbent-enhanced process via wind-powered NH3 production modules in fertilizer supply chains makes renewable NH3 economically viable at approximately 25% lower conventional NH3 prices than if the traditional synthesis process is simply scaled down. The economic competitiveness of synergistic renewable NH3 production and utilization systems is maximized through combined optimal design and scheduling (CODS). These CODS models select and size the best technologies for given applications while simultaneously scheduling their operation to accommodate renewable intermittency. Performing CODS for wind-powered production of NH3 for use as fertilizer, agricultural fuel, and energy storage enabled 95% emissions reduction at a cost less than $20/tonCO2. Then, the optimal economics of H2- and NH3-based electrical energy storage were investigated for 15 locations throughout the continental U.S. which comprehensively represent its different climate-demand regions. Lowest cost systems in every location included both H2 and NH3 storage pathways and optimized the trade-off between H2's higher overall efficiency and NH3's lower storage cost. This hybrid energy storage concept was extended to combined heat and power systems in remote locations as a potential market for early adoption. Low cost, long term NH3 storage and subsequent power and heat cogeneration enabled fully renewable systems to be economically competitive with those that could purchase power and heat from conventional sources. Overall, the results of this thesis demonstrate the promise of renewable NH3 and the power of mathematical optimization in achieving its full potential.enDesignEnergy storageFertilizerOptimizationRenewable ammoniaThesis or Dissertation