Chemical looping technologies have evolved into a promising alternative for the efficient conversion of carbonaceous fuels to electricity and/or high value chemicals with minimal carbon emissions. These processes utilize an oxygen carrier solid material to indirectly supply oxygen to the fuel source eliminating the need for costly and energy intensive gas-gas separation techniques. In the case of power production, the chemical looping scheme allows for high exergy efficiency, as the high grade heat produced from the oxidation of the oxygen carrier can be extracted for steam production, while the lower grade heat is recuperated in the oxygen carrier to perform its endothermic reduction. With the exponential growth of research and publications in this field, chemical looping has expanded to encompass power and chemical production with in-situ gas separation. The Ohio State University (OSU) has successfully developed the syngas chemical looping (SCL) and coal direct chemical looping (CDCL) processes from laboratory studies to two fully integrated pilot scale demonstration facilities for the conversion of gaseous and solid fuels, respectively, to high purity H2 and heat with nearly 100% CO2 capture.
The present paper summarizes key developments in the SCL and CDCL processes Specifically, TGA tests on the oxygen carrier recyclability and reactivity as well as jet cup and crush strength tests on the particle attrition resistance are provided. The results from over 1,000 hours of operation of two 25 kWth sub-pilot units showing nearly 100% conversion of 7 gaseous and solid fuel types to CO2 are summarized. A comprehensive techno-economic analysis of the CDCL was completed with Babcock & Wilcox Power Generation Group. The results indicate the CDCL process for power generation can exceed Department of Energy’s target of <35% increase in cost of electricity with greater than 90% carbon capture. An overview of the SCL pilot unit design, construction, and commissioning is provided. The operation results of the pilot unit under high pressure and temperature conditions are also discussed.
See more of this Group/Topical: Topical Conference: Innovations of Green Process Engineering for Sustainable Energy and Environment