Abstract
Using wood chip gasified gas WCG as the design fuel, under the operation restriction of the fuel cell, reformer and gas turbine, the performance of an intermediate temperature-solid oxide fuel cell(IT-SOFC) and a gas turbine(GT) hybrid system was analyzed. Using non-design fuels (such as cotton wood gas CWG, grape seed gas GSG and corn stalk gas CSG), the system operation performance in design and off-design conditions were deeply researched, with the IT-SOFC of 1026K being constant. Results show that, using the design fuel WCG, the output power of hybrid system is 177.72kW, the electrical efficiency is 58.74%, the working temperature of IT-SOFC and GT both satisfy the design requirements, the compressor surge margin is 21.07% and the S/C boundary value is 1.98, the hybrid system has good operation performance. Under the design condition, using non-design fuel GSG, the system output power and efficiency both decrease, the S/C boundary value is higher than 2, the reformer is prone to carbon deposition phenomenon. Using CSG and CWG as fuel, the system output power increases and the efficiency decreases. Under the off-design condition, using the design fuel WCG, the efficiency of fuel cell and hybrid system are higher than that of the non-design fuel. Using GSG as fuel, the S/C boundary value is higher than that of the other fuel, the issue of carbon deposition should be aware. When using the four types of fuel, the system efficiencies are higher than 60% at low load operation, contrarily, the system performances become weak at high load operation. Using the CSG and CWG, the system can have a higher load capacity, however, the carbon deposition is easy to occur. Hence, the types of fuel should be selected appropriately based on the load demand, hybrid system economy and security.
