Heat losses in a oil tank

[hianbotech]

We have this problem.

We are designing a tank that will receive 2200 BPD of foamy oil at 80°C. The inlet nozzle will be located at the top of the tank. Inside of the tank the normal liquid level is 5 feet. This equipment is not insulated; only personal protection insulation is needed, because it is not required to maintain the temperature. The Residence Time in the tank is 2 hr. The outlet stream is sent to a oil gathering network though the pumps. The maximum allowable temperature in the network is 50 °C.

We are doing a thermal study in order to know the temperature for the fluid leaving the tank 0 (Considering there is no accumulation of the foamy oil), and if an air fan cooler is needed.

Best Regards
Hianbo

 

[hianbotech]

I did not complete the post. The question is:

How can I calculate the temperature in the bottom of the tank?.

Best Regards, Hianbo

 

[KazakhJeff]

This is a difficult one to solve, with in my opinion too many unknowns to get an accurate answer, such as the outside temperature and wind effects, plus parameters from the tank design and operation, such as tank design (round, spherical, conical bottom, etc) any mixing in the tank (direction of nozzle, height of nozzle above the fluid, etc), if the tank is painted, height of bottom nozzle, position of the different nozzles with respect to each other, etc. You will also need to know the oil characteristics (density and specific heat) to make any reasonable calculations.

If getting this information is too complicated, and/or if you are at risk if you exceed the 50 Deg temperature, then I think that you should place a cooler on the entry line.

If you wanted to make a stab at the calculation my suggestion would to derive a heat transfer coefficient at the worst conditions, ie outside highest summer temperature, with the desired tank temperature (50 Deg C), and knowing the outside surface area derive the theoretical time to drop to drop 1 Deg C, remembering that you need a difference in temperatures for heat transfer to work. This will give you a feel for if you are in the right ball park or not.