Evaporative Crystallization with Recycle

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram CDF Player or other Wolfram Language products.

Requires a Wolfram Notebook System

Edit on desktop, mobile and cloud with any Wolfram Language product.

This Demonstration shows mass balances for an evaporative crystallization process. A 60% potassium chloride/40% water feed is mixed with a recycle stream and fed to an evaporator, which evaporates water and increases the KCl concentration in the exiting solution. This solution enters a crystallizer and filter. A filter cake of KCl crystals and a portion of the saturated KCl solution are removed from the crystallizer and filter. The rest of the KCl solution is recycled and mixed with the fresh feed. Use sliders to set the fraction of crystals in the product stream, and the temperatures of the evaporator and crystallizer/filter. The solubility of KCl increases linearly with temperature.

Contributed by: Rachael L. Baumann (October 2013)
Additional contributions by: Janet deGrazia, John L. Falconer and Nick Bongiardina
University of Colorado Boulder, Department of Chemical and Biological Engineering
Open content licensed under CC BY-NC-SA


Snapshots


Details

Overall material balances

= mass flow rate of fresh feed (kg/h)

= mass flow rate of water exiting evaporator (kg/h)

= mass flow rate of solid KCl crystals exiting the crystallizer and filter (kg/h)

= mass flow rate of slurry exiting the crystallizer and filter (kg/h)

= mass fraction of water in fresh feed

= mass fraction of KCl in saturated solution

= mass fraction of water in solution exiting crystallizer and filter

Material balance around crystallizer and filter

= mass flow rate of solution exiting evaporator (kg/h)

= mass flow rate of recycle (kg/h)

= mass fraction of KCl in stream exiting evaporator

= mass fraction of KCl in solution exiting crystallizer and filter

= mass fraction of KCl in recycle stream

Material balances around mixing point

= mass flow rate entering evaporator (kg/h)

= mass fraction of KCl in fresh feed

= mass fraction of KCl in stream entering evaporator

Material balance around evaporator

Dependence of solubility on temperature

= solubility of KCl in 100 kg

= evaporator operating temperature (°C)

= solubility of KCl in 100 kg

= crystallizer and filter operating temperature (°C)

Note that and , where is the stream.

View the screencast video at [1] for more practice with material balances on a crystallizer.

Reference

[1] Crystallizer Material Balance with Recycle [Video]. (Oct 29, 2013) www.youtube.com/watch?v=Dnfgc4_OFhI.



Feedback (field required)
Email (field required) Name
Occupation Organization
Note: Your message & contact information may be shared with the author of any specific Demonstration for which you give feedback.
Send