結果顯示配置1和2隨操作壓力越高，系統效率越低；配置3則是隨操作壓力越高，系統效率越低。水碳比影響部分，配置1在操作壓力是1-2(bar)時，提高水碳比會降低效率，而配置2與配置3則是提高效率。燃料當量比部分，所有配置都會隨燃料當量增加，系統效率同樣增加。分流率改變部分，所有配置都會隨分流率增加而系統效率增加。若考慮所有的結果，配置3比起配置1和配置2擁有較佳的性能。配置1、配置2和配置3的系統效率分別為48.93%、62.63%和67.79%。研究發現在配置3中，若熱交換器之熱交換速率大於5 W/K，探討的參數影響性將大幅下降。藉由成本分析並選取適當系統裝置來建立配置3。與能量分析相比，有用能分析也有相同趨勢，但數值不相同。因為過程中有用能會有損耗，因此，能量的數值會比有用能來的高，為了瞭解有用能損耗，我們利用熵的增加來計算，將系統中裝置依有用能損失由高到低排列依序為燃燒室60.235[kW]、pSOFC 22.773[kW]、壓縮機21.706[kW]、幫浦5.535[kW]、燃料熱交換器0.886[kW]、重組器0.681[kW]、水熱交換器0.345[kW]、空氣熱交換器0.225[kW]和微型渦輪機0.21[kW]。
Conducting Proton-Solid Oxide Fuel Cell (pSOFC), by attaching Micro Gas Turbine (MGT) is oneof the outstanding hybrid system nowadays. The intermediate temperature of pSOFC (around 700 – 800 [0C])is used to raise the performance of micro gas turbine in apower plantsystem. pSOFC has a lower temperature characteristic than old type of SOFC, which can afford more rapid start up/down and improve durability. A new model is proposed in the research based on themodels developed by earlier researchers.The proposed hybrid system is simulated using Matlab-Simulink. Simulations were performed to study the behavior of the pSOFC-MGT hybrid system by changing respective parameters such as pressure, steam to carbon ratio, and fuel utilization.In our research, we proposed, three different configurations by changing the bypass position in my proposed system i.e., with placing the bypass(i) after the combustor, (ii) after turbine, and (iii) after the combustor and turbine.
The results show that the higher operating pressure will reduce system efficiency for configuration 1 and 2, and increase the efficiency for configuration 3. The effect of raising Steam to Carbon Ratio will reduce the efficiency of configuration 1 for anoperating pressure of 1 – 2 [bar], but it increasesthe efficiency of configuration 2 and configuration 3. The higherfuel utilization will increase the efficiency for all configurations. For bypass ratio variation, increase in bypass ratio will increase the efficiency of all configurations. Considering all the results ofconfiguration 3 provide the best performance compared to configuration 1 and 2 in all three models. The efficiencies of configuration 1, configuration 2, and configuration 3 are 49%, 63%, and68% respectively. The study obtained that using the overall heat exchanger over 5 W/K will not give an effect to configuration 3 performance so much. The cost analysis can be taken into consideration bychoosing an appropriate device to build a configuration 3 model. The exergy analysis has a same tendency with energy analysis, but it will different in value. Due to the exergy destruction during the process, the value of energy is higher than exergy. To know an amount of exergy destruction, it carried out thecalculations based on the amount of entropy generation and found the devices that have lost exergy from the largest to the smallest in a sequence is combustor 60.2[kW], pSOFC 22.8 [kW] Compressor 21.7 [kW], Pump 5.5 [kW], Fuel Heater 0.9 [kW], reformer 0.7 [kW], water heater 0.4 [kW], air heater 0.23 [kW], and MGT 0.21 [kW].
Keywords: Proton-Conducting Solid Oxide Fuel Cell (pSOFC), Micro Gas Turbine (MGT), Matlab-Simulink, Hybrid configuration mode