FUEL-WASH Mercaptan Removal


Courtesy of FreshAWL, LLC

Finding the right treating solution to remove impurities from hydrocarbon streams is a challenging task for any refiner and one of the chief research scientists from the Merichem Company found the FreshAWL chemistry as an interesting and plausible solution to assist in their processing systems for the removal of Mercaptans from RSH (Mercaptan Laden) Kerosene.

FreshAWL FUEL-WASH is the mercaptan scavenger answer to help restore crude oils and fuels to optimal mercaptan levels. FUEL-WASH would also prove to remove highly concentrated levels of mercaptans from the Merichem samples of RSH Kerosene. FUEL-WASH would also show a separation of the remaining mercaptan free sample into reusable kerosene along with reclaimable sulfur.

By using FreshAWL solutions in hydrocarbon treatment systems there are additional value benefits of:

  • Reduction of the mercaptan along with H2S and sulfur compounds in RSH kerosene
  • Corrosion inhibition
  • Improved environmental impact through use of non-toxic treatments
  • Safety of non-hazardous chemical usage and storage


The FUEL-WASH chemistry and the treatment methodology for removing mercaptans from kerosene solutions, more specifically, the RSH Kerosene that was provided by Merichem was able to consistently achieve better than 90% mercaptan removal.

Research reveals that currently utilized fuel washing processes are only able to obtain from between 10-20% mercaptan removal.

The FUEL-WASH processing has been refined to prove that variable factors are needed to finalize the successful mercaptan removal and separation results including:

  • Contact time
  • Agitation time,
  • Mixing methodology
  • Incorporating air into the FUEL-WASH,M/RSH Kerosene mixture

A multifaceted methodology is required to achieve the 90% reduction levels including:

  • Wetting
  • Activation
  • Creation of emulsified chemical
  • Solubilizing/De-solubilizing of chemical versus kerosene
  • Solubilizing/De-solubilizing of mercaptan from kerosene (to air or water)
  • Creation of a rag layer
  • Split of the kerosene fraction from the reacted mercaptan
  • Optional split of the mercaptan layer from the chemical treatment (third layer sulfur compound)

Although the method is multifaceted it is not complex. In fact, another positive feature of FUEL-WASH is its ease of use.


FreshAWL has worked into the fuel washing methodology the conclusions that the ratios of the reactants will modify the process effectivity and efficiency.

Also, the period of inactivity after reaction between the mercaptan-laden fuel and FUEL-WASH finishes the mercaptan removal process by forming a polymer that congeals into a separate layer. This occurs through a selective volatilization of the mercaptan that keeps the kerosene layer intact. The addition of water was utilized for activating the surfactant, which reactivates the reaction when it has ceased the initial mercaptan reaction.

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