Plant Receiver

[GBRD]

G'day All,

How do we calculate volume of a receiver in a plant? What if receiver needs to be pumped down? What's the relation (may be thumb rule) between "Plant Capacity" & "Refrigerant Quantity"?

[mrfreezeit]

I generally use cylinder formula 3.14(r^2)*L and multiply by the percentage of full.
More accurate:
V=D^3(a + 5.86 L/D)*% full.

V= Volume in gallons
D= Diameter in feet
L/D= Length of Cylinder section to diameter ratio

a = constant= 1.164 for ASME flanged and dished heads

1.909 for 2 to 1 Elliptical heads
3.92 for hemispherical heads

The first way is conservative and the second does not take into account the stubs off the vessel and the liquid they could hold.

You want to be able to move the liquid around the system during pumpouts without removing the refrigerant.
The receiver should be sized to handle seasonal fluctuation in load. It needs to big enough to hold the liquid needed during the summer during winter months. There are no requirements contrary to some popular belief requiring that a receiver hold the entire charge of the facility.

[lowcool]

i dont recommend a 2kg receiver for a 5 kg refrigerant charge on a multiple system.
rule of my thumb says capacity should equal charge,with a bit to spare on supermarket type systems.

[Jasonismyname]

On large scale NH3 systems, we want the receiver sized to hold the entire charge in case the plant needs to be de-inventoried for maintenance. Could be an iterative calculation because you have to "pick" a receiver size with a normal operating level, then use that volume to calculate the entire system charge. Then see if that system charge fits in the receiver volume you "picked".

[charlie n]

In a large NH3 system it's redundant to make the HP receiver big enough to hold the entire plant charge. There will be pump receivers, liquid separators and even large evaporator and condenser coils where charge can be stored for maintenance. A main High pressure receiver can often have a storage volume as low as 70% of the plant charge and still fulfill it's function of storing variations in operating charge.

[US Iceman]

G'day All,

How do we calculate volume of a receiver in a plant?

You have to calculate the volume of the entire plant and then determine the density (at the operating temperature) of the refrigerant phase (liquid or vapor) existing at any one location (pipe, vessel, etc.)

Once you get the total mass you have to convert this to volume at the storage temperature in the high pressure receiver.

Before doing all of this though, you should first ask why do you need to store all of the liquid in one vessel?

You have a lot of other vessels. Find out how to use those also.