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Tighter Regulations, Cleaner Air

NEW REGULATIONS issued by various authorities are forcing pulp mills to continuously reduce all air emissions, including odors,” Erkki Jauhiainen of Enviroburners Oy, Helsinki, Finland, told delegates attending the Thursday morning session on ‘Air Issues’, sponsored by the Environment Committee.

With 28 years experience in the industry, Jauhiainen explained that because pulp mills worldwide are known for odor problems, environmental requirements have been the most significant factor for building NCG treatment systems into pulp mills.

But Jauhiainen said the industry must not worry, because by using custom designed NCG burners, the pulp industry can continue normal operation under more and more stringent environmental regulations in the present and in the future.

“It will be possible for mills to be odorless with these burners,” he said. “

Tighter regulations are not only for newly-established mills, said Douglas Bruce, AGRA Simons Ltd., Vancouver, BC.

“Existing mills face ever-tightening regulations when undergoing a major modernization,” he said. “New greenfield mills tend to match or even better the tightest regulations anywhere,” he added.

He explained that governments use regulations to control air quality as part of their mandate in safeguarding public health and the environment.

“In most stringent jurisdictions, the two main regulatory tools are limiting source emissions, and ambient air quality standards,” he said. Source emission limits are often industry-specific in the major pulp and paper-producing countries.

In Canada, he said, the Canadian Council for Ministers of the Environment is currently developing national standards for TRS in addition to those for fine particulate. Several provinces are participating in this process to develop a consensus on Canadian standard.

But he informed the delegates that an area currently untouched by regulation and permits is greenhouse gas emissions. He predicted that reduction of this emission parameter will be the focus of significant efforts over the next years.

“Voluntary reduction programs will be the mechanism in the first phase,” he said. “But subsequent sector specific regulation is likely,” he added.

B.W. Hrebenyk, SENES Consultants Ltd., Vancouver, BC, gave a lecture entitled, When ISC3 isn’t enough! Use of refined regulatory dispersion models. He explained that most regulatory agencies in Canada and the United States rely on ISC3 model for conducting air quality assessments of non-reactive pollutants. But ISC3s have limitations since its basic formulation is over 20 years old, making it unsuitable for some recent regulatory applications.

“ISC3 is likely to continue as a primary choice for regulatory applications,” said Hrebenyk. “But more refined models such as CALPUFF will continue to be applied on a case-to-case basis where its advantages outweigh the use of the less expensive ISC3,” he explained.

Tom Mullen of Air Products Canada Ltd., Brampton, ON, talked about the application of the THR process to reduce TRS emissions.

“Stop doing it with air and start doing it with oxygen,” he advised the delegates.

He outlined the air oxidation drawbacks. These include poor energy efficiency; poor selectivity; TRS and hazardous air pollutant emissions; limited NaSH conversion and limited capacity. These he compared to the advantages of resorting to the THR process. With THR, he said, there will be a high energy efficiency; good selectivity; no vent and no HAPS emissions; and an excellent NaSH conversion via polishing.

“THR Process is energy-efficient, is more selective and produces no fugitive emissions,” he concluded.

The delegates also learned about the effects of salt cake properties on precipitator performance, through the lecture of Inga-Lill Samuelsson, ABB Power Oy, Helsinki, Finland.

“The combustion conditions affect the chemical composition of the particulate as well as the size distribution,” said Samuelsson. “By optimizing the mechanical design and rapping, it is possible to handle salt cake, comparatively complicated from the cleaning point of view.”

He warned that a very sticky salt cake will always cause trouble in a dry precipitator.

“If it is possible to change the properties of the salt cake, other types of cleaning equipment are recommended,” he said.