气相色谱法测定汽油馏分中微量小分子含氧化合物  

DETERMINATION OF TRACE LEVEL LIGHT OXYGENATES IN GASOLINE BY GAS CHROMATOGRAPHY

作　　者：李长秀[1] 王亚敏[1] 金珂[1] 

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油炼制与化工》2016年第8期102-108,共7页Petroleum Processing and Petrochemicals

摘　　要：建立了一套带有反吹组件和微流控中心切割组件及3根毛细管色谱柱的色谱系统，可以用于测定汽油中微量小分子含氧化合物的含量，通过载气压力切换的方式也可用于直接测定微反产物汽油馏分中微量小分子含氧化合物的含量，样品中所含的大量烃类组分不干扰测定结果。通过载气压力的切换使得只有沸点小于正十一烷的组分全部从2m长的预切柱流出进入与之相连的非极性色谱柱，其余的重组分被反吹出色谱系统。沸点小于正十一烷的组分进入一根30m长的非极性色谱柱后，通过中心切割组件电磁阀的切换仅使沸点小于2己酮的组分进入与之相连的10m长强极性OxyPLOT色谱柱，实现烃类组分和含氧化合物的分离，并通过火焰离子化检测器检测，采用外标法定量。该方法可以定量检测汽油馏分中微量的C1～C4醇、C2～C5醛、C3～C6酮、甲基叔丁基醚、乙基叔丁基醚和甲基叔戊基醚的含量，单组分的检测限为0．5～2．0μg／g，各组分测定的加标回收率基本在80％～120％之间，测定结果的相对标准偏差在2％～5％的范围内。对催化裂化和催化裂解工艺的汽油产品中含氧化合物的分析测定结果显示，汽油中的小分子含氧化合物以酮类化合物为主，同时含有少量的醛、醇、醚类组分。A gas chromatographic system equipped with back-flush and heart-cutting （microfluidic deans switch） parts and three connected columns is established for determination of trace level light oxy- genates in gasoline products. The oxygenate in gasoline comprising heavy hydrocarbons can directly be analyzed by pressure changes of carrier gas, and the hydrocarbon components in the sample do not inter- fere with the determination results. Through the pressure changes of carrier gas, the components with the boiling points lower than n-undecane can be eluted from a 2 m long pre-column into a 30 m long non polar column, meanwhile the heavy fractions are back-flushed to the vent port to leave the system. The components coming into the 30 m long column are separated by switching solenoid valve of heart-cutting parts, only the separated components with boiling point lower than 2-hexanone can be eluted from the non-polar column and enter into a 10 m long polar OxyPLOT column to separate the light oxygenates and hydrocarbons, and then the effluents are detected by flame ionization detector and quantitatively de- termined with external standard method. Light oxygenate contents such as C1-C4 alcohols, C2 -C5 al dehydes, C3- C6 ketones, methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in gasoline can be analyzed. The detection limit for single component is between 0.5 2.0 μg/g, the adding standard recovery rate for different components is 80%- 120%, and the RSD （relative standard devia- tion） is in the range of 2 %- 5 %. The results of analysis of products from catalytic cracking and catalyt- ic pyrolysis process show that the main oxygenates in these products are ketones with little amount of alcohols, aldehydes, and ethers.

关 键 词：汽油 含氧化合物 中心切割 气相色谱 

分 类 号：O657.71[理学—分析化学] TE626.21[理学—化学]