标题: 钙-镍-铝水滑石触媒对于乙醇蒸气重组反应之二氧化碳捕获及产氢研究
Ca–Ni–Al Layered Double Hydroxides for CO2 Capture and Hydrogen Production from Ethanol Steam Reforming
作者: 陈雅棱
Chen, Ya-Leng
陈三元
许火顺
Chen, San-Yuan
Sheu, Hwo-Shuenn
加速器光源科技与应用硕士学位学程
关键字: 乙醇蒸气重组;产氢;二氧化碳捕获;ethanol steam reforming;hydrogen production;CO2 capture
公开日期: 2012
摘要: 本研究以钙-镍-铝层状水滑石结构做为前驱物,制备出一系列不同钙-镍莫耳比例之钙-镍-铝氧化物。首先利用X光绕射(XRD)鉴定结构,并以电子显微镜(SEM)、比表面积仪(BET)分析其物理特性。藉由热重分析(TGA)对其二氧化碳捕获能力与稳定性进行量测,结果发现钙-镍-铝氧化物之最佳捕获温度范围约在600-700℃之间,经15次捕获/脱附循环回圈测试后,其材料仍可保有极高的二氧化碳捕获量约41.6wt%,且无明显劣化的迹象,其捕获循环维持率约为98%,展现出极佳的稳定性。
其次,针对钙-镍-铝氧化物应用于乙醇重组系统催化之效能探讨,实验以两组乙醇重组系统进行分析:第一部分为通入氮气的二氧化碳捕获强化重组产氢系统,在此系统中,水-乙醇进料比例、反应温度等操作条件改变皆会对二氧化碳捕获与乙醇重组产生显着影响。经由二氧化碳捕获强化辅助,镍含量0.15之样品于水-乙醇莫耳比为5、催化温度为600℃的条件下可获得最高产氢量约5.14莫耳。第二部分则为通入空气的乙醇自供热重组系统。相较于调变催化温度,实验发现将钙-镍-铝氧化物还原成金属触媒的方式更可有效获得高氢气产出。其中,高镍含量0.67之样品经还原后可具有最高之氢气产量约3.15莫耳;即使减少镍含量如0.33之样品,其经长时间乙醇重组连续测试24小时,氢气产量亦可达2.98莫耳,维持在96%,拥有优秀的催化稳定性;而低镍含量0.15的样品经还原后,则可获得最多的氢气提升量0.76莫耳。
综合以上结果,钙-镍-铝氧化物兼具优异的稳定性、良好的二氧化碳捕获及氢气产量,本研究成功开发出具备二氧化碳捕获与乙醇重组催化效能之多功能钙-镍-铝复合材料。
This study presentsthe experimental results of ethanol steam reforming to produce hydrogenviaCa-Ni-Al mixed oxidesderived from hydrotalcite-like compounds (HTlcs). These multifunctional catalysts were characterized by X-ray powder diffraction(XRD), scanning electron microscopy (SEM) and Nitrogenadsorption/desorptionisotherms. In addition, theperformance of CO2capture was evaluatedby thermogravimetry analysis(TGA). Owing to homogeneous distributedCa, Ni and Aloxides, the catalystshoweda high capacity of CO2and high stability of cyclic reactions during the carbonation/ decarbonation cycles in the range of 600-700℃.
To further investigatethe catalytic activities in the process of ethanol
steam reforming, two different systems, sorption enhanced steam reforming(SESRE) and autothermal reforming of ethanol(ATRE), were chosen to examine the performance. Inthe first part, it was found that optimizingthe molar ratio of steam/ethanol and the operating temperature would benefitboththe capacity of captured CO2and the production of hydrogen. The maximum yield of hydrogenas 5.14mol/mol ethanol was obtained from overLDO-Ni-0.15 catalystwith S/E=5 at 600℃. Furthermore, in the second part, it was demonstrated that not only the production of hydrogen but the catalyticstability could be more obviously improved by reducing the NiO to Ni,which was more prominent forthe Ni-poor catalysts. Finally, multifunctionalCa-Ni-Al oxide catalyst was successfully developed withhigh hydrogenproduction enhanced by excellentCO2capture capacity.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079901503
http://hdl.handle.net/11536/48958
显示于类别:Thesis