2 replies to this topic

[anggara]

Hello everyone,

 

I am a student currently working on design project involving the separation of hydrochloric acid (HCl) from an aqueous HCl solution (33 wt%). The objective of the unit is to vaporize neraly all HCl into the gas phase, so that the bottom liquid stream contains as little residual HCl as possible. I would like to ask what type of evaporator would be most appropriate for this condition? And what key data should I consider when selecting and designing the evaporator (e.g., VLE data, partial vapor pressures, etc.)? 

Any guidance, practical experience, or recommended references would really help me understand.
Thank you in advance!

[breizh]

Hi,

The material of construction should be graphite.

Google graphite evaporator.

PolyBlock Graphite Heat Exchanger | HEPL

 

For thermodynamic model , Check for NRTL and/or eNRTL  ,e stands for electrolyte.

Thermodynamic modeling of HCl-H2O binary system with symmetric electrolyte NRTL model - ScienceDirect

HCL/water presents an azeotrope ,

Data available using your favorite search engine.

Process separation ( Pressure swing distillation and Extractive distillation).

 

EP1099666A1 - Method for separating hydrogen chloride and water from an aqueous hydrogen chloride solution - Google Patents

 

 

Recovery of Azeotropic mixture of Hydrochloric Acid and Water | DOCX

 

Breizh

[MrShorty]

Remember that evaporator/distillation types of operations trend towards azeotrope compositions. Spoiler alert: the HCl + H2O is well known to form an azeotrope. You will need to know the type and compositions of the azeotrope. Then you will need to either accept the limitations imposed by the azeotrope, or you will need to figure out how to "break" the azeotrope.