Pavilion produces polypropylene properly (sidebar)

Sept. 1, 2004
Bettina Rathaj is staff manager, polypropylenes, at SABIC Polyolefine GmbH, Gelsenkirchen, Germany. To maximize plant utilization, she uses advanced process control products from Austin, Texas-based Pavilion Technologies, including Virtual Online Analyzer and Process Perfector, as well as Clockworx, which she says is being installed to manage discrete production sequences.

Rathaj says “100 percent payback” came on SABIC’s total investment in “less than six months.”

During the first six months of installation, the APCs accelerated changeovers in production of various chemical grades. Prime production, which is the manufacture of “first-class” material within specifications, increased by 4.5 percent. And transition times—those intervals needed to switch production from one product grade to another—improved 25 percent.

Another derived benefit was a flexible product wheel. That is the “possibility to change from each product grade to another grade, without restrictions due to transition procedures that are needed, to minimize the amount of off-spec material during a transition,” explains Rathaj. Product consistency improved 35 percent. Variability in chemical-reactor contents decreased 30 percent. The APCs also reduced the plant’s environmental impact, she notes. She projects an annual reduction of 300 metric tons of polypropylene waste.

The vendor’s technologies stabilized plant operation, adds Rathaj. That means “less cycling, for example, in the reactor hydrogen dosing,” and that gives improved and more stable quality of product. The controls also minimized human-generated variability. “Each shift operator operates the plant a little bit differently. APC is like the ‘best operator’ all the time.”

Michael Tay, a Pavilion technical account manager, adds that the components of his company’s APCs include: 1) a predictive process model (i.e., empirical, first-principle, or a combination thereof) built on process knowledge and historical process data, where available; 2) control and optimization algorithms to solve toward multiple objectives; and 3) real-time process data.

See the story that goes with this sidebar: Advanced Process Control Finds Future Through Past