A Blue Hydrogen Framework for Regional Energy Resiliency

High-pressure gasification is gaining attention as an emerging solution for sustainable energy production due to its potential to achieve higher efficiencies, improved syngas quality and smaller equipment footprints. High operating pressures and temperatures can increase the synergistic reactivity of biomass and organic materials, consequently enabling higher in situ tar reformation and ultimately reducing the number of gas treatment requirements. Additionally, higher operating pressures result in a more concentrated CO2 stream and reduce the amount of post-gasification compression requirements in the carbon capture and storage (CCS) unit, improving overall system efficiency. Plus, pressurized CO2 streams from the gasifier also provides routes for direct conversion to valuable products via reactive carbon conversion (RCC) pathways and provide options for incentivizing the blue hydrogen production process. This approach also saves energy by eliminating the need for additional pressurization of hydrogen for storage, making the process more environmentally friendly and cost-effective.The realization of a hydrogen economy in the US requires significant end-to-end infrastructure developments from production to consumers. Significant investments are being made to establish new hydrogen plants and hubs to meet the growing demands. However, most of the investments are concentrated in the coastal areas, which face significant challenges in supply and delivery to far inland regions and require thousands of miles of pipeline infrastructure development, coupled with existing challenges in hydrogen storage can create potential resiliency risks and increase the levelized costs of per unit hydrogen. This research explores a high-pressure gasification system integrated into an IGCC framework to produce both hydrogen and electricity utilizing locally available resources (pecan shells, cotton gin waste, and municipal solid waste (MSW)) to create regional energy resiliency and improve energy security. A unique strategy of recirculating CO2 and steam from IGCC gas turbine exhaust gas is utilized, which has improved system thermal efficiency. Additionally, a trade-off study has been performed to identify the optimum hydrogen extraction amount from syngas while balancing the required power generation from the IGCC cycle, which creates a chance for sustainable hydrogen production with power generation. Through experiments and simulations, the study identified optimal operating conditions, such as an equivalence ratio (ER) of 0.18â??0.22 and temperatures of 850â??950°C, to maximize syngas quality and hydrogen production. A blend of 60% MSW and 40% pecan shells was found to minimize emissions while achieving a plant efficiency of 41% with a 50 v/v% hydrogen extraction from syngas for end-use purposes while other 50 vol% being utilized in gas turbine to power auxiliary units and meet additional 50 MWe demand of the community. Compared to that, an 80 v/v% extraction of Hydrogen from the syngas with the same IGCC power output has improved the combined efficiency of the plant and hydrogen generation to 61%, mainly due to higher volumetric energy density of methane in the syngas, allowing greater hydrogen extraction. A Life Cycle Assessment (LCA) was conducted to measure greenhouse gas emissions from feedstock collection to CO2 capture. A cradle to grave approach with relevant system boundaries have been developed for the LCA. Local sourcing of feedstock kept transportation emissions low, while the choice of feedstock blend and operating parameters influenced the overall environmental impact. Aspen Plus and LCA software were used to analyze emissions data and ensure accuracy, highlighting the potential for MSW and biomass blends to reduce waste and emissions. This study demonstrates how high-pressure gasification can provide a reliable and scalable solution for regional energy systems. By optimizing operating conditions and integrating efficient processes, this thesis provides a roadmap for producing clean energy while reducing emissions and advancing sustainability, energy independence and energy security.