Chevron’s Technology Marketing invites you to contact our New Business Development group to learn about licensing our MERCAWAYSM process technology as well as MERCAWAYSM technical services provided to our licensees.

Mercury in crude oil and condensate can be effectively reduced by up to 98%

MERCAWAYSM process technology is a straightforward process for reducing mercury (Hg) content in crude oil and condensate using easily understood chemistry and well-proven unit operations. It is a semi-continuous operation with a single filter while continuous operation can be achieved by online switching between two filters. There are four key steps in the MERCAWAYSM processing scheme as follows:

  1. Desanding to remove sand and other particles
  2. Reaction to convert elemental mercury, Hg°, to particulate HgS
  3. Filtration to separate HgS particles from treated crude/condensate stream
  4. Polishing to adsorb most of the remaining mercury after the filtration step

Desanding Step

The Desanding Step is accomplished using a hydrocyclone to achieve removal of sand and other particulates. The Desanding Step reduces the filtration load and improves cycle length. Depending on the nature of the produced crude/condensate stream, this step may be omitted.

Reaction Step

The Reaction Step is conducted by introducing a treat chemical bearing at least one Hg reactive sulfur (S). The treat chemical dosage required can be readily determined using laboratory test methods for the crude or condensate to be treated. The reaction takes place in a stirred reactor at modest temperature and pressure. The key reaction is

Hg° + S donating compound → HgS

Filtration Step

The Filtration Step uses a pressurized precoat filtration system with operating cycle expected to range from 12 - 48 hours depending on feed and other filtration variables. In the current application, diatomaceous earth, DE, is added first as a filter precoat and later a finer grain DE is added to the feed to achieve filtration to 0.7μ. DE addition rate is determined during laboratory testing phase. Filtration has proven to provide 98% removal of HgS. The Hg containing filter cake is discharged at the end of every cycle for environmentally acceptable disposal.

Polishing Step

The Polishing Step is conducted in a fixed absorbent bed for further reduction of Hg content of the crude. This step may be unnecessary if acceptable levels of Hg removal are achieved after the Filtration Step.

 


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