| 摘要: | 本研究旨在研究由碳氫化合物燃料供給之質子陶瓷燃料電池（PCFC）和燃氣輪機（GT ）混合動力系統。本研究建構了三個系統：案例1、案例2和案例3。案例1、2和3將來自 GT 的高質量熱量分別流入陰極預熱器、重整器，並按比例分別流入陽極和陰極預熱器。選擇甲醇、甲烷、丙烷和丁烷等烴類燃料作為輸入燃料，其中甲醇在外部重整，其他氣體燃料在內部重整。接下來，還分析了空氣和燃料化學計量、蒸汽碳比（S/C）、燃料利用率（Uf）和陽極廢氣再循環比（AOGR）等幾個參數。
本研究使用Thermolib軟體並使用其從參考中獲得的輸入參數來構建此系統。甲醇進料 PCFC/GT 混合系統的結果表明，合適的配置是當來自 GT 的高質量熱量按比例流入陽極和陰極預熱器，如案例3所示。其實現的最大效率為73%，總能質損耗為211 kW。結果表明，燃料電池的可用能效率通過將熱量從 GT 回流到預熱器而提高。此外，利用冷卻劑作為重整器和蒸發器的熱源可以提高系統效率。
AOGR 位置的結果表明，在甲醇進料 PCFC/GT 混合系統中，將陽極出口氣體回流到陽極入口是合適的，因為可以維持重整器的工作溫度。 此外，如案例3所示，陽極預熱器可以在低能質損耗的情況下以最大功率運行。
參數變化的結果表明，PCFC 功率輸出隨著 AOGR 比的增大而增加。它與大量流入陽極的氫氣密不可分。相反，GT 功率輸出隨著渦輪入口溫度和燃燒室反應物的降低而降低。結果表明，與燃料電池功率上升相比，GT功率降低相對較小，因此系統效率隨著AOGR比的增加而增加。此外，安裝 AOGR 還可以維持 PCFC/GT 混合系統在不同燃料利用率（Uf）變化下以最大功率運行。
燃料利用率（Uf）變化的結果表明，該參數對於 PCFC 和 GT 的能量分配至關重要，其中電池功率輸出隨著燃料利用率（Uf）的增加而增加，而 GT 功率輸出減少。結果還表明，PCFC/GT 混合系統可以在低燃料利用率（Uf）下使用 AOGR 產生最大功率，而混合系統在沒有 AOGR 的情況下以及高燃料利用率（Uf）下具有峰值功率。
反應物影響的結果表明，燃料的增加必須隨著空氣的增加而增加，反之亦然。其目標是在最佳條件下運行並使系統功率達到71%–72%。舉例來說，燃料化學計量1.05、1.1和1.2需要分別與空氣化學計量2.5、3和3.5一起進料。
分析的第二個系統是 IR-PCFC/GT 混合系統。結果表明，按比例分配到陽極和陰極預熱器的熱量可以提高系統效率，如案例3所示。該系統的優化參數如下：空氣化學計量比為2，燃料利用率（Uf）為0.85，蒸汽碳比（S/C）為2，以及使用甲烷作為燃料。
這項工作有助於學者確定（i）PCFC/GT 混合系統中的適當配置，（ii）了解良好的 AOGR 位置，（iii）選擇合理的燃料、蒸汽碳比（S/C）、燃料利用率（Uf）、空氣化學計量和燃料化學計量。
;This study aims to investigate protonic ceramic fuel cell (PCFC)/gas turbine (GT) hybrid systems fed by hydrocarbon fuels. Three designs are built: case 1, case 2, and case 3. Cases 1, 2, and 3 flow high-quality heat from GT into a cathode preheater, a reformer, and proportionally into anode and cathode preheaters, respectively. Hydrocarbon fuels such as methanol, methane, propane, and butane are chosen as the input fuels, in which methanol is reformed externally, and other gaseous fuels are reformed internally. Next, several parameters such as air and fuel stoichiometry, steam-to-carbon ratio (S/C), fuel utilization factor (Uf), and anode off-gas recycling ratio (AOGR) are also analyzed. Thermolib is employed to build the system with input parameters obtained from references.
The results in methanol-fed PCFC/GT hybrid systems show that the appropriate configuration is when the high-quality heat from GT flows proportionally into anode and cathode preheaters, as indicated in case 3. The maximum efficiency achieved is 73%, with a total exergy destruction of 211 kW. The results show that the exergy efficiency of fuel cells increases by reflowing the heat from GT to preheaters. Moreover, utilizing the coolant as the heat source for a reformer and evaporator can improve system efficiency.
Results of the AOGR location study show that reflowing anode outlet gas into anode inlet is appropriate in a methanol-fed PCFC/GT hybrid system as the operating temperature of the reformer can be maintained. Moreover, an anode preheater can work maximally with low exergy destruction, as indicated in case 3.
The results of the parameter variation show that PCFC power output increases along with a larger AOGR ratio. It is inseparable from an enormous amount of hydrogen flowing into the anode. Conversely, GT power output decreases as turbine inlet temperature and reactant of combustor decrease. The results show that GT power reduction is relatively small compared to fuel cell power rise, so the system efficiency increases with a larger AOGR ratio. Moreover, installing AOGR also can maintain a PCFC/GT hybrid system operating at maximum power under different Uf variations.
The results of Uf variations show that this parameter is essential in energy distribution into PCFC and GT, in which cell power output increases along with increasing Uf, while GT power output decreases. The results also show that PCFC/GT hybrid system can produce maximum power at low Uf with AOGR, and a hybrid system has peak power at high Uf without AOGR.
The results of the reactant effects show that an increase in fuel must follow an increase in air and vice versa. The objective is to run the system under the best possible conditions: 71% to 72%. For example, the fuel stoichiometry 1.05, 1.1, and 1.2 need to feed with the air stoichiometry 2.5, 3, and 3.5, respectively.
The second system analyzed is IR-PCFC/GT hybrid system. The results show that a proportional heat distribution into anode and cathode preheaters can enhance the system efficiency, as indicated in case 3. The optimized parameters for this system are as follows: air stoichiometry of 2, Uf of 0.85, S/C of 2, and methane as a fuel.
This work contributes to the scientific community for (i) determining an appropriate configuration in PCFC/GT hybrid system, (ii) understanding a good AOGR position, (iii) and choosing the reasonable fuel, S/C, Uf, air stoichiometry, and fuel stoichiometry. |
