The abstractly industrial world of an ExxonMobil chemical plant seldom gets compared with a playground.

“It’s like a huge see-saw,” said ExxonMobil Chemical Plant Manager Paul Stratford, as an enormous crane held a 225-ton steel tower — shaped like a tube — outfitted with piping, platforms and other gadgets some six stories in the air.

ExxonMobil lowered the tower, which is a necessary piece of equipment for the many industrial processes performed at the olefins chemical plant, into place Wednesday morning.

The job is one of the final acts of a nearly four-year maintenance and updating project the chemical plant is undertaking. Completion is expected at the end of the year.

Holding up the tower was a crane designed and built by Deep South Crane and Rigging in Baton Rouge. It is capable of lowering objects as heavy as 2,500 tons into place. And in this case the tower had to be moved 430 feet away, prompting the need for 2.5 million pounds of large steel counterweights — each one about half the size of a car — to offset the leverage created when moving the heavy piece of equipment more than a football field away. Hence, the see-saw reference.

“It’s basically a big math problem,” added Bruce Lilly, an ExxonMobil engineer working on the project.

The $150 million project — in industrial-speak called a “turnaround” — is in many ways part of the ongoing maintenance and updating industrial plants must undergo, both for safety and improved efficiency, said Patrick Fontenot, another ExxonMobil engineer who assembled the project team that included about 1,600 workers.

“We have lots of towers that do different things,” Fontenot explained. “This tower was getting older. It was undersized for what we were needing from it. It was causing reliability and energy-efficiency issues for us, because of its age and its size. So by replacing this tower we’re actually able to be more energy efficient and set ourselves up to be more productive moving forward.

“So strategically, it’s a big step for us to remain competitive over time,” he added.

The new tower, which is about 20 feet shorter than its 30-year-old predecessor, was manufactured in Corpus Christi, Texas, brought over on a barge and then trucked to the site, said ExxonMobil officials.

The crane was also brought to the site in parts and required nearly a month to assemble this summer.