Chemical Looping Beyond Combustion: Syngas Production From Methane in a Periodically Operated Fixed-Bed Reactor

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

Intellectual Merit: Periodically operated fixed-bed reactors are an emerging type of catalytic reactors with increasing application in energy and environmental applications. The present project aims to demonstrate the application of chemical looping, an emerging combustion technology, to the partial oxidation of methane to synthesis gas in a periodically operated fixed-bed reactor configuration. The resulting process has significant practical advantages (alleviating safety concerns in methane partial oxidation by avoiding direct contact between methane and oxygen, and allowing direct utilization of air without diluting the syngas with nitrogen), and will at the same time allow the investigation of the dynamics of coupled endothermal/exothermal gas-solid reactions in periodic fixed-bed reactors. The project team will furthermore extend the chemical looping principle onto a fully multifunctional reactor design by integrating desulfurization of the product stream, resulting in a strongly intensified, highly scalable, and efficient syngas process. The approach builds on a combination of materials synthesis, reactor design and experimentation, and reactor modeling, and involves specifically the following steps: - Design and construction of a fixed-bed reactor with high-resolution in-situ measurement of kinetics and spatio-temporal reactor dynamics; - Synthesis, characterization, and evaluation of high-performance nanostructured materials as oxygen carriers and partial oxidation catalysts; - Detailed reactor experimentation, including evaluation of key reactor operating parameters (co- and counter-current flow pattern, periodicity, etc.) on reactor dynamics and process efficiency; - Integration of S-capture and separation, and - Reactor modeling and detailed reactor simulation. Overall, the main objectives of this research are (1) to advance our understanding of the dynamics of periodically operated fixed-bed reactors with heat-integration (specifically for gas-solid reactions) through a combination of experiments and reactor modeling; (2) to demonstrate the great potential of chemical looping (CL) beyond combustion (including integrated contaminant separation) and further establish the advantages of fixed-bed CL processes; and (3) to highlight the exciting possibilities of state-of-the-art nanomaterials as ?enablers? for advanced reactor engineering concepts . The project will advance our knowledge and current understanding of periodically operated of fixed-bed reactors, specifically for gas-solid reactions, an area with importance well beyond chemical looping. It will furthermore highlight the enabling role that emerging nanomaterials can play in the realization of advanced reactor concepts. Finally, it will help to further establish and broaden ?chemical looping? applications by demonstrating the simultaneous use of chemical looping for a partial oxidation reaction combined with contaminants removal, and, through thorough experimental and model based analysis, lay the groundwork for extending the concept onto a broad range of new applications. Broader Impact: Demonstration of a novel, compact, efficient, and safe reactor concept for natural gas utilization could have broad impact at a time where proven domestic gas reserves in the US are seeing explosive growth. Furthermore, this technology could enable the use of small-scale distributed sources, such as landfill gas and agricultural waste gas, resulting in tangible environmental benefits. The project will contribute to the education of graduate and undergraduate students, and involve outreach to high school students from underrepresented groups. Finally, active distribution of the developed methodologies and tools through collaborations, publications and conference contributions will help to foster partnerships and make the advances available to the scientific community at large.