Extractor Shell Reinforcement (Olomouc, Czech Republic)
The existing steel structure of an extractor is a cylindrical shell with a radius of 3.25 m and a height of 6.82 m, originally made of a sheet with thickness of min 6 mm, which is reinforced by circumferential rings. Numerous openings of various shapes are made in the shell: rectangular reinforced with flanges and circular for connecting pipes, sight glass or lighting. Two conical parts with bell-shaped central elements carrying rotors are installed in the middle and at the bottom of the main cylinder.
The extractor shell was locally affected by corrosion up to 2 mm in thickness. Deformations observed on the extractor shell were related to this. It was difficult to determine the exact geometry of the structure and the geometry of the deformations as the extractor is located inside a building and surrounded by several operating platforms. It was necessary to perform the actual state detection during the operation, at short intervals, with a risk of a possible hexane explosion. Therefore, 3D scanning was used.
We used SCIA Engineer’s 2D shell elements to model the shape of the structure corresponding to the scanned one. A linear analysis was performed to determine the distribution of stresses and a geometrically non-linear analysis was applied to verify the deformations of the structure. The critical load factor was determined as a part of the stability check of the shell.
"This project concerned a very complex steel equipment in a terrible state. With thorough analysis they were able to save the construction with local strengthening."
Quote of the Jury
This project is the winner of the SCIA User Contest 2020 – Category 3, Industrial Buildings and Plants.