高溫高壓之電解水產氫效率分析; Analysis of water electrolysis energy efficiency under high presssure and high temperature

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Title:	高溫高壓之電解水產氫效率分析;Analysis of water electrolysis energy efficiency under high presssure and high temperature
Authors:	蔡宗澤;Tsung-tse Tsai
Contributors:	能源工程研究所
Keywords:	電解水、高溫高壓水電解、活性過電壓、產氫;hydrogen production;activation overvoltage;water electrolysis
Date:	2009-07-07
Issue Date:	2009-09-21 11:30:35 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本論文主旨是為探討高溫高壓之下，電解水產氫的效率，主要以電流對電壓圖作為表現依據，其中，又將電流電壓表現，細分為四種不同的反應機制，個別加以詳細探討，四種不同反應機制如下: 1.可逆電位(reversible voltage) 2.活性極化(activation polarization) 3.歐姆極化(ohmic polarization) 4.濃度極化(concentration polarization)。每個不同反應機制的結果為: 1.可逆電位:隨著溫度壓力愈高，其電位愈低。2.活性極化: 隨著溫度愈高，其過電位愈低，而活性過電位受到壓力的影響可以忽略。3.歐姆極化:分為電極電阻過電位以及氣泡電阻過電位來考慮，其中隨著溫度上升，電極電阻過電位增加，不受壓力影響，而隨著溫度上升，氣泡電阻過電位增加，隨著壓力上升，過電位下降，但在電流密度小於1A/cm2的情況下，氣泡電阻過電位十分小可以忽略4.濃度極化: 隨著溫度愈高，其過電位愈低，其受到壓力的影響可忽略。但在電流密度小於1A/cm2的情況下，濃度過電位十分小可忽略。而最後的整體電能消耗部分，500bar/370oC比起1bar(約1atm)/80oC節省了約17%的電能，若我們再考慮把1bar的氣體壓縮到500bar的壓縮能量花費，則500bar/370oC節省了約22%的電能。 This work aims at analysing the energy efficiency of a high pressure, high temperature water electrolysis by current-voltage diagram. Four different kinds of reaction mechanisms,namely,1. reversible voltage, 2. activation polarization, 3. ohmic polarization,and 4. concentration polarization,are investigated in details.。 The results of each different reaction mechanisms are: 1. Reversible voltage: The higher the temperature and pressure are, the lower its potential is. 2.Activation polarization: The higher the temperature is, the lower its potential is. However,the influence of pressure can be neglected. 3. Ohmic polarization: it can be divided into electrode resistance and bubble resistance . Between them, the electrode resistance overpotential rises with temperature, but is not effected by pressure. The bubble resistance overpotential increases as temperature rises,and drops as the pressure rises.However, as the current density is smaller than 1A/cm2, the bubble resistance overpotential is very small and can be neglected.4. Concentration polarization: As temperature gets higher, the concentration overpotential decreases, and the influence of pressure can be neglected. The whole electric energy consumption at 500bar/370oC, compared with that at 1bar/80oC, is saved about 17%. If the consumption of compressing the gas from 1bar to 500bar is considered, then the water electrolysis at 500bar/370oC saves about 22% of the electric energy.
Appears in Collections:	[Energy of Mechatronics] Electronic Thesis & Dissertation

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