Post on 07-Aug-2015
1/23/2015 High Pressure Piping
High Pressure Piping
“Design of a High Pressure Pipe transporting live steam”
Project Supervisor:
Prof. Dr.-Ing. B. Jatzlau
Participants:
Manas Shidore
Ahmed Hussein
Hochschule Offenburg University of Applied Sciences
Operational data
• This high pressure pipe is applied to transport a live steam from the
boiler to the steam turbine in a conventional steam power plant.
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Fluid flow rate “Q” Fluid quality “X” Point of operation (Press. &
Temp.)
555.555 kg/sec. at
operation conditions
X=1 (100% Steam) Super heated
steam
(Single-phase region)
Toper.= 550 C°, Tdesign= 565 C°
P= 26 Mpa, Ploss=1 Mpa
Hochschule Offenburg University of Applied Sciences
Fluid properties
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Composition “SC” 1.0-2.0 µS/cm
Phase Gaseous (live steam)
Density “ ” 82.34 kg/m3
Viscosity “ ” 32.81E-6 Pa.s
Toxicity Nontoxic
Combustibility Nonflammable
Fluid group Group 2
Flow type Turbulent
Thermal conductivity “λ” 100.9*10-3 W.m-1.K-1
Compressibility Compressible (Psteam= 260 bar > 1.513 bar)
Hochschule Offenburg University of Applied Sciences
Material properties
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Grade: X8CrNiMoNb 16-16 (Solution Annealed)
Number: 1.4981
Standard: EN 10302 : 2008 Creep resisting steels, nickel
and cobalt
alloys
Classification: Austenitic Steels
Nominal design creep strength (test) “Re” 215 N/mm2 (Mpa)
Tensile strength “Rm” 530/690 N/mm2 (Mpa)
Density “ ” 8.01 kg/m3
Verification by PED Quality grade lll
C Si Mn Ni P S Cr Mo N
0.04 - 0.1 0.3 - 0.6 max 1.5 15.5 - 17.5 max 0.035 max 0.015 13.5 - 17.5 1.6 - 2 max 1.2
Hochschule Offenburg University of Applied Sciences
Corrosive and abrasive properties
• In the range 500-800 degrees for any reasonable time there is a risk that
the chrome will form chrome carbides (a compound formed with carbon)
with any carbon present in the steel. This reduces the chrome available to
provide the passive film and leads to preferential corrosion, which can be
severe.
• Because of the high Nickel content in Austenitic materials which
gives it a relatively higher formability in higher temperatures and
because of stress corrosion cracking, preferential corrosion and
recrystallization dangers at high temperature ranges as well as taking
both partial and usage Factors of safety into considerations, the FOS
is chosen relatively high 1.5 (as it usually ranges from 1.05 - 1.5).
1/23/2015 High Pressure Piping 5
Hochschule Offenburg University of Applied Sciences
Calculations
• All calculations were done for only one train with the aid of the
MATLAB 7.0 as the main computing software
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Number of trains Number of fittings (max.)
2 (parallel) 20
The number of trains has been limited to only 2 because of the
summation of the total losses at parallelized trains. A compromise
must be done for optimum design and fabrication between using few
numbers of trains with big diameters or using large numbers of trains
with small diameters.
Hochschule Offenburg University of Applied Sciences
Thickness calculations (Thin)
• Going for the calculations of smooth cylinderical thin pipe and at different
values for “Di” and “t”, Da/Di=1.33 and hence not satisfying the thin-walled
cylinderical pipe condition which is Da/Di≤1.2.
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Hochschule Offenburg University of Applied Sciences
Thickness calculations (Thick)
1/23/2015 High Pressure Piping 8
Hochschule Offenburg University of Applied Sciences
Thickness calculations (Thick)
• Going for the calculations of smooth cylinderical thick pipe and according to
DIN-2917, Di=308.95 mm at v=45 m/sec.
• For both velocity and diameter value corrections, v at Di=320 mm equals to
41.94≈42 m/sec. and hence t=50 mm (according to DIN-2917).
• Choosing this specific velocity was based on the fact that the minor
losses (losses due to fittings) were relatively high at the same range
of velocity variations from 20-70 m/s. With the fact that major losses
increase at high velocities (smaller diameters), while the minor losses
increase at larger diameters (lower velocities), so a compromise has
been done for choosing this velocity.
1/23/2015 High Pressure Piping 9
Hochschule Offenburg University of Applied Sciences
Losses calculations
1/23/2015 High Pressure Piping 10
majorminorlosslossPPPP
elevationtotal
Major losses:
Hochschule Offenburg University of Applied Sciences
Losses calculations
1/23/2015 High Pressure Piping 11
Major losses Minor losses Elevation losses
3.73 bars 4.2 bars 0.072 bars
Hochschule Offenburg University of Applied Sciences
Stress calculations for T fittings
• For tees: di=Di/2=160mm, di=200 mm and hence ts=32 mm (according to
DIN-2917)
1/23/2015 High Pressure Piping 12
Hochschule Offenburg University of Applied Sciences
Stress calculations for T fittings
1/23/2015 High Pressure Piping 13
Hochschule Offenburg University of Applied Sciences
Stress calculations for T fittings
1/23/2015 High Pressure Piping 14
Hochschule Offenburg University of Applied Sciences
Flange calculations
1/23/2015 High Pressure Piping 15
1215.7 KN
1170.1
501.4
= 2887.27
Hochschule Offenburg University of Applied Sciences
Flange calculations
• Annular force:
1/23/2015 High Pressure Piping 16
= 164.66 KN
Total pressure force:
= 1380.36 KN
Gasket force:
1- assembly [using Metall-Flächdichtung (stainless steel) with strength = 350
N/mm2]
= 2.858 MN
Hochschule Offenburg University of Applied Sciences
Flange calculations
• 2- operation:
1/23/2015 High Pressure Piping 17
= 414.12 KN
= 2561.3 KN
3- safeguard against lifting flanges:
= 276.0 KN
Hochschule Offenburg University of Applied Sciences
Flange calculations
• 4- allowable gasket load:
1/23/2015 High Pressure Piping 18
= 4109.6 KN
5- forces on bolts:
= 3731.4 KN
= 2295.88 KN
= 5991.36 KN
Hochschule Offenburg University of Applied Sciences
Flange calculations
• 6- dimensions: @ assembly (class 8.8 at 20 C)
1/23/2015 High Pressure Piping 19
= 24.62+c mm, = 27.62 mm
@ initial operation (class 8.8 at 20 C)
= 31.2+c mm, = 29.33 mm
Hochschule Offenburg University of Applied Sciences
Flange calculations
• @ operation (class 8.8 at 300 C)
1/23/2015 High Pressure Piping 20
= 22.72+c mm, = 25.7 mm
So we choose M36 for class 8.8 (nearest bigger diameter is 30.5 mm)
Hochschule Offenburg University of Applied Sciences
Flange calculations
• External moments:
1/23/2015 High Pressure Piping 21
= 508354.8 N.mm
= 451258.4 N.mm
Hochschule Offenburg University of Applied Sciences
Flange calculations
• Moments of resistance:
1/23/2015 High Pressure Piping 22
= 6011761.6 mm3
= 26.54 mm
= 42.49 mm
Hochschule Offenburg University of Applied Sciences
Flange calculations
1/23/2015 High Pressure Piping 23
= 4077287.8 mm3
= 6630492.1 mm3
Hochschule Offenburg University of Applied Sciences
Life time calculations
Life (h)
cycle
% C° Allowed
load time
Factor
200 1 570 40000 5 5
1000 5 560 60000 3.3 16.66
2000 10 530 280000 0.714 7.14
3000 15 540 180000 1.1 16.6
15000 75 550 120000 1.6 125
20000 100 170.47
1/23/2015 High Pressure Piping 24
Damage expected by 200000/1.705 = 117302 h
After 100000 hrs. of operation, first repeated inspection should be done.
Hochschule Offenburg University of Applied Sciences
Questions ?
Finally
1/23/2015 High Pressure Piping 25