(620b) The Syngas Chemical Looping Pilot Unit Development and Demonstration

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. As one of the most advanced chemical looping processes to date, the Ohio State University (OSU) has successfully developed the syngas chemical looping (SCL) process for gaseous fuel conversion from small scale laboratory studies to a large scale, fully integrated pilot demonstration facility. The unique counter-current moving bed reactor design allows the OSU SCL process to achieve full fuel conversion to CO₂/H₂O while minimizing the solid circulation rate and the ability to produce high purity H₂ for further chemical production. The SCL pilot facility represents a high temperature and high pressure operation of the OSU chemical looping technology for electricity and H₂ cogeneration with nearly 100% CO₂ capture. The construction, commissioning, and preliminary operations of the SCL unit have been completed. To date, the pilot SCL unit has completed over 184 hours of integrated operation.

The present paper summarizes key developments in the SCL process used for the pilot unit design. Specifically, the thermodynamic considerations of metal oxide and reactor contacting pattern are discussed. The results from TGA and bench studies are used to develop a 1-D kinetic model of the moving bed reactor. The kinetic model results identifying the critical flow ratio of fuel to metal oxide required for the pilot unit operation are presented. An overview of the pilot SCL unit design, construction, and commissioning is provided. The operation results including solid circulation studies under high pressure and temperature conditions are also discussed.