Storage and Transportation Technology: [Weekly Topic] 10-11-23～28 – Inspection of storage tanks operating at atmospheric pressure

It’s not very safe; it’s best to carry out cleaning and ventilation after transferring methanol, before proceeding with any maintenance work.

Question 1: The storage tank contains methanol, and its explosion protection rating is Class A. Question 2: How to create a DN250 inspection hole on the top of the tank? Question 3: Oil and gas escape from the top of the tank during testing; how can proper safety measures be taken? In my opinion, the materials should be exported, the manholes of the steam tank opened for natural ventilation or forced ventilation, and then monitoring should be carried out.

Our storage tank may experience damage to its twin-midspan shell structure due to negative pressure; the tank is used to store methanol. Prepare to open the roof observation port for inspection using a camera; the diameter of the port is approximately DN250, and a slight positive nitrogen pressure should be maintained during the inspection. What other safety measures need to be taken, and is this method feasible? It is recommended to conduct an inspection after the tank is emptied. If this really needs to be done, it’s not clear what the structure of this tank is; it’s uncertain whether it is an internal floating roof tank, as 10,000 cubic meter tanks sometimes use mesh shell structures as well. Internal floating roof tanks result in less oil and gas evaporation. Once the inspection holes are opened, it is essential to ensure that the inspection equipment is explosion-proof and that the safety of the personnel involved is protected; under these conditions, the process should be feasible. It is advisable to use negative pressure during the operation, such as by reversing the flow of liquid in the tank, in order to prevent oil and gas from escaping. However, it’s not known what explosion-proof cameras look like, as they have never been used before.

A tank cleaning plan should be developed! Pour out the material – safety first, people first……

It is recommended to export the materials; after replacement, perform positive pressure calibration using nitrogen or water, ensure proper pressure control, and install overpressure relief devices.

1. It’s too dangerous; it’s not advisable. The container must be emptied before proceeding. 2. The positions of workers working on the tank top should not be too concentrated, and protective equipment must be worn properly. 3. Avoid metal dragging on the top of the tank. 4. During testing, nitrogen should not be continued to be introduced into the storage tank; it should be kept at atmospheric pressure.

The material must be exported to empty the tank, and nitrogen gas must not be used – it’s too dangerous! ! ! If there are problems with the storage tank, especially when the materials stored inside are dangerous, the tank should be emptied before any inspections can be carried out; it’s too risky to inspect it while the materials are still inside – accidents can definitely happen! ! !

Not feasible; it is necessary to pour out the contents, purge, replace, and analyze before it can be used

In the owner’s case, it is necessary to empty the tank first before conducting inspections. Additionally, to ensure the safe operation of the storage tank, regular inspections must be carried out

General deformation does not affect operation; check again after it is emptied and cleaned. It may need repair, and cleaning the tank will still be necessary at that time! If a crack has formed as a result of the deformation and gas is leaking, it is even more necessary to clean the tank promptly, as its functionality is already compromised. If there is an internal floating disk, the tank must be inspected immediately; otherwise, a damaged floating disk will interfere with the loading and unloading of products, leading to even greater product loss.