Toward Sustainability of the Aqueous Phase Reforming of Wastewater: Heat Recovery and Integration

Abstract

Featured Application: Aqueous-phase reforming is a promising process for hydrogen production; however, the energy demand is one of the main drawbacks of its potential feasibility. The mass and heat balances shown in this work suggest that it could be possible to achieve the heat self-covering of the process as long as adequate operating conditions are used. Aqueous-phase reforming has been revealed as a novel, interesting and efficient process for the treatment of wastewater containing organic pollutants. However, due to the relatively severe operating conditions (above 15 bar and 200 °C), this process could become economically competitive if any solution for energy or material valorization is implemented. Most research has been devoted to direct the process to H2 production as an alternative to reach economic sustainability, but the results obtained were not competitive in the current market of hydrogen and syngas. In this work, a preliminary simulation study (using Aspen HYSYS software) of the process heat balance in different conditions was implemented to induce a heat integration that would allow the auto-sustainability of the process, even generating in some cases an excess of energy that could constitute an opportunity for a positive economic balance. The results showed that this approach would only be possible by maximizing the methane production to the detriment of hydrogen production.