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.
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
Start-Up
Shut-down
