石脑油中有机氯化物的形态鉴定及分子尺寸估算

Morphological Identification and Molecular Dimension Estimation of Organochlorine Compounds in Naphtha

对两个石脑油样品中的有机氯化物进行形态鉴定及分子尺寸估算。配有电子捕获检测器的气相色谱分析结果表明,两个石脑油样品中的有机氯化物多为氯代芳烃,也含有少量氯代烯烃和氯代烷烃。石脑油Ⅰ中主要有机氯化物(>3 mg/L)按质量浓度由高到低分别为1,2⁃二氯苯、1,4⁃二氯苯、1,6⁃二氯己烷、1,1⁃二氯乙烯、2⁃氯乙基苯和1,2⁃二氯丙烷,而石脑油Ⅱ中的主要有机氯化物为1,2⁃二氯苯和1,4⁃二氯苯。利用软件确定了14种已鉴定出有机氯化物的三维尺寸,并进一步确定其最小横截面直径为0.4~1.0 nm。有机氯化物在石脑油重整预加氢过程中易转化为腐蚀性的氯化氢和氯化铵,故石脑油中高丰度的有机氯化物是导致该装置故障增多的一个重要原因,而与分子直径匹配的多孔吸附材料有利于有机氯化物的吸附脱除。

The morphological identification and molecular dimension estimation of organochlorine compounds(OCCs)in two different naphtha samples were performed.The analysis result of gas chromatography equipped with an electron capture detector indicates that the chloroaromatics are predominant OCCs in the two naphtha samples,and a small amount of chloroolefins and chloroalkanes coexisted with them.The main OCCs(>3 mg/L)in naphtha I are 1,2⁃dichlorobenzene,1,4⁃dichlorobenzene,1,6⁃dichlorohexane,1,1⁃dichloroethylene,2⁃chloroethylbenzene and 1,2⁃dichloropropane,and that in naphtha II are 1,2⁃dichloropropane and 1,4⁃dichlorobenzene.The three⁃dimensional dimension of 14 identified OCCs are determined by softwares,whose minimum cross⁃sectional diameter is between 0.4 nm and 1.0 nm by further estimation.The high abundance of OCCs,which easily are converted to corrosive hydrogen chloride and ammonium chloride during processing,in naphtha may be a primary cause of increased malfunction in naphtha prehydrogenation unit.The porous adsorption material with micropore close to the molecular diameter is beneficial for the adsorption removal of OCCs.