Patent ID: 8372247

Claim:
A method for automatic distillation of liquid samples of petroleum products under atmospheric pressure in accordance with ASTM D86, the method comprising the steps of: classifying the sample to be analyzed in a group defined by ASTM D86, the classification defining distillation characteristics of the sample to be analyzed including a time to the initial boiling point (IBP) and/or the 5% distillation point and/or the point at which there is only 5% of sample to be analyzed remaining in the distillation flask; providing a distillation device, the distillation device comprising: a distillation flask having a neck closable by a fluid-tight stopper; a heating element; a condenser connected to the distillation flask for condensing evaporated vapors; a collecting cylinder connected to the condenser for collecting a quantity of condensate condensed by the condenser; a thermometer positioned to measure the temperature of evaporated vapors in the distillation flask; and a controller which controls an operating variable of the heating element in accordance with the defined distillation characteristics; introducing a predefined quantity of the sample to be analyzed into the distillation flask, positioning the distillation flask on the heating element, closing the distillation flask, and connecting the distillation flask to the condenser; initiating the distillation of the sample to be analyzed; constantly measuring the quantity of condensate collected in the collecting cylinder, the temperature of the evaporated vapors, the temperature of the liquid sample present in the distillation flask, and the operating variable of the heating element during the distillation; and controlling the operating variable of the heating element with the controller to obtain the distillation characteristics in accordance with ASTM D86; wherein, before the IBP, the temperature T chauf of the heating element is adjusted based on the temperature T liq of the liquid sample present in the distillation flask in accordance with the formula: ( T chauf −T liq )= A ( dT liq/ dt ) 0.2513 where dTliq/dt is 95 ⁢ ° ⁢ ⁢ C . - 36 ⁢ ° ⁢ ⁢ C . 600 ⁢ sec - 300 ⁢ sec when the liquid sample is a group 1 or group 3 sample according to ASTM D86, 211 ⁢ ° ⁢ ⁢ C . - 76 ⁢ ° ⁢ ⁢ C . 600 ⁢ sec - 300 ⁢ sec when the liquid sample is a group 2 sample according to ASTM D86, and 327 ⁢ ° ⁢ ⁢ C . - 182 ⁢ ° ⁢ ⁢ C . 900 ⁢ sec - 300 ⁢ sec when the liquid sample is a group 4 sample according to ASTM D86.