Measuring the level in solvent deasphalting units

Level Measurement for solvent deasphalting units

Solvent Deasphalting Units


Solvent deasphalting is a solvent extraction method used to extract up to two thirds of the vacuum reduced crude to be used as good quality feed for a fluid catalytic cracking unit to convert it to gasoline and diesel fuel blending stock. This technology uses light hydrocarbons (propanes to pentanes) as the solvents and use subcritical extractions methods but supercritical techniques to recover the solvents thus increasing cost efficiencies. This technology can be used in conjunction with delayed cokers and resid hydrocrackers such as CLG’s LC-Fining and AXEN’s H-Oil processes. Typical uses of radiometric devices within an SDA unit includes: Extractor, Pitch stripper, DAO Stripper, Resin Stripper and DAO Separator.

In the extractor is an interface measurement between the solvent and the extracted asphaltenes. This interface is typically not a clean interface, meaning that there as a zone that the two products of different densities separate. This zone is a gradient change in density.  Level is typically measured by means of a float or differential pressure. Besides having the tendency to foul due to coating/buildup, they measure a physical characteristic of the fluids.  If the physical characteristics change slight, this leads to errors in the level measurement.

The other vessels using radiometric  devices in this process takes advantage of the fact that other level technologies have a tendency to malfunction, or have errors in the measurement due to the coating that can occur with heavy asphaltenes, since radiometric is non-intrusive, this coating and fouling does not affect the radiometric level measurement.

Solvent Deasphalting Units Procedure Graphic

Solvent deasphalting - Customers benefit


  •     Highly reliable measurement not affected by coating or fouling by the product
  •     Can be used on high temperature and high pressure vessel
  •     Easy to install on existing columns, without process downtime



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