低密度聚乙烯生产过程中二次机及中冷器结垢分析

Analysis of Fouling in Super Compressor and Intercooler During Production of Low Density Polyethylene

LDPE树脂工业化过程中二次压缩机及中冷器普遍存在聚乙烯结垢问题。熔融指数、密度测试结果显示,二次机和中冷器结垢物熔融指数及密度均分别为0.03g/10min,0.942g/cm3及0.12g/10min,0.936g/cm3,表明污垢并非来自高压循环气系统夹带。FT-IR测试结果,显示合格LDPE树脂和结垢物图谱在1364.69cm-1,1375.24cm-1中均出现叔丁基特征峰;在1721.42cm-1及1740cm-1均出现了酯类C=O伸缩振动吸收峰。红外图谱并未出现醚类碳-氧吸收峰,表明过氧化引发剂参与结垢物形成,氧气并未参与组合阀及中冷器污垢形成反应。本文证实了自由基来源、聚乙烯白色污垢的成因,对解决LDPE工业化过程中组合阀、中冷器结垢问题具有重要参考价值。

Fouling is widely found in super compressor and intercooler during the production of low densitypolyethylene.Melt index and density measurements show that polyethylene samples from super compressorand intercooler are 0.03 g /10 min,0.942 g /cm3,and 0.12 g /10 min,0.936 g /cm3,respectively,which indicatesthere are not entrainments from high pressure cycle gas system.FT-IR results of merchantable polyethylenepellets and fouling samples both show characteristic peak of tert-butyl at 1364.69cm-1,1375.24cm-1,and C=O of ester at 1721.42cm-1,1740cm-1.Characteristic peak of C-O is not found in the spectrum which meansoxygen does not work as initiator during the formation of the fouling.This article has fairly explained thesource of the free radical and formation of fouling in the super compressor and intercooler which is meaning-ful in the ways to solving this specific problem.