Problem HY.1 Questions
team_name
date
0. What are the temperature in °F and the heat flow in BTU/hr of a process stream containing a
tertiary mixture of benzene, hexane, and toluene? The stream is at 2 atm and has a vapor
fraction equal to zero.
The temperature is ________°F and the heat flow is ____________ BTU/hr.
1. Which HYSYS simulation algorithm in Appendix C (p. C-5 or C-7) would you use to solve the
above problem? What temperature does this algorithm calculate?
 ____, ____, ____ 
 ____  ____, ____, ____   ____ F
for Stream i = to feed
2. Which assumption(s) listed in Appendix C support the fact that a process stream has uniform
properties throughout its length?




(i.e., constant temperature)
(i.e., isobaric)
3. What steps in Mathematical Algorithm A would you use to calculate the mass fractions from
the mole fractions? Verify that HYSYS has done this calculation correctly?
 4
2.
_
Mj
_.
____


molwt  pure j 
for j  1, 2,
, nc
nc
 ____  ____
for Stream i
____ ____/ ____
for j  1, 2,
j 1
_
_.
____

M BZ  78.11; M HX  86.18; M TL  92.14;
, nc
from HYSYS
3
M i   _____  0. ____(____)  0. ____(____)  0.5217(____)
j 1
 ____
HYSYS reports ____
wi , BZ 
______
0.1739  ____

 0. ____
Mi
87.88
HYSYS reports 0.____
wi , HX 
______ 0.3043  ____

 0. _____
Mi
87.88
HYSYS reports 0.____
wi ,TL 
______
Mi

0.5217  ____
 0. _____
87.88
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HYSYS reports 0.____
Problem HY.1 Questions
team_name
date
4. What is the specific enthalpy of the stream in BTU/lbm based on the heat flow in BTU/h and the
molar flow rate in kgmol/h?
Eˆ i
Hˆ i 

ni  ___
BTU
h
_______ lbm
kgmol
kg
_____
 _____

h
kgmol
1 kg
_________
 _______
BTU
lbm
HYSYS reports ______ BTU/lb
5. What are the definitions of the dew-point temperature and bubble-point temperature?
Dew point
– sat’d vapor where first _____ of _____ forms when ______ the vapor.
Bubble point – sat’d liquid where first _____ of _____ forms when ______ the liquid.
6. How might you find the dew-point temperature of this stream? What is its value?
 ____, X i , Yi   vle V f  ____, ____, ____   ____ F
for Stream i = to feed
7. How does HYSYS calculate the bulk molar enthalpy for Vf =0.40 (see p. C-8)? Verify it.
H i  _____________________
Hˆ SV  hmixSV Ti , Pi , Yi 
Hˆ SL  hmixSL Ti , Pi , X i 
BTU
Hˆ SV  ________
;
lbmol
Hˆ
for Stream i = to feed
BTU
Hˆ SL  ________
;
lbmol
BTU 
BTU 


 ____  ________
  1.0  ____    ________

lbmol 
lbmol 


 ________
BTU
lbmol
HYSYS reports _____ BTU/lbmol
Each molar enthalpy value was obtained by copying it from HYSYS and pasting it here.
If you expand the property view of a process stream, HYSYS will display its bulk, saturated vapor,
and saturated liquid properties for the vapor-liquid equilibrium that exists in that process stream.
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