At what temperature is it appropriate to start measuring the cold filter point of diesel after adding a pour point depressant?
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As the title suggests, the determination of the cold filter point of blank diesel generally starts a few degrees above its cloud point, with measurements taken at intervals of one degree until the conditions for the cold filter point are reached. After adding antifreeze agents or low-temperature flow improvers, at what condition should the cold filter plugging point be measured? If the cold filter plugging point test for blank diesel is still used, could there be a significant difference compared to the results under actual conditions? Or should the cold filter point requirement reach a certain temperature after adding the additive, and testing should begin at that exact temperature? It seems that there will be a significant difference in the experimental data between the two, with the latter showing a much smaller reduction. Thank you!
The testing method is the same as that for the blank; conducting a test each time should not have a significant impact – it’s just that more tests need to be carried out. The standards also state that testing can start immediately after adding the sample, or the cloud point can be determined first.
I thought the same at first. For example, if we start measuring from 0 degrees and take readings at intervals, the cold filtration point can reach -13 degrees. However, in parallel experiments, if we skip some measurements and go straight to taking a reading at -10 degrees, it is common for the process to fail.
There is a standard method for this. Follow the standard method for determining the cold filtration point directly. It is not advisable to start at a lower temperature; although this method is faster, the varying microcrystalline states in the oil may affect the reproducibility of the measurements.
Thank you! Previously, we have always followed the standard procedures. Recently, a client requested that measurements be taken at a specific temperature; what they meant was to simulate external conditions after adding antifreeze, as the vehicle might remain stationary for an entire night, resulting in temperatures dropping to several degrees below zero. In such cases, there is no gradual cooling process before oil is introduced – instead, the oil is added at that lower temperature. The idea is to keep drawing oil as the temperature continues to drop; under actual conditions this would not be feasible, but taking measurements at intervals might still work, albeit with significant errors. This is quite confusing, and it’s not really about speeding up the measurement process.