Recipient Organization
PROTON ENERGY SYSTEMS, INC.
10 TECHNOLOGY DR
WALLINGFORD,CT 064921955
Performing Department
(N/A)
Non Technical Summary
The Haber-Bosch process, one of the most impactful developments in human history, has provided enough fertilizer to the world that it is estimated nearly half of the nitrogen found in our bodies originated in a Haber-Bosch chemical plant. However, this technological marvel comes at a price. On U.S. farms, 29% of energy consumed (directly and indirectly) is in the form of fertilizers, and these same fertilizers are the second largest contributor to green house gas emissions. This is because the Haber-Bosch process must operate at high pressures and high temperatures to convert highly inert nitrogen gas to fertilizer. In addition, to obtain hydrogen for the reaction, fossil fuel reforming is used, resulting in a high carbon foot print. The extreme conditions and pre- and post-processing steps combined with the low equilibrium conversion makes these facilities highly capital intensive, inefficient and polluting. More sustainable and economical ammonia production methods will be required to support growing world demand for fertilizer.One alternative approach is to use electricity to drive the ammonia production reaction, decreasing the need for high pressure and heat thereby decreasing the energy demand and making the process more efficient. This electrochemically driven process is compatible with the use of renewable electricity, eliminating CO2 emissions from the production step. A natural synergy exists in using wind power for fertilizer production. In the Plains and Upper Midwest, excess wind production capacity, transmission limitations, and high regional demand for N-fertilizers combine to create excellent economic drivers for this technology. In addition, because electrolysis technology is highly scalable, further reduction of emissions will be realized through the reduced need for ammonia transport. Products could be envisioned that support a range of small to mid-sized farms, or could be designed on a larger scale to distribute ammonia locally for multiple farms.Our team proposes development of an efficient solid state electrochemical process utilizing anion exchange membrane (AEM) technology, which can be optimized for use with distributed renewable energy sources. This AEM-based technology is ideal for ammonia synthesis because the membranes are not expected to readily react with ammonia, enable low-cost materials of construction, and they allow the utilization of a wider array of low-cost catalysts. Results from our Phase I work showed that our AEM-based electrochemical technology is uniquely capable of low temperature and low pressure ammonia generation at an efficiency which will match the energy requirements of the Haber-Bosch process. The team has extensive competencies in cell design, tailoring of membrane and catalyst properties, and balance of plant design and integration, providing a strong foundation for the proposed work.
Animal Health Component
17%
Research Effort Categories
Basic
17%
Applied
17%
Developmental
66%
Goals / Objectives
The major goal will be to design and construct a breadboard system capable of operating at a relavent performance level for small-scale applications. To achieve this goal, and answer the above questions, specific objectives for the Phase 2 approach include:1) Plan and execute modifications to existing Proton hardware for ammonia production.2) Develop a nanostructured catalyst that has increased stability and efficiency over Phase 1 formulations.3) Develop a membrane system that maximizes membrane lifetime and conductivity while minimizing ammonia crossover and is fully integrated with the catalyst in the electrode.4) Evaluate performance of down-selected membrane and catalyst materials in breadboard device capable of 10 mA/cm2 and 10% efficiency.5) Compare performance and cost metrics to competing technologies.
Project Methods
1) Plan and execute modifications to existing Proton hardware for ammonia production.The Phase 1 test program was conducted using lab-scale 25 cm2 cell hardware. In Phase 2, Proton will transition to commercial-level cell hardware (28-86 cm2). This configuration leverages existing endplates, MEA tooling, and other equipment in order to focus research funding on demonstration experiments and materials development.Proton will leverage the Phase 1 proof-of-concept system for the scale-up effort, reducing the overall cost burden. It is expected that major modifications will include safety sensors and circuits for unattended operation and greater control over important system parameters including temperature and pressure. This effort will rely heavily on Proton's past experience in translating its expertise to workable prototypes for multiple types of electrochemical devices. While the main hazard in this case will be ammonia exposure, the experience gained from the successful safety review held in Phase 1 will be flexed in the scale up design for Phase 2.2) Develop a nanostructured catalyst that has increased stability and efficiency over Phase 1 formulations.Nanoparticle catalysts will be synthesized in collaboration with Lauren Greenlee who has substantial experience with the characterization of these materials. Dr. Greenlee also developed a modified electrochemical setup during Phase 1 of this project to capture ammonia produced, and many pH experiments were performed to establish the relationship between pH and ammonia measurement and identify the best assay. These developments in experimental procedure will be continued in Phase 2 of the project.3) Develop a membrane system that maximizes membrane lifetime and conductivity while minimizing ammonia crossover and is fully integrated with the catalyst in the electrode.AEM membrane selection will be tailored to optimize conductivity, durability and crossover in the ammonia system. Dr. Herring leads a Multidisciplinary University Research Initiative (MURI) sponsored by the Army Research Office to optimize the properties of these polymers and has already developed many simple hydrocarbon materials based on co-polymers an isoprene or ethylene with benzyltrimethyl ammonium cations. For this project we will start with materials for which a solubilized form is available, that can easily be modified and that have already been shown to have high ionic conductivity, suitable mechanical properties, and stability.The Herring group will expose the AEMs to ammonia/hydroxide to determine their stability in the system, as an accelerated aging test. IEC and conductivity will be determined before and after testing. The team will also demonstrate that a solubilized version of the membrane can be applied to the base AEM and that the layer does not delaminate under the conditions of the test. Adhesion quality will be observed and documented before and after testing.4) Evaluate performance of down-selected membrane and catalyst materials in breadboard device capable of 10 mA/cm2 and 10% efficiency.A general approach for the scaled-up demonstration will be to establish operability with baseline catalyst and membrane materials before implementing down-selected materials from Andrew Herring and Lauren Greenlee. Tests exploring operational parameters such as residence time, recirculation, cell configuration, temperature and pressure will be added to the test matrix in Phase 2.5) Compare performance and cost metrics to competing technologies.Results from down-selected performance tests will be used to estimate cost and compared to literature and the current industry standard. The final products include cost and performance estimates of down-selected materials (e.g. estimated kWh/ton NH3 produced, or projected production rates) compared to current technology and baseline.