Electrolyzers are the key technology for producing “green” hydrogen using renewable energy. However, a new reactor platform aims to facilitate electrolysis without the need for any external electricity. The Electroless Coupled Exchange Reduction Oxidation technology platform (eXERO), developed by Utility Global, Inc. (Houston; www.utilityglobal.com), removes the external electrical circuit from a traditional electrolyzer and instead drives the electrolysis reaction with the overpotential (voltage) that is present between different gas compositions being introduced at the system anode. This inherent overpotential facilitates the conversion of variable gas streams into hydrogen and synthesis gas (syngas) onsite. “Similar to a conventional solid-oxide electrolyzer, oxygen ions are transferred from the cathode to the anode through an ion-conducting electrolyte. However, unlike a conventional electrochemical reactor, electrons are transferred from the anode to the cathode through an electronically conducting phase within the electrolyte, also known as a mixed-conducting electrolyte,” explains DeLome Fair, vice president of engineering at Utility Global. This counter-exchange of oxygen and electrons means that one gas stream is being reduced while the other is simultaneously oxidized, all without the application of any external current.
A key differentiator of eXERO is the ability to use a wide range of waste gases — even those that are dilute or variable in concentration — to drive the conversion reaction, and the ability to directly produce a high-purity product without any additional purification steps.
Utility Global, in partnership with the Colorado School of Mines (Golden; www.mines.edu), was recently granted funding from Colorado’s Office of Economic Development to further develop and commercialize the eXERO platform. The proprietary ceramic reactor will be tested across a wide range of temperatures and pressures at the Colorado Fuel Cell Center. Utility Global is also field-testing eXERO technology with Canadian steelmaker Stelco at an integrated steelmaking site located in Nanticoke, Ontario. “This field demonstration will also validate that the reactor can process varying blast-furnace gas directly from an operating blast furnace and produce high-purity hydrogen,” adds Fair, noting that eXERO can also handle waste-gas streams from steel processing, petroleum refining and biodigesters and landfills, as well as ammonia or CO2.
Edited by: Dorothy Lozowski