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Engineers: St. Lawrence Cement plant design has not kept pace with the ‘state-of-the-art’

DEC asked to review German success with advanced pollution control technology

HUDSON, N.Y. -- An investigation by a major U.S. engineering firm has identified an important state-of-the-art technology, found to be highly effective in the control of cement plant emission, yet not included in the design of St. Lawrence Cement’s Greenport proposal.

The results of the investigation, sent Tuesday to the New York State Department of Environmental Conservation (DEC), follow months of research by experts at Camp, Dresser and McKee, one of the largest consulting, engineering and construction firms on the East Coast with over 3,100 employees.

CDM engineers found that a modern pollution control technology widely used to reduce emissions from coal-fired power plants has now been successfully adapted for cement plants as well. Under the Clean Air Act, applicants like SLC have a legal obligation to update their design as new information becomes available, even after submitting their proposal.

The engineers found that by adapting a technology called Selective Catalytic Reduction (SCR), a German cement plant has achieved nitrogen oxide (NOx) emission reductions in the range of 80 to 90 percent, and even higher. Those success rates are “far in excess of those offered by St. Lawrence Cement” at Greenport, CDM states. If SCR were added to the Greenport design, that could eliminate an estimated 1,820 tons (3,640,000) of emissions yearly.

As part of Tuesday’s submission, lead Friends attorney Jeffrey S. Baker called upon DEC “to reassess the technical feasibility of SCR at the SLC plant” and instruct the company to employ it in their Greenport design. If DEC were to decline to do so, Baker indicated that Friends of Hudson would likely file a motion to introduce this as a new issue for adjudication.

CDM determined that Lurgi, a leading European engineering design and construction firm, supplied an SCR unit to Solnhofer Portland-Zemetwerke AG, a cement plant in southern Germany located between Munich and Nuremburg. Prior to installation of SCR, the Solnhofer plant was achieving NOx emissions of 2.8 - 3.2 pounds per ton of clinker; with SCR in place, the plant has since achieved a much improved rate of 0.8 pounds per ton of clinker.

Speaking directly to St. Lawrence’s outdated objections to the use of SCR, CDM chemical engineer Frank A. Sapienza, P.E., found that “the experience of the German cement plant demonstrates that the concerns regarding catalyst poisoning and fouling, which caused SLC to dismiss SCR as a technically feasible alternative, have been addressed with the development of a special catalyst specifically designed for the cement industry.”

SCR involves injections into the flue gas or process exhaust which mix with nitrogen oxides in the exhaust, and then pass through a catalyst bed where the NOx is converted to nitrogen gas (N2). Tuesday’s request to DEC describes many of the technology’s advantages, including:

-- A high degree of NOx removal;
-- “End-of-pipe” control technology;
-- Potential use of urea rather than ammonia as a reducing agent.

CDM, which primarily consults to major industrial and commercial developers, was founded in 1947 and was retained several years ago by Friends of Hudson as part of its ongoing challenges to SLC’s coal-fired project. The group is drawing upon the expertise of consultants in CDM offices in New York, New Jersey, and Massachusetts, among others.

“St. Lawrence Cement has been caught trying to cut corners before,” said Friends of Hudson executive director Sam Pratt. “This investigation by a respected engineering firm brings to light a proven state-of-the-art technology that could help reduce local health risks. Will SLC embrace these findings , or will the company continue to promote a cheaper, dirtier design?”

Pratt cited the company’s strenuous objections to employing another control technology, a Regenerative Thermal Oxidizer (or “RTO”), as another example of St. Lawrence Cement cutting costs at the expense of public health. Two administrative law judges identified use of the RTO as a substantive issue to go to trial, but SLC appealed that decision. DEC Commissioner Crotty has not yet ruled on that and other key air quality issues before her.