乙酸水蒸气重整制氢过程的热力学分析

Thermodynamic Analysis on Steam Reforming of Acetic Acid for Hydrogen Production

对乙酸水蒸气重整制氢过程进行了热力学分析,研究了常压下反应温度、水碳比对气体产率的影响。结果表明,随着反应温度的升高,H2产率先升高后降低,最佳的反应温度范围为600~700℃。增大水碳比有利于提高H2产率,当水碳比大于3时,在反应温度为600~700℃下的H2产率相差不大。通过对乙酸水蒸气重整制氢体系进行简化,建立了不同反应温度、不同水碳比下三个主要反应的竞争机制。当水碳比较小时(S/C=0、1),在较低反应温度下(500~600℃)乙酸的脱羧基反应占据优势,在较高反应温度下(600~900℃)乙酸的热裂解反应占据优势;当水碳比较高时(S/C=2、4),乙酸的重整反应在整个反应温度范围内(500~900℃)占据绝对优势。

Thermodynamic analysis on steam reforming of acetic acid for hydrogen production was carried out. The influences of reaction temperature and steam to carbon ratio on gas yields under atmospheric pressure were investigated. Results show that the hydrogen yield increased and then decreased as the reaction temperature rose, the optimal reaction temperature range was 600 ~ 700℃. Higher steam to carbon ratio should be selected for the maximum hydrogen production, the hydrogen yield was almost the same at the temperature range of 600 ~ 700℃ when the steam to carbon ratio was 3. The competitive mechanism of the three major reactions under different reaction temperatures and steam to carbon ratios was established by simplifying the reaction system. When the steam to carbon ratio was low （S/C = 0, 1）, the decarboxylation reaction was the major pathway at lower temperatures （500 ~ 600℃）, and the decomposition of acetic acid was the main reaction at higher temperatures （600 ~ 900℃）. When the steam to carbon ratio was high （S/C = 2, 4）, the steam reforming of acetic acid was dominated in the whole range of reaction temperatures （500 ~ 900℃）.