Pressure and Flow Calculations for Pressurized Tanks

What is the size of the tank, is the tank full when you start?

The pressure needed to force the acid out is equal to the weight of the acid. What is the acid? 7 or 8 lbs per gallon? How many gallons is in the tank?

Well, that won't really matter, but once you apply the compressed air, the limiting factor is the size of the drain pipe. Bigger pipe, quicker drain.

Hello Guest,

With your proposed use of compressed air to increase acid flow from a tank, please ensure first that the tank is able to withstand the proposed pressure, (with a good safety margin), without splitting or rupturing.

The last thing you need is to have acid sprayed over workers, machinery, electrical equipment, and the factory floor.

There is also the explaining you will have to do, apart from facing possible criminal charges ensuing.

Kind Regards....

Please listen to Sparkstation and be very careful. It is possible that by pressurising with air you are in fact hitting the pressure:volume limit and you are now looking at what should be classed as a pressure vessel not a tank. Your inspection authorities could then get very annoyed with you about this if you happen to rupture the tank and kill someone. "Tanks" are normally designed for atmospheric pressure or very slightly above it and must be protected by PV safety valves.

Again, I would be very careful about doing that, make sure, triply sure, that you are not over-pressurizing the tank. To calculate, wouldn't you make use of Mr. Bernoulli and his wonderful equation? It is an incompressible fluid so it should be fairly straight-forward. As the tank empties, your static head will decrease but depending on the size of the tank this may or may not be a large factor.

I'd spend some time looking at the downstream piping as well, doubling the mass flowrate will double the velocity as well, will it not? Is your piping set up to handle such an increase or will you need to enlarge the downstream piping as well?

A lot of data are required to propose the solution:

a. Data related to the fluid itself.

b. Data related to the pressure vessel containing the fluid.

c. Data related to lengths and elevations.

Hi Guest

The flow of acid out of your tank with the initial pressure is determined by the pressure. Flow = K (constant) x pressure. The constant is determined by the weight and viscosity of the acid and the size of the pipe or valve that it is being propelled through. K x 2 x pressure = 2 x flow. Double the air pressure to double flow rate of the acid (all else being equal). Do I hear the sound of one hand clapping? Tom

Einstein said everything should be made as simple as possible but no simpler.