(7.1)--任务1（1.1）测定水溶性酸、碱的意义.ppt
Task 1(1.1)Significance of Determination of Water Soluble Acid and Alkali.the significance of determining water-soluble acids and alkalis1.Water-soluble acid,alkali water-soluble acid and alkali in petroleum products,refer to those mixed with oil products during refining,transport,and storage,which will affect the quality of oil products.Similarly,if law enforcement officers deceive or mislead people,not only does it harm the legitimate interests of the people but also shake the Partys position among the people.Therefore,the Party should be strictly governed.2.Meaning of determination (1)It is predicted that the corrosive water-soluble acid of the oil has a strong corrosive effect on almost all metals,especially when there is water in the oil,its corrosion is more serious.(2)Water-soluble acid,unqualified alkali and refined oil are not allowed to leave the factory.(3)the detection of water-soluble acid and alkali in Guide the production of oil products indicates that the acid-base refining process is not completely treated and the process conditions need to be optimized.II.Overview of Method of determinationAccording to GB/T 259-1988 Standard Test Method for Determination of Water-solution Acid and Alkali in Petroleum Products.Suitable for the determination of liquid petroleum products,additives,greases,paraffin wax,ground wax and water-soluble acids and alkalis containing wax components.Measurement fundamentals:mix the sample with distilled water of equal volume,After shaking,oil and water are sufficiently contacted with each other.The water-soluble acid and alkali are extracted into water.Separate the water phase from the bottom of the separating funnel Use methyl orange,phenolphthalein indicator or an acidimeter to measure its pH value so as to determine if there is water-soluble acid and alkali in the sampleII.Overview of Method of determination For gasoline,solvent oil and other light petroleum products,extract samples with distilled water at normal temperature whose kinematic viscosity greater than 75mm2/s at 50.The sample needs to be diluted with a neutral solvent and then be extracted by adding 5060 distilled water;For solid samples,add distilled water after sampling and heat it to a solid melting stateII.Overview of Method of determinationSampleExtraction methodLight Petroleum ProductsExtract with distilled water at room temperatureKinematic viscosity at 50 is greater than 75mm2/sAfter diluting the sample with neutral solvent,add 5060 distilled water for extractionSolid stateAdd distilled water to the sample and heat it until the solids are melted for extractionIf emulsion that is not easy to separate is shaped when the sample is mixed with distilled water,use 5060 95%ethanol water solution at 1:1 ratio to extract.Add dilution solvent if necessary to reduce the viscosity of the sample so as to realize Use acid-alkali indicator to judge the existence of water-soluble acid and alkali in the sample:If the solution does not discolor methyl orange,the sample does not contain water-soluble acid.If the solution does not discolor phenolphthalein,the sample does not contain water-soluble alkali.The pH value is used to judge if there are water-soluble acid and alkali in the sample as shown in Table 7-1.When there is an inconsistency in the quality evaluation of oil products,the arbitration test of water-soluble acid and alkali should apply the acidimeter method.2Main influencing factors of testing (1)Sampling uniformity The sample should be shaken thoroughly before sampling.When measuring water-soluble acid and alkali in solid petroleum products like paraffin and ozocerite which contains wax ingredients,heat and melt the sample before sampling.(2)Reagent and vessel cleanness.Dilution solvents such as extraction solvents and gasoline must be neutral,and instruments must be clean.(3)Sample viscosity.If the kinematic viscosity of the sample is greater than 75mm2/s at 50,the sample can be diluted with a diluent solvent and heated to a certain temperature before being measured.(4)Oil emulsification.When the sample is mixed with distilled water to generate an emulsion that is difficult to separate,it is necessary to use 5060 neutral 95%ethanol water solution at 1:1 ratio as an extraction solvent to separate acid and alkali from the sample.
