The Role of Supercritical Water in Pyrolysis of Carbonaceous Compounds

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• 作者：Tao Xu ; Qingya Liu ; Zhenyu Liu ; Junfei Wu
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：June 20, 2013
• 年：2013
• 卷：27
• 期：6
• 页码：3148-3153
• 全文大小：258K
• 年卷期：v.27,no.6(June 20, 2013)
• ISSN：1520-5029

文摘

Supercritical water (SCW) has been studied widely for upgrading complex and low-value carbonaceous materials due to its ability to depress coke formation and improve product quality. Many researchers attributed these effects to SCW鈥檚 hydrogen donation ability, including H鈥?and H⁺, while others to physical effects, such as the cage effect or the solvent effect. To clarify the role of SCW, three probe compounds, naphthalene, p-benzoquinone, and azobenzene, are treated individually in SCW at 400 掳C and 25.3 MPa, and their products are analyzed and compared with the products obtained under other conditions, including hot compressed water, SCW with tetralin, and an inert atmosphere with or without tetralin. The products from reaction of the compounds with HO鈥?or HO^{鈥?/sup> are used as the key indicators to identify the hydrogen donation ability of SCW. Results indicate that SCW cannot donate H鈥?radicals and condensation of carbonaceous materials is responsible for generation of H鈥?in the temperature range of SCW. H+ may play a role at a higher extent of water ionization. The different product distribution under the SCW conditions from the inert atmosphere can be attributed mainly to the increased dispersion of radicals due to the solvent effect of SCW.}