Copyright c 2017 by Pearson Education, Inc.. Pressure head is a method for expressing pressure in terms of the equivalent height of a fluid, where the pressure head is the pressure at th
Trang 1Solutions Manual for Chemical Process
Equipment Design
(2017)
by Richard Turton Joseph A Shaeiwitz
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 21
02
first term: enthalpy term
second term: kinetic energy, often written as (v)2)/2
third term: potential energy
fourth term: frictional losses
fifth term: shaft work
2
mass flowrate constant, so, if larger pipe is 1 and smaller pipe is 2
2 2 2 1 1
1A v A v
m , where A is cross sectional area for flow, if density constant,
then
2 2 1
1v A v
A , so if area goes down, velocity must go up in pipe 2
3
Pressure head is a method for expressing pressure in terms of the equivalent height
of a fluid, where the pressure head is the pressure at the bottom of a that height
of that fluid From the mechanical energy balance, the value is obtained by dividing
Trang 31-2
5
v Av
m
mass in = mass out, so if single pipe, mass flowrate must remain constant
if density remains constant, volumetric flowrate remains constant
if density and area remain constant, velocity must remain constant
6
forcesviscous
forcesinertial
Re
inertial forces keep fluid flowing, viscous forces resist fluid flow
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 4all of the following have similar shape
f
laminar flow
flow in packed bed
Trang 51-4
pipe length: linear relationship, as pipe gets longer, friction increases proportionally
velocity in pipe (or flowrate): in turbulent flow, friction increases as square of velocity or flowrate, linear in laminar flow
pipe diameter: strong inverse relationship; in turbulent flow, friction goes with d-5;
for incompressible flow, density constant, so first term is simplified
02
u P
12
frictional drag due to “skin friction,” which is contact with solid object/surface
form drag is from energy loss due to flow around object (fluid changing direction takes energy)
13
in a packed bed,
void fraction = volume of bed not occupied by solid (void space)/total volume of bed
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 614
total volume is volume of bed if empty
solid volume is total volume of solids in bed
void volume is volume of bed not occupied by solids
total volume = solid volume + void volume
P manometer fluid fluid flowing
( ) , where h = is the difference in manometer fluid
height
So, for a large pressure drop, the height difference (and hence the height of the manometer required) decreases if the manometer fluid is dense, like mercury However, for very small pressure drops, accuracy is lost due to the small height difference in a mercury manometer, so a less dense manometer fluid is better
17
That is the flowrate at which the available net positive suction head equals the required net positive suction head For higher flowrates, the fluid will vaporize upon entering the pump, causing cavitation, which damages the pump However, it is physically possible to operate at higher flowrates
Trang 7Energy in compression is minimized with isothermal compression, which is not possible, since compressing a gas causes the temperature to increase Isothermal operation could be approached with an infinite number of compression/intercooling stages with infinitesimal pressure and temperature increases, which is a nice limiting case, but impossible Staging compressors with intercooling is an attempt to approach the limiting case in a practical way The economics of a process determines the number of stages to use
There is also the problem that if the temperature in a compressor stage increases too much, the seals will get damaged, which is a good reason the keep the compression ratio low
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 8For fully developed turbulent flow, it is assume that the friction factor has reached its asymptotic value The proportionalities are
5 2
D
v L
5
D
v , so, for constant pressure drop, the flowrate increase significantly
d it is exactly a proportional increase
e v L 0 5, so the flowrate decreases, but it is a one-half-power decrease, so the decrease in flowrate is less than the increase in length
f subscript 1 is for the original, long segment; subscript 2 is for the shorter parallel segments; take the ratio of pressure drops in both cases, noting that the diameters are constant, that the length of pipe 2 is half of pipe 1, and that the flowrates in each pipe are one-half of the original, so the pressure drop goes down by a factor of eight; note that minor losses due to the parallel piping are neglected
125.0)5.0(5
5 2
5 1 2 1
2 2 1 2 1
v L
L P
P
Trang 9d it is exactly a proportional increase
e v L 1, so the flowrate decreases in proportion to the increase in length
f subscript 1 is for the original, long segment; subscript 2 is for the shorter parallel segments; take the ratio of pressure drops in both cases, noting that the diameters are constant, that the length of pipe 2 is half of pipe 1, and that the flowrates in each pipe are one-half of the original, so the pressure drop goes down by a factor of four; note that minor losses due to the parallel piping are neglected
25.0)5.0(5.0
4 2
4 1 1 2 1 2 1
v L
L P
Trang 10Av v
v Av m
/sm00706.0
/sm00706.0kg/m850
kg/s6
2 4 3
1
1 1
3 3
1 1
m v
1063.79
/sm0106.0
kg/s9.01/s)
m0106.0)(
kg/m850(
2 4 - 3
2
2 2
3 3
2 2
v m
m00529.0)(
kg/m850(
m/s00529.0)m10m/s)(13.13032
.4(
3 3
3 3
2 -4 3
3 3
A v v
4
4 3 2 1
/sm0124.0
/sm0124.0kg/m850
kg/s51.10
2 4 3
4
4 4
3 3
4 4
m v
Trang 11m1013.13(kg/m1000
kg/s2.79m/s)
5)(
m10574.5(kg/m1000
2 4 3
2 2 2
2 4 3
1 1 1
v A m
4 3
4 3 2 1
m m m m
kg/s73.6
2 4 3
c
2 4 3
3
3
m/s)18.2(kg/m1000
kg/s73
Trang 122
i i
(0.02ft63
ft0.0491-
ft/sec)4(ft0.0218-
ft/sec)8(ft0.0873/sec
ft39.0
3
3 2 2
2 3
z g v
assume inlet and outlet at same pressure since no information provided
uniform pipe diameter, so kinetic energy term zero
pipe length not needed, since frictional loss given
gal/min487
)gal/ft487sec/min)(
60(lb/ft62.4
lb/sec7.67
lb/sec7.67
0sec))(hp/lb
ft hp)(5500.8(20
/lblb
-ft 80ft)50()seclb/(lb
ft 32.2
ft/sec2.32
3 3
f f
2 f 2
Trang 131-12
02
inlet and discharge both at atmospheric pressure, so pressure term is zero
inlet velocity is zero, since reservoir is like tank, so level is assumed constant
multiply 20 m of head by g to get frictional loss in correct units
M W84.7 W1084.7s
mkg1084.7
0)kg/m/s)(1000m
25(80.0)m/sm(9.8110
m)50(m/s81.92
0m/s)1
(
6 3
2 6
3 3
2 2
z g v
velocities both zero since tank levels
m6.7
0)kg/ms)(1000h/3600
/h(1m10
J/s)0.75(100-
J/kg3.5m) 10)(
m/s81.9
Trang 14frictional loss assumed zero, since nothing stated
location 1 is reservoir, location 2 is discharge
hp3723
0lb/sec)65000(55.0
sec))/(hplb
ft 550()/seclb/lb
ft 32.2(2
sec/ft 13.26ft)
60(/seclb/lb
ft 32.2
ft/sec32.2
ft/sec26.134
ft)(10lb/ft
62.4
lb/sec65000
f 2
f
2 2 2
2 f 2
2 3
/sm10305.5kg/m
1000
N/m34500-3168
m/s10305.54
m)1.0(
mL)10/s)(m/60mL/min(min250
2 2 2 4 2
2 3
2
4 2
6 3 1
Trang 151-14
02
z g v
velocities both zero since tank levels
density of water in lb/gal = (62.4 lb/ft3)(ft3/7.48 gal) =8.3 lb/gal
a
hp37.1
0lb/gal)sec)(8.3in/60
gal/min)(m30
(
sec))(hp/lb
ft hp)(5500.8(
/lblb
-ft 200ft)928873()seclb/(lb
ft 32.2
ft/sec2
f 2
f 2
928-zft200
0/lblb
ft 200ft)()seclb/(lb
ft 32.2
ft/sec2.32
f 2
f 2
Trang 16900
N/m)1000)(
6.1156.762(
kg/s0.7
2 4 - in
Trang 171-16
calculate velocity in 1-in pipe
2 2 2
1 2 2
2 4 - in
1
s/m62
pumpacross
m/s946.0)m10kg/s(82.19900
kg/s0.7
A
m v
Trang 18J/s)1000(kg/m
1000
N/m)1000)(
5.346.551(
0
3 3
m
W P
z g v
Trang 191-18
02
z g v
0)lb/ft4.62(/secft5
sechp
lb
ft 55075
.02
secft 366.646.25)lb/ft0.88(62.4
lb/lb
ft 2381.2
ft/sec46.254
ft)5.0(
sec/ft5 ft/sec366.64
ft)1(
sec/ft5
lb/lb
ft 2381.2ft)
1012()seclb/(lb
ft 32.2
ft/sec2.32)
lb/ft4.62)(
88.06.13(
3 3
f 2
2 2 2
3 f
2 3 2
2 3 1
f 2
f
2 3
Trang 20max height is z when pump is at 35.1 hp
ft8.79
0)lb/ft4.62(/secft5
sechp
lb
ft 550hp)1.35(75.0)seclb/(lb
ft 32.2
sec/ft2.32)
/ftin144()lb/ft0.88(62.4
ft/25)lb-(14.7
3 3
f
2 f
2 2 2
2 3
2 f
source tank and subtract 2 ft for destination tank, so answer is 77.8 ft
Trang 211-20
a
m/s27.1)m10(63.79kg/m
800
kg/s5.6
2 4 - 3
b
MEB from source tank level to pump inlet
first need velocity in suction line
m/s989.0)m10(82.19kg/m
800
kg/s5.6
2 4 - 3
kPa8.164
0J/kg30)m5(m/s81.92
m/s)989.0(kg/m
800
N/m000,150
0)
(2
3
2 2
3
2 3
1 3
2 3 1 3
0kg/s5.6
J/s)1500(7.0J/kg80)m(m/s81.92
m/s)27.1(kg/m
800
N/m000,150000,200
0)
(2
2 2
3 2
1 4
2 4 1 4
W e
z z g v P
so, height above ground = 6.86 m
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 222 2 1
2 1
1 2
liquidsinceconstant density
)(
v dt
dh A
A
A v dt
dh A
v A dt
h A d
h A h A V m
v A m
m
W e
z g v
f
0)(
02
1
2 1 2 2
Trang 231-22
integrate from initial height to any height from time zero to time t
2 5
0 0
0 5 0
5 0 2 1
2
2define
dt a h
dh
ah dt
dh
g A
A a
t h
5 0 0
2
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 24(2
02
4 5
2 4 4 5
2 3 2 4 3 4
4 3 2 1
e z z g v P P
W v
v P P
m m m m
first equation suggests mixing
second equation suggests pump with suction and discharge pipes having different diameters
third equation suggest pressure loss due to friction and height change, with deceleration upon entering tank, since zero velocity at point 5
Trang 251-24
1 6
2 5 5 6 5
6
2 4 2 5 4 5
1 6
2 2 1 2 1
2
5 4 2 3
02)(
02
0)
(
02)(
z z
v z z g P P
W v
v P P
W z
z g
v z z g P P
m m m m
s p
s p
first equation suggest mixing
second equation suggests height change with acceleration, probably flow out of tank, since no pump, assume downward
third equation suggests open-air tanks, since no KE term and no pressure terms
fourth equation suggests flow across pump with different pipe diameters
fifth equation suggest flow up to tank
inequality suggests destination tank level higher than source tank level
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 2602
1
2 1 2 2 1 2
m
W e
z g v
assume no friction, no height change, no pump (away from heart)
1 denotes normal artery, 2 denotes balloon region, where diameter is larger
so, if v 2 < v1, since velocity goes down in larger diameter region (from m Av, at constant density and flowrate, of area goes up, velocity goes down), pressure must
go up, because if velocity term is negative, pressure term must be positive, so they can add to zero
pressure going up makes aneurysm worse, since it would keep expanding
Trang 272 2
2 2
Re
81.67
.3log41
equalmust power pump
andsection,pipe
on 02
02
toreduces
M EBdiameter,uniform
andhorizontalassumed
since
02
21
D f
A
v v
v m
P D
fLv P
m
W d
fLv
m
W D
fLv z
g v P
s p
s p
1064.7lb/ft/sec
1072.6
)lb/ft.4ft/sec)(6278
.4(ft12
067.2Re
lb/sec95.6gal48.7
ftsec60
gal50)lb/ft4.62(
ft/sec78.4ft
0.02330
gal48.7
ftsec60
gal50
4 4
3
3 2
2 3
1064.7
81.6in)
3.7(2.067
in0018.0log41
Re
81.67
.3log41
9 0 4 10
9 0 10
Companion to Chemical Process Equipment Design, ISBN-13: 9780133804478 Copyright (c) 2017 by Pearson Education, Inc.
Full file at https://.
Trang 28ft 550
sechpsec/lb
ft 2004
seclb
ft 2004
0lb/sec95.6)sec/lb/lb
ft 2.32)(
ft12/067.2(
f f
f
2 f
.2
m/s51.2
00788.0
)kg/m1000(m)0525.0(
kg/m/s)001
.0(81.6m)
0525.0(7.3
m000045
0log41
0m)0525.0(
m)50(2m)10(m/s81.92
zeroassumed
in tank velocity
point,dischargeis
2location level,
tank is1location
uslysimultaneoequations
twosolvemust
81.67
.3log41
02
2
1
work termno
sopump,no
openis tank sourceand
catmospheri
at emergessince
droppressurezero
02
21
3 2
4 - 2
9 0 3 2
10
2 2 2
2 2
9 0 10
2 2
2 2
v f
v
dv D
f
D
fLv z
g v
m
W D
fLv z
g v
Trang 2944.181
/hp/sec)lb
ft (5507
.0
)seclb/lb
ft ft)(32.212
/25.10(
ft/sec)ft)(5.8310
713.3)(
00776.0(2seclb/lb
ft 32.2
ft)100(ft/sec2.32)lb/ft4.62(87.0
ft/lb)144(25
ft106713.33.1676)5280(70so
ft3.1676)
12/25.10(1(50)0.55(50)
15(9)50(35)
exittank entrance
tank valves
elbowsmethod
length equivalent
00776.0
10057
81.6)25.10(7.3
0018.0log41
10057cP)
lb/ft/sec/
10cP(6.7240
)lb/ft87)(62.4ft/sec)(0
ft)(5.8312
/25.10(Re
lb/sec44.181)lb/ft62.4)(
87.0(gal48.7/ftsec60
gal1500
ft/sec83.5ft
12
25.10
4gal
48.7/ftsec60
gal1500
ninformatiopipe
20-schedulein,
10uplook must
-Re
81.67
.3log41
02
2
methodheads
velocity use
ifor,method,length
equivalentuse
if
02
zero termKEso tank,tank to
02
21
f
2 f
2 5
2 f
2 3
2 f
5
9 0 10
4 -
3
3 3
2 3
9 0 10
2 2
2
2 2
s p i
s p eq
s p
W
W L
m
W v
K D
fLv z
g P
m
W D
v fL z g P
m
W D
fLv z
g v P
Trang 30the virtuallygive
methodsboth
that observe
hp3438
0lb/sec
44.181
/hp/sec)lb
ft (5507
.0ft/sec)83.5()seclb/lb
ft 32.2(2
)155.0)17.0(15)75.0(50(
)seclb/lb
ft ft)(32.212
/25.10(
ft/sec)ft)(5.835280
)(
70)(
00776.0(2seclb/lb
ft 32.2
ft)100(ft/sec2.32)
lb/ft4.62(87.0
ft/lb)144(25
f 2
2 f
2 f
2 2
f
2 3
2 f