金属盐(SO_(4)^(2-)/Cl^(-))固体酸催化剂在污泥制生物柴油中的应用

Application of modified metal salt hydrates containing SO_(4)^(2-)/Cl^(-) in the production of biodiesel from sewage sludge

研究NaHSO_(4)·H_(2)O(布朗斯特酸位为主)和AlCl_(3)·6H_(2)O(路易斯酸位为主)两类金属盐固体酸催化剂在污泥制取生物柴油过程中的催化性能.结果表明,经过130℃脱水的NaHSO_(4)·H_(2)O较AlCl_(3)·6H_(2)O表现更为优异,两种催化剂的最优催化条件为催化剂投加量1.2g/10g冷冻干燥污泥、反应温度130℃、反应时间4h.虽然对粗脂肪的酯化率NaHSO_(4)·H_(2)O低于AlCl_(3)·6H_(2)O,分别为(63.4±2.6)%和(68.9±1.4)%(对应的生物柴油产率分别为9.73%~10.69%和10.80%~11.39%(污泥干基)),但经过GC-MS分析发现NaHSO_(4)·H_(2)O催化的生物柴油纯度更高,品质更好;两种催化剂的重复使用性<3~5次.两种催化剂均可实现低成本、高性能且环境友好的催化污泥制备生物柴油.

The catalytic performance of two kinds metal salt solid acid catalysts(NaHSO_(4)·H_(2)O that mainly were Bronsted acid sites and AlCl_(3)·6H_(2)O that mainly were Lewis acid sites)for biodiesel production from sludge was compared.The results showed that NaHSO_(4)·H_(2)O dehydrated at 130℃ had better performance than AlCl_(3)·6H_(2)O.The optimal catalytic conditions of the two catalysts were as follows:catalyst dosage of 1.2g/10g freeze-drying sludge,reaction temperature of 130℃,reaction time of 4h.The esterification rate of crude fat catalysed by NaHSO_(4)·H_(2)O(63.4±2.6)% was lower than that of AlCl_(3)·6H_(2)O(68.9±1.4)%,the corresponding biodiesel yields were 9.73%~10.69% and 10.80%~11.39%(sludge dry base).However,the GC-MS analysis showed that the biodiesel catalysed by NaHSO_(4)·H_(2)O had higher purity and better quality.The reusability of the two catalysts was <3~5times.Therefore,both of the two catalysts were excellent in biodiesel production from sludge with low cost,high performance and environmental friendliness.