'Tell It Like It Is' Panelists See Clean-Diesel Deadline Problem

Diesel Fuel News, Nov 13, 2000 by Jack Peckham

Washington -- Meeting U.S. EPA's super-tough proposed nitrogen oxides (NOx) and particulate matter (PM) limits for heavy-duty highway diesels in mid-2006 may look feasible to U.S. EPA, but engine makers, automakers and refiners see problems that must be solved in a very short period -- if they can be solved in time.

"We might not be ready for the 2007 EPA deadlines," former General Motors fuels director Joe Colucci pointed out at the popular "Tell It Like It Is" panel discussion at the recent Hart World Fuels Conference here. "The lower the sulfur limit [on diesel fuel], the higher the cost and the higher the hurt on refiners. The higher costs for 15 ppm sulfur -- or even lower sulfur limits -- could lead to lower supplies, trucker protest and damage to the U.S. economy. Are we all -- industry and EPA -- creating a haunted house of horrors, or will we all be okay?" he asked.

While pointing out that advanced refinery catalyst and process technology makes U.S. production of 15 ppm sulfur diesel technically feasible, Criterion Catalyst VP Art Suchanek wondered whether EPA's mid-2006 deadline makes sense, and whether a 50 ppm sulfur cap along with more sulfur-tolerant exhaust catalyst technology might be a more practical alternative to what EPA proposes. Earlier in the Hart conference, engine maker Cummins pointed to enormous technical problems facing diesel makers to meet EPA's 2006/7 heavy-duty NOx and PM standards.

By contrast, Europe seems to be moving toward technologically proven emissions technologies and fitting emissions standards to technical feasibility.

"If 50 ppm sulfur is good enough for Europe, then why not the U.S.?" Suchanek asked. "We have almost no light-duty diesels here. It's almost all heavy-duty," so supersensitive, sulfur-intolerant catalyst technology designed for European cars may have little relevance for the U.S. market.

Defending the proposed diesel plan, U.S. EPA mobile source official Margo Oge countered that diesels must slash NOx, PM and "toxics" dramatically in order to protect public health.

"The Clean Air Act says that when we're setting standards, the [pollution control] technology must be available [by the deadline proposed], while considering cost, energy and safety factors," Oge said. "We've based our proposal on the expectation that catalyzed traps will be able to meet those 90% particulate reductions and NOx adsorbers will achieve these 97% NOx reductions.

"Today, catalyzed PM traps are working in Europe -- when using around 10 ppm sulfur fuel -- but they don't always work with 50 ppm.

"We have data - it's very clear in our own labs - and from engine makers, that catalyzed traps can work. We also have data on NOx adsorbers, and although these are not as well developed, we have data on four NOx adsorbers in our own labs, as well as data from a number of catalyst companies, and DOE research [on NOx traps] is also underway, so we will be there in the 2007 time frame, and the major hurdle is sulfur."

Engine and bus maker International isn't worried about the U.S. EPA 2007 heavy-duty limits on PM emissions - if a 15 ppm sulfur ULSD is available. "We're quite comfortable with EPA's PM standard and we'll have a school bus that meets this standard next year," International's Warren Slodowske said.

"There's no issue with that, as long as we have a 15 ppm sulfur fuel." But as for meeting EPA's super-tough 0.2 grams/brake-horsepower hour NOx limit, Slodowske would only say that "maybe" engine makers can meet that target.

However, International is "optimistic that NOx adsorber technology will be developed to allow compliance with EPA's NOx targets," assuming certain test changes are allowed.

"We've proposed a bit different NOx phase-in [compared to EPA's proposal], with three years extra to develop the NOx adsorbers, though we intend to market NOx adsorbers in 2007" if a practical system emerges.

Complicating the practicality of such systems are EPA's ultra-tough emissions test cycle schemes for 2007 engines, he said. New testing schemes include supplemental steady state and "not-to-exceed" (NTE) limits on the test cycle, including a very wide range of engine and ambient conditions. "There's nil margin of error for these, and there just isn't technology for these NTE limits, though EPA is willing to discuss this," Slodowske said.

From the small refiner's point of view, the availability of 15 ppm sulfur ULSD refining technology isn't the only question. Rather, cost and return on investment is the critical question, United Refining VP Jerry Moos pointed out.

"For straight-run distillate, yes, you can get to 15 ppm, but is it practical and economic?" he asked. "With more typical high-sulfur crude and light-cycle oil and coker gasoil streams, the answer is no,' especially if you're a small refiner. And we've not yet been given a complete answer from EPA about lube oil sulfur contamination [poisoning vehicle exhaust catalysts], and what about pipeline fuel sulfur contamination?

"Maybe in the laboratory and pilot plants and European refineries they've found that they can do this, but not economically on a largescale in the USA," Moos said.