An evaporation-crystallization process

Introduction to Chemical Engineering Thermodynamics
8th Edition
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Chapter1: Introduction
Section: Chapter Questions
Problem 1.1P
icon
Related questions
Question
4.45. An evaporation-crystallization process of the type described in Example 4.5-2 is used to obtain solid
potassium sulfate from an aqueous solution of this salt. The fresh feed to the process contains
19.6 wt% K₂SO4. The wet filter cake consists of solid K₂SO4 crystals and a 40.0 wt% K₂SO4
solution, in a ratio 10 kg crystals/kg solution. The filtrate, also a 40.0% solution, is recycled to join
the fresh feed. Of the water fed to the evaporator, 45.0% is evaporated. The evaporator has a
maximum capacity of 175 kg water evaporated/s.
(a) Assume the process is operating at maximum capacity. Draw and label a flowchart and do the
degree-of-freedom analysis for the overall system, the recycle-fresh feed mixing point, the
evaporator, and the crystallizer. Then write in an efficient order (minimizing simultaneous
equations) the equations you would solve to determine all unknown stream variables. In each
equation, circle the variable for which you would solve, but don't do the calculations.
(b) Calculate the maximum production rate of solid K₂SO4, the rate at which fresh feed must be
supplied to achieve this production rate, and the ratio kg recycle/kg fresh feed.
(c) Calculate the composition and feed rate of the stream entering the crystallizer if the process is
scaled to 75% of its maximum capacity.
(d) The wet filter cake is subjected to another operation after leaving the filter. Suggest what it might
be. Also, list what you think the principal operating costs for this process might be.
(e) Use an equation-solving computer program to solve the equations derived in Part (a). Verify that
you get the same solutions determined in Part (b).
Transcribed Image Text:4.45. An evaporation-crystallization process of the type described in Example 4.5-2 is used to obtain solid potassium sulfate from an aqueous solution of this salt. The fresh feed to the process contains 19.6 wt% K₂SO4. The wet filter cake consists of solid K₂SO4 crystals and a 40.0 wt% K₂SO4 solution, in a ratio 10 kg crystals/kg solution. The filtrate, also a 40.0% solution, is recycled to join the fresh feed. Of the water fed to the evaporator, 45.0% is evaporated. The evaporator has a maximum capacity of 175 kg water evaporated/s. (a) Assume the process is operating at maximum capacity. Draw and label a flowchart and do the degree-of-freedom analysis for the overall system, the recycle-fresh feed mixing point, the evaporator, and the crystallizer. Then write in an efficient order (minimizing simultaneous equations) the equations you would solve to determine all unknown stream variables. In each equation, circle the variable for which you would solve, but don't do the calculations. (b) Calculate the maximum production rate of solid K₂SO4, the rate at which fresh feed must be supplied to achieve this production rate, and the ratio kg recycle/kg fresh feed. (c) Calculate the composition and feed rate of the stream entering the crystallizer if the process is scaled to 75% of its maximum capacity. (d) The wet filter cake is subjected to another operation after leaving the filter. Suggest what it might be. Also, list what you think the principal operating costs for this process might be. (e) Use an equation-solving computer program to solve the equations derived in Part (a). Verify that you get the same solutions determined in Part (b).
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 5 steps with 5 images

Blurred answer
Recommended textbooks for you
Introduction to Chemical Engineering Thermodynami…
Introduction to Chemical Engineering Thermodynami…
Chemical Engineering
ISBN:
9781259696527
Author:
J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:
McGraw-Hill Education
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemical Engineering
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
Elements of Chemical Reaction Engineering (5th Ed…
Elements of Chemical Reaction Engineering (5th Ed…
Chemical Engineering
ISBN:
9780133887518
Author:
H. Scott Fogler
Publisher:
Prentice Hall
Process Dynamics and Control, 4e
Process Dynamics and Control, 4e
Chemical Engineering
ISBN:
9781119285915
Author:
Seborg
Publisher:
WILEY
Industrial Plastics: Theory and Applications
Industrial Plastics: Theory and Applications
Chemical Engineering
ISBN:
9781285061238
Author:
Lokensgard, Erik
Publisher:
Delmar Cengage Learning
Unit Operations of Chemical Engineering
Unit Operations of Chemical Engineering
Chemical Engineering
ISBN:
9780072848236
Author:
Warren McCabe, Julian C. Smith, Peter Harriott
Publisher:
McGraw-Hill Companies, The