Share
November 3, 2008 4:30 PM, EST

SCR Group Urges Strict Urea Guidelines

By Frederick Kiel, Staff Reporter

This story appears in the Nov. 3 print edition of Transport Topics. Click here to subscribe today.

When heavy-duty engines with selective catalytic reduction technology start rolling in 2010, truckers refilling their trucks’ urea tanks will need to follow strict guidelines to protect the product’s purity to avoid damaging the aftertreatment system, urea experts said.

SCR, which most new trucks built after January 2010 will use to meet federal nitrogen oxide emission standards, will require the vehicles to have new tanks holding about 30 gallons of urea, also called diesel emission fluid.

“DEF is not a conventional urea solution,” said John Lounsbury, marketing director of chemical producer Terra Environmental Technologies, which makes DEF under the brand name TerraCair.

“Both the specific purity of the product and the concentration of product are essential to the function of SCR,” Lounsbury said. “All along the line of distribution, storage and sale, all of the handlers will have to be trained in order to preserve this protocol.”

Lounsbury is a member of the SCR Stakeholders Group, an organization that meets monthly with Environmental Protection Agency officials. He and other group members spoke in an Oct. 28 teleconference organized by the Oil Price Information Service.

“All the members of the stakeholders group reached a consensus on a very specific grade of urea for SCR,” said Vijay Srinivasan, an official with a company that has designed storage and dispersing systems for DEF.

“We want to differentiate DEF from agricultural and industrial-grade urea, because it needs to meet very stringent specifications . . . Off-grade urea or contaminated urea has the potential to kill or poison the catalytic converter,” Srinivasan told TT.

Srinivasan, general manager of Balcrank Products Inc., Parsippany N.J., spoke at the OPIS conference and later with Transport Topics.

The SCR group decided that the SCR catalytic agent will be designated “Diesel Emission Fluid,” a combination of high purity urea and deionized water. The group decided on the term partly to make sure truckers understand that it is a special product.

Lounsbury said that TerraCair uses natural gas as the raw material and “cracks it” in a process that produces ammonia, which is mixed with carbon dioxide to make urea.

That pure form of urea is mixed at a ratio of 32.5% with the remaining 67.5% being “ultrapure” water that has all minerals removed, he said.

Lounsbury said the solution has to be tested in a laboratory before it is given a certificate of analysis that guarantees it as ISO 22241. “It has to be manufactured under very strict protocols to meet the standards of ISO 22241, the international grade for auto and truck use.”

ISO is the designation of the International Organization for Standardization, a nongovernmental organization representing 157 nations.

DEF can be stored only in stainless steel or in specific high-density plastic containers, they said. It also freezes below 12 degrees F. or deteriorates above 86 degrees.

“It will probably be several years before enough trucks are using it to justify the expense of storage in large underground tanks,” Srinivasan told OPIS. “We are developing several systems that hold up to 500 gallons that will be stored inside, or outside in temperature-controlled aboveground systems.”

DEF will also be sold in smaller 2.5-gallon and 5-gallon containers for use in diesel-powered cars and light trucks and for emergency use in over-the-road trucks.

Brian Routhier, automotive engineer at American Trucking Associations, told the OPIS conference that ATA was talking to the EPA about not requiring that trucks be built to gradually shut down the entire powertrain if it runs out of DEF.

“Under EPA rules, the truck eventually will have to stop running without SCR, because it will be polluting,” Routhier said. “It’ll be done by steps, starting with a low-volume warning, then with more violent warnings, then slowing to a crawl, and eventually, the vehicles are supposed to stop operating, once the DEF tanks are empty.”

Routhier said that ATA was concerned about what could happen if the shutdown occurred while a truck was crossing a desert or a mountain range.

“We argue, ‘Don’t shut the truck down entirely, because it could put the person in danger,’ ” Routhier said. “Let them get somewhere, even if it is at a very slow rate, 20 miles per hour, for example.”