ASTM D97, Customary Test Methodology for Pour Point of Crude Oils. The specimen is cooled inside a cooling bath to permit the formation of paraffin wax crystals. At about 9 C above the expected pour point, and for every subsequent 3 C, the check jar is eliminated and tilted to check for floor movement. When the specimen does not circulation when tilted, the jar is held horizontally for five sec. If it does not flow, three C is added to the corresponding temperature and the result is the pour level temperature.

It is also useful to note that failure to circulation on the pour level may also be due to the effect of viscosity or the previous thermal historical past of the specimen. Due to this fact, the pour level may give a deceptive view of the dealing with properties of the oil. Further fluidity checks might also be undertaken. An approximate range of pour level may be noticed from the specimen’s upper and decrease pour level.

Automatic method[edit]

ASTM D5949, Standard Check Methodology for Pour Point of Petroleum Products (Computerized Pressure Pulsing Methodology) is an alternative to the manual test procedure. It makes use of automated apparatus and yields pour point leads to a format just like the handbook technique (ASTM D97) when reporting at a 3 C.[1]

The D5949 take a look at methodology determines the pour point in a shorter time frame than handbook methodology D97. Less operator time is required to run the check utilizing this automatic method. Moreover, no external chiller bath or refrigeration unit is required. D5949 is able to figuring out pour point within a temperature range of 鈭?7 C to +fifty one C. Outcomes might be reported at 1 C or three C testing intervals. This check methodology has better repeatability and reproducibility than manual method D97.

Below ASTM D5949, the test pattern is heated and then cooled by a Peltier machine at a rate of 1.5卤0.1 C/min. At both 1 C or 3 C intervals, a pressurized pulse of compressed gasoline is imparted onto the surface of the pattern. Multiple optical detectors repeatedly monitor the sample for motion. The lowest temperature at which motion is detected on the pattern surface is determined to be the pour point.

Measuring the pour point of crude oils[edit]

Two pour points may be derived which can provide an approximate temperature window depending on its thermal historical past. Inside this temperature vary, the sample may appear liquid or stable. This peculiarity happens because wax crystals form less readily when it has been heated within the past 24 hrs and contributes to the lower pour level.

The upper pour point is measured by pouring the check pattern immediately into a test jar. The sample is then cooled and inspected for pour level as per the usual pour point technique. The method often offers higher pour point because the thermal historical past has not been cancelled by a protracted thermal remedy.

The lower 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 eliminated and cooled for a brief while. The pattern is then poured into a check jar and immediately closed with a cork carrying the thermometer. The sample is then cooled after which inspected for pour point as per the usual pour level method.