Plate and Frame HEX sizing

[KC12]

Hello Gentlemen,

I am working on replacing some existing plate and frame HEX with units that can handle more process flow, about 30 percent more. With that, more steam mass flow will be required to give the desired heating. The steam comes from multiple effect evaps.

What would be the best way to verify our evaporators can supply the new higher mass flows? A mass balance around the evaporators would be the first step, but data for this is hard to obtain as the process is so variable. I do have current gauge pressures at the steam inlets for our existing hex's.

 

[rmw]

Wow, you have left out so much. It is hard to start to give an answer. First, can you measure the condensate from any of your evaps? Are the Hx's in question that you want to update the only users of bleed from the evaps? You have got to be able to measure something and start from there. Thermodynamics is all about balance.

Your evaporators will probably be able to provide the bleed steam needed for these Hx's, but possibly at a price to the downstream effects.

Are the Hx's you want to upsize by any chance in the flow of the feed to the multiple evap station? If so and you are increasing the feed by 30%, then in theory, you should generate more vapor from each effect some of which can be used for bleed.

There is a lot of information needed here in order to be able to help you with an answer.

Whether or not your application is sugar, if you know the brix of your feed and concentrate, you can use the evaporator sizing hardware at

http://www.sugartech.co.za

. I used it recently to simulate a multi effect sea water evaporator.

rmw

 

[KC12]

Acquiring data for a proper balance is difficult in this situation. The Hx's are in the flow of feed to the multiple evap station and in theory I do think that we will be able to generate enough vapor from each effect.

Perhaps I will check out the application and toy around with it a bit, thank you for the reference!!