Shell & Tube HE Blanketing 2

[JohnRobinsonOz]

I have a series (~96 in an array) of shell and tube heat exchangers that are heating a slurry (tube side) with the heating medium (shell side) being steam from an alumina digestion process. The steam has about 3% vol of non-condensable gas that if left to its own devices will soon "blanket" the exchangers and ruin the thermal efficiency. In order to stop this happening the operators "bleed" the shell to atmosphere causing a continual vent stream from the top of the shell. For a number of reasons this practice, which has been in place for the last 20 years, is seen as environmentally unacceptable. The plant is proposing to gang the vents together and burn the vent gas. In my opinion it's an inelegant solution as a lot of steam is "burnt". Has anyone seen a more elegant solution of separating non-condensibles from shells of heat exchagers? I look forward to any ideas.

 

[TD2K]

You can install a non-condensible vent valve. This are essentially a termostatic steam trap in fuction however you will still vent some steam along with the non-condensibles, that's unavoidable in this service unless you want to install some sort of condenser for the steam.

 

[MJCronin]

JR,

I agree..... the vent valve is the most common solution used for a steam heated S&T exchanger is the automated vent valve.

Spirax Sarco and other steam trap vendors would have these.

Good luck

let us know about your final soulution

MJC