3 replies to this topic

[fortius123]

I have confusion regarding the Vapour flow direction  in falling film reboiler under.

 

The vapours generated by surface heating of liquid films flowing downwards along the tubes in majority of the cases travels in the co-current direction with the liquid (downwards).

 

Vapours being lighter should ideally rise up instead of going down. Can anyone explain in  this behaviour ??

 

[Raj Mehta]

The sump of the Falling film evaporators are connected to the Vapor Liquid Separator (VLS). The liquid actually comes in the sump as a saturated liquid (i.e no vapor is still yet formed) and is then flashed at a lower pressure inside VLS, where the liquid is re-fed to the evaporator along with the feed and the vapors are collected and sent to the next effect.

 

Thanks.  

[fortius123]

Thanks for your reply.

 

The datasheet for a typical falling film reboiler talks about vaporization % as the temperature increases along the length of tube. If the state of liquid is saturated then shouldn't the vaporization ratio be 0 all along the tubes ??

 

Thanks

[breizh]

Hi,

take a look at this brochure , it should help.

 

Breizh