Transmix is a mixture of refined products that form when transported in pipelines. This mixture is typically a combination of gasoline, diesel, and/or jet fuel. Transmix processing plants use distillation to separate the products.

Transmix is received by either pipeline or tanker truck and is offloaded through a filter and meter into storage tanks. The product is then pumped from the tank through a second filter and onto a process heater. The heater can be natural gas-fired, fuel oil or electric or steam unit that raises the product temperature to approximately 260˚C. The light ends (gasoline) go overhead and the heavy ends (diesel) is taken off from the bottom of the column.

Process Steps:

1st: The Transmix enters a Transmix storage tank or tanks. Depending on the mix percentages ofTransmix it may take 1 or more tanks. A minimum of 10-day storage capacity is required based on the rated capacity of the Transmix unit. As the Transmix processing unit requires a relatively consistent mix of the Transmix feedstock, blending of the Transmix may or may not be required.

2nd: After leaving the Transmix storage tank it flows into an electric heater. A fired heater is an option, however then a flare stack will also be required. The use of an electric heater does not require a flare stack. Based on the boiling points noted in the distillation column, a temperature is selected that allows the gasoline product to fully vaporize while leaving the diesel product in its liquid state. The diesel is pumped off to a diesel storage tank, while the gasoline is condensed back to a liquid in the upper trays of the distillation column and is pumped off to a gasoline storage tank.

In some cases, the Transmix is not at designed specifications.  Any Product that is off-specification after going through reclamation can be reclaimed again through the unit by means of adjusting the temperature which will result in the desired product.


Batch-wise operations


  • Once Transmix is received, start heating cycle (in recycle mode)
  • Purge N2 out of the system
  • Allow pressure to built-up and start the reflux
  • Draw products from TRU and send to storage


  • Once the Transmix is reclaimed, pressurize the TRU
  • Inert Gas (like N2) may be used; Prevent air ingress into the system
  • Keep the system in this state until next batch


  • Designed with safety in mind
  • All rotating equipment is suitably isolated
  • All operations and maintenance space requirements complied with
  • Flame-proof electricals and instruments
  • Safety distances in layouts and plot plan as per NFPA guidelines

Special Considerations

  • VRU for
  • Electric Heater
  • Chiller for reflux, rundown cooling, and VRU
  • N2 Plant for start-up and shutdown
  • Fence, roads, gate
  • Space planning, layouts, and distances as per regulatory requirements
  • Vent N2 clean up
  • Emergency Relief


  • Transmix is effectively reclaimed into original products
  • No slop blending/disposal issues
  • Complete reclamation & quick turnaround
  • Inherently safe system
  • Flexible towards all refinery products
  • Small footprint
  • Low energy requirements