Ideal Gas Calculation

Question

Ideal Gas Calculation

doomster (Chemical)

(OP)

21 Jul 20 13:47

An oxygen plant is supplying 1200 Nm³/h of nitrogen at 7 bars for miscellaneous gas as by-product. For the end users, they require nitrogen at 4 bars.
Now the consumption of nitrogen is already at 1100 Nm³/h but at 4 bars. If I convert the end user consumption at 7 bars, I will get 733.33 Nm³/h of nitrogen, assuming no temperature change. If this will be the case, then I have approximately 460+ Nm³/h of nitrogen left.

If I add a load of not more than 460 Nm³/h at 6 bars, will my original supply of nitrogen suffice?

Thanks!

katmar (Chemical) · Answer 1 · 2020-07-21 16:12:11

Why will the end users use less nitrogen if you supply it at 7 bar than if you supply it at 4 bar? If each user has a local pressure regulator to provide the pressure that they actually need then the quantity consumed should remain the same. If the end users do not have local regulators they may actually consume more nitrogen if it is at the higher pressure.

Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

doomster (Chemical) · Answer 2 · 2020-07-22 13:17:40

The nitrogen is stored in a pressure vessel at 8 bars, and distributes nitrogen to end users at 7 bars max. There many end users and different pressure rating requirement, but mostly of the end users require at 4 bars for process and safety issues. There is a pressure regulator before each end user to ensure that they will be only using 4 bars max.

Now if I add another load which is at 2 bars at around 500 Nm³/h will it suffice?

Latexman (Chemical) · Answer 3 · 2020-07-22 13:34:54

The "N" means "normal" temperature and pressure (NTP). Some folks use a similar "standard" temperature and pressure (STP), or "S". When a gas volumetric flow rate is specified with a temperature and pressure, the molar/mass flow rate is fixed too. Per the OP, you have 100 Nm³/h of excess capacity, no matter what pressure the end user uses.

Good Luck,
Latexman
Pats' Pub's Proprietor

processengineerx (Chemical) · Answer 4 · 2020-07-29 18:42:06

Dear Sir,

Kindly consider Nm3 as the moles supplied.

They will remain constant.

Only the actual volumetric flow rate will change.

For example,

1 pound mole = 379 Standard ft3

Standard ft3 means at 1 atm and 60 Deg. F

Similarly Normal ft3 means at 1 atm and 32 Deg. F.

Kind Regards,

Muhammad Waqas,
Process Engineer from Pakistan

Come Join Us!

Posting Guidelines

Ideal Gas Calculation