Waste Oil Co-Distillation

Refinery operators constantly ask whether dissimilar hydrocarbon waste streams can be run through a single line. Waste oil co-distillation answers that question: combining waste motor oil with pyrolysis oil from tire or plastic breakdown is workable, but only when the process handles two very different chemistries deliberately. Treating the two as one feedstock without adjustment invites coking and premature catalyst loss.

Two Streams, One Challenge

Used motor oil is largely stable, long-chain paraffinic and naphthenic material that must be cracked down into the diesel range. Pyrolysis oil is the opposite: reactive, olefin-rich, heavy in aromatics and sometimes carrying suspended carbon and chlorine. Mixing a stable stream with a reactive one is the central engineering problem of waste oil co-distillation, and it grows worse as the pyrolysis share rises.

Blending Ratios and Coking

Roughly, a conservative majority of waste motor oil blended with a minority of pyrolysis oil keeps coking manageable. As the pyrolysis proportion climbs toward half, the risk of rapid thermal coking and faster catalyst depletion rises sharply, and the final fuel darkens unless polishing is increased accordingly.

Dehydration and Pre-Treatment

Pyrolysis oil carries moisture and fine carbon. The blended feed should be dehydrated quickly before the reactor and the residual moisture driven low to avoid pressure surges. Thorough pre-filtration protects the downstream column from carbon soot deposits.

Feedstock quality also governs the blend. A stream with heavy chlorine from plastics or high sulphur from tires poisons the vapour catalyst more quickly, so the blend composition should be watched as closely as the temperatures.

Distillation and Finishing Adjustments

The volatile fraction of pyrolysis oil cracks at lower temperature, so the heating ramp and column reflux must be kept in check to avoid vapour flooding and carryover that softens the flash point of the finished diesel. Higher dosing in the polishing stage counteracts the olefins that quickly re-darken cracked fuel exposed to air. A conservative ratio, tighter column control and a more aggressive finish make blended operation stable and profitable.

Learn More:

• Feasibility Studies for Waste-to-Value Projects
• Turn-Key EPC Delivery
• Plant Design & Engineering
• Facility Efficiency Upgrades
• Resource Recovery Projects

Turn mixed waste streams into one stable fuel line

Feedstock flexibility is where the margin is, but only with tight process control protecting output and equipment life.

Klean engineers co-distillation plants tailored to your feedstock blend, from drying to polishing.

Considering a waste oil co-distillation project?

Contact Klean Industries about waste oil co-distillation » GO.