The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
Separation Processes
Instructor: Prof. Xijun Hu (Room 4557,
Tel: 2358 7134, Email: kexhu)
www page: http:/ihome.ust.hk/~kexhu
TAs:
HE Kailin (kheaa@ust.hk) &
WANG Qingyue (qwangav@ust.hk)
Aims:
Understand the basic design principle of
various s
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
SEPARATION PROCESSES
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Example 1. Heat Transfer Area in Single Effect Evaporator
A continuous singleeffect evaporator concentrates 9072 kg/h of a 1.0 wt % salt solution entering at
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
SEPARATION PROCESSES
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Example 1. Phase Diagram & Equilibrium Curve
Determine the Txy relationship for ethanol and water using Antoine Equation
assuming that ethanolwater form an
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Due by 2:30pm, 12/10/2016 to room 7109 (lift 19)
CENG 3210
SEPARATION PROCESS
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Problem 1 A liquid mixture of benzenetoluene is to be distilled in a fractionating tower at
101.3 kPa pressure.
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Example D7. Distillation Using EnthalpyConcentration Method
A liquid mixture of benzenetoluene is to be distilled in a
fractionating tower at 101.3 kPa pressure. The feed of
100 kmol/h is liquid, containing 45 mol % benzene and
55 mol % toluene, and ente
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Table B.2: Constants for the Antoine Equation for Vapor Pressures of Pure
In P sat/kPa = A [B/(T/K + C)]
Latent heat of vaporization at the. normal boiling point (A H") and normal boiling point (Tl)
Parameters for Antoine Equation Temperange Range AH
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
SEPARATION PROCESSES
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Example 1. External balances for binary distillation
A steadystate, countercurrent, staged distillation column is to be used to separate ethanol from
water. T
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
Homework 3
SAMIN, Felicia
(SID: 20215443)
Problem 1
Given that,
F=100 kmol/h
PF =689.5 kPa
T F =366.5 K
Propane (3)
Ki
zi
nButane (4)
4.2
0.1
1.75
0.2
nPentane
(5)
0.74
0.3
nHexane (6)
0.34
0.4
*The K value is given by DePreiester Chart
Assum
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210 Separation Process
Homework 4
Felicia Samin (SID: 20215443)
Problem 1
Given that
F=100 kmol/h
R=4
T=327.6K
P=101.325 kPa
xF=0.45
xD=0.95
xB=0.10
F=B+ D and F x F =D x D + B x B , we can calculate
(100)(0.45)=D(0.95)+ ( 100D )(0.1)
4510=D ( 0.85
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
CENG 3210
SEPARATION PROCESSES
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
H OMEWORK #1
PROBLEM
P.No.1. A single effect evaporator is used to concentrate 9070 kg/hr of 20% caustic soda
solution to 50% solids. The gauge pressure of ste
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Due by 2:30pm, 5/10/2016 to room 7109 (lift 19)
CENG 3210
SEPARATION PROCESS
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Problem 1 A 100kmol/h feed containing of 10, 20, 30 and 40 mol% of propane (3), nbutane
(4), npentane (5), and
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Equilibrium stage operations
Principles of stage process
The individual contact
units in a cascade are
numbered serially, starting
from one end.
Terminology
yn+1 = mole fraction of
component A in the V
phase leaving stage n+1
Vn+1 = molal flow rate of
the
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Multicomponent Distillation
need more than one distillation tower, for n
components, n1 fractionators are required
Specification Limitations
The following are established at the beginning
1. Temperature, pressure, composition, and rate of
the feed.
2. Pr
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
(LiquidSolid) Leaching
Preparation of Solids for Leaching
Leaching is a liquidsolid operation. The two phases
are in intimate contact, the solute(s) can diffuse from
the solid to the liquid phase, which causes a separation
of the components originally i
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Fractional Distillation using
EnthalpyConcentration Method
molal flow rates need not to be constant
using enthalpy as well as material balances
When the operating lines are plotted with the
equilibrium curve on the xy diagram, the McCabeThiele stepby
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Distillation
Distillation may be defined as the separation of the
components of a liquid mixture by a process involving
partial vaporization. The vapor evolved is usually
recovered by condensation.
Volatility
The volatility of any substance in a liquid so
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
LiquidLiquid Extraction (LLX)
Extraction is a liquidliquid operation. It is a process of
transferring a solute from one
liquid phase to another immiscible
or partially miscible liquid in
contact with the first. The two
phases are chemically quite
differ
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Int
troduc
ction to Separ
o
ration P
Processes
Wha are s
at
separat
tion pr
rocesse
es?
th
hose o
operatio
ons wh
hich tr
ransform a m
m
mixture of
e
substances into tw or m
wo more pro
oducts which differ from
each other i comp
h
in
position.
A ge
enera
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Due by 2:30pm, 289/2016 to room 7109 (lift 19)
CENG 3210
SEPARATION PROCESSES
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
H OMEWORK #2
PROBLEM
Problem 1. Phase Diagram & Equilibrium Curve
Use Raoults law to calculate the vapor and li
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
Due by 2:30pm, 12/10/2016 to room 7109 (lift 19)
CENG 3210
SEPARATION PROCESS
H ONG K ONG U NIVERSITY OF S CIENCE AND T ECHNOLOGY , F ALL 2016
Problem 1 A liquid mixture of benzenetoluene is to be distilled in a fractionating tower at
101.3 kPa pressure.
The Hong Kong University of Science and Technology
CENG 3210

Fall 2015
It its bubble point is 92.50C, the ethanol content of the vapor at equilibrium is 24% of
ethanol in the solution.
The bubble point temperature for 76 wt% alcohol is 780C and 95 wt% alcohol is 790C