Terri-Jane Yuzda

The Perfect Mix of Academia and Industry

University of Alberta Professor is Instrumental in Creation of Industrial Mixing Handbook

Freelance Writer

An Expert Mixer
Dr. Suzanne Kestra, P.Eng., stands before a less-than-perfect mixing system. Surface feed, says the expert, is acceptable for slow blending operations - but can reduce yield in competitive-consecutive chemical reactions by up to 20 per cent. Better to subsurface feed at the impeller, says Dr. Kestra. That's the kind of wisdom imparted in the book she helped edit, the Handbook of Industrial Mixing.

Dr. Suzanne Kresta, P.Eng., admits to some mix-ups in preparing what will likely become the bible of one of her areas of expertise - industrial and chemical mixing.

The University of Alberta professor of chemical engineering recalls some tense moments during her four years as corresponding editor of the Handbook of Industrial Mixing. For instance, there was the frantic call from a contributor in Freeport, Tex., explaining that flooding from a hurricane had "drowned" his computer and data. Fortunately there was a back-up.

In any case, it's now water under the bridge. September marks the release of the 2,500-copy initial press run of the 1,450-page tome, complete with more than 600 illustrations. Making the book unique is that teams of academic and industrial practitioners joined forces to write each of the 22 chapters covering best practices on industrial mixing. The result is a what's-what by the who's-who of mixing.

"Everyone who's anybody in the field has written a definitive chapter. We have 44 contributors with a combination of more than 1,000 years of mixing-engineering experience," says Dr. Kresta, herself a leading expert on turbulent mixing. She's also the recipient of both APEGGA's and the Canadian Council of Professional Engineers' 1998 early accomplishment awards.

Along with two American colleagues — veteran Merck process development engineer Edward (Ed) L. Paul was senior editor, and Victor Atiemo-Obeng of Dow Chemicals was industrial editor — Dr. Kresta was part of the editorial trio guiding this impressive project, sponsored by the North American Mixing Forum. DuPont Fellow Art Etchells, a member of the forum of mixing experts, seeded the idea for such a handbook almost a decade ago.

Bringing It All Together

While texts and many journals deal with industrial mixing, the information is fragmented. There was a need to gather theory and practice within one cover ¾ a notion embraced by academia and industry alike.

A number of industries have much riding on the right mix. Industries relying on effective and efficient mixing (of liquids, slurries or even solids) are diverse. The list includes producers of pharmaceuticals, chemical commodities, fertilizers, cosmetics, food, pulp and paper, petrochemicals, and polymers. Add to that processes such as water treatment and bioreaction that depend on stirring.

Among industry's biggest challenges — be it drug manufacturers measuring product in kilograms or chemical plants outputting by the tonne ¾ is the leap from the laboratory bench to huge industrial-scale vessels.

"Anyone can make a pizza for 10 people. But how about for 10,000 people?" asks Dr. Kresta. "The problem of scaling-up is very critical for chemical engineering."

Consistency and quality require careful balancing of variables such as heat transfer, chemical reactions, solid suspensions and gas dispersion. Plant designers and operators often face the added challenge of using the same vessels for different mixing procedures.

Tremendous strides have been made in the past half-century as industrial mixing emerged as a bone-fide science and set aside a reputation that sometimes stirred up images of a hit-and-miss black art.

As mixing research progressed, academics documented their findings. Although engineers and other industry practitioners found workable solutions to specific mixing problems, once an answer was in hand, they tended to move on. Often, this meant that valuable insight remained uncaptured and unavailable to someone with similar troubles.

The handbook, says Dr. Kresta, "brings together years of plant and trouble-shooting experience."

Academia Meets Industry

An important editorial challenge lay in selecting the right topics. With topics chosen, editors sought suitable pairing of "town and gown" partners expert in specific fields, and arranged meetings between them.

As corresponding editor, Dr. Kresta became facilitator, go-between, diplomat and sometimes cajoler pushing the process forward. Her co-editors readily acknowledge her enormous contributions.

Victor Atiemo-Obeng is "completely convinced we are where we are with this project to-date because of her complete belief in the project, her technical contributions, her tireless effort in diplomatically addressing sticky and thorny issues that emerged, and her tenacity in keeping the project moving toward the target."

Says senior editor Ed Paul: "Her technical expertise was demonstrated both in being a co-author of two excellent chapters as well as by her ability to bring critical technical editorial input to the authors of virtually all of the other chapters, thereby serving as an expert internal reviewer and editor."

Face-to-face meetings proved important, but e-mail provided the sustaining lifeline for this ambitious project, which Dr. Kresta pursued while maintaining her considerable teaching and research load. Her computer became an electronic Grand Central as e-mails sped in from as far away as the Antarctic. "Nothing arrived as hardcopy in my mailbox; everything arrived in my e-mail box."

So why not also publish electronically? That option was considered, Dr. Kresta concedes. However, it was decided there were advantages in printing at least the first edition. It lets the publication benefit from the distribution network and profile of a recognized and well-established publisher, John Wiley.

While a Web-based version would allow cross-linking, editors thought a print version better exposed readers to the book's collaborative approach. A CD-ROM that comes with the handbook provides video illustrations of many mixing processes, however, and it wouldn't surprise Dr. Kresta if a follow-up edition were published electronically.

Until then, expect to see the new handbook in many industry libraries and on desks in consulting, design and processing firms.

"It should be accessible to any chemical engineering operation with more than 15 engineers," suggests Dr. Kresta.

If that recommendation is heeded, it bodes well for sales of the Handbook of Industrial Mixing.


Dr. Suzanne Kresta, P.Eng.

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