Research On Measuring Method Of Crude Oil Moisture And Development Of It's Reference Material

The petrochemical industry urgently needs a method that is accurate and resistant to sulfur compounds as well as the crude oil water content reference materials.Here we mainly studies the method of azeotropic distillation-Karl Fischer coulometric titration method for measuring crude oil water content,and develops crude oil water content reference material.In this thesis,based on the principle of azeotropic distillation,a sampling system was built;and connected to the coulometric titrator,in which the azeotropic distillation-Karl Fischer coulomb titration method was established.An azeotropic distillation-Karl Fischer coulomb titration method was established and used for crude oil water content measurement.The azeotropic distillation method,Karl Fischer coulomb titration method and azeotropic distillation-Karl Fischer coulomb titration method were compared.The azeotropic distillation-Karl Fischer coulomb titration method was used to calibrate liquid moisture reference materials to achieve traceability of water content.The influencing factors of the method were systematically studied,including sample polarity,injection volume and oil type.The sulfur dioxide-free reagent was used to measure the amount of iodine consumed by the reduction of sulfur-containing compounds,and its contribution was deducted from the water measured by conventional reagents,thereby eliminating the systematic error of sulfur compounds on the azeotropic distillation-Karl Fischer Coulomb method.The results show that the azeotropic distillation-Karl Karl Fischer coulomb titration method show high accuracy,does not require frequent reagent replacement and electrode cleaning.The measurement is fast and simple,and suitable as a standard method for crude oil moisture.The crude water content reference material was prepared by gravimetric method.The water content of crude oil is calculated based on the water content of blank crude oil,the quality of blank crude oil and the quality of pure water added.The water content of the blank crude oil is determined by the Karl Fischer coulomb titration method and the azeotropic distillation-Karl Fischer coulomb titration method.The certified values of the water content of the three reference materials are 10048 ?g/g,5144 ?g/g and 3142?g/g,respectively.And the relative expansion uncertainties are 3.2%,3.7% and 1.4%,respectively.This series of reference materials can be used for calibration and verification of crude oil water content measurement methods such as azeotropic distillation method and Karl Fischer coulomb titration method.In summary,we studied and established the azeotropic distillation-Karl Fischer coulomb titration method for the measurement of crude oil moisture.The method results are accurate,convenient,and fast.Three crude oil moisture reference materials have also been developed,which can be used for calibration and verification of crude oil moisture measurement methods.This series of reference materials can be used to calibrate and verify crude oil moisture measurement methods such as azeotropic distillation method and Karl Fischer coulometry method.