Analytic Method For Benzene In Lean And Fat Oil Before And After Benzene Washing Tower

Crude benzene is an important component of raw gas generated in the process of coking.Benzene mixture containing a variety of organic compounds is recycled after deamination of raw gas.Determination of concentration of benzene mixture in poor or rich oil is crucial to control the quality of crude benzene and calculate the yield of crude benzene products.It is also an important parameter to control the purification degree of the coke oven gas.The method of determining benzene content in rich oil and poor oil before and after the process of washing gas was studied.By comparing gas chromatography external standard method,gas chromatography area method and traditional distillation method,it was shown that the deviation of gas chromatography external standard method is 2.04%,the relative standard deviation is 1.97%,which can meet the accuracy and precision of determination.By the optimization of the chromatographic conditions,the suitable chromatographic condition was that with CS₂ as the standard sample,the temperature of sample injector and detector was 280℃.the initial temperature of the column was 50℃,the increasing rate was 25℃/min and ended at 270℃.The flowing rates of nitrogen,hydrogen and air were 30 m L/min（0.06MPa）,30mL/min（0.08 MPa）and 300mL/min（0.11 MPa）respectively.The diversion ratio was 1:70.The application showed that the use of gas chromatography method for determination of crude benzene content in the oil was completely feasible.Compared with the traditional distillation method,gas chromatography has the excellent properties of quick analysis,small amount of sample,simple operation,fast detection speed,quanlitive and quantitative accuracy.It is beneficial to control the production of crude benzene and to decrease the consumption in the process,and it is also a good solution to decrease the toxic substances in the analysis and improve the analytical environment.