study of a single pass shell and tube heat exchanger
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ChE 304
Chemical engineering laboratory - III
Experiment No. 3 Group No. 03 (A2)
Name of the experiment:
STUDY OF A SINGLE PASS SHELL AND TUBE
HEAT EXCHANGER
Submitted by:
Md. Hasib Al Mahbub
Student Id: 0902045
Level: 3; Term: 2
Section: A2
Date of performance: 21/01/2014
Date of submission: 28/01/2014
Partners Student Id. 0902041
0902042
0902043
0902044
Department of Chemical Engineering.
Bangladesh University of engineering and technology, Dhaka.
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Summary
The objective of this experiment was to study a single pass shell and tube heat exchanger which
included the comparison between theoretical and experimental results of both individual and
overall heat transfer coefficients and tube side pressure drops. In this experiment, cooling water
was used to recover heat form saturated steam. The cooling water was flown through the pipe
and the saturated steam was flown through the annulus. The experiment was performed at
different steam pressure. The values of overall heat transfer coefficient found experimentally
vary from 173.7199- 290.2413 J/sec.m2.K where the theoretical values range from 1651.821-
2593.331 J/sec.m2.K. The tube side pressure drop were in between 8092.587-39451.36 Pa
experimentally, where the theoretical pressure drop range from 1987.478- 12326.29 Pa.
Colburn JH factor (JH) vs. Reynoldss number (Re) and pressure drop (P) vs. velocity (v)
graphs are plotted both for 2.5 and 5 psig. The graphs show deviation from the theoretical graphs.
The possible discrepancies are described in discussion.
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1-1Shell
andTube
Heat
Exchanger
Manometer
SteamIn
Condensate
Out
WaterIn
WaterOut
WaterTank
Pump
Steam
Trapper
Thermometer
Guage
Pressure
Controller
Figure1:Schematicdiagramoftheexperimentalsetup
Experimental Setup
2
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Figure 3: Temperature profile of the Shell and Tube Heat Exchanger
Figure 2: Schematic Diagram of a 1-1 Shell and Tube Heat Exchanger
T1Water Ts Steam
T2
Steam
Condensed
Cold Water
Hot Water
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Observed Data
Weight of Bucket = 1.5 Kg
Heat Exchanger
Shell: Nominal Size 6
Schedule No. 40
Passes: Shell side=1
Tube side=1
Tubes: OD= 0.5 inch
BWG=16
Length=96 inch
Number= 19
Pump
Centrifugal pump
1.5 kW; 240 V; 50 Hz; 2900 rpm
Hmax =38m; Qmax = 250 l/h
Table 1: Table of observed data for the study of a single pass shell and tube heat exchanger
No.
of
Obs
Steam
pressure
Flow
meter
reading
Water
temperature
Weight of
Bucket
+
Condensate
Collection time Manometer
reading
Inlet Outlet Water Condensat
e
Left Right
psig Litre oC oC Kg sec sec inch inch
1
2.5 10 23
30 2.35 14.75 60 33.5 36
2 29 2.4 10.57 60 32.6 36.5
3 28.5 2.5 8.47 60 31.5 37.3
4 27.5 2.55 6.75 60 30 385 27 2.6 5.25 60 27.6 39.3
6
5 10 23
31 2.1 11.47 60 33.4 35.8
7 30.75 2.3 9.54 60 32.3 36.5
8 30.5 2.5 8.56 60 31.5 37
9 29.5 2.6 7.09 60 30 37.7
10 28.75 2.65 5.41 60 27.5 39
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Calculated Data
Table 2: Table of different water bulk temperatures and flow rates of water and condensate
No.of
Obs
Steampressure
Waterbulk
temperature
(Tb)
Weight Flow rate
Water
(mw)
Condensat
e
(mc)
Water
(Ww)
Condensate
(Wc)
psia oC kg kg kg/sec kg/sec
1
17.2
26.5 9.96653 0.85 0.675697 0.014167
2 26 9.96787 0.9 0.943034 0.015
3 25.75 9.96853 1 1.176922 0.016667
4 25.25 9.96984 1.05 1.477013 0.0175
5 25 9.9705 1.1 1.899143 0.018333
6
19.7
27 9.96517 0.6 0.868803 0.017 26.875 9.9655 0.8 1.044602 0.013333
8 26.75 9.96585 1 1.164235 0.016667
9 26.25 9.9672 1.1 1.405811 0.018333
10 25.875 9.9682 1.15 1.842551 0.019167
Table 3: Properties of water at bulk temperature
No.of
Obs
Waterbulk
temperature(Tb)
Density
(w)
Viscosity() Heat Capacity(c) ThermalConductivity
(k)oC Kg/m3 Pa-sec KJ/Kg-Kelvin Watt/m-Kelvin
1 26.5 996.653 0.00086 4.181 0.60972 26 996.787 0.00087 4.181 0.60893 25.75 996.853 0.00088 4.182 0.6084 25.25 996.984 0.00089 4.182 0.6085 25 997.05 0.00089 4.182 0.607
6 27 996.517 0.00085 4.181 0.611
7 26.875 996.55 0.00085 4.181 0.618 26.75 996.585 0.00086 4.181 0.619 26.25 996.72 0.00087 4.181 0.609
10 25.875 996.82 0.00087 4.181 0.609
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Table 4: Properties of condensate at film temperature
Table 5: Table of heat balances, LMTD and experimental overall heat transfer coefficient
No.
of
Obs
Heat absorbed
by water
(Qw)
Heat released
by steam
(Qc)
Average heat
transfer
(Qavg)
LMTD Overall heattransfer co-
efficient
(Experimental)
(UOE)
KJ/sec KJ/sec KJ/sec oC J/sec.m2. K
1 19.77562261 31.25350833 25.51456547 77.64741898 177.7150635
2 23.6569524 33.09195 28.3744512 78.16162176 196.3346702
3 27.07038471 36.76883333 31.91960902 78.41785647 220.1434079
4 27.79591392 38.607275 33.20159446 78.92862108 227.5032022
5 31.76886171 40.44571667 36.10728919 79.18316212 246.6182049
6 29.05972155 22.355 25.70736077 80.03337223 173.7198577
7 33.84796699 29.80666667 31.82731683 80.1625715 214.7293829
8 36.50749315 37.25833333 36.88291324 80.29162756 248.4380115
9 38.20502268 40.98416667 39.59459467 80.8064335 265.0043796
10 44.29630391 42.84708333 43.57169362 81.19106797 290.2413437
No. of
Obs
Film
temperature
(Tf)
Viscosity
()
Density
(w)
Thermal
Conductivity
(k)oC Kg/m3 Pa-sec Watt/m-Kelvin
1 75.0625 0.00037 974.82 0.667
2 74.875 0.00038 974.93 0.667
3 74.78125 0.00038 974.99 0.667
4 74.59375 0.00038 995.1 0.667
5 74.5 0.00038 975.15 0.666
6 77.0625 0.00037 973.61 0.668
7 77.015625 0.00036 973.64 0.668
8 76.96875 0.00037 973.67 0.668
9 76.78125 0.00037 973.78 0.66810 76.640625 0.00037 973.87 0.668
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Table 6: Table of nusselt number, prandtl number, shell and tube side heat transfer co-
efficients and theoretical overall heat transfer coefficient
No.
of
Obs
Nusselt
number
(Nu)
Prandtl
number
(Pr)
Heat transfer
co-efficient
(Tube side)hi
Heat transfer
co-efficient
(Shell side)
ho
Overall heat
transfer co-
efficient(Theoretical)
(UOT)
J/sec.m2. K J/sec.m2. K J/sec.m2. K
1 53.08764109 5.897424963 3443.354763 4694.305766 1651.820895
2 69.72368795 5.973838069 4516.463148 4655.903542 1945.816467
3 83.74419646 6.052894737 5416.645899 4652.332961 2153.43645
4 100.968729 6.121677632 6530.743325 4692.60798 2381.073628
5 123.1305926 6.131762768 7951.092521 4636.44016 2593.330737
6 64.72125544 5.816448445 4206.881604 4676.51856 1869.194017
7 75.04255252 5.825983607 4869.782664 4706.898753 2041.264854
8 82.29696073 5.89452459 5340.547451 4673.020676 2141.4348439 96.27353274 5.972857143 6237.295898 4666.042579 2320.590061
10 119.5366115 5.972857143 7744.446425 4660.863049 2570.638783
Table 7: Table of Reynolds number, friction factor, jh, velocity, and mass velocity of water
No.
of
Obs
Reynolds
number
(Re)
Friction
factor
(f)
Velocity of water
(Vw)
Mass velocity
(Gt)
jH
ft2/in2 m/sec Kg/sec.m2
1 5536.655319 0.00033 0.514156 512.4351199 26.6662382
2 7727.213425 0.0003 0.717483538 715.1782638 34.81625786
3 9643.689957 0.00028 0.895372019 892.5542833 41.56792595
4 12102.63527 0.00027 1.123526074 1120.13752 49.8502936
5 15561.56116 0.00025 1.444533524 1440.27215 60.95457329
6 7118.96444 0.00031 0.661185789 658.882879 32.60597739
7 8559.457667 0.00029 0.794947694 792.2051245 37.78511626
8 9539.730612 0.00028 0.885958061 882.9325141 41.20905477
9 11519.20394 0.00027 1.069647532 1066.139088 47.91833705
10 15097.84657 0.00025 1.401811645 1397.353884 59.49709619
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Table 8: Table of tube side experimental and theoretical pressure drops
No.
of
Obs
Diff. in manometer
reading
Pressure drop
(Experimental)
(p)
Pressure drop
(Theoretical)
(p)
Wall
temperature
(Tw)
Viscosity at
wall
temperature
()m Pa Pa oC Kg/m3
1 0.063500772 8429.778306 1987.477737 65.35 0.00043
2 0.099061205 13150.45416 3496.852602 65.1 0.00043
3 0.147321791 19557.08567 5133.144374 64.975 0.00043
4 0.203202471 26975.29058 7953.500684 64.725 0.00043
5 0.297183614 39451.36247 12326.28535 64.6 0.00044
6 0.060960741 8092.587174 3096.933688 67.05 0.00042
7 0.106681297 14162.02755 4227.592083 66.9875 0.00042
8 0.139701699 18545.51227 5109.137718 66.925 0.00042
9 0.195582378 25963.71718 7364.585232 66.675 0.00042
10 0.292103552 38776.98021 11789.0593 66.4875 0.00042
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Sample Calculation
Sample calculation for observation no. 6
Water inlet temperature, T1 = 23oC
Water outlet temperature, T2 = 31oC
Water Mean temperature, Tm =2
TT21
=
2
3123= 27 oC
Properties of water at mean temperature (27 oC),
Density, = 996.517 Kg/m3
Heat capacity, Cp = 4.181 KJ/Kg-kelvin
Viscosity, =0 .00085 Pa-sec
Thermal conductivity, k = .611 Watt/m-kelvin
Weight of bucket and condensate = 2.1 kg
Weight of bucket = 1.5 kg
Weight of condensate = (2.1-1.5) kg
= 0.6 kg
Flow rate of condensate, mc =sec60
Kg0.6
= 0.01 Kg/sec
Heat of condensation, c = 2235.5 KJ/Kg
Heat released by condensation, Qc= mcc
= (0.012235.5) KJ/sec
= 22.355 KJ/sec
Volume of water = 10 L
Weight of water = 10996.517/1000 = 9.96517 Kg
Flow rate of water, mw = (9.96517/11.47) Kg/sec
= 0.868802964 Kg/sec
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Heat absorbed by water, Qw = mwCp(T2-T1)
= 0.868802964 4.181(31-23)
= 29.05972155KJ/ sec
Average heat transfer, Qavg =2
QQ cw
=2
29.05972355.22
= 25.70736077 KJ/sec
Saturation temperature at 5 psig (=19.7 psia), Ts= 107.1oC
Logarithmic Mean Temperature Difference,
LMTD =
2s
1s
2s1s
TT
TTln
)T(T)T(T
=
2s
1s
12
TT
TTln
TT
=
131.071
321.071ln
3213
= 80.03337223 K
The outside area of a 0.5 inch 16 BWG tube = 0.03991 m2/ lin m
Length of each tube = 96 inch = 2.438 m
Number of tubes = 19
Total outside area, A0 = 19 2.4384 0.03991
= 1.849 m2
Experimental overall heat transfer co-efficient,
UOE =LMTDA
Q
0
avg
= 3600143.3259849.1
35.23095
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= 173.72 J/sec.m2. K
Prandtl Number, Pr =kCp
= 5.81645
Flow area of tube, Ai = 0.0000694 m2
Velocity of water, Vw =i
w
A
m
=190.0000694996.517
0.868803
= 0.66119 m/sec
Reynolds number, Re =
vD wi
= 7118.96
Tube wall temperature (steam side),
Tw =2
)]TT(0.5[Ts 21
=2
)]3132(0.5[107.1
= 67.07 oC
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Using Seider-Tate equation,
Nu =0.027 Re0.8 Pr1/3(f/ w)0.14
= 0.027(7118.96)0.8 (5.81645)1/3(0 .00085/0.00042)0.14
= 32.606
Water side heat transfer co-efficient for turbulent flow,
hi = Nu i
D
k
= 4206.88 J/ sec. m2. K
Film temperature, Tf = Ts 0.75(Ts-Tw)
= 107.1 0.75 (107.1- 67.05)
= 77.0625 oC
Properties of condensate at film temperature (77.0625 oC),
Density, f = 973.61 Kg/m3
Viscosity, f = 0.00037 Pa-sec
Thermal conductivity, kf= 0.668 Watt/ m-kelvin
Heat of condensation, hfg = c= 2235500 J/Kg
Density of steam, v 0
Saturation temperature, Tg =Ts = 107.1oC = 380.1 K
Using Nusselt equation, steam side heat transfer co-efficient,
ho = 0.725
25.0
wgf
3ffgvff
)Tnd(T
kgh)(
= 0.725
25.0
wgof
3ffg
2f
)T(TD
kgh
= 4676.52 J/ sec. m2.oC
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Theoretical overall heat transfer co-efficient,
UOT =
-1
ii
o
0 hD
D
h
1
= 1869.19 J/ sec. m2.K
jH factor calculation, jH = Nu .Pr-1/3.
14.0
w
= 32.606
Tube side Pressure Drop Calculation,
Specific gravity, s = 1
Internal diameter, D = 0.37 inch = 0.031 ft
Length of the tube, L = 8 ft
No. of pass in tube side, n = 1
The factor, t =
14.0
w
=
14.0
0.00042
0.00085
= 1.10373
Mass velocity, Gt = 658.883 lb/hr.ft2
For this mass velocity,2g'
V 2
144
52.5= 0.03 psi
For Reynolds number of 7118.96,
Friction factor, f = 0.00031ft2/in2
Pressure drop, pi =t
10
2
t
Ds105.22
LnGf
= 0.3288 psi
Pressure drop due to velocity head,
p r=
2g'
V
s
4n 2
144
52.5
= 0.12042 psi
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Total theoretical pressure drop, p = pi+ pr
= (0.3288 + 0.12042)
= .4493psi
Again,Manometer reading (left) = 33.4 in
Manometer reading (right) = 35.8 in
Difference = (35.8 33.4) in
= 2.4 in
Experimental pressure drop, p = 1.174 psi
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Results and Discussions
The results are summarized bellows
Heat transfer co-efficient (Shell side), h0 4636.44016-4706.898753 J/sec.m2. K
Heat transfer co-efficient (Tube side), hi 3443.354763-7951.092521 J/sec.m2. K
Overall heat transfer co-efficient
(Theoretical), UOT
1651.821- 2593.331 J/sec.m2.K
Overall heat transfer co-efficient
(Experimental), UOE
173.7199- 290.2413 J/sec.m2.K
For the jHFactor vs. NReplotted on log-log coordinate
1. The slope for 2.5 psig = 0.8 is shown at figure 4
2. The slope for 5 psig = 0.8 is shown at figure 5
All the graphs had shown their expected characteristics. The slope for steam pressure 2.5 psig
is 0.8 and for steam pressure 5.0 is 0.8 whereas the theoretical value is 0.8. Thus, the graphs
establish the validity of Sieder-Tate equation.
The theoretical and experimental results shows some discrepancies. The possible causes are
discussed here-
1. The theoretical values obtained in this experiment are not wholly theoretical. Thesevalues are found based on some parameters that are determined experimentally in one
way or another. Hence, they cannot be said to be purely theoretical.
2. There might be some heat loss through the pipes and wall which was not accountedduring the calculation. This might have brought the discrepancy. The theoretical value
was not a pure literature value. It was calculated by manipulating some data or
parameters.
3. The apparatus was very old and proper maintenance is not taken for several years.Excess fouling may encounter in tube side which decrease the overall heat transfer co-
efficient.
4. Heat absorbed by water was greater than the heat released by the steam which isnormally impossible. Uses of steam trapper caused this.
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5. We assumed that the convection heat transfer co-efficient are constant through the heatexchanger, but experimentally the heat transfer co-efficient were not constant while
operation.
6. The steam pressure was considered constant during operation, but, it was not constantwhile operation.
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NuPr (-1/3)(u/uw) -.014 vs. Reynolds Number (2.5 psig)
Figure 4: Graph of NuPr (-1/3)(u/uw) -.014 vs. Reynolds Number at 2.5 psig pressure
y = 0.027x0.8
10
100
5000
NuPr^(-1/3)(u/uw)^-.014
Reynold's Number
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NuPr (-1/3)(u/uw) -.014 vs. Reynolds Number (5 psig)
Figure 5: Graph of NuPr (-1/3)(u/uw) -.014 vs. Reynolds Number at 5 psig pressure
y = 0.027x0.8
10
100
5000
NuPr^(-1/3)(u/uw)^-.014
Reynold's Number
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Pressure drop vs. Water velocity (2.5 psig)
Figure 6: Graph of Pressure drop vs. water velocity at 2.5 psig pressure
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
0.4 0.6 0.8 1 1.2 1.4 1.6
Pressu
redrop
Water velocity
Theoretical
Experimental
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Pressure drop vs. Water velocity (2.5 psig)
Figure 7: Graph of Pressure drop vs. water velocity at 2.5 psig pressure
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5
Pressuredrop
Water velocity
Theoretical
Experimental
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