發(fā)布時間：2018-02-23 02:40

  本文關鍵詞： 直接碳燃料電池 液態(tài)銻陽極 反應機理 性能特性 流化床電極　出處：《清華大學》2014年博士論文　論文類型：學位論文

【摘要】：液態(tài)銻(Sb)陽極直接碳燃料電池(DCFC)是一種新型發(fā)電技術，開展相關機理與反應特性研究對該技術發(fā)展具有重要意義。本文系統(tǒng)地研究了液態(tài)Sb陽極反應特性，Sb陽極浸潤性和電解質表面形貌對電池性能的影響機制，碳燃料在Sb陽極中的反應機理，脫灰煤在Sb陽極中的反應和輸運特性，在此基礎之上構建了流化床管式液態(tài)Sb陽極DCFC原型樣機。 采用表面粗糙度為納米級的光滑YSZ單晶電解質(Ra=0.69nm)，能夠剝離電解質表面形貌的影響，獲得液態(tài)Sb陽極的本征反應特性。在800oC下，Sb陽極的本征陽極阻抗為0.143cm2，本征交換電流密度為141.4mA/cm2。800oC下液態(tài)Sb和Sb2O3與YSZ單晶表面的接觸角分別為45o、0o，Sb2O3的生成有利于提高液態(tài)Sb陽極與電解質表面的接觸面積。采用Ra=540nm的粗糙電解質表面時，液態(tài)Sb陽極與YSZ單晶電解質的有效接觸面積提高了38%，表面粗糙度的適度增大有利于提高液態(tài)Sb陽極的交換電流密度。 在液態(tài)Sb陽極中碳還原Sb2O3反應的主要路徑是3C+2Sb2O3=4Sb+3CO2，尾氣中CO2的比例可達90%。由于CO在液態(tài)Sb中的輸運速率慢，使得中間產物CO難以還原液態(tài)Sb陽極中的Sb2O3。在陽極-電解質界面處的碳燃料能夠發(fā)生電化學反應，但是由于缺少良好的催化劑，使得碳燃料的電化學反應對電池性能的影響甚微。 太西脫灰煤能使液態(tài)Sb陽極性能恢復至電池模式初始性能，脫灰煤中的雜質能夠被液態(tài)Sb層隔離，避免在陽極-電解質界面積累。脫灰煤在液態(tài)Sb中的輸運方式有擴散和自然對流兩種，但是由于粘性力的影響，，使得自然對流對脫灰煤在液態(tài)Sb中的輸運作用并不顯著。 采用管式固體氧化物燃料電池，構建了流化床管式液態(tài)Sb陽極DCFC原型樣機，實現了液態(tài)Sb陽極DCFC的連續(xù)給料和穩(wěn)定運行，驗證了流化床電極應用于液態(tài)Sb陽極DCFC中的可行性。流化床管式液態(tài)Sb陽極DCFC中碳燃料轉化率可達90%，電池的實際效率可達41%。
[Abstract]:Liquid antimony (SB) anode direct carbon fuel cell (DCFC) is a new generation technology. It is of great significance to study the mechanism and reaction characteristics for the development of this technology. In this paper, the effects of liquid SB anodic reaction characteristics and electrolyte surface morphology on the performance of the battery are systematically studied. On the basis of the reaction mechanism of carbon fuel in SB anode and the reaction and transport characteristics of demineralized coal in SB anode, a prototype of fluidized bed tubular SB anode DCFC was constructed. A smooth YSZ single crystal electrolyte with surface roughness of nanometer size of 0.69 nm can be used to peel off the influence of the surface morphology of the electrolyte. The intrinsic reaction characteristics of liquid SB anode were obtained. At 800oC, the intrinsic anode impedance of Sb anode was 0.143 cm 2, and the exchange current density was 141.4 Ma / cm 2.800oC. the contact angle between liquid SB and Sb2O3 on the surface of YSZ single crystal was 45oTO 0oSb 2O 3 at 800oC. Contact area between SB anode and electrolyte surface. When using Ra=540nm rough electrolyte surface, The effective contact area between liquid SB anode and YSZ single crystal electrolyte is increased by 38%, and the exchange current density of liquid SB anode is increased with the increase of surface roughness. The main route of carbon reduction Sb2O3 reaction in liquid SB anode is 3C _ 2SB _ 2O _ 3N _ 4SB _ 3CO _ 2, and the proportion of CO2 in tail gas can reach 90%. Due to the slow CO transport rate in liquid SB, It is difficult for the intermediate product CO to reduce SB _ 2O _ 3 in liquid SB anode. The carbon fuel at the anodic electrolyte interface can react electrochemical, but due to the lack of good catalyst, The electrochemical reaction of carbon fuel has little effect on the performance of the battery. Tacey deashing coal can restore the performance of liquid SB anode to the initial performance of battery mode, and the impurities in the ash removal coal can be isolated by liquid SB layer. The transport modes of deashing coal in liquid SB are diffusion and natural convection, but due to the influence of viscosity, natural convection has little effect on the transport of deashing coal in liquid SB. The prototype of fluidized bed tubular SB anode DCFC was constructed by using tubular solid oxide fuel cell. The continuous feeding and stable operation of liquid SB anode DCFC were realized. The feasibility of using fluidized bed electrode in liquid SB anode DCFC is verified. The conversion rate of carbon fuel in liquid SB anode DCFC of fluidized bed tube can reach 90% and the actual efficiency of battery can reach 41%.
【學位授予單位】：清華大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM911.4

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本文編號：1525925