Pulp & Paper

Industrial Access was contracted to perform repair and replacement services to the liner of a reinforced concrete chimney in a paper plant. The existing borosilicate glass block liner system was starting to separate and crumble, so a section needed to be removed and reinstalled to ensure the chimney could continue operating safely and efficiently.

A pulp and paper plant in the southeastern United States was in need of liner repair and replacement services. This 350’ reinforced concrete chimney had a borosilicate glass block lining system bonded across its interior. Past inspection concluded that the top six courses of liner blocks were in the poorest condition and had to be replaced first. Upper sections of chimneys are often most vulnerable to their corrosive gases and harsh environmental conditions, which is why regular inspections and maintenance are key to structure longevity.

IA’s expert engineers designed and built a custom knee-brace exterior scaffold system that was suspended around the circumference of the top of the chimney. In addition, IA built a suspended platform inside the chimney using temporary beams and providing access to the interior work surface safely and efficiently. Making both of these two access systems available simultaneously enabled the crew to multi-task and save time.

Firstly, IA removed the stainless steel cap because the cap and the top of the chimney’s concrete shell were in poor condition and to be replaced. Then, IA crew started from the top of the chimney and worked downward to remove approx. 300 sq. ft of existing borosilicate glass block lining with hand tools. Next, they needed to prepare the interior surface of the liner for the application of a new lightweight borosilicate glass block lining system. The work area surface of the concrete shell was thoroughly washed and cleaned to eliminate any buildup and debris, and all of the existing holes and cracks were filled with mortar.

Once the surface was repaired, primed, and dry, the crew applied the required adhesive membrane and continued to lay down the new liner blocks layer by layer up to the top of the stack. This lining material is an excellent option for this type of structure because it’s impermeable to acid gas and acid condensates, resistant to humidity and high temperatures, and easy to install with minimal maintenance required. In the meantime, the top of the concrete shell was repaired and restored, and a newly designed stainless steel cap was installed.

The installation of new borosilicate glass blocks and stainless steel cap was completed successfully and on time. Since the client had a limited outage window, IA was available to mobilize and rig prior to the shutdown and to work in double shifts to ensure the repairs would be complete before the chimney goes back on-line. Per client’s request, IA finished up this mobilization with a visual inspection of the rest of the chimney’s interior to identify existing defects and plan for future continuation of liner block replacement for the entirety of the stack.