Nitrogen sealing requirements for storage tanks

First, it is necessary to understand the purpose of nitrogen sealing: is it for ensuring the safety of ammonia, or for preventing oxidation and air pollution?； As long as it is safe and does not affect the product, that’s fine; there probably isn’t any specific standard for this. Let me know if I find one!

Your basis is the use of nitrogen with a concentration of four nines as the sealing gas. It is necessary to determine whether this sealing gas reacts chemically with the feed gas; if there is no reaction, then it is acceptable, but if a reaction does occur, it is not feasible. It should be specifically noted here whether gases other than the four nines have undergone chemical reactions with the feed gas, thereby altering the chemical composition of the feed gas.

No reaction will occur; it’s just to prevent environmental pollution

No reaction; liquid pressure is provided to prevent external gases from entering. Using one is fine; the issue is having a gas balance line and considering where the excess pressure will be discharged.

Currently, the main concern is the purity of nitrogen; it is being considered whether it is possible to use nitrogen with a lower purity. Nitrogen with a purity of four nines results in less quantity but higher energy consumption.

I didn’t understand what the original poster meant. 1. What is the purpose of nitrogen sealing? . Is it to prevent the medium from oxidizing? For the environmental protection of storage tanks? Tank safety? 2. How many storage tanks are you planning to connect in series using a single nitrogen pipeline? 3. The purity issue of the nitrogen used for nitrogen sealing? 4. What relevant specifications should be referred to and followed for nitrogen sealing?

7.4.1 The installation of nitrogen sealing facilities is necessary in the following situations: 1. Storing materials that are prone to oxidation, polymerization, or instability； 2 Spaces within the storage tank where explosive flammable gases can form ； 3 Storing oils with high sulfur content can easily lead to spontaneous combustion of FeS. 7.4.2 For Class A and B liquid storage tanks sealed with nitrogen, emergency pressure relief devices such as pressure relief manholes and breathing manholes should also be installed to ensure the safety of the tanks. 7.4.3 The sealing of accessories such as vent holes on nitrogen-sealed storage tanks should be designed to be removable, so that normal tank operation can be resumed promptly once the nitrogen sealing is no longer in use. 7.4.4 Gas connection lines should be provided between nitrogen-sealed storage tanks. A shut-off valve and pressure monitoring instruments should be installed on the gas connection line. 7.4.5 The control valves, pressure gauges, and pressure transmitters for the nitrogen sealing system should be installed at the platform on top of the tank. 7.4.6 Use of nitrogen seals 1 Under normal circumstances, sampling and measurement on the tank roof should not be carried out on tanks equipped with nitrogen seals. When it is necessary to work inside the tank, a portable detector equipped with functions for detecting oxygen, flammable gases, and hydrogen sulfide must be worn; when opening the tank is involved, a self-contained breathing apparatus should be used. 2 The operation of the nitrogen-sealed tank should be checked regularly. The roof vent valves should be inspected once every quarter, while the self-standing pressure control valves or control valves need to be inspected monthly; in winter, inspections should be carried out weekly. In cases of special weather conditions such as rain or snow, the frequency of inspections should be increased, and inspection records must be kept. Before filling the nitrogen-sealed tank with oil for the first time, the oxygen content inside the tank must be checked to ensure it is within acceptable levels. 5 When nitrogen supply is interrupted, stop the oil transfer operation from the tank.