Distillation data is an intrinsic part of refining processes with data embedded in product specifications and regulatory compliance. In order to maximise product value, precise distillation data is vital.
ASTM D86 (1) is the basic test method of determining the boiling point range of petroleum products and is one of the oldest methods still applicable within ASTM jurisdiction. ASTM D86 entails a rather basic controlled physical distillation, and it has some drawbacks in today use:
• It has a long cycle time, in most cases over 30 minutes, whereas many laboratories and processes require a faster delivery.
• The method requires 100ml of sample. In some cases the amount of sample available is too small to run the test. Moreover, sample size of 100ml may be regarded as environmentally unacceptable.
• A manual method requiring constant operator attention, has much lower productivity, and is less (cost) effective.
• A physical distillation of flammable samples in an open laboratory does come with an inherent safety risk that may be eliminated
Traditional DHA is way too slow as a method, and Simulated Distillation, despite being widely accepted, and sometimes even acceptable from regulatory point of view, does not provide the level of detail needed for the more volatile fractions and streams available.
This application note details a new method, based on high speed DHA style chromatography and data modelling specifically geared towards TBP data for volatile streams.
This Fugacity-Film model approach was first described some two decades ago, and it is based on Fick’s Law and Henry’s Law and has already been proven to allow for experimental prediction/modelling of TBP curves with relatively good precision.