Physical Distillation - ASTM D 2892 Method

This technique is performed on a 15 theoretical plate fractionation column to obtain a true boiling point curve while maintaining an approximate 5 1 reflux ratio. The still pressure is reduced in order to prevent decomposition 

These narrow fractions are sent for physieal property measurements as well as ehemical typing analysis. A typieal eutting seheme is listed below. 

The atmospheric resid taken from the D 2892 distillation run is charged into the vacuum potstill. The method produces distillation fractions in the gas oil and traditional lube oil range as well as producing a vacuum resid. While there is no industry standard cutting scheme for Hivac distillation runs, narrow cuts in the 25-50 degree intervals are common. The final cut temperature is normally done to 565°C, a temperature that most crudes can attain. 

Care needs to be taken to identify the early stages of cracking. It is recommended that the last distillation cut be taken within one hour of the pot temperature reaching 310°C. 

---