Analysis and optimization of a solid oxide fuel cell and intercooled gas turbine (SOFC-ICGT) hybrid cycle

The power generation community faces a major challenge: to protect the environment while producing a plentiful supply of clean low-cost energy. "21st Century Energy Plants" (Vision 21 Plants) have been proposed and conceptualized to meet the energy and environmental challenges. The solid oxide fuel cell and intercooled gas turbine (SOFC-ICGT) hybrid cycle introduced in this work is one example of a Vision 21 Plant. The system includes an internal-reforming tubular-SOFC, an intercooled gas turbine, a humidifier, and other auxiliary components. A recently developed thermodynamic analysis computer code entitled advanced power systems analyses tools (APSAT) was applied to analyze the system performance of the SOFC-ICGT cycle. Sensitivity analyses of several major system parameters were studied to identify the key development needs and design and operating improvements for this hybrid cycle. A novel optimization strategy including a design of experiments (DOEx) approach is proposed and applied to the hybrid system. Using this optimization strategy, a system electrical efficiency higher than 75% (net ac/lower heating value (LHV)) could be achieved when the system was designed to operate under a high operating pressure (50 bara) and with a low percent excess air (EA) (55%) in the SOFC. (C) 2003 Elsevier B.V. All rights reserved.