(16e) Design, Construction and Preliminary Tests of the Sub-Pilot Scale Syngas Chemical Looping System

The national energy strategy focus is on the reduction of greenhouse gas emissions and energy security. Therefore, clean energy technologies that are feasible for industrial applications are extensively pursued. Fossil fuels are projected to remain a dominant energy source for the next several decades. Therefore, a process capable of reducing greenhouse gas emissions from fossil fuel as well as utilizing renewable energy sources is highly attractive. A promising candidate is the Syngas Chemical Looping (SCL) process. The SCL system developed at the Ohio State University demonstrates flexibilty in fuel source and products. A unique iron based composite particle synthesized at OSU makes this process possible. The particles are used as a looping medium which undergo redox cycles passing through three reactors namely; the reducer, oxidizer and combustor. In the reducer, the gaseous fuel is fully combusted while reducing the iron oxide particles. Steam reacts with the reduced particles in the oxidizer to yield high purity H₂. Finally, the partially oxidized particles enter the combustor to complete the re-oxidation step of the looping medium accompanied by heat generation. Prior work on the individual reactor studies indicated the possibility of producing Hydrogen and/or heat based on the reaction scheme. With encouraging results, initiative was taken to further scale up the process to demonstrate the continuous operation of all three reactors. In this article, we will focus on the design, construction and preliminary tests of a 25 kW_th sub-pilot SCL system. Details on the safety features and startup operations are also discussed. Particle attrition and reactivity results are highlighted. The ability of SCL to simultaneously produce high purity hydrogen and a concentrated CO₂ stream ready for sequestration is validated.