The Part-Load Performance Research Of SOFC-MGT Hybrid System

Solid Oxide Fuel Cell is a new type of energy conversion device compared with traditional power generation equipment, the theoretical energy conversion efficiency as high as60%-80%, due to its high exhaust gas temperature, high-grade waste heat have utilization value. Micro gas turbine makes full use of the heat to generate electricity, which can improve the efficiency of energy use and reduce the emission of pollutants. In recent years, SOFC-MGT hybrid system attract more and more attention in the field of clean and efficient distributed generation, many countries join to development the new energy technologies.The research content of paper is a part of "distributed SOFC-MGT hybrid system integrated research"(The natural science foundation of Liaoning Province). In the paper, the main research work was presented as follows:1. A SOFC model using nature gas with controllable output power was established, and the performances of SOFC at off-design conditions was investigate based on the structure of fuel cell and the features of the material with detailed calculation of three polarization. In addition, influences of system parameters (such as fuel utilization factor Uf, air utilization factor Ue, air inlet temperature and steam-carbon ratio) on the system performance on off-design conditions were analyzed. Numerical results show that the effects of system parameters on the efficiency of SOFC are significant on a certain output power. And the efficiency of SOFC rises greatly with the decrease of the system output power.2. By means of general functional forms of characteristic equations of the gas turbine and heat exchanger, a220kw SOFC-MGT hybrid system was established. Three part-load control modes were proposed in this paper, and the influence of inlet temperature was calculated. Finally, a new mode is proposed and the results show that the adjustable range increases to45%of the design-point output power and hybrid power system efficiency maintains at above56.4%.3. The SOFC-MGT of the combined cold, heat and power system(CCHP) was established in combination with lithium bromide absorption refrigerating machine and water source heat pump. In the case of summer, the maximum refrigerating capacity and efficiency were calculation in the mode of case2. The results show that refrigerating capacity decreases from76.6kw to44kw when the output of SOFC-MGT hybrid system reduces from220kw to161kw, however, the efficiency of SOFC-MGT with CCHP keeps in76%.