Research On Measuring Fuel Micro-water Content And Saturated Dissolved Water

The undissolved water in fuel has a crucial impact on the safety,stability and service life of engine operation.The evaluation of micro-water content is an important part of controlling fuel quality.In actual production,Karl Fischer titration is the most commonly used method to measure the water content of fuel oil.At present,it is only used to measure the total water content in fuel oil,and cannot directly measure the undissolved water content.Aiming at this defect,this paper studies the saturated dissolved water content in diesel and aviation kerosene and its influencing factors.The difference between total water and saturated dissolved water is used as the method of undissolved water content,which provides technical support for the accurate measurement of fuel moisture content.In this paper,the uncertainty and representativeness of the standard substance measured by Karl Fischer titration were analyzed,and the feasibility of measuring the undissolved water content in fuel by Karl Fischer titration was demonstrated.The two methods of preparing dissolved water saturated fuel samples by gas phase equilibrium method and liquid phase equilibrium method were studied,and the liquid phase equilibrium method was improved,which saved the sample preparation time and improved the accuracy of the measured value.Diesel fuel and jet fuel samples saturated with dissolved water were prepared according to the liquid phase equilibrium method,and the effects of temperature and additives on the saturated dissolved water content of fuel were investigated.The experimental results show that:(1)Temperature has a great influence on the saturated dissolved water content of diesel fuel and jet fuel.In the fuel and additives involved in the test,the saturated dissolved water content of the fuel is linearly positively correlated with the temperature,and when the pour point depressant is added to the diesel fuel,and the ethylene glycol dimethyl ether is added to the diesel fuel and jet fuel,the saturated dissolved water content of the fuel is exponentially positively correlated with the temperature.(2)The effects of additives on the saturated dissolved water content of fuel are diverse.The addition of naphthenic acid and2,6-di-tert-butyl-p-methylphenol according to the test content has little effect on the saturated dissolved water content of fuel.Glycerol monooleate,petroleum sulfonate,KB-8045 C,diethylene glycol monomethyl ether,dimer acid and ethylene glycol dimethyl ether will increase the saturated dissolved water content.Isooctyl nitrate will decrease at low temperature and increase at high temperature.Methyl stearate will reduce the saturated dissolved water content of diesel fuel,but increase the saturated dissolved water content of jet fuel.In summary,this paper uses Karl Fischer titration to measure the micro-water content of fuel,improves the preparation method of saturated dissolved water fuel,studies the effects of temperature,additives and their doses on saturated dissolved water of fuel and gives quantitative analysis,in order to provide necessary theoretical and data support for fuel water pollution control.