Can safety valves be shared?
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In our facility, one nitrogen storage tank and one compressed air storage tank are of the same model and manufactured by the same manufacturer. The two tanks are connected by pipes to ensure unobstructed flow of fluid. Nitrogen is stored in one tank while compressed air is stored in the other; these two gases are not stored in both tanks at the same time. Is it sufficient to install a safety valve on either of these two tanks?
Nitrogen and compressed air cannot be mixed in certain situations. The two tanks should have separate valves when being filled separately, right? Safety valves should be installed separately
Since both storage tanks are for non-corrosive gases, one safety valve can be used, provided that its discharge capacity is sufficient to meet the combined discharge requirements of the two tanks.
The original poster didn’t explain it very clearly; I think in some cases the two tanks store the same gas, and at such times the two tanks are connected in series to each other； Sometimes each of the two tanks stores a different gas, and in such cases valves or other means are used to isolate the two tanks from one another; I’m not sure if that’s what the original poster meant. If so, the poster should install safety valves on each of the two tanks that are capable of meeting the discharge capacity of that tank.
Your storage tanks can hold two types of gases – aren’t you concerned about insufficient purity? ? Ours are all independent, and the safety valves are also installed separately. Normally, each one should have its own safety valve. If your two tanks contain compressed air in one and nitrogen in the other, using just one safety valve wouldn’t be appropriate from a process perspective. . . . It will cause instability in the process. . .
According to the poster’s description, as long as the leakage rates of the two gases meet the requirements, and since these two gases are not stored at the same time, it is possible to install a safety valve in either of the two storage tanks.
I personally think it won’t work! Both are pressure vessels, so they should each be used separately, right? Moreover, the safety valve should be installed on the tank; therefore, a common pipeline cannot serve as a basis for installing the safety valve
Reply 2# haoqm11: Only one type of gas is stored when in use.
The two tanks are used in series, so they should be able to share one safety valve.
At any given time, only one type of gas is present in each tank; this seems to happen not very often. Isn’t there a risk that the nitrogen could get contaminated? In that case, repeated evacuation and cleaning are necessary. In this case, it is also necessary to consider whether the starting pressures of the two gases and the discharge flow rates need to be the same. If all three of these conditions are met, it should be possible to use just one safety valve.
Is the pressure the same? Since the back pressure isn’t necessarily identical, how can it be shared?