The removal of naphthenic acids from dewaxed VGO via esterification catalyzed by Mg–Al hydrotalcite
The removal of naphthenic acids from dewaxed VGO via esterification catalyzed by Mg–Al hydrotalcite
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DOI：
10.1016/j.fuproc.2013.01.016
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发表时间：
2013-07
影响因子：
7.5
通讯作者：
Xiaohui Li;Z. Jianhua;Liu Qingliu;W. Bencheng
中科院分区：
文献类型：
--
作者：
Xiaohui Li;Z. Jianhua;Liu Qingliu;W. Bencheng
以固体碱水滑石为催化剂，对脱蜡减压馏分油进行酯化脱酸，以达到降低油品总酸值的目的。采用尿素法合成了Mg/Al摩尔比为4的镁铝水滑石，并对其进行了煅烧和再水化处理。采用PXRD、BET、CO2-TPD、FTIR、TG/DTA等手段对镁铝水滑石及其煅烧和再水化产物进行了表征。采用间歇反应器考察了催化剂对脱蜡蜡油中环烷酸转化的催化活性。考察了醇油质量比、催化剂油质量比、反应温度、反应时间等因素对环烷酸转化率的影响，并对结果进行了讨论。煅烧后的催化剂的活性低于未煅烧的催化体系的初始活性。考察了固体催化剂的基本性质与脱蜡蜡油酯化反应活性的相关性。碱性布朗斯特中心在酯化过程中起着重要的作用。水复水后的水滑石催化剂的酯化效率略高于合成前的水滑石催化剂，且合成后的水滑石催化剂可重复使用多次而活性无明显损失。结果表明，Mg-Al水滑石作为非均相催化剂可以有效降低油品的酸值，且具有较高的催化活性和稳定性，是一种很有前途的催化剂。
This work focused on deacidification of dewaxed VGO by esterification on solid base hydrotalcite catalyst to achieve the target of lowering the total acid number (TAN) of oil. Mg–Al hydrotalcite with Mg/Al molar ratio of 4 was synthesized via urea method, and followed by calcination and rehydratation. Mg–Al hydrotalcite and its calcined and rehydrated products were characterized by PXRD, BET, CO2-TPD, FTIR, and TG/DTA. The catalytic activity of the prepared catalyst was evaluated using batch reactor for investigating the conversion of naphthenic acids in dewaxed VGO. The effects of various reaction parameters such as mass ratio of glycol to oil, mass ratio of catalyst to oil, temperature, time etc. on the conversion of naphthenic acids were studied and the findings were discussed. The activity of the calcined catalyst was lower than the initial activity of the non-calcined catalytic system. The correlation between the basic properties of the solid catalysts and the activity in the esterification in dewaxed VGO was investigated. The basic Brønsted sites played an important role in the esterification process. The hydrotalcite catalyst rehydrated by water exhibited a slight higher esterification efficiency compared to the as-synthesized one, and the as-synthesized one can be reused several times without significant loss of activity. Therefore, it was verified that Mg–Al hydrotalcite as a heterogeneous catalyst could be used to esterify naphthenic acids to lower TAN value of oil effectively, and Mg–Al hydrotalcite may be a promising catalyst for its sufficient high catalytic activity and stability.