Worldwide Inline Process Control Solutions

Phase Separation of Refined Fuels

Interface Detection

Using real-time data provided by optek AF26 inline color sensors, pipeline operators are able to cut product or detect product interfaces precisely. This monitoring ensures that fuels are not downgraded by intermixing of low quality products. Throughout the entire production process including terminalling facilities, fuel color can be monitored in order to ensure specifications and minimize product losses.

Refineries often use density measurements to distinguish between the different hydrocarbons in the pipeline. However, with the high value gasoline and premium gasoline products this method is ineffective and color separation is the more effective solution.

Hydrocarbons such as Kerosene or diesel are easily distinguishable by their normal colors. whereas gasoline and premium gasoline often have dyes or markers added ensuring that they are more easily distinguishable. The main colors used for dyeing fuels are red, blue, green and yellow. The dual channel AF26 with various wavelength combinations can be configured to distinguish between any of these dyes, even down to low ppm levels.

optek AF26-EX-VB Dual Channel Absorption Sensor with Calibration Adapter

Dyeing of Fuels

In some countries it is required by law to add dye to low- taxed fuels in order to distinguish them from the higher-taxed fuels. Avaition fuel is dyed both for tax and safety reasons and some companies will dye fuel to prevent theft. Amounts of dye added vary, but ranges are usually between 2mg/l to 10mg/l. Precise dosage of these dyes can be controlled with the optek AF26 colorimeter ensuring consistant product quality.


An optek C4000 converter transmits measurement signals to the PLC or plant DCS using up to four mA-outputs. Remote signals from the PLC or plant DCS can be sent to the C4000 converter to zero the instrument or to make product changes. Additionally, PROFIBUS® PA or FOUNDATION™ Fieldbus communication is available for advanced control systems.