MTBE碱洗-萃取蒸馏脱硫实验研究

EXPERIMENTAL STUDY ON DESULFURIZATION OF MTBE BY ALKALI WASHING AND EXTRACTIVE DISTILLATION

根据硫醇具有弱酸性的特点,采用碱洗-萃取蒸馏法对MTBE进行了脱硫实验研究。研究结果表明:在NaOH质量分数28%、m(NaOH)∶m(MTBE)=0.015、碱洗温度35℃、碱洗时间6s、相分离温度35℃、相分离时间5min的条件下,MTBE中硫质量分数可从132.5μg/g降至76.2μg/g;采用DMF为萃取剂,将碱洗后的MTBE在蒸馏温度80℃、蒸馏时间25min、剂油质量比1.5的条件下进行3级萃取蒸馏,MTBE的硫质量分数可降至8.7μg/g,质量收率为99.64%;将萃取溶剂在空速60h-1、温度100℃的实验条件下用N2汽提再生,经6次再生后回用,MTBE的硫质量分数均能降到10μg/g以下,再生效果较好。

Methyl tert-butyl ether（MTBE）is an important high octane additive for the production of clean gasoline.It is necessary to reduce sulfur in MTBE to less than 10μg/g to meet increasingly stringent standard for motor gasoline.According to the weak acidity property of mercaptan,this work uses an alkali washing-extractive distillation combination process for MTBE desulfurization.The S content is reduced from 132.5μg/g to 76.2μg/g in alkali washing stage at conditions of NaOH of 28%,NaOH/MTBE mass ratio of 0.015,alkali washing temperature of 35℃,alkali washing time of 6s,separated temperature of 35 ℃,separation time of 5min.The MTBE after alkali washing then undergoes three-stage extraction distillation by DMF at 80 ℃,distillation time of 25 min,solvent/oil mass ratio of 1.5.The results show that the sulfur content of MTBE can be further reduced to 8.7μg/g and the total liquid yield of the combined process is 99.64%.The solvent after six times regeneration recycle can still reduce the sulfur in feed to less than 10μg/g.The regeneration conditions are：N2stripping with space velocity of 60h^-1 at 100 ℃.