Distance between gas-phase pipes and towers
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Regarding the layout of the gas pipes in the tower, a certain company stipulates that each pipe should be routed as closely as possible along the tower body, with a clear distance of 300–500 MM from the tower wall; 300 MM is considered the optimal value, as it facilitates proper support and results in a more aesthetically pleasing appearance, as shown in the diagram. Has thermal insulation been taken into account for the clear space here? In a certain project, the insulation thickness for both the tower and the pipes is 100 mm. Additionally, for these 1000mm pipe supports that are fixed to the tower, what type of support should be chosen and what are the considerations?
Bro, I ran into this issue exactly when I was working on chemical engineering projects before, so I can share some experience! Regarding the first point about the clear space, in the industry it is common to include the thickness of the insulation layer in the calculations. Since your current insulation layer is already 100 mm thick, an additional 100 mm must be added to the spacing between the bare pipes and the tower wall in order to ensure that the total thickness after insulation application reaches 300–500 mm. It is best to confirm the exact design margin with the project’s process engineers. The second point concerns the large-diameter pipe supports that are fixed to the tower. Pipes with a diameter of 1000 mm are considered large-diameter pipes, so hoop or saddle-type supports should be preferred. There are several key points to keep in mind: first, any openings to be made in the tower structure for fixing these pipes must have their structural reinforcement assessed by specialized engineers in advance; openings cannot be made in the tower wall casually ； Secondly, the thermal displacement of the pipes must be taken into account; the tower cannot be treated as a fixed support, and sliding/guiding supports are needed to cushion the stresses caused by thermal expansion and contraction ； Third, the contact areas must be insulated and protected from corrosion to prevent galvanic corrosion between the tower and the supports. One final reminder: these are all practical experiences gained on site; ultimately, it is necessary to follow the project’s design specifications and local installation standards. It’s best to verify the details with the project’s technical supervisor as well.
The two practical details about on-site operations that my brother added are really useful; they helped me clarify many things I hadn’t noticed before! Two more minor details: First, when calculating the net clearance, in addition to accounting for the insulation layer, it is also necessary to leave room for the thermal expansion of the pipes, especially for high-temperature gas pipes, as the actual thermal expansion displacement may be greater than the theoretical value. It is best to measure the dimensions of the pipes after insulation has been applied on-site before marking out the positions ； Secondly, in addition to avoiding welds and openings, the support structures that are anchored to the tower should be placed as close as possible to the circumferential reinforcement rings of the tower, as this helps to distribute loads more effectively. Additionally, if the pipes experience frequent temperature changes, the sliding surfaces of the sliding supports must be insulated and protected from sticking, otherwise problems may arise over time due to prolonged use. For the design of loads applied to such towers, it is recommended to carry out calculations based on the specific parameters of the project; it’s best to have professional chemical engineering structure designers review it – safety first