In response to DOEs SBIR topic 21-b, Innovative Energy Systems: b. Ammonia Reforming for Gas Turbine Applications, Advanced Cooling Technologies, Inc. (ACT), together with Solar Turbines, Inc. (ST) and Unversiity of Southern California (USC), propose a novel Swiss-roll style reformer for improving combustion characteristics of ammonia fuels to meet gas turbine requirements. The unique thermal design of Swiss-roll allows for near-complete ammonia conversion at conditions required by gas turbines while maintaining excellent fuel flexibility, energy efficiency, and long lifetime. It is achieved without the need for expensive catalytic materials, which keeps the capital costs low. The transition towards a carbon-free energy economy finds ammonia an attractive fuel option due to its relatively high volumetric energy density and already established manufacturing & transportation infrastructure. As a result, ammonia-based power plants and gas turbines are potential solutions for future carbon-free electric energy mix and high energy density applications such as aviation. However, the poor combustion characteristics of ammonia, particularly its slow flame speeds and narrow flammable range, create significant issues for stable gas turbine operation. Furthermore, improper combustion of ammonia may generate high amounts of nitrogen oxides, potent atmospheric pollutants. A viable solution to the poor combustion properties of ammonia is partial or complete reforming (pre-cracking) into constituent hydrogen and nitrogen, which allows for more reliable and cleaner combustion inside the gas turbine. The approach proposed by ACT uses a Swiss-roll style heat recirculating reformer design to thermally decompose ammonia at high temperatures and pressures. A small amount of ammonia is combusted during the operation to provide the necessary energy for reforming the remainder of the fuel. The exceptionally heat efficient design recycles enthalpy from hot products back into fresh reactants, assuring effective energy utilization. Furthermore, the unique ability to sustain superadiabatic temperatures within the core allows for substantially better conversion rates than lower temperature catalytic solutions, especially at higher pressures required for gas turbine integration. The resulting hydrogen-rich reformate is mixed with fresh ammonia to provide a mixture with combustion characteristics similar to classic hydrocarbon fuels, hence requiring minimal modifications to targeted gas turbine equipment. The main benefits of this solution are: ? Unique thermal design leading to excellent energy efficiency ? The superadiabatic core operation enables complete reforming at higher pressures ? Catalyst-free operation for excellent fuel flexibility and limiting capital cost ? Autothermal process that does not require external energy inputs ? Simple construction allows a long lifetime and minimal maintenance The Phase I work will focus on demonstrating the reforming capabilities of Swiss-roll design with ammonia at atmospheric and high pressures characteristic of gas turbines. The sub-scale reformer will be manufactured and tested at ACT to examine the conversion rate and energy efficiency of the process. Additionally, the experimental data obtained will be used for validation of numerical modeling at USC, leading to tools for designing and predicting the performance of an optimized Swiss-roll device for a full-scale reformer. Furthermore, consulting with ST will guide the activities to address gas turbine industry-specific issues and aid future commercialization efforts. In Phase II, ACT will implement the USC optimized design in a full-scale reformer capable of interfacing with an actual ST gas turbine.
