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The organic solvent gas can't be condensed problems

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silebi66

Chemical
Dec 15, 2012
71
Dear eng-tips professional members :

There is the 200kg/hr organic solvent Dichloromethane(DCM), 10kg/hr HCl (90%),40kg/hr Isopropyl chloride(IPC) feeding to the 5m3 Vessel to be produced resin (Operating at 3kg/cm2g and 25C), and 5 kg/hr Nitrogen gas purged at 3kg/cm2g in get rid of water in the vessel.

After the feeding streams is passed through the flash vessel , the vapor is generated around 4.2kg/hr DCM, 4.5kg/hr N2, and should vent out through the top vertical condenser (chilled by chilled water).

But,after calculating through aspen plus, there still 1.7kg./hr DCM, 5.3kg/hr HCl(46%), and 4.5kg/hr N2 couldn't be condensed and vent to waste gas burner.
May you guys please suggest any method to condensed the HCL out since the no condensable gas N2 may increase their partial pressure and make it difficult to be condensed ?
And, I calculated total pressure is 2*10^14 mmHg at 5C , 1atm (please see attached).

Is it reasonable? Please shine any light in this matter and I appreciated for your generous help.
 
 http://files.engineering.com/getfile.aspx?folder=813ff824-e171-4973-bc6d-5657c0f18bbe&file=eng_tip.png
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Silebi66
Your vapor pressure for dichloromethane is way off. I did not check the others but dichlormethane boils at 312.8K so the vapor pressure at 278K should be less than 760mmhg. You need to go back and set the temperatures to the boiling point and then check your spreadsheet to see if it accurately predicts the boiling points for each compound. Once you get that fixed you can solve the problem.

Regards
StoneCold
 
This does sound like a difficult problem, which may require a different approach. Instead of using dry N2 as the purge medium, can we not use some vaporised dry DCM to remove water in the vessel ?
 
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