Trainer A.R.KANADE
avi2kan@yahoo.co.in
15%
Flue
gases
Boiler
Plant
80%
HP steam
Fuel
100%
PRS unit
Power
Plant
PRDS
Unit
Process
Plant
55% to process
2%
losses
Blow
down
5%
losses
3%
Condensate
20%
Standard Steam Circuit - Energy Balance
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Selection of Working Pressure
• What is the right pressure for given process
Objective should be process temp.
Heating water to 850C can be achieved using
steam at any pressure above atmospheric.
• Would you use steam at (a) 2 barg.sat.
Or (b) at 7 barg.sat.
Or (c) superheated at 2barg.2000C?
• For indirect heating, latent heat released will be (a) 517.6 Kcal/Kg.
(b) 489.9 Kcal/Kg. 5.3% more consumption
(c) 517.6 Kcal/Kg. At a very slow rate
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Selection of Working Pressure contd.
For indirect heat transfer process -
The right choice is ‘the lowest possible’.
Rule of thumb - Pressure giving T(steam) + 350C
For Direct heat transfer process It does not matter so long as you ensure
thorough mixing of steam with the product.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Distribute at High Pressure
This will have the following advantages:

Smaller bore steam mains needed and therefore less heat (energy) loss
due to the smaller surface area.

Lower capital cost of steam mains, both materials such as pipes, flanges
and support work and labour.
Lower capital cost of insulation (lagging).

Dryer steam at the point of usage because of the drying effect of pressure
reduction taking place near the equipment.

The boiler can be operated at the higher pressure corresponding to its
optimum operating condition, thereby operating more efficiently.

The thermal storage capacity of the boiler is increased, helping it to cope
more efficiently with fluctuating loads, and a reduced risk of priming
and carryover
How much reduction in thermal storage capacity of a 10.5 barg rated boiler
operated at 7 barg.?
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Spirax
Customer
How Do We Pipe Size?
On the basis of:


Fluid Velocity
Pressure Drop
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Pipe Sizing






Greater Cost
Greater Heat Loss
Greater Volume of Condensate Formed
Lower Pressure to Steam Users, or
Not Enough Volume of Steam
Water Hammer and Erosion
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Methods of Steam-pipe Sizing
Velocity Method
For saturated steam system
Ideally suited for Process use
Pressure Drop Method
For superheated steam
Ideally suited for Power Plants & Co-gen
units
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Methods of Steam-pipe Sizing - contd.
Factors governing the method to be used Steam Pressure and Temperature
Size of distribution network
Longer lengths
Larger pipe sizes
Criticality of pressure drop & th.stresses
Mostly for Power plants and HP
cogen
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Methods of Steam-pipe Sizing
Rules of thumb to be followed Maximum velocity 15 m/s for LP wet steam(flash steam)
25 m/s for sat.steam long lengths
30 m/s for sat.steam short tappings
40 m/s for superheated steam
Normal Pressure Drop
Less than 10% inlet pressure
Less than 1 Kg/cm2 for given
length of piping.
Equivalent length of piping - Add 10% for fittings in the line.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
PressureVelocity
bar
m/s
150mm
1.0
4.0
Pipeline Capacities at Specific Velocities
15mm
20mm
15
8
17
29
65
112
260
470
25
12
26
48
100
193
445
730
40mm
50mm
80mm
100mm
1020
1660
40
19
39
71
172
311
640
1150
2500
15
19
42
70
156
281
635
1166
2460
25
40
10.0
kg/h
25mm
15
30
49
116
41
25
63
197
95
66
115
270
456
155
145
372
257
450
1080
1980
4225
796
1825
3120
7050
626
562
1485
990
2495
2205
5860
3825
8995
40
104
216
408
910
1635
3800
6230
14390
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Steam-pipe Sizing Examples
Size the line to carry (a) 300 kgs/hr.steam at 1 barg to FWT 150 m.away
(b) 1100 kgs/hr.steam at 10 barg to a drier 300m.away
(c) Superheated steam 2TPH at 15 barg.300C to turbine
at a distance of 50 m.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Waterhammer - a phenomenon
Steam has low density but high velocity
WP 10 barg Density 5.5 Kg/m3 Velocity 25m/s
Condensate has high density but low velocity
WP 10 barg Density 909 Kg/m3 Velocity 3m/s
Impact or Momentum =
Mass X Velocity
Condensate having 160 times mass density travelling
at 10 times it’s normal velocity will exert
1600 times greater impact.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Waterhammer
SAGGING MAIN
Condensate
Vibration and noise
caused by
waterhammer
Slug of water from
condensate
Trainer A.R.KANADE
avi2kan@yahoo.co.in
What is water-hammer?
Water-hammer is the hammer like impact due to
fluid flow in a pipeline.
This can happen in any line carrying two-phase flow
Steam lines with lot of condensed steam not properly drained
Condensate lines with flashing of condensate in the line.
The effect would be - Severe mechanical vibrations
Heavy leakages from joints
Ruptured pipelines
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Ineffective, and Proper Drain Points
Cross-Section
Steam
Correct
Condensate
Steam trap
Pocket
25/30mm
Cross-Section
Steam
Incorrect
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Steam Line Reducers
Correct
Steam
Condensate
Incorrect
Steam
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Branch Connections
Steam
Steam
Condensate
Incorrect
Correct
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Drop Leg
Main
Shut off Valve
Trap Set
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Warm Up Loads/Running Loads(kg)
per 50m of Steam Main
Steam
Pressure
Bar g
50
65
80
100
125
150
200
250
300
350
400
450
500
600
9
9.5
9.3
15.1
11.3
19.7
14.1
28.1
16.5
38.1
20.6
49.4
24.5
74
31.5
105
39
139
46.5
164
51.5
216
60
272
64
320
72
436
88
10
9.9
9.8
15.7
11.9
20.4
14.6
29.2
16.9
39.6
21.3
51.3
25
77
33
109
41
144
49
171
54
224
62
282
67
332
75
463
90
12
10.4
10.9
16.5
13.0
21.6
15.7
30.7
17.7
41.7
22.5
54.1
26
81.1
36
115
45
152
53
180
59
236
67
298
73
350
81
488
97
MAINS SIZE-mm
Figures in italics represent running loads
Ambient temperature 200C, insulation efficiency 80%
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Calculation of Pipe Expansion
E x p a n s io n (  ) = L x  x  (m m )
0
W h e re :
t
L = L e n g th o f p ip e b e tw e e n
a n c h o rs (m )
 = T e m p e ra tu re d iffe re n c e C
 = E x p a n s io n c o e ffic ie n t
0
o
t
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Recommended Support Spacing
for Steel Pipes
Nom. Pipe
Size mm.
Steel/Copper
Interval of Horizontal run
metres
Bore
O/D
12
15
Interval of Vertical run
metres
Mild Steel
Copper
Mild Steel
Copper
15
18
-2.0
1.0
1.2
-2.4
1.2
1.4
20
25
22
28
2.4
2.7
1.4
1.7
3.0
3.0
1.7
2.0
32
40
35
42
2.7
3.0
1.7
2.0
3.0
3.6
2.0
2.4
50
65
54
67
3.4
3.7
2.0
2.0
4.1
4.4
2.4
2.4
80
100
76
108
3.7
4.1
2.4
2.7
4.4
4.9
2.9
3.2
125
150
133
159
4.4
4.8
3.0
3.4
5.3
5.7
3.6
4.1
200
250
194
267
5.1
5.8
---
6.0
5.9
---
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Chair & Roller
Rollers for Steel Pipework
Chair Roller & Saddle
Twin Pipe
Support
Bracket
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Air Venting
Balanced Pressure
Air Vent
Steam Main
Thermodynamic Steam Trap
with optional Blowdown and
for ease of maintenance a universal coupling
Air
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Heat Emission from Bare Pipes
Temp. diff.
Steam to Air
o
Pipe Size
15mm
20mm
25m
32mm
C
40mm
50mm
65mm
80mm
100mm 150mm
W/m
56
54
65
79
103
108
132
155
188
233
324
67
68
82
100
122
136
168
198
236
296
410
78
83
100
122
149
166
203
241
298
360
500
89
99
120
146
179
205
246
289
346
434
601
100
116
140
169
208
234
285
337
400
501
696
111
134
164
198
241
271
334
392
469
598
816
125
159
191
233
285
321
394
464
555
698
969
139
184
224
272
333
373
458
540
622
815
1133
153
210
255
312
382
429
528
623
747
939
1305
167
241
292
357
437
489
602
713
838
1093
1492
180
274
329
408
494
556
676
808
959
1190
1660
194
309
372
461
566
634
758
909
1080
1303
1852
Trainer A.R.KANADE
avi2kan@yahoo.co.in
Calculation of Heat Transfer
Q = U. A. t
Where
Q
U
A
t
=heat transfer rate (W)
=overall heat transfer coefficient (W/m2K)
=mean surface area (m2)
=temperature difference (K)
Trainer A.R.KANADE
avi2kan@yahoo.co.in
THERMAL INSULATION
TO REDUCE HEAT LOSS
TO PROTECT FROM DAMAGE/BURNS
TO PROVIDE WEATHER PROOFING
Trainer A.R.KANADE
avi2kan@yahoo.co.in
DESIRED PROPERTIES
THERMAL
–TEMP.RESISTANCE
–LOW CONDUCTIVITY
MECHANICAL
–SHOCK RESISTANCE
–POROSITY FOR AIR BINDING
CHEMICAL
–INERT ACTIVITY
Trainer A.R.KANADE
avi2kan@yahoo.co.in
INSULATION MATERIALS
MINERAL WOOL (IS-3677)
- Most commonly used
GLASS WOOL
- Specified as alternative
CALCIUM SILICATE OR MAGNESIA
- Use as Refractory
ASBESTOS
- Used for small lines
Trainer A.R.KANADE
avi2kan@yahoo.co.in
INSULATION MATERIALS
• WIRENETTING
- TO KEEP INSULATION IN PLACE
• SURFACE COVERING
- TO PROTECT INSUL. FROM DAMAGE
- GI/AL SHEET OF 22/24g THK.
- CEMENT PLASTER
- THERMOSETTING COMPOUND
Trainer A.R.KANADE
avi2kan@yahoo.co.in
INSULATION
APPLICATION METHODS
WIREBRUSHING HOT SURFACES
PREPARATION OF INSULATION MATTRESSES OF CORRECT DENSITY
(USUALLY 120 OR 150 Kg/M3)
WRAPPING WITH WIRENETTING
(USUALLY 24g GI WIRENET USED)
BINDING THE LINEAR JOINTS
Trainer A.R.KANADE
avi2kan@yahoo.co.in
APPLICATION (contd.)
SURFACE COVERING WITH METAL
(USUALLY AL.CLADDING WITH 22g OR 24g SHEET)
JOINT PREPERATION WITH OVERLAP TO AVOID WATER SEEPAGE.
MAKING BOXES FOR FITTINGS SUCH AS VALVES AND FLANGES.
MITER CUT SHAPES FOR BENDS.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
INSULATION STANDARD
CURRENTLY IS-7413 IS APPLICABLE
SPECIFIES METHODS OF
–MATERIAL SELECTION
–APPLICATION OF INSULATION MATERIALS
–MEASUREMENTS OF FINISHED SURFACES.
Trainer A.R.KANADE
avi2kan@yahoo.co.in
HEAT LOSS FROM UNINSULATED
SURFACES
INTERNAL TEMP.
IN DEG.C
•
•
200
•
400
HEAT LOSS
IN KCAL/HR.M2
291
894
3065
6690
12115
Trainer A.R.KANADE
avi2kan@yahoo.co.in
HEAT LOSS FROM INSULATED
SURFACES
Temp
25thk
40thk
50
47
36
100
135
95
73
200
338
244
420
300
400
50thk
65thk
80thk
190
150
122
310
255
220
170
455
370
320
244
Temp.in deg.C Thk. In mm. and Heat Loss in Kcal/hr/sq.mtr.
100thk
Trainer A.R.KANADE
avi2kan@yahoo.co.in
ECONOMIC THICKNESS OF
INSULATION
TEMP.
Dia < 50
Dia > 50
Dia >150
Flats
50
25
25
25
25
100
25
25
40
50
150
25
40
50
65
200
40
50
50
80
300
40
50
65
80
400
50
50
80
80