Difference between TBP and ASTM type of distilliation sampling methods.

Greetings...

There are actually quite a few laboratory distillation tests that can be utilized when characterizing the volatility of crudes and petroleum fractions.

ASTM D-86 and ASTM D-1160 are distillations with one equilibrium stage and no external reflux. The former test is used on substances that decompose (cracking) when vaporized at atmospheric pressure and temperatures greater than 750 degrees F. While the latter is used for substances not covered by the former and take place under a vacuum.

ASTM D-3710 and D-2887 (simulated distillation) have become more or less the standard these days. They are a more robust version of the previous two. A distillation column is still used but with more trays (~100) and a different reflux. But that's not all, unlike the other tests, the entire boiling point curve is matched by gas chromatography (GC).

TBP is similar to the simulated tests but it doesn't use as many trays (15+) and no GC characterization.

Of all the tests, the simulated ones are the fastest, most reproducible, and can better define initial and final boiling points.

So yes ASTM type distillation testing is preferred but more importantly simulated ASTM distillation testing is preferred.

-David