2 replies to this topic

[renjith553]

I would like to calculate the ventilation requirement for LPG storage room... As butane is having high vapour pressure , I know that it is going to flash off to vapour..How can I calculate the vapour that is getting created ?

.My requirement is given below

 

 

A room measures 2m (H) x 2.5m (L) x 2.5m (W).  During a normal filling process for aerosols, butane liquid is released at the rate of 5 mL (milli-litres) per second.

 

How many air changes per hour are required to keep below 25 % of LEL?  LEL of butane is 1.8%..?

[TS1979]

Here is my thought:

 

You already know that the released liquid butane will flash off and the butane release rate, the problem will become simple. You know the rate of butane vapor created. For a steady state, you can quickly calculate the air required to lower the butane concentration below 25% LEL by using

V(butane volume flow rate or mole flow rate)/V (Air flow rate or mole flow rate) < 1.8%

 

It is recognized that the vapor is not uniformly distributed within the room, you possibly can add a safety factor 2~5 to calculate the air required.

[chemks2012]

renjith553

 

Agree what TS1979 said above. However, take little bit care as the volume rate you quoted is liquid while you need to convert it into gas volumetric rate.

 

See attached rough calcs which I did based on assumptions.

 

Hope it helps?

 

KS

Attached Files

•  Butane.xlsx   14.32KB   20 downloads

Edited by chemks2012, 17 March 2014 - 04:14 AM.