Hydrogen production from waste aluminum at different temperatures, with LCA
Hydrogen production from waste aluminum at different temperatures, with LCA
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DOI：
10.2320/matertrans.46.1052
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发表时间：
2005-05-01
影响因子：
1.2
通讯作者：
Akiyama, T
中科院分区：
文献类型：
--
作者：
Hiraki, T;Takeuchi, M;Akiyama, T
化学用能高、精炼过程耗电量大的废金属铝回收利用不足。特别是，在回收的一部分重熔过程中产生的所谓渣滓需要昂贵的处理，特别是当金属浓度低于20%时，才能进行填埋。本研究的目的是利用废铝源制氢。如渣滓，在烧杯和高压釜中使用氢氧化钠水溶液。在研究过程中，主要考察了水溶液温度对产氢速率的影响。XRD分析结果表明，实验过程中析出的白色产物中含有氢氧化铝，随着氢氧化钠浓度和水溶液温度的升高，生成氢的速率显著提高。活化能为68.4kJ mol（-1）。在高压灭菌器实验中，氢气快速释放，同时内压增加到最低1.0 MPa，温度增加到473 K以上。结果表明，废铝制氢和氢氧化钠副产可能是一种经济有效的新工艺。利用废铝生产1 kg氢和26 kg氢氧化铝的工艺进行了生命周期评估（LCA），以评估能源需求和二氧化碳排放量。结果表明，与传统方法相比，我们的工艺能耗仅为2%，二氧化碳排放量为4%。
The recycling of waste metallic aluminum with high chemical exergy, which consumes a large quantity of electricity in the refining process, is insufficient. In particular, the so-called dross generated during the remelting process a part of recycling requires expensive treatment, particularly when the metallic concentration is less than 20%, before it can be landfilled. The purpose of this study is to produce hydrogen from waste aluminum sources. such as dross, using an aqueous solution of sodium hydroxide in a beaker and an autoclave. During the study, the effects of temperature of the aqueous solution on the rate of hydrogen generation are to be chiefly examined. The result obtained from an XRD analysis showed that the white product that precipitated during the experiments contained aluminum hydroxide, the rate of hydrogen generation significantly increased with the concentration of sodium hydroxide and temperature of the aqueous solution. and the activation energy was 68.4kJ mol(-1). In the autoclave experiments, hydrogen is released quickly, along with an increase in the inner pressure to a minimum of 1.0 MPa and an increase in the temperature above 473 K. The results suggested a possibility of a new cost effective process of hydrogen production from waste aluminum along with the by prodution of sodium hydroxide. The life cycle assessment (LCA) of the proposed process for producing not only I kg of hydrogen but also 26 kg aluminum hydroxide from waste aluminum was carried out to assess the energy requirement and amount of carbon dioxide emissions. Results suggest that the energy requirement of our process is only 2% and the amount of carbon dioxide emissions is 4%, in comparison to a conventional method.