Thermodynamic Analysis of Hydrogen Generation from Methanol鈥揊ormic Acid鈥揝team Autothermal System

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• 作者：Zebao Rui ; Hongbing Ji
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：September 19, 2013
• 年：2013
• 卷：27
• 期：9
• 页码：5449-5458
• 全文大小：569K
• 年卷期：v.27,no.9(September 19, 2013)
• ISSN：1520-5029

文摘

This work examines the H₂ production from methanol (MeOH)鈥揻ormic acid (FA)鈥搒team (H₂O) system (FSRM) by thermodynamic analysis using the Gibbs free energy minimization method. The compounds considered in FSRM are CH₃OH, HCOOH, H₂O, CO₂, CO, H₂, HCOOCH₃, HCHO, and CH₃OCH₃ and together with or without CH₄ and C (graphite). The addition of FA lowers the enthalpy of the system and favors the heat recycle. Thermal-neutral (TN) conditions are obtained, at which the heat released from exothermic reactions makes up exactly for the requirement of the endothermic reactions. For the case with consideration of CH₄ and C formation, C and CH₄ formation is thermodynamically dominated at a low temperature (<400 掳C). High temperature is favorable for H₂ production and can effectively inhibit CH₄ and carbon formation, but it also leads to high CO yield. High H₂O/MeOH ratio can effectively suppress CO, CH₄, and C formation and improve H₂ mole fraction at 200, 400, and 600 掳C. Although the increase in FA/MeOH ratio leads to low equilibrium H₂ mole fraction and high CO concentration, TN conditions can be realized for wide range of H₂O/MeOH and FA/MeOH ratios. For the case without consideration of CH₄ and C formation, which are only applicable to situations in which byproducts C and CH₄ formation are limited, the thermodynamic data may be more agreeable with the reported experimental results. Under TN conditions, the H₂ mole fraction can be around 0.51 with a CO mole fraction as low as 0.001 for H₂O/MeOH = 2 and FA/MeOH = 5 or 6.