When PCL was contracted by a petrochemical company to construct a new furnace for its ethylene plant in Baytown, Texas, the company was challenged to think outside the box. Or, rather, outside the plant.
Typically, a project of this size and scope would be a stick build. Piece by piece, the furnace would be built in place right inside the plant, with cranes and dozens of craftspeople working at increasing heights while carefully navigating around existing structures and respecting the needs of an operating facility.
In this case, the client asked PCL to develop a modularization and heavy-lift strategy that would allow for a significant portion of the furnace to be constructed as modules and pre-assembled offsite, before being transported to the operating plant for the remaining construction. This modular construction approach would bring myriad benefits, including reducing costs and timelines. By significantly reducing the work at heights and removing the need for fire retardant clothing in the scorching Gulf Coast summer heat, it would also create a safer environment for workers.
Although PCL had experience with both furnace construction and modularization, these skillsets had never intersected at quite so large and complicated a scale. According to Danny Evans, project manager with PCL, the first major hurdle was convincing all parties that this novel approach was doable.
"In the beginning, there was some skepticism," Evans said. "But once we got past that tipping point where everybody got on board, it became a lot more about team building and working through solutions instead of saying that it can't be done. That was a big deal for us."
Thus began a nearly two-year planning process to modularize the furnace. Rick Hermann, manager of construction engineering with PCL, explains that extensive modeling was done to not only divide the furnace into workable modules, but also to anticipate any additional structural supports needed to ensure stability before and during the move.
"Had it been a stick build, we may have been able to copy-and-paste an approach based on similar projects from the past," Hermann said. "Here, we needed to take the time to get the modeling correct and hold numerous model reviews to visualize the execution plan. The additional planning up front ultimately helped us save about three months from the project's overall duration."
Ultimately, the furnace comprised four major pre-assemblies and 17 modules. Assembly began in September 2021 in a laydown area approximately one mile away from the plant. Layer by layer, the modules were stacked until the furnace reached a pre-transport size of approximately 128 feet tall, 139 feet long and 62 feet wide, about the size of a mid-rise apartment building. With a weight of 2,800 tons - the equivalent of 14 Boeing 747 airplanes - the challenge then became transporting the tall and narrow structure down the road.
The furnace was lifted onto three self-propelled modular transporters containing a total of 416 tires. At 8 a.m. on September 24, 2022, the furnace started its slow roll down the road. It took approximately three hours to travel the one mile stretch and a few hours more to carefully maneuver the furnace into place. The crew completed final alignment at 2:00 p.m. on the same day. With the furnace firmly in place, work is now underway to add the remaining structures and modules to its ultimate height of roughly 190 feet. Completion is slated for August 2023.
The fact that the build proceeded safely and efficiently is a credit to incredible coordination between several disciplines working in harmony, Hermann said. This project is much more than merely a unique feat of engineering. It's also a testament to what can happen when you have a diversity of expertise on hand and a willingness to try something new and bold, he added.
"We benefitted from having a client that was willing to invest on the front end of this project," Evans said. "They pulled the teams together to work through it collaboratively. We collectively worked through the unknowns and now we're all able to showcase this project as an example of what we're capable of doing."
For more information, visit pcl.com/houston or call (281) 249-8001.
