ARI-100 Series of Catalysts

ARI Technologies was founded in the 1970’s. During that time, ARI Technologies developed a patented process to manufacture an oxidation catalyst used in hydrocarbon sweetening. ARI Technologies is now called Merichem Gas Technologies (MGT), and is a wholly owned subsidiary of The Merichem Company. MGT offers 3 unique cobalt catalytic reagents used to accelerate the oxidation of mercaptans in petroleum fractions. The process of oxidizing mercaptans in hydrocarbons is called “hydrocarbon sweetening” requiring a regenerative caustic treating unit, caustic solution, air, and a cobalt-based catalytic reagent. MGT’s cobalt-based catalytic reagents are called ARI-100EXL, ARI-120L, and CAC-120S.

Merichem Gas Technologies recently developed new as well as improved versions of ARI-100 Series of Catalysts. The first is a solids free catalytic reagent called ARI-100EXL. This is a liquid catalyst used in the liquid-to-liquid contact process. The solids free ARI-100EXL provides the following benefits compared to other competitive catalytic reagents.

  • Is a 100% soluble solution
  • Causes no solids formation or solids settling issues
  • No DSO carryover
  • Is compatible with continuous catalyst injection systems

ARI-120L is a catalytic reagent used in the fixed bed process. This catalyst is now offered in powder form providing the following benefits:

  • Reduced shipping costs
  • Unlimited shelf life
  • Carbon bed impregnation time is reduced by 50%
  • MGT provides simple catalyst slurry preparation procedure
  • Catalyst is packaged in 5 gallon plastic pails for easy operator handling and transport
  • 80% less containers are required
  • Plastic pail includes access port for water addition, mixing, and pumping

CAC-120S is the newest catalyst in our series of ARI-100 catalytic reagents. CAC-120S is a long-lasting, durable activated carbon with the catalytic reagent already adsorbed on the carbon surface. CAC-120S is used in the fixed bed process and provides the following benefits:

  • Eliminates the need for in-situ impregnation
  • Is forecasted to last 3–4 years without additional field impregnations
  • The pre-impregnated carbon quality is superior compared to the in-situ carbon impregnation yielding results

The following case illustrates the benefits due to the improvements made in MGT’s catalytic reagents. In this case, a refinery in the Gulf Coast Region recently introduced the solids free ARI-100EXL catalytic reagent with very positive results. The refinery operates several caustic extraction units to remove mercaptans from liquid hydrocarbon streams. In the past, this refinery employed a once through caustic solution process. The caustic was then disposed of and replaced with fresh caustic. To reduce operating costs due to the high caustic consumption and disposal costs, the refinery decided to install a Merichem REGENSM unit.

In the extraction process, a liquid hydrocarbon stream is contacted with a caustic solution in a mixing chamber where the following reaction takes place;


Once extracted, the caustic stream is separated from the hydrocarbon stream and sent to the caustic regeneration or REGENSM unit. Air and ARI-100EXL are injected into the caustic stream. The mercaptans are oxidized and converted to disulfide oil (RSSR) and the caustic is regenerated according to the following reaction:

4 RSNa + 4 H2O + O2 2 RSSR + 4 NaOH + 2 H2O

The RSSR/Caustic is sent to a disulfide oil separator where RSSR is removed from the regenerated caustic by gravity separation, and the regenerated caustic is sent back to the extractor.

The Merichem REGENSM unit also includes a continuous catalyst injection system for the following reasons:

  • A desire to deliver a continuous flow of catalyst solution at a set feed rate to improve catalyst addition efficiency
  • To minimize operator handling
  • To safeguard against environmental spills

In summary, Merichem Gas Technologies has been working to strengthen positions in the hydrocarbon sweetening market by offering technical field support and developing and improving oxidation catalysts for use in Protech’s licensed process technologies i.e., MERICATSM, MERICAT IISM, and THIOLEX/REGENSM. Merichem Gas Technologies will continue to develop new process technologies as well as catalytic reagents to better serve the HPI market.