ASTM D97, Customary Take a look at Method for Pour Level of Crude Oils. The specimen is cooled inside a cooling bath to allow the formation of paraffin wax crystals. At about 9 C above the anticipated pour level, and for every subsequent three C, the check jar is eliminated and tilted to verify for surface movement. When the specimen doesn’t movement when tilted, the jar is held horizontally for 5 sec. If it doesn’t move, three C is added to the corresponding temperature and the result’s the pour point temperature.
It’s also helpful to note that failure to movement at the pour point may also be as a result of effect of viscosity or the earlier thermal history of the specimen. Subsequently, the pour point might give a misleading view of the dealing with properties of the oil. Further fluidity assessments may also be undertaken. An approximate vary of pour level may be observed from the specimen’s upper and lower pour level.
ASTM D5949, Commonplace Check Method for Pour Level of Petroleum Products (Automated Stress Pulsing Method) is an alternative to the guide take a look at process. It makes use of computerized apparatus and yields pour level leads to a format similar to the guide technique (ASTM D97) when reporting at a 3 C.
The D5949 check methodology determines the pour point in a shorter time period than guide method D97. Much less operator time is required to run the check utilizing this automatic method. Additionally, no external chiller bath or refrigeration unit is needed. D5949 is able to determining pour point within a temperature range of 鈭?7 C to +51 C. Outcomes can be reported at 1 C or 3 C testing intervals. This take a look at method has higher repeatability and reproducibility than guide methodology D97.
Below ASTM D5949, the test sample is heated and then cooled by a Peltier device at a price of 1.5卤0.1 C/min. At either 1 C or three C intervals, a pressurized pulse of compressed fuel is imparted onto the floor of the pattern. Multiple optical detectors continuously monitor the sample for motion. The bottom temperature at which movement is detected on the pattern surface is determined to be the pour point.
Measuring the pour point of crude oils
Two pour factors can be derived which can provide an approximate temperature window depending on its thermal historical past. Within this temperature vary, the sample could appear liquid or strong. This peculiarity happens as a result of wax crystals form less readily when it has been heated throughout the past 24 hrs and contributes to the lower pour level.
The upper pour point is measured by pouring the test pattern straight into a take a look at jar. The sample is then cooled and inspected for pour point as per the usual pour level technique. The tactic normally provides larger pour level because the thermal historical past has not been cancelled by a prolonged thermal remedy.
The decrease pour point is measured by first pouring the pattern into a stainless steel strain vessel. The vessel is then screwed tight and heated to above 102 C in an oil bath. After a specified time, the vessel is removed and cooled for a short whereas. The sample is then poured into a take a look at jar and immediately closed with a cork carrying the thermometer. The pattern is then cooled after which inspected for pour level as per the same old pour point methodology.