This Small Business Innovation Research Phase I project investigates the use of electrochemical devices for separation and compression of hydrogen from low-pressure mixed gas streams which are being developed for critical industrial gas and energy applications. Many applications will derive hydrogen from reformation of hydrocarbons resulting in a product stream rich in CO2, CO and H2. It has been well-documented that low-temperature electrodes similar to those used in these devices are often contaminated by carbon monoxide, negatively affecting their operation. While state-of-the-art solutions rely upon implementation of advanced catalysts or high temperature membranes, these solutions are not viable for systems having significant levels of CO in the feed stream. This project investigates the viability of a system modification that removes CO and other impurities from the electrode surface during normal operation thereby allowing the system to operate continually at high efficiency. Research efforts will leverage results from a fluids transport model to optimize the cell and system design. Laboratory cells will be constructed and evaluated over a range of operational parameters to develop a better understanding of the performance improvement associated with this approach. Finally, durability tests will be conducted to assess the long-term viability of this design.
The broader impact/commercial potential of this project will help alleviate the depletion of fossil fuel reserves by advancing the prospect of hydrogen-based energy. Production, purification, and compression of hydrogen represent key technical challenges for the implementation of a hydrogen economy, especially in the transportation sector where new sources and modes of delivery of hydrogen fuel are needed. These technologies must be robust, efficient, and cost effective in order to have value in meeting our growing energy needs. Furthermore, since hydrogen energy markets are emerging, viable product solutions must meet near-term industrial gas application needs as a commercial bridge toward low-cost products for a hydrogen economy. The current market for hydrogen is large and growing, with the vast majority of hydrogen produced from hydrocarbon sources resulting in gas streams containing appreciable quantities of CO and CO2 along with hydrogen. Current methods for separation and subsequent compression of hydrogen are very expensive and these costs are passed to the end-user. Successful development of the proposed technology will integrate the separation and compression functions, and expand the applicability of this device to separation of reformate and other mixed gas streams in a low-cost configuration.
Overview With the depletion of fossil fuel reserves and a global requirement for the development of a sustainable economy, the prospect of hydrogen-based energy is becoming increasingly important. Production, purification and compression of hydrogen represent key technical challenges for the implementation of a hydrogen economy, especially in the transportation sector where new sources and modes of delivery of hydrogen fuel are needed. These technologies must be robust, efficient, and cost effective in order to have value in meeting our growing energy needs. Furthermore, since hydrogen energy markets are emerging, viable product solutions must meet near-term industrial gas application needs as a commercial bridge toward low-cost products for a hydrogen economy. Sustainable Innovations, LLC is developing an efficient, solid state electrochemical hydrogen separator and compressor (EHS+C) to allow end-users such as heat treaters and silicon wafer manufacturers to significantly reduce their hydrogen consumption allowing them to purify and recompress process gas, passed through a process environment, for subsequent reuse. This product is expected to meet the process environment needs of certain industrial gas customers. While this system projects to serve a key role in industrial applications, many energy applications will derive hydrogen from reformation of hydrocarbons resulting in a product stream rich in CO2, CO and H2. Intellectual Merits Unfortunately, the anode of this device (hydrogen consumption electrode) suffers from severe performance loss due to contamination by CO. This has been well-documented in research associated with PEM fuel cells, and the same performance loss phenomenon applies to the EHS+C. While advanced, high temperature membranes and CO tolerant catalysts have been investigated for PEM fuel cells to combat this issue, neither of these advances will completely solve the problem for the EHS+C, largely because of the very high concentrations of CO present in the raw reformate stream. Real solutions to this problem must be developed to meet emerging industrial and energy needs for hydrogen and take advantage of substantial, existing, market opportunities. This research has focused on a development that significantly reduces the impact of these impurities on system performance, yielding a Regenerative EHS+C, or REHS+C. Broader Impacts Most hydrogen is produced commercially through reformation of hydrocarbons and therefore contains appreciable quantities of impurities such as carbon monoxide and carbon dioxide. Purification and compression represent complex and costly steps in the production of pure hydrogen. The REHS+C combines these functions into one unit and efficiently performs the separation and compression steps in a single device having no moving parts. This development allows the process to be carried out with equipment having a lower capital cost and much more efficiently than the conventional method. This opens up opportunities and reduces cost for commercial hydrogen production as well as generation of pure, high pressure hydrogen which is critically important to provide fuel for fuel cell vehicles.