丁二烯装置乙腈溶剂损失原因分析及优化措施

Cause analysis of acetonitrile solvent loss in butadiene unit and its optimization measures

对中化泉州石化有限公司新建130 kt/a丁二烯抽提装置乙腈溶剂损失的原因进行了分析,并优化了工艺流程和操作条件。结果表明:丁二烯装置乙腈溶剂损失的主要原因为乙腈溶剂水解,循环溶剂中杂质含量高,物料及工艺污水夹带;通过采取优化溶剂再生流程,使用高效阻聚剂20 Y 3103,控制汽提塔塔底温度为136.5~137.0℃,混合碳四中碳五质量分数小于0.2%,原料罐罐底温度不高于53℃,各系统含氧量小于10μg/g,同时将溶剂再生塔塔顶压力提至0.035 MPa,再生塔塔底温度不低于113.5℃,增加水洗塔水烃比等措施后,循环乙腈中二聚物质量分数由0.34%降至0.20%以下,抽余碳四中含乙腈量低于2μg/g,液化燃料和工艺污水中含乙腈量分别降至19~23,10~12μg/g,乙腈溶剂损失降至0.9 kg/t。

The casues of acetonitrile solvent loss in the new 130 kt/a butadiene extraction unit of Quanzhou Petrochemical Co Ltd,SINOCHEM,were analyzed,and the process flow and operating conditions were optimized.The results showed that the main cause of the acetonitrile solvent loss in the butadiene unit was the hydrolysis of acetonitrile solvent,high impurity content in circulating solvent and material and process effluent entrainment.By optimizing the solvent regeneration process,using a high-efficiency polymerization inhibitor 20 Y 3103,maintaining the temperature at the bottom of the stripper at 136.5-137.0℃,the mass fraction of C5 in the optimized mixed C4 was less than 0.2%,the bottom temperature of the raw material tank was not higher than 53℃,the oxygen content of each system was less than 10μg/g,the top pressure of the solvent regeneration tower had risen to 0.035 MPa,the bottom temperature of the regeneration tower was not lower than 113.5℃,increasing the water-hydrocarbon ratio of the scrubber etc,the mass fraction of dimer in circulating acetonitrile was reduced from 0.34%to below 0.20%,the mass fraction of acetonitrile in the raffinate C4 was less than 2μg/g,the mass fraction of acetonitrile in the liquefied fuel and process wastewater had dropped to 19-23,10-12μg/g,and the acetonitrile solvent loss was reduced to 0.9 kg/t.