Calculation of tower wall thickness strength
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The design pressure is 0.1 MPa, the operating pressure is 0.038 MPa; the designed wall thickness is 16 mm, the inner diameter of the vessel is 6000 mm, and the net height of the tower is 30 meters. The wall material is Q235B, the medium handled is semi-water gas, and the corrosion allowance is 2 mm. The net weight of the equipment is 190,000 KG. Currently, the average thickness of the vessel’s wall plates after corrosion measurement lies in the range of 5–6 mm. It is necessary to determine whether the strength of this vessel still meets the required standards. Could you provide the relevant calculation formulas?
Based on the data you provided, we can estimate whether the strength of the container meets the required standards by considering the thickness of the container walls and the properties of the materials used. First, it is necessary to apply some basic formulas for pressure vessels to carry out the calculations. Below are some key calculation steps and formulas: 1. **Stress calculation**: The hoop stress in the container can be calculated using the following formula: $ \sigma = \frac{P \cdot r}{t} $ Where: - \( P \) is the operating pressure (0.038 MPa) - \( r \) is the inner radius of the container (3000 mm, since the outer diameter is 6000 mm) - \( t \) is the actual wall thickness (the thickness after accounting for corrosion should be used; an average value of 5.5 mm is assumed here) 2. **Allowable stress of the material**: The allowable stress for steel of Q235B grade at normal temperatures is approximately 160 MPa. For safety reasons, the actual allowable stress may need to be appropriately adjusted in accordance with design standards. 3. **Safety factor check**: The safety factor \( n \) should generally satisfy \( n > 3.5 \). The calculation method is: $ n = \frac{}{\sigma} $ where \( \) represents the allowable stress of the material, and \( \sigma \) is the actual stress calculated using the formula above. By following the above steps, you can calculate the current safety factor of the container to determine whether it still meets the usage requirements. If the calculated safety factor is less than 3.5, the strength of that container may not be sufficient for safe use. Finally, the impact of corrosion on the strength of the container also needs to be considered. Since the average wall thickness you provided has been reduced from the designed 16 mm to around 5.5 mm, this clearly indicates that corrosion has had a significant impact, and the strength is likely to be severely insufficient. It is recommended to conduct a detailed engineering assessment and consider taking necessary repair measures or replacing the container. .
This post was last edited by Aoki_EXZM on 2024-4-24 at 14:38. For the formulas, please refer to GB/T150.3-2011 and NB/T47041-2014; there are many pages. Do I have to do this by hand? ? ? The workload is a bit heavy; find a calculation software such as SW6, and there are also quite a few missing parameters
It is also necessary to consider whether the bending stress at the bottom of the tower when it is erected, under the condition of the greatest load, is less than the allowable stress of the material. Specifically, books such as chemical equipment design manuals provide detailed design and calculation procedures.
Find the documents related to this tower, or ask the manufacturer for the calculation sheet.
It’s still pretty good, isn’t it? Haha
It is recommended to perform the calculations in accordance with NB/T47041; not only circumferential stress but also axial stress needs to be taken into account