多電極固態薄膜型電解質之氫氣產生器製造與性能分析

Desing and Fabrication of multi-cell Solid Polymer Electrolyte（SPE-Type）Hydrogen Generator and It’s Performance Analysis

蔡明璋(Ming-Chang Tsai)

指導教授 ： 郭景宗

國立臺灣大學/工學院/機械工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.02149

摘要

本研究旨在研究發展多電極組固態質子交換膜氫氣產生器，其優點為: 1.不含腐蝕性電解液；2.產氣純度高；3.能量轉換效率高，且可在大電流密度下操作；4.以雙極板設計組裝stack進而提升產氫量。本實驗由基本的材料選擇及理論分析出發，選擇高抗腐蝕的流道板材料，並嘗試以直接噴塗觸媒於膜上的方式製作MEA，使得觸媒分布能更平均並保持膜在噴塗過程能夠平整；在流道設計上先以計算流體軟體模擬避免提高製造成本。多電極組固態質子交換膜氫氣產生器的性能與內部二相流流動、MEA反應特性與機械結構等變因息息相關，其中包含了溫度、壓力、流量、極板間距、觸媒量…等，均在本文中予以討論。本論文分別探討流道板材料，溫度、觸媒量及電流收集網對電解器之電壓效率、法拉第效率及能源轉換效率所造成的影響。
以單電極的實驗結果為依據，組裝五個電極的多電極組氫氣產生器為本研究最後的目標，其效能在加溫後獲得大幅的改善，並可長時間操作而效能不會逐漸衰退。組裝多電極組電解器之密封為另ㄧ個重點，此處採用O-ring密封，並採用陰陽極各自獨立的O-ring，其效果可由氣相分析儀檢驗產生的氫氣，氫氣純度為99.7%，證明設計的氣密效果良好。
本實驗所設計的固態電解質純水電解器目前最好的效能為:
1. 單電極:2.47V@200mA/cm2，產氫量70ml/min，能源轉換效率55.66%，法拉第效率92%。
2. 多電極組:12.94V@200mA/cm2，產氫量355ml/min，能源轉換效率52.85%，法拉第效率94.1%。

關鍵字

質子交換膜 ； 多電極組 ； 雙極板

並列摘要

This study is focused on developing a multi-cell, solid-polymer-electrolyte type hydrogen generator. The characteristics of the SEP hydrogen generator are: (1) non- corrosive electrolyte is used, (2) higher purity of hydrogen gas was obtained without extra purification, (3) higher energy conversion efficiency was achieved at high current densities, (4) stack is fabricated by bipolar plate to improve the hydrogen generation rate. The MEA was fabricated by coating the catalyst on the surface of membrane directly, which allowing the uniform coating of catalyst, and consequently the surface of membrane could be kept smooth. The optimum flow field geometry was selected in accordance with the simulation result of CFD. The effect of temperature and volumetric rate of water, gaseous pressure in stack, distance between two electrodes, and catalyst loading on performance of SEP hydrogen generator, was investigated experimentally.
Experimental results of single-cell electrolyzer and five-cell electrolyzer show that the energy conversion efficiency could be significantly improved by increasing the water temperature to 70℃. Hydrogen content of producer gas can be achieved up to 99.7% if the cathode and anode was both equipped with an O-ring, respectively.
The optimum performance of the SPE electrolyzer made in this study is:
(1) single cell: 2.47V@200mA/cm2，H2 generation rate 70ml/min，energy conversion efficiency 55.66%，Faraday efficiency 92%。
(2) stack:12.94V@200mA/cm2，H2 generation rate 355ml/min，energy conversion efficiency 52.85%，Faraday efficiency 94.1%。

並列關鍵字

Nafion 117 ； stack ； bipolar plate

參考文獻

13.許盈盈，“固態電解質純水電解器產氫元件之設計與性能分析”，國立台灣

Int. J. Hydrogen Energy 23(12), 1998, p1113-1120..

2. K. Onda et al., “Performance Analysis of Polymer-Electrolyte Water Electrolysis Cell at a Small-Unit Test Cell and Performance Prediction of Large Stacked Cell”,

J. Electrochem. Soc. 149(8), 2002, A1069-A1078.

3. K. Onda et al., “Prediction of Production Energy for High-pressure Hydrogen by High-pressure Water Electrolysis”, J. Power Sources 132, 2004, p64-70.