September 28, 2008
Transitions – Then and Now
By McMahon, Terry
You never step twice into the scone river for ever newer waters are flowing on you. - Heraclitus of Ephesus (circa 400 B.C.)
The U.S. chemical enterprise (and probably those in other developed economies) may be in a historic transition from petro- based to bio-based processes and products. It is happening in fits and starts, but the momentum is building. In the spring of 1997, DuPont CEO John Krol, in an address at The Chemists' Club of New York, indicated that commercial production of trimethylene glycol (3G) from glucose via bacterial fermentation was approaching commercialization. Polyester fibers derived from 3G have superior properties to conventional polyesters derived from ethylene glycol. A joint venture plant with Tate & Lyle (a U.K. sugar producer) is now in operation in Tennessee.
Since the rise of the petrochemical industry following World War II, countless new synthetic materials with beneficial properties have transformed the chemical enterprise. A vast technological infrastructure (skills, techniques, instruments, controls) has been erected based on the unique properties of petroleum-based feedstocks and associated processes. Petrochemical processes are typically highentropy producers (with large irreversible energy losses) that are characterized by fast reactions driven by high temperatures and pressures yielding relatively high product concentrations. Biological processes are typically low-entropy producers (modest irreversible energy losses) that are characterized by slow reactions at room temperature and atmospheric pressure yielding relatively dilute product concentrations. Clearly, a new technological infrastructure will be required to preserve the thermodynamic advantages of bioprocesses while compensating for disadvantages in reaction velocity and separation free-energy change.
The chemical engineering profession will be challenged to support both existing and emerging chemical enterprises, and the opportunities for creative exploration should be welcomed. Process automation is just one technical specialty in this emerging infrastructure, but an important one. The tools of process automation (e.g., instruments, analyzers, controllers, actuators, software and systems) account for close to 20% of the capital cost of a new facility. Add to this engineering know-how in the use, application and maintenance of these tools and process automation becomes an even more significant investment.
A recent publication from ISA (Research Triangle, NC), "New Directions in Bioprocess Modeling & Control," by Michael Boudreau and Gregory McMillan, reviews in detail many aspects of established process-control technology as applied in this new landscape. Boudreau brings bioreactor control experience with Amgen, Bayer and Genentech; McMillan, a highly respected process automation veteran, is a retired Senior Fellow at Solutia and Monsanto, and is currently a contract consultant and affiliate professor at Washington Univ. in St. Louis. Both are now associated with Emerson Process Management and acknowledge contributions from a host of colleagues, academics and industry partners.
Biopharmaceutical production represents the most economically and technically important current implementation of bio-based processing. Arecent publication from Blackwell Publishing (Ames, IA), "Advanced Technologies in Biopharmaceutical Processing," edited by Roshni Dutton and Jeno Scharer, provides comprehensive coverage of the industry and its regulatory and manufacturing environment. Detailed coverage of process monitoring, analysis, control and automation as applied to this industry is also included. Dutton, a biopharmaceutical process development consultant, and Scharer, Professor Emeritus of ChE at the Univ. of Waterloo specializing in bioprocess optimization, have also assembled an impressive group of contributors.
Both of these volumes (and many others) will help in establishing the new technical infrastructure for the biochemical enterprise. For process automation in particular, new variables need to be measured, new controlling relationships need to be analyzed and understood, and entire classes of chemical composition analyzers are likely to be required.
In a little-known but historically significant report to a group of New Haven businessmen organized as the Pennsylvania Rock oil Co., Benjamin Silliman, professor of chemistry in Yale College, comments on his experimentation on a sample of "rock oil" (literally in Latin petrv oleum) from seeps in western Pennsylvania. Silliman's report from April 1854 notes that a distilled fraction of rock oil (probably kerosene) burns with a brightness exceeding that of whale oil, the world standard since the mid-18th century. The availability of crude-oil-derived kerosene was a major boon to the thinning population of whales in the North Atlantic. The transition to bio- based processing may have similar secondary benefits.
The heroine in "Indiana Jones and the Temple of Doom," when offered an hors d'oeuvres tray of stuffed grasshoppers and other delectable insects, remarks "No thanks, I had bugs for lunch." It may well be that the micro-organisms on the plates of chemical industry professionals are not necessarily for lunch.
TERRY MCMAHON has been an independent consultant Jn industrial automation for 40 years (McMahon Technology Associates. 135 Fort Lee Rd., Suite LL-2, Leonia, NJ 07605; Tel: (201) 585-2050; Fax: (201) 585-1968; Email; [email protected]). His experience includes control system application development and sales at IBM Corp. and Realtime Systems, Inc. He has written a chapter in the 1998 and 1999 editions of U.S. Industrial Outlook, a feature in the industry newsletter Measuring Markets and a monthly column in Control magazine called "Around the Loop." McMahon earned a BSChE from MIT and MS and PhD degrees in chemical engineering from Yale Univ. He is a member of AICnE, ACS, ISA, NY Academy of Sciences, The Chemists' Club and Sigma Xi.
Copyright American Institute of Chemical Engineers Sep 2008
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