煤油、柴油、生物柴油中水分含量检测方案(卡氏水分测定)

智能文字提取功能测试中

HIITACHIInspire the Next HIRANUMAAPPLICATIONDATA Karl Fischer Titrator Data No. KF4 Water contents Oil products 1.Abstract Water content of Oil products are determined by Karl Fischer coulometric titrator. In coulometric titration， iodine of Karl Fischer reagent isgenerated by electrolysis and generated iodine quantitatively reacts with water. Reaction formula is described below. Kerosene and diesel oil do not interfere the Karl Fischer reaction and direct injection method could apply. Anode solution for Oil is selected todissolve samples. It is known that some of the oil additives interfere Karl Fischer reaction. In that case，azeotropic distillation method with Oil evaporator isappropriate. Water is separated from oil sample by distillation and introduced to electrolytic cell with carrier gas. Mercaptanes and hydrogen sulfide in oil interfere Karl Fischer reaction. Since these side reactions occur quantitatively， water content result could becorrected with concentration of mercaptanes and hydrogen sulfide. 1 ppm of mercaptanes or hydrogen sulfide lead 0.3 ppm or 0.6 ppm higher watercontent respectively. 2. Apparatus and Reagents 3. Procedure 3.1.Direct injection method (1) Fill 100 mL of anode solution and one ampoule of cathode solution into the electrolytic cell as shown in Fig.3.1. (2) Start blanking to attain stable background. (3) Wash the syringe with sample. (4) Draw the sample into syringe and then weigh the syringe. (5) Inject sample from rubber septum of electrolytic cell as shown in Fig.3.2. (6) Start titration. Measurement parameter is shown in Table 4.1. (7) Weigh the syringe again and then set the difference of weight to sample size. Fig.3.1.Preparation of the reagents. Fig.3.2. Injection of sample. 3.2. Azeotropic distillation method (1) Fill 100 mL of anode solution and one ampoule of cathode solution into the electrolytic cell as shown in Fig.3.1. (2) Start blanking to attain stable background. (3) Connect electrolytic cell and evaporation chamber with tube. Flow carrier gas with 50 mL/min. (4) Fill 5mL of distillation solvent in evaporation chamber and heat the chamber at 120℃. (5)Keep blanking to attain stable background with carrier gas flowing into electrolytic cell. (6) Wash the syringe with sample. (7) Draw the sample into syringe and then weigh the syringe. (8) Inject sample from rubber septum of distillation chamber as shown in Fig.3.3 and Fig.3.4. (9) Start titration. Measurement parameter is shown in Table 4.2. (10) Weigh the syringe again and then set the difference of weight to sample size. EV-2000L Fig.3.3. Schematic diagram of azeotropic distillation method. Fig.3.4. Sample injection into evaporation chamber. 4. Parameters and results Table 4.1. Parameters for direct injection method. Condition File Cal Mode O：Sample weight(net) X=(H2O-BLANK)/SIZE Interval Time 20 sec Current SLOW S-Timer 0 min Blank Value 0 ug Unit Mode AUTO Auto Interval 0 g Minimum Count 5 ug Back Ground ON Sample Size Input Every Time Cell Type Standard/Fritless Table 4.2. Parameters for azeotropic distillation method. Condition File Cal Mode 0：Sample weight(net) X=(H2O-BLANK)/SIZE Interval Time 40 sec Current SLOW Min.Timer 5 min Blank Value 0 ug Unit Mode AUTO Auto Interval 0 g Minimum Count 5 ug Back Ground ON Sample Size Input Every Time Cell Type Standard/Fritless Sample Apparatus Cell Reagent Sample Water Water Size (g) (ug) Content kerosene AQ Standard AG-H 2.3483 65.5 27.9 ppm CG 2.3482 61.5 26.2 2.4432 63.5 26.0 diesel oil AQ Standard AG-H 2.0817 72.7 34.9 ppm CG 1.9804 68.4 34.5 2.0600 70.4 34.2 Sample Apparatus Cell Reagent SampleSize (g) Water(ug) Water Content Biodiesel AQ Standard AG-H 0.9719 977.9 0.1006% CG 0.9108 914.9 0.1005 0.8408 839.2 0.0998 Transmission AQ+EV-2000L Standard AG 0.7267 246.6 339.3 ppm fluid CG 0.9484 329.1 347.0 0.9051 311.9 344.6 Fritless AG 0.8201 300.4 366.3 ppm 0.8152 289.4 355.0 0.9452 330.4 349.6 5. Note (1) Use dried syringe and syringe vial for preventive of contamination by atmospheric water. To measure 100 pg or less water detection， make sure stability of blanking. Low and stable background value is important factor for trace level of water(2) measurement. Put appropriate anode solution in use according to the solubility of the sample. For example， Hydranal Coulomat AG-H and Oil are suitable for oils with directinjection method. (3) Note： these reagents does not correspond to Fritless cell. Science fora better tomorrowL热线电话：立科学仪器(北京)有限公司 本实验采用平沼卡尔费休库伦法测定仪对油品的水分含量进行测试