Fuel Gas KO Drum for heater

[Janator]

Hello all,
please I need advice.

I am designing "Fuel Gas KO Drum" for the Heater. It's only pre-eliminery calculation, but anyway I have few questions.

I know, It's two phase vertical separator. So for designing
terminal velocity I have to use the well-known formula:

V=k((Rl-Rv)/Rv)^0.5

k-therminal velocity constant [m/s]
Rl-density of liquid [kg/m3]
Rv-density of vapors [kg/m3]

But I don't know what K factor shal I use. Could you give me any recommendation?

About Fuel Gas I know Molecular Weight, LHV, Consumption, Pressure and Temperature.

And next thing is the liquid, which is usually separated in these Fuel Gas KO Drums. I should consider to separate water, which is part of the Fuel Gas, Am I right?

At the moment I have no information about composition of the Fuel Gas

Thank you very much for answers,
Have a nice day

 

[zdas04]

"For the Heater" doesn't tell us much. Is this heater a million BTU's/hr? A billion BTU's/hr?

I keep running into people who do this sort of detailed calculation and then don't put a level controller on the vessel. A liquid knockout without automated liquid removal is far worse than worthless. The more effective it is at removing liquid, the more harm it does. Contrary to "Engineering Judgement", field and plant operators have stuff to do. Blowing a liquid knock out doesn't often make the top of their list. If you don't automate it then you are assuring that periodically it will overflow and a blast of liquid will hit the heater and put the fire out. It gets really messy when the pilot comes off the same line and the slug puts it out also. Shortly after that the unburned gas finds an ignition source and relights itself, possibly with the added feature of blowing up a building or two.

David

 

[dcasto]

.4 feet/sec is a good value, but it depends on what you expect in the amount of free liquids to get a good residence time. you need that info on the fuel gas composition to aid your decisions.

In any case, not only a level control as zdas states, a separate high level shutdown and if criticle an alarm with sufficient time that an operator can manually dump the separator.

 

[Janator]

for zdas04: OK, so the duty is 2,4 MW -> 8196430 BTU/HR

thnx