减压渣油高温模拟蒸馏误差分析及对策

摘要

Based on ASTM D 7169 principle and the simulated distillation experiment of vacuum residue analysis,the main reasons of high temperature simulated distillation error of vacuum residue were determined with CS2 as cleaning liquid of gas chromatograph,C5-C120 n-alkanes as calibration sample,boiling range 354-541 ℃ reference sample as external standard sample and vacuum residue as sample in high temperature simulated distillation gas chromatography.The results showed that baseline fluctuated more than 5 × 10-12 A by residual sample in blank analysis,it could lead to above 3 ℃ deviation of the distillation temperature.The shifted nalkanes retention time directly affected the distillation data accuracy,and it was necessary to analyze boiling point calibration sample every 14 days;the analysis results error was caused by the accuracy of reference sample size and weighing,and sample pad gas tightness.%以CS2(空白试样)为气相色谱仪的清洗液,C5～C120正构烷烃为校正试样,沸程为354～541℃的参考试样为外标试样,减压渣油为样品,在气相色谱高温模拟蒸馏仪中,通过对ASTM D 7169原理的剖析,以及对减压渣油样品模拟蒸馏实验的分析,确定了引起减压渣油高温模拟蒸馏误差的主要原因.结果表明:在对空白试样分析时,残留样品引起基线5×10-12 A以上的波动,即可使馏出温度产生3℃以上的偏差;正构烷烃保留时间的漂移直接影响馏程数据的准确性,因此,需每14d分析1次沸点校正样品;参考试样进样量的准确性、进样垫的气密性和称量的准确性均是导致分析结果出现误差的主要原因.