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Chilling out VOCs

Cryogenics suppliers ready systems for small-volume fine chemicals, pharmaceutical producers

May 31, 2004 | A version of this story appeared in Volume 82, Issue 22

Engineer inspects cryogenics installation.
Engineer inspects cryogenics installation.

According to a guide to pollution control published last month by consultants at London-based Environmental Industries Commission, the future is clear: European rules governing emissions of solvents containing volatile organic compounds (VOCs) are being tightened and will gradually draw in small and medium-sized producers that up to now have escaped notice of regulators.

Integrated Pollution Prevention & Control standards within the European Union are now set by the European Commission's IPPC Bureau, located in Seville, Spain. The first draft of the Best Available Techniques Reference document covering pollution control in the organic fine chemicals sector--home to many smaller chemical companies--was just completed in March. These documents will be guidelines to countries incorporating the standards into their own national codes.

In the U.K., as one example, all new and substantially changed production installations are already covered by emissions standards. And major producers of petrochemicals and other large-volume chemicals have long been covered by other sets of pollution prevention and control regulations. However, existing installations in the pharmaceutical, plant health, and biocide sectors must have authorization applications in by March 31, 2006, and must be in compliance by 2007.

That timetable may be a shock to smaller companies, predicts Diana Raine, business manager for cryogenics at Air Products & Chemicals in the U.K.

For example, she notes that about 5,000 U.K. installations in a variety of business sectors will come under the IPPC regime between now and 2007. The emissions limits are going down, she says: "The hurdles are getting more difficult as the deadline is approaching. More companies are going to be hit."

Moreover, Raine says that number could rise substantially if the British government follows through on proposals to lower the threshold for registration of per-plant solvent emissions levels--currently at more than 50 metric tons per year--to less than 50 metric tons. "That will encompass more companies, more small companies--we figure about 10,000 companies would be hit that wouldn't otherwise."

She adds, "We are concerned that some solvent-using industries, particularly smaller installations falling under IPPC for the first time, may be taking a piecemeal approach to readiness and may not be prioritizing air pollution prevention early enough."

STEP FORWARD an old standby: cryogenic solvent recovery systems, already used by many large facilities. Both Air Products and the BOC Group are developing customized solutions for small companies that are based on cryogenic systems, which Raine says "operate to near-zero emissions and comply with the toughest European emissions limits. It is probably the 'greenest' of all technologies."

Air Products calls cryogenic condensation "a good way to remove volatile organic compounds from gas streams. Under the right conditions, it compares favorably in cost and effectiveness with both thermal oxidation and adsorption using activated carbon." The company has tailored its CryoCondap ExStream system to remove volatile organics from low flows and from low exit concentrations.

Cryogenic technology is also highly flexible, Raine says, a feature with particular appeal to the pharmaceutical industry. "They need to have the flexibility in their abatement systems," she says.

Graham Raymond, principal cryogenics engineer at BOC, agrees that it is the smaller operations that will be most affected by the new VOC emissions requirements. He says such companies must look at their solvent-management regimes from a variety of directions. "Can they eliminate the use of solvents? Are there other alternatives to solvents? If companies must still use [volatile] solvents, then they must implement appropriate abatement techniques," he says.

And although there are a variety of ways of achieving abatement--including thermal oxidation, adsorption, incineration, and biological control systems--cryogenic systems offer a proven technology for the control and recovery of volatile organics, Raymond notes.

"While BOC has historically installed systems capable of treating vent stream flows as high as 2,000 m3 per hour, our market research indicated that most customers were interested in significantly lower flows," he says. So about five years ago, "we engineered our Kryoclean VOC abatement technology into standardized modules to handle 100, 200, and 400 m3 per hour." Modules can be linked together to cope with higher flows of air.

"If, as seems likely, there is an increased demand from smaller scale operators, then our established range should be compatible with their flow-rate requirements," Raymond says.

With the tightening of solvent emissions regulations, he adds, the government "is bringing into play companies that currently have no problem meeting the standards--producers of adhesives, paint finishers, dry cleaners, and so on," as well as specialty and fine organic chemicals producers.

However, he adds, "we won't be seeing cryogenic technology on [Main Street]--its uses will be mostly industrial and the specialized areas we normally supply, such as pharmaceuticals and fine chemicals. We could easily accommodate smaller manufacturers."



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