Problem solving in a chemical plant requires using data and the fundamentals of chemistry and engineering to link “cause and effect” relationships between the chemistry, the process, the control system, and the problem. Once the underlying cause is identified, it is about resolving the root cause(s) that can be manifest in a myriad of symptoms in the plant. That is the way problem solving should be approached. However, in manufacturing when the process goes awry, demands for pounds are high, financial losses mount, and frustration increases by the minute, it is easy to make changes to “respond” to the symptoms to show that “something” is being done. These types of reactions to drive “solutions”, which are often not supported by data, typically fail to solve the underlying problem because they address the symptom. Although the problem may momentarily go away it will likely reappear in the future. In this case, more pounds and money is destined to be lost.

The case study used to showcase Dow's approach to problem solving focuses on how a decades-old fouling problem within a Dow plant was solved. The highly-integrated plant is part of a much larger chemical complex that produces several valuable products and intermediates for Dow. The individual plants in the complex use different raw feedstocks. Streams from the plants within the complex also supply reclaimed feedstocks, catalysts, and chemical intermediates to each other. Outside the site they supply downstream intermediates for other Dow plants. As expected, asset utilization losses in any one of these plants quickly become upsets in all the plants.

During the summer of '05, a high frequency of plugging incidents in a “heavies” unit, used to separate catalyst and “heavies” from a lighter product stream, disrupted and limited sales for several of Dow's products. With the impacted plant only operational for periods of 3 to 9 days followed by plant shutdowns of 2 to 3 days for cleanup, each incident cost the business critical pounds for one of its primary products. Unfortunately, plugging was not a new occurrence for the plant, as the “heavies” unit had experienced severe plugging episodes in the past. Several previous efforts in the plant had attempted to resolve the plugging problem over the years; however, those efforts were unsuccessful.

Market demands and the earlier lack of success led the business in the fall of '05 to form a multi-discipline team of chemists and engineers to understand the fundamentals of plugging. The objective for the team was to use this fundamental understanding to devise chemical, engineering, and operational strategies to mitigate the effect of heavies so the plant could operate without plugging for a minimum of 5 months. This paper will discuss how that team worked together using the weapons of fundamental chemistry, engineering, the scientific method, and Six Sigma to fight the Tar Wars. The team won the decades' old battle in less than three months by addressing the underlying cause of plugging.