| Fuel cell as an energy device that can that converts chemical energy directly into electrical energy with low emission and high efficiency.Compared with other kinds of fuel cell,Proton exchange membrane fuel cell(PEMFC)is widely used in combined heat and power cogeneration(CHP)system for residential application due to its low operating temperature and fast start-up speed.CHP system with PEMFC as generation device that can not only provide the necessary electrical energy for residential life,but also can supply heating and hot water,leading to realize the cascade utilization the of different grade energy as well as improve the conversion efficiency of energy.Therefore,the energy analysis of the applied CHP system will be contribute to optimizing the design of CHP system.According to the structural compositions of a CHP system for residential application,the actual process flow of the system was analyzed.Based on the Aspen plus chemical simulation software platform,the corresponding model and process of simulation were established.Using the actual quantity of raw material consumed by the family in February as the input data of model,the simulation data of the output was calculated.Compared with the measured data of actual energy usage in the family,the error of measurement data is less than 5%,suggesting that the established model was reliable.On basis of this,with the internal hydrogen production system of the CHP system as the main object and LPG composed of propane(C3H8)and nbutane(C4H10-1)with a molar ratio of 6:4 as raw fuel,The influence of different process parameters of hydrogen production system on the thermal efficiency of LPG fuel were simulated and investigated.Its results showed that reasonable operating conditions were: the auto-thermal reactor inlet temperature(Tin)of 450 ?,the water carbon ratio(Wc)of 2.0 while the oxygen/carbon ratio(Oc)of 0.4.The thermal efficiency of raw material reached the highest level.The foundation of this paper was the measured data of input and output of the CHP system from February to December in Japan.The measured data were collated into averages monthly and then 11 sets of data were obtained.While considering the influence of the environment temperature,the measurement data after arrangement was input into the model,and then the output results of each simulation were obtained.By comparing the monthly output measurement data and the corresponding simulated data,its results showed that the simulation results of the model could reflect the real energy distribution of each part of the CHP system.The thermodynamic based on each group of simulated data were calculated,its results showed that the average efficiency of energy value and exergy value of the CHP system for residential application from February to December were 68.03% and 27.36%,respectively.Among them,the highest energy value efficiency and highest exergy value efficiency was reached 71.48% and 29.58%,respectively.The influence of environment temperature on the energy efficiency and exergy efficiency of the whole system was only 6.33% was 4.47%,indicating that the environment temperature was not the key factors of efficiency.The energy loss of all modules was about 95% of the whole energy loss,while the exergy loss of all modules was about 99%.Moreover,the main energy and exergy loss concentrates on the modules,including BURNER1,BURNER2,PEMFC,PIPE1 and PIPE2.Based on this,corresponding improvement about BURNER,PEMFC and PIPE were proposed to improve the energy and exergy efficiency of the whole system. |
PDF Full Text Request