BARTLESVILLE, OKLA. — Donald Norwood's invention in 1957 of the loop reactor to produce polyethylene slashed production costs by 70 to 80 percent, and the material spread through nearly every conceivable type of package.
Milk jugs. Detergent bottles. Trash bags. Pipe. A flood of consumer products that continues today.
In 1951, Phillips Petroleum Co. scientists discovered the first transition metal catalyst capable of polymerizing olefins — polyethylene and polypropylene — at low pressure. By the time Norwood came to the Bartlesville-based company in 1957, excitement was in the air.
“People working on the development had a great attitude. They were gung-ho, because it was a new event for them,” he said. “For a little town, they were paying good wages. We had great management support here in Bartlesville.”
The U.S. economy was booming after World War II. At Phillips, scientists regularly talked with executives, pilot-plant technicians and marketing people. “They were high-spirited in those days. The lab people were interested in what was going on,” Norwood said.
Now Norwood, 88, is going into the Plastics Hall of Fame. He spent his entire career at Phillips, now Chevron Phillips Chemical Co.
Simple invention changes process
The loop reactor was “new and daringly simple,” wrote Max McDaniel, catalysis scientist at Chevron Phillips. Norwood was nominated for the Plastics Hall of Fame by McDaniel and Don Peters, retired principal engineer at Phillips, and himself a hall of famer. Both men worked with Norwood in Bartlesville.
Norwood, a Missouri native, was an infantryman in World War II. He was in the invasion of the Philippines and the occupation of Japan. After the war, he earned a chemical engineering degree from the University of Missouri-Rolla.
For four years, he worked on the separation of uranium isotopes in Oak Ridge, Tenn. He joined Phillips in 1956. They put him on a team assigned to PE development.
“It was well organized, and they had what they called group leaders,” he said.
Phillips was using the solution-form process in conventional, pot-type vessels. Norwood worked at a solution-form Marlex pilot plant for his first few months. Pressures had been greatly reduced, but the new technology had some weaknesses. The solution process still required that the polymer be dissolved in a heavy hydrocarbon liquid, and removing the solvent afterwards was costly, by centrifuge and filtration. And removing heat caused by the ethylene conversion required longer residence time in the reactor. It all added up to low production rates and higher costs.
And the pot vessels had quiescent zones — areas of inactive flow and turbulence, where polymers could build up. In extreme cases, they had to shut the reactor down and burn it out.
Norwood came up with the idea of a reactor in an unusual shape of a vertical loop.