己内酰胺加氢精制过程的影响因素分析

Analysis of influencing factor in hydrofining process of caprolactam

介绍了己内酰胺加氢精制的工艺流程,总结了国内某15万t/a固定床己内酰胺加氢精制装置的运行数据,探究了反应压力、温度和催化剂等对加氢精制效果的影响。结果表明:当反应压力在由0.3 MPa升高至0.5 MPa时,加氢出口高锰酸钾吸收值(PAN值)逐渐降低,继续提高反应压力,PAN值变化不明显;当反应温度在50℃~60℃时,PAN值基本可稳定在0.8~1.6,碱度在0.13 mmol/kg左右波动,可保证己内酰胺水溶液质量达标;经过加氢反应,己内酰胺水溶液吸光度小幅降低、碱度小幅升高,但不会影响成品己内酰胺的质量;固定床加氢催化剂寿命较短,其活性下降的主要原因是催化剂结块和表层被己内酰胺覆盖。

The caprolactam hydrofining process flow was introduced,the operation data of a 150000 t/a caprolactam plant with fixed-bed hydrofining in China were summarized,and the effects of reaction pressure,temperature and catalyst on the hydrofining were explored.The results showed that when the reaction pressure increased from 0.3 MPa to 0.5 MPa,the absorption value of potassium permanganate(PAN value)at the hydrogenation outlet gradually decreased,but when the reaction pressure continued to increase,the change of PAN value was not obvious.When the reaction temperature was 50℃-60℃,the PAN value was stable at 0.8-1.6,and the alkalinity fluctuated at about 0.13 mmol/kg,which could ensure that the quality of caprolactam aqueous solution met the standard.Through the hydrogenation reaction,the absorbance of aqueous caprolactam decreased slightly and the alkalinity increased slightly,but the quality of finished caprolactam products would not be affected.The service life of hydrogenation catalyst used in fixed-bed reactor was short,and the main reason for the decline of its activity was the catalyst caking and its surface covered with caprolactam.