What is Microdieseling?
Microdieseling is also called Compressive Heating and is a form of pressure induced thermal degradation.
The oil goes through 4 stages in this degradation process:
1. There is a transition of entrained air from a low pressure to a high pressure zone
2. This produces localized temperatures in excess of 1000°C
3. The Bubble interface becomes carbonized
4. The oil darkens rapidly and produces carbon deposits due to oxidation
The conditions required for microdieseling can be either:
- Low flashpoint with LOW implosion pressure
- Low flashpoint with HIGH implosion pressure
For a low flashpoint with a HIGH implosion pressure, this constitutes to ignition products of incomplete combustion such as soots, tars and sludge
However, for a low flashpoint with a LOW implosion pressure, adiabatic compressive thermal heating degradation occurs to produce varnish from carbon insolubles such as coke, tars and resin.