Weld it. Stack it. Line it.
The construction of a very large project like the Sadara chemical complex requires that each and every part is completed reliably, on time, and on budget. This rule also applies to the welding, the erection, and the lining of the six steel chimneys.
The climate in Saudi Arabia is always warm but the region around Jubail, close to the Arabian Gulf, is particularly hot. This had to be taken into account for planning the work sequence on the six chimneys.
Each chimney was welded on ground level, with all ladders, lighting and appendages already installed before erection. Then, the sections were stacked using a very large crane.
Once the chimneys were in place, the PennguardTM lining system was installed in three steps.
A suspended, motor driven platform was installed to allow the installation crews to reach all internal surfaces of the chimneys. Through the center of the platform, a smaller, faster hoist was used to transport the installation team and their tools, as well as the PennguardTM lining materials.
The internal steel surface of each chimney was grit blasted to SA 2 1/2 cleanliness (ISO 8501-1:1988). At the end of each work day, the grit blasted area was cleaned and coated with PennguardTM Block Primer.
The grit blasting and primer application work took seven days per chimney, including a final water wash after all primer had sufficiently dried.
The PennguardTM lining was applied from bottom to top by teams of four installers. Due to the very hot climate in the area, this work had to be limited to the evening hours.
On this work schedule, the PennguardTM lining installation in each chimney, including Hadek’s final QA inspection, took 11 days to complete.
PennguardTM linings minimize maintenance and repair – both internally and externally
linings in the Sadara chimneys will protect the internal surfaces of these steel stacks from acid dewpoint corrosion caused by low temperature semi dry scrubber operation. In the long term, they will also help to prevent external corrosion to these chimneys.
This is because PennguardTM linings are strongly insulating, so the designers can avoid using any external insulation system.
Why is this a good thing?
The answer is that external insulation systems are fixed to the external surface of a steel chimney using anchors and supports, and that they are typically protected against ingress of rain water by a metallic plating system. Over time, the influence of rain, wind and thermal cycles can cause leaks to develop in the metallic plating system. This allows water and condensate to become trapped in the insulation system, creating a severe corrosion hazard that could potentially threaten the structural integrity of the steel chimney.
This photo shows an example of severe external corrosion to a steel chimney that had been externally insulated.
PennguardTM-lined steel chimneys avoid this risk, using only an external coating system to protect the structure against the elements. A modern, well applied coating can protect these chimneys over many years, possibly for the life of the chimney itself.
PennguardTM linings are strongly insulating, so no external insulation system is needed