5 replies to this topic

[rche]

Hi! I'm computing for condenser duty as part of my study. However, I'm not quite sure if what I did is correct. The two condensers in the drawing are used to partially condense a vapor using tempered water. The water also evaporates as steam as it condenses the vapor and is used for heating in other process. Could someone please check if my heat balance is correct?

 

I did the heat balance around the two condensers since I do not know how much is being condensed on each condenser. I also do not know the temperature of the exiting vapor after the first condenser. Though I think that most of the condensing duty is being done by the first condenser.

 

 Condenser Heat Balance.xls   45.5KB   701 downloads

 

 

 

 

[shan]

Your assumption of 100% vaporization and no steam super heating is too ideal.

[Pilesar]

Is this a student project or real equipment? I have a difficult time seeing how this would work as depicted in the sketch. You have a flooded inside-the-tube boiler and are adjusting boiling pressure to change the duty? I think control will be a bear. Do you have a basis for controlling the boilers at different pressures? If you have two boilers sending steam to the same header, why not control them with a single pressure control valve? What advantage do two boilers give you that one larger boiler would not? Is there a reason you do not use water circulation and a steam drum? You do not show a liquid outlet for your water, but I think you will need something to remove concentrated impurities.

[rche]

This is a real equipment. Sorry, I had left some features of the equipment. I uploaded a new sketch which is based on PID. The tempered water I mentioned above is actually, as I've checked, steam condensate coming from the feed water tank for steam boiler. This is the one used as cooling medium for the heat exchangers. Both heat exchangers have same total area. They are controlling the amount of distillate produced by adjusting the temperature of evaporated steam. 50% and 60% level are fixed. I think, they do this for fine tuning. I'm still studying the whole process and equipment that is why I made this heat balance which might help my understanding.  Condenser Heat Balance.xls   51KB   509 downloads

[rche]

Your assumption of 100% vaporization and no steam super heating is too ideal.

 

I actually find it hard to represent this vaporization on the balance. How should I go on with it?

[rche]

The steam recovered from these heat exchangers is used to heat an equipment of another process.For the first, it's around 126deg C and 0.13MPa based on data. For the second, it's 104deg C and 0.03Mpa.

Edited by rche, 14 April 2013 - 07:59 PM.