| 摘要: | 本研究旨在探討與外部甲醇蒸氣重組器(Methanol Steam Reformer, MSR)結合的高溫質子交換膜燃料電池(high temperature proton exchange membrane fuel cell, HT-PEMFC)和有機朗肯循環(Organic Rankine Cycle, ORC)、聯合熱電(Combined-Heat-and-Power, CHP)、微型燃氣渦輪(micro-Gas Turbine, micro-GT)混合系統。本研究分析了三種系統配置：第1種系統配置只有HT-PEMFC、ORC、CHP和MSR；第2種系統配置結合了HT-PEMFC、ORC、CHP、MSR和micro-GT；第3種系統配置結合了HT-PEMFC、ORC、CHP和micro-GT。在每個系統中，目的是重複利用HT-PEMFC未使用的氣體，以提供每個組件所需的熱量，而無需外部的熱供應。研究目標是提高系統能量(Energy)和可用能(Exergy)效率，特別是micro-GT，過去研究從未在HT-PEMFC系統中使用過。研究將針對不同的參數進行變化以觀察其對系統的影響：HT-PEMFC的燃料利用因子、燃料流量、空氣流量和水蒸氣對燃料的比率。對於每個變量，系統中使用的不同分流器都會進行調整，以獲得相同的運行條件。每個系統都將與“基礎參數”和文獻進行比較。這些系統是使用MATLAB(用於HT-PEMFC建模)和Thermolib插件(用於系統建模)所構建的。
基於基礎參數的結果顯示，包括MSR和GT的配置2性能最佳。系統能量效率達到53.75%，而配置1(有MSR，無micro-GT)為49.24%，配置3(使用micro-GT，純氫作為燃料)為52.93%。配置1還顯示出54.44%的最可用能效率。根據基本參數，此配置能產生2403W的淨功率，其中177W由HT-PEMFC提供，543W由微型GT提供，303.4W由ORC系統提供，89.9W由CHP系統提供。改變參數的結果顯示，增加燃料流量會增加所有系統的功率產出，但會降低效率。為了達到最大的系統效率，燃料使用因子必須盡可能地低，這樣可以增加CHP和micro-GT的功率產出。增加蒸汽對燃料的比率對系統的功率產出和效率沒有太大的影響。增加空氣流量和燃料使用因子表明，該系統在其自身的熱供應方面存在一些限制。超過某些值，系統將無法為自己提供所需的全部熱量。
總而言之，本研究揭示燃料使用因子和燃料流量是兩個關鍵參數，可以提高HT-PEMFC或CHP的功率產出。藉由調整這些參數可允許系統應用不同的應用場景，例如在"夏季"可選擇產生更多的電力，而"冬季"可產生更多的熱能。本研究的進步性與新穎性包括：(i)設計了一個包含micro-GT的HT-PEMFC混合系統，(ii)提升的系統的能量和可用能效率，(iii)詳細揭露了不同參數對系統性能的影響。
;This study aims to investigate the high-temperature proton exchange membrane fuel cell (HT-PEMFC) combined with organic Rankine cycle (ORC), combined-heat-and-power (CHP), micro gas turbine (GT) hybrid systems with an external methanol steam reformer (MSR). Three systems systems are analysed in this study: one with only HT-PEMFC, ORC, CHP, and MSR, the second one with HT-PEMFC, ORC, CHP, MSR, and GT, and the last one with HT-PEMFC, ORC, CHP, and GT. In each system, the idea is to reutilize the unused gas of the HT-PEMFC to supply the heat needed by each component without any external heat production. The objective is to increase the system energy and exergy efficiencies, particularly the GT, which has never been included in a HT-PEMFC system. Then, different parameters are varied to see their influence on the system: HT-PEMFC fuel utilisation factor, fuel flow rate, air flow rate, and steam-to-fuel ratio. For each variation, the different splitters used in the systems are evolving to obtain the same operating conditions. Each system will be compared with the base parameters and the literature. These systems are built using MATLAB (HT-PEMFC modelling) and THERMOLIB (systems modelling).
The results with the base parameters show that system 2 (including MSR and GT) has the best performance compared to the other systems. The system energy efficiency reaches 53.75% against 49.24% in system 1 (MSR, no GT) and 52.93% in system 3 (GT, pure H2 as fuel). This system also shows the best exergy efficiency with 54.44%. With the base parameters, this system produces 2403W of net power, including 1777 W by the HT-PEMFC, 543 W by the GT, 303.4 W by the ORC system, and 89.9 W by the CHP system.
The parameter variations results reveal that a higher fuel flow rate increases all the power production but lowers the efficiency. The fuel utilisation factor must be as low as possible to maximize systems efficiency and increase CHP and GT power production. Increasing the steam-to-fuel ratio does not significantly influence power production and system efficiencies. Increasing the air flow rate and fuel utilisation factor shows that the system has some limits regarding its heat supply. Above specific values, the system cannot supply itself with all the heat required.
Finally, this study reveals that the fuel utilisation factor and fuel flow rate are two critical parameters that can improve either HT-PEMFC or CHP power production. These parameters allow us to choose and alternate between a summer use by generating more electrical than heat power and winter use by generating more heat and less electrical power.
This work contributes to the actual scientific research by (i) designing a new system in a HT-PEMFC hybrid system by including a GT, (ii) improving the system energy and exergy efficiency, and (iii) understanding the effect of different parameters on the systems performance. |
