New ideas hatch in process development

Don’t expect pilot plants to disappear as better tools and techniques enhance efforts.

By Mike Spear, editor at large

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As to whether companies would prefer not to pilot at all — relying instead, for instance, on process simulation models developed from lab-based experimentation — the AIChE survey (which, after all, was of pilot plant users) probably doesn’t provide many answers. But Zeton’s Edwards says that, while companies may be more selective about which processes they pilot in the future as resources become scarcer, “the need to pilot at a meaningful scale before moving to a commercial scale will always be a requirement. The risk is too great in not piloting a new process, because there are always surprises during piloting — byproduct accumulation, catalyst performance issues, corrosion issues and so on — and models are not too good in revealing such surprises.”

Acknowledging that his views are those of someone working for a company that designs and builds pilot plants for others to operate, Edwards nevertheless acknowledges the importance of the other stages of process development. “I think lab work, computer models and pilot plants all have an important role to play in process development,” he says. “Fundamental lab work will always be needed and a model can screen which potential new processes should be piloted.”

UOP’s Pintar takes a similar view. “There’s always going to be a need for the pilot plant in our current paradigm,” he argues, “because people want to see data. They want to see proof. Although, if you could develop a good kinetic model based on your pilot-plant data, then you might not need to run the plant all the time to generate estimates for customers or to do revamp studies. The problem is that we are always trying to push the units, to push the processing conditions outside of the regime for which the model was built.”

Faster screening
To develop any process model, however, presupposes a process in the first place. And for this we still need the laboratory bench and what was once the laborious work of screening many different compounds and assessing how they react under different catalytic conditions. This is now the realm of combinatorial chemistry — in which large numbers of reactions can be performed simultaneously in high throughput, small-scale systems.

An example is the HTS (High Throughput Screening) system of Symyx Technologies, Santa Clara, Calif., which has just won Frost & Sullivan’s 2005 Technology Leadership Award. “Symyx’s high throughout approaches offer significant advantages over conventional methods of catalysts discovery,” says F&S industry analyst, Anil Naidu. “The systems can rapidly screen materials to achieve the desired properties, delivering results faster and at a much lower cost.”

The success of Symyx’s combination of high throughput experimentation with its proprietary software tools for handling the data produced was highlighted last year with the start-up by Dow Chemical in Tarragona, Spain, of its first commercial plant to produce Versify plastomers and elastomers. These speciality propylene-ethylene copolymers are manufactured using a new catalyst system developed in collaboration between Dow and Symyx. “This is an important milestone for Symyx,” commented chairman and CEO Steve Goldby, “when an innovative discovery coming out of our labs goes into full commercial production.”

Earlier this year, Symyx announced a $120-million five-year strategic alliance with Dow “to effect a broad change in Dow’s R&D capabilities and efficiencies.” This deal follows a similar alliance with ExxonMobil signed in 2003 to run for five years and worth more than $200 million to Symyx.

As noted earlier, companies in the pharmaceuticals sector tend to have different priorities in process development than the bulk commodity chemical producers. According to David Ainsworth of engineering/procurement/construction contractor Foster Wheeler Energy, Reading, U.K., the use of simulation models — such as Batch Plus from Aspen Technology, Cambridge, Mass., and SuperPro Designer from Intelligen, Scotch Plains, N.J. <em dash>— can help pharmaceutical companies investigate numerous design alternatives quickly and easily. “The computer model adds value at all stages of the design process,” he says, “from early conceptual design through to the ultimate operation of the facility.”

Ainsworth also cites the value that early involvement of an experienced process contractor can add — particularly in the pharmaceutical industry where processes are typically developed by teams of chemists. “Analyzed in a methodical manner, the specific characteristics of each process become evident and alternative processing methods can then be identified.”

Better tools
In its analysis arsenal, Foster Wheeler includes weapons developed by Britest, Cheadle, U.K. This not-for-profit company was set up in 1998 by a group of leading chemical and pharmaceutical companies, including AstraZeneca, Avecia, GlaxoSmithKline and Rhodia, to follow up on new approaches to process technology coming out of the universities at the time and to encourage technology transfer. Using what are known as the Britest tools — a set of proprietary procedures and software programs — is, says Ainsworth, a time-effective way of starting the development process and determining all the potential (and infeasible) process options.

One area the Britest toolkit considers is  process intensification (PI), not just in the development stages but through to the commercial stage, as well. At Zeton, Edwards also is seeing a trend among the company’s pilot plant customers towards PI techniques and equipment — “although it’s still very much in its infancy,” he says. “We think operating companies are going to be interested enough to want to try it, but nervous enough not to go full scale until they have tried it on a pilot scale.”

UOP’s Pintar notes that at the same time as “pilot plants themselves have shrunk in terms of reactor size,” there is a growing drive for more data collection and on-line analyses from the plants. Fulfilling both of these goals, a new process analytical tool has recently been successfully trialed by specialty chemicals producer Clariant Chemicals at its plant in Leeds, U.K.

The plant used a patented “constant flux” reaction calorimeter developed by Ashe Morris, Radlett, U.K. The Coflux technology — which is akin to a variable area, rather than variable temperature, heat exchanger — is said by co-developer Robert Ashe to permit stirred tank reactors of virtually any size or type to be operated as precision calorimeters, offering a simple solution for on-line monitoring of chemical and biological processes. The R&D manager at the Leeds plant, Jim Wilson, said Clariant was able to monitor the rate of change (powder dissolution and reaction) throughout the trial experiments and could successfully detect the start and finish of each step in real time.

Real-time monitoring and increased automation were certainly among the trends identified by the AIChE study, as was an increasing emphasis on the safety of pilot plant operations. This highlighted something of a paradox because, as Pintar observes, despite the increasing levels of automation, “the majority of companies don’t allow unattended operation of their pilot plants.”

No doubt this will be a topic for the next benchmarking exercise, expected in three to five years time. Until then, however, the future for the pilot plant at the heart of process development seems assured.

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