SBIR Phase I: Recovery of NH3 from Livestock Manure for Clean, Zero-Carbon Fuel

The broader/commercial impact of this SBIR Phase I project is to promote the swift decarbonization of industries, in particular the synthetic nitrogen (N) fertilizer industry which generates 33.8 Megatonnes (Mt)/year (y) of life cycle assessment (LCA) carbon dioxide equivalent (CO2eq) emissions in the U.S. The proposed technology provides an alternative to the current N fertilizer production by recovering N from livestock manure and producing renewable, low-carbon ammonia (NH3) as a fuel. Green NH3, on the other hand, is costly and still requires long-term development to be commercially viable. Until Green NH3 becomes affordable, the renewable NH3 produced by the proposed technology can serve as a bridge fuel to help the industries start energy transition now. This technology could replace half the current synthetic N fertilizers. Manure generates 180 Mt of CO2eq emissions by applications to the soil. This technology has a significant potential to reduce GHG emissions. The market value of the N fertilizers is about $10 billion in the U.S. The estimated dollar value of the target market would be half that amount. The proposed innovation will help advance a fundamental scientific and engineering understanding of a consecutive liquid-gas (LG) and gas-liquid (GL) multiphase and multi-component mass transfer coupled with chemical reactions, a common phenomenon in many chemical and biochemical processes. This project's intellectual merit is in acquiring the knowledge involved in a complex, consecutive LG-to-GL mass transfer, which is essential to a wide range of industries. A new kinetic model for such a mass transfer of NH3 will be developed and applied to optimize the operating parameters to maximize the NH3 recovery efficiency, which has never been accomplished before. The Phase I objective is to increase the NH3 absorption mass transfer rate by an order of magnitude by applying the model. The model will be validated by comparing the model against experimental data to be collected in Phase I. The experiments will be conducted using two columns: one for the NH3 stripping and another for the NH3 absorption. The operating parameters will be explored to maximize the mass transfer kinetics based on the model for flushed manure samples. The anticipated result would be a new, validated consecutive LG-to-GL mass transfer model, establishing the relationship between the mass transfer rate and the operating parameters and optimizing parameters that would significantly increase the NH3 recovery efficiency, making the technology affordable to livestock farmers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.