once through thermosyphon reboiler

[Pkhokhar]

In once through thermosyphon reboiler,when reboiler outlet temperature is higher than column bottom temperature then what types of problem can arise and how can we deal with it?

 

[georgeverghese]

Typical problem is with hydraulic slugging. Thermosyphon reboilers have a limited hydraulic turndown, so one way of keeping out of slug flow regime is to over reflux at the ovhds condensor, if you dont mind the increase in utility demand at the condensor.

 

[Pkhokhar]

What is Hydraulic slugging ? I searched it on Google but I couldn't get the satisfactory answer ,so can u explain me what actually it is?

 

[georgeverghese]

Hydraulic slugging occurs when the 2phase flow is in the slug flow regime - this results in erratic flow and is characterised by large plugs of liquid coming through erractically - check Google for slug flow regime or read up on 2phase flow regimes in your Uni hydraulics text book. This flow regime causes level and / or pressure / other control scheme instabilities.