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Handling DEF Correctly Avoids Costly Consequences

Farmer filling tractor from bulk diesel exhaust fluid tank

New diesel engine standards call for reductions in particulate matter (PM) and nitrogen oxides (NOx) to near zero levels. Engine manufacturers have found solutions to these mandates in a variety of ways. The use of selective catalytic reduction (SCR) technology utilizing diesel exhaust fluid (DEF) is one of the most common.

DEF is mixed with the exhaust in the presence of the SCR catalyst. This changes the NOx into nitrogen and water that safely releases into the atmosphere.

“DEF is an easy-to-use, non-hazardous fluid,” says Curt Dunafin, GROWMARK Energy Services Manager. “The challenge lies in properly handling and storing it. It is easy to contaminate, and impurities in DEF solution can cause premature failure of the catalyst in the SCR system, which can cost $15,000 to $20,000 to replace.” Dunafin provides these recommendations to avoid contamination of DEF.

Choose the Right DEF Supplier

It does not take much dust, dirt, tap water, etc. to contaminate an entire bulk storge tank. As little as a tenth of a teaspoon of some minerals can pollute the tank. To prevent contamination, we recommend using a closed-loop system that provides evidence of tampering. 

We use Micro Matic dry disconnect couplers that seal off and protect the storage tank and pumping system. In addition to preventing contamination, FS Energy Specialists can determine the right storage tank options for your DEF needs.

Store DEF Properly to Increase Shelf Life and Prevent Impurities

Storage life varies for DEF, but in proper conditions it can maintain quality up to 12 months. DEF should be:

  • Stored in stainless steel, coated carbon steel, or specific high-density plastic containers. DEF can corrode other materials and introduce contaminants.
  • Kept in a temperature-controlled location and out of direct sunlight. DEF is best stored between 12 and 86 degrees F (-11 and 30 degrees C). Since it is water based, DEF can freeze into a solid state.

Freezing DEF has no effect on its quality or performance, but it can expand up to 7 percent when frozen. In freezing conditions, do not fill your vehicle or storage tanks completely. This allows for expansion, which prevents tanks from cracking.

Prevent Contamination During DEF Use

Do not use funnels, jugs, or other equipment to fill tanks with DEF. Using funnels or jugs that have been used for other fluids or refilling previously used DEF containers will not maintain the pharmaceutical-grade purity needed in the SCR system. Additionally, don’t add any other fluids, including tap water, to DEF. 

Keep an eye on and change filters as needed. The injectors that meter DEF into exhaust are similar to fuel injectors. Each component of the dispensing system must be used exclusively for DEF to prevent cross-contamination, including the tank, piping, pump, filter, and filling stations.

Use API Licensed DEF

GROWMARK, Inc., is an American Petroleum Institute licensee. The API DEF Certification Program is for suppliers who have demonstrated that their products meet the required specifications.

“FS Energy Specialists not only make sure you have the equipment you need, they also work with you to find the right type of DEF system for your operation,” says Dunafin. “Contaminated DEF can lead to expensive consequences, but it doesn’t have to be difficult to use. It’s all about finding the right system for your operation.”

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