Pipe Sizing

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PRESENTATION TO TRAINEES PRESENTATION TO TRAINEES ONON

PIPE SIZINGPIPE SIZING

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PIPE SIZINGPIPE SIZINGPIPE SIZINGPIPE SIZING

PIPING CENTRE, CHENNAI

Length – “ l ”

Diameter – “d ”

Cross Sectional Area of Cylinder = * d2/4

Volume of Cylinder = Area * Length = (* d2/4) * ( l )

Suppose the Cylinder is filled with Water, Mass of Water in the Cylinder

= Volume * density of water = (* d2/4) * (l) *

Density = Mass / Volume (unit is kg/m3)

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Mass of water in the Cylinder (m) = (* d2/4) * (l) *

Suppose the water in the cylinder is flowing at a rate of ‘m’ kg in time ‘t’

Flow rate (Q) = m/t = (* d2/4) * (l/t) *

Velocity of flow in the cylinder – (Displacement / time) = (l/t) = ‘v’ m/s

Q = (* d2/4) * (v) *

Q – flow rate (kg/s) , d – Internal diameter of Pipe in “m’

V – velocity of fluid in m/s , – density in kg / m3

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Q = (* d2/4) * (v) *

Q – flow rate (kg/s) , d – Internal diameter of Pipe in “m’

V – velocity of fluid in m/s , – density in kg / m3

Normally following units are used

Q – flow rate (tonnes/hr) , d – Internal diameter of Pipe in “mm’

V – velocity of fluid in m/s ,

Instead of density – density in kg / m3,

Specific Volume “”= 1/ , unit in m3/kg

Q = (* d2/4) * (v) * becomes

Q * (1000/3600) = * (d/1000)2/4 *(v) * (1/ )

Therfore d2 = 4*Q*(1000/3600) *(1/v)*(1000)2/

ID of Pipe ‘d’ in mm = 595*SQRT(Q* / v)

d = 595*SQRT(flow*spvol/velocity)

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INPUTS REQUIRED FOR PIPE SIZINGINPUTS REQUIRED FOR PIPE SIZINGINPUTS REQUIRED FOR PIPE SIZINGINPUTS REQUIRED FOR PIPE SIZING

FLOW (TONNES / HR)FLOW (TONNES / HR)

VELOCITY OF FLUID (M/S)VELOCITY OF FLUID (M/S)

SPECIFIC VOLUME OF FLUID (MSPECIFIC VOLUME OF FLUID (M33/KG)/KG)

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FLOWFLOWFLOWFLOW

The flow to various equipments are The flow to various equipments are decided by the respective Equipment decided by the respective Equipment Manufacturers. The Turbine Manufacturer Manufacturers. The Turbine Manufacturer decides the quantity of steam or water decides the quantity of steam or water from / to various TG equipments like from / to various TG equipments like Turbine, Condenser, Heaters etc. The Turbine, Condenser, Heaters etc. The Boiler manufacturer decides the quantity Boiler manufacturer decides the quantity of steam or water to from various Boiler of steam or water to from various Boiler side equipments like Boiler, Air heaters, side equipments like Boiler, Air heaters, Fans etc. Fans etc.

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SPECIFIC VOLUMESPECIFIC VOLUMESPECIFIC VOLUMESPECIFIC VOLUME

SPECIFIC VOLUME OF A FLUID SPECIFIC VOLUME OF A FLUID DEPENDS ON THE WORKING PRESSURE DEPENDS ON THE WORKING PRESSURE AND WORKING TEMPERATURE OF THE AND WORKING TEMPERATURE OF THE FLUID. THE SPECIFIC VOLUME IS FLUID. THE SPECIFIC VOLUME IS OBTAINED FROM THE STEAM TABLES.OBTAINED FROM THE STEAM TABLES.

WORKING PRESSURE IS EXPRESSED IN WORKING PRESSURE IS EXPRESSED IN THE UNIT kg/cmTHE UNIT kg/cm22(abs) ie Reading of (abs) ie Reading of Pressure Gauge + Atmospheric Pressure Pressure Gauge + Atmospheric Pressure which is 1 kg/cmwhich is 1 kg/cm22

WORKING TEMPERATURE IS WORKING TEMPERATURE IS EXPRESSED IN THE UNIT DEGREE EXPRESSED IN THE UNIT DEGREE CELSIUS - CELSIUS - ooCC

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SPECIFIC VOLUMESPECIFIC VOLUMESPECIFIC VOLUMESPECIFIC VOLUME

For Steam at a Pressure of 16 kg/cmFor Steam at a Pressure of 16 kg/cm22(abs) (abs) and 210and 210ooC the specific volume is 0.12991 C the specific volume is 0.12991 mm33/kg./kg.

For Steam at a Pressure of 179 For Steam at a Pressure of 179 kg/cmkg/cm22(abs) and 540(abs) and 540ooC the specific C the specific volume is 0.01884 mvolume is 0.01884 m33/kg/kg

For Water at a Pressure of 200 For Water at a Pressure of 200 kg/cmkg/cm22(abs) and 160(abs) and 160ooC the specific C the specific volume is 0.00109 mvolume is 0.00109 m33/kg/kg

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CHARACTERISTICS OF SPECIFIC VOLUMECHARACTERISTICS OF SPECIFIC VOLUMECHARACTERISTICS OF SPECIFIC VOLUMECHARACTERISTICS OF SPECIFIC VOLUME

For Steam and water at the same pressure , specific volume For Steam and water at the same pressure , specific volume increases with temperatureincreases with temperature

16 kg/cm16 kg/cm22, 210, 210ooC – 0.12911 mC – 0.12911 m33/kg/kg


For Steam, at the same temperature, specific volume decreases For Steam, at the same temperature, specific volume decreases with increase in pressurewith increase in pressure



For Water specific volume does not change with increase in For Water specific volume does not change with increase in pressure, being an incompressible fluid.pressure, being an incompressible fluid.



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ALLOWABLE VELOCITYALLOWABLE VELOCITYALLOWABLE VELOCITYALLOWABLE VELOCITY

SELECTION OF THE MAXIMUM ALLOWABLE SELECTION OF THE MAXIMUM ALLOWABLE VELOCITY OF A FLUID IS IMPORTANT FROM VELOCITY OF A FLUID IS IMPORTANT FROM FOLLOWING POINTS OF CONSIDERATIONFOLLOWING POINTS OF CONSIDERATION

PRESSURE LOSS OF THE FLUID IN THE PRESSURE LOSS OF THE FLUID IN THE PIPE LINE (BEING DIRECTLY PIPE LINE (BEING DIRECTLY PROPORTIONAL TO SQUARE OF PROPORTIONAL TO SQUARE OF VELOCITY OF FLUID).VELOCITY OF FLUID).

EROSIONEROSION

VIBRATIONVIBRATION


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ALLOWABLE VELOCITYALLOWABLE VELOCITYALLOWABLE VELOCITYALLOWABLE VELOCITY

ALLOWABLE VELOCITY SHOULD BE CHOSEN AS ALLOWABLE VELOCITY SHOULD BE CHOSEN AS PER GOOD DESIGN PRACTICE OR AS PER THE PER GOOD DESIGN PRACTICE OR AS PER THE GUIDELINES SPECIFIED FOR VARIOUS SYSTEMS BY GUIDELINES SPECIFIED FOR VARIOUS SYSTEMS BY

THE PROJECT CONSULTANT / CUSTOMERTHE PROJECT CONSULTANT / CUSTOMER..


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ALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHEL

SUPERHEATED STEAM – 50 to 70 m/s SUPERHEATED STEAM – 50 to 70 m/s

(STEAM WITH PRESSURE GREATER THAN 50 kg/sqcm and (STEAM WITH PRESSURE GREATER THAN 50 kg/sqcm and TEMPERATURE GREATER THAN 400 DEG C)TEMPERATURE GREATER THAN 400 DEG C)

APPLICATIONS - MAIN STEAM, HOT REHEAT, COLD REHEAT, HP APPLICATIONS - MAIN STEAM, HOT REHEAT, COLD REHEAT, HP BYPASS U/s & LP BYPASS U/s BYPASS U/s & LP BYPASS U/s

LP BYPASS D/s & HP BYPASS D/s – 100 m/sLP BYPASS D/s & HP BYPASS D/s – 100 m/s

AUX STEAM (SATURATED) – 20 to 30 m/sAUX STEAM (SATURATED) – 20 to 30 m/s

(STEAM WITH PRESSURE LESS THAN 20 kg/sqcm and OPERATING (STEAM WITH PRESSURE LESS THAN 20 kg/sqcm and OPERATING TEMPERATURE VERY CLOSE TO SATURATION TEMPERATURE AT TEMPERATURE VERY CLOSE TO SATURATION TEMPERATURE AT THAT PRESSURE)THAT PRESSURE)

AUX STEAM (SUPERHEATED) – 30 to 40 m/sAUX STEAM (SUPERHEATED) – 30 to 40 m/s

(STEAM WITH PRESSURE LESS THAN 20 kg/sqcm and (STEAM WITH PRESSURE LESS THAN 20 kg/sqcm and TEMPERATURE 20-30 deg MORE THAN SATURATION TEMPERATURE 20-30 deg MORE THAN SATURATION TEMPERATURE AT THAT PRESSURE)TEMPERATURE AT THAT PRESSURE)


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ALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHELALLOWABLE VELOCITY GUIDELINES USED IN BHEL

CONDENSATE DISCHARGE – 1.5 – 3 m/sCONDENSATE DISCHARGE – 1.5 – 3 m/s

BFP SUCTION – 1 – 1.5 m/sBFP SUCTION – 1 – 1.5 m/s

BFP DISCHARGE – 3-6 m/sBFP DISCHARGE – 3-6 m/s

COOLING WATER LINES – 1- 2 m/sCOOLING WATER LINES – 1- 2 m/s


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STEAM (TEMPERATURE – ENTHALPY DIAGRAM)STEAM (TEMPERATURE – ENTHALPY DIAGRAM)STEAM (TEMPERATURE – ENTHALPY DIAGRAM)STEAM (TEMPERATURE – ENTHALPY DIAGRAM)


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PIPES ARE NORMALLY SPECIFIED BY PIPES ARE NORMALLY SPECIFIED BY THEIR OUTER DIAMETER IN MM AND THEIR OUTER DIAMETER IN MM AND THICKNESS IN MM . IN SOME SPECIAL THICKNESS IN MM . IN SOME SPECIAL CASES A PIPE IS SPECIFIED BY ITS CASES A PIPE IS SPECIFIED BY ITS INNER DIAMETER WHICH IS THEN INNER DIAMETER WHICH IS THEN CALLED AN ID CONTROLLED PIPE.CALLED AN ID CONTROLLED PIPE.

ASME STANDARD ASME B36.10 LISTS ASME STANDARD ASME B36.10 LISTS THE VARIOUS STANDARD OUTER THE VARIOUS STANDARD OUTER DIAMETERS AND THICKNESSES IN DIAMETERS AND THICKNESSES IN WHICH PIPES ARE MANUFACTUREDWHICH PIPES ARE MANUFACTURED

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INCH NB OD STD XS XXS 10 20 30 40 60 80 100 120 140 1601/2 15 21.3 2.77 3.73 7.47 2.77 3.73 4.781 25 33.4 3.38 4.55 9.09 3.38 4.55 6.35

1-1/2 40 48.3 3.68 5.08 10.15 3.68 5.08 7.142 50 60.3 3.91 5.54 11.07 3.91 5.54 8.74

2-1/2 65 73 5.16 7.01 14.02 5.16 7.01 9.533 80 88.9 5.49 7.62 15.24 5.49 7.62 11.134 100 114.3 6.02 8.56 17.12 6.02 8.56 11.13 13.496 150 168.3 7.11 10.97 21.95 7.11 10.97 14.27 18.268 200 219.1 8.18 12.7 22.23 6.35 7.04 8.18 10.31 12.7 15.09 18.26 20.62 23.0110 250 273 9.27 12.7 25.4 6.35 7.8 9.27 12.7 15.09 18.26 21.44 25.4 28.5812 300 323.9 9.53 12.7 25.4 6.35 8.38 10.31 14.27 17.48 21.44 25.4 28.58 33.3214 350 355.6 9.53 12.7 6.35 7.92 9.53 11.16 15.09 19.05 23.83 27.79 31.75 35.7116 400 406.4 9.53 12.7 6.35 7.92 12.7 16.66 21.44 26.19 30.96 36.53 40.4918 450 457 9.53 12.7 6.35 7.92 11.13 14.27 19.05 23.83 29.36 34.93 39.67 45.2420 500 508 9.53 12.7 6.35 9.53 12.7 15.09 20.62 26.19 32.54 38.1 44.45 50.0122 550 559 9.53 12.7 6.35 9.53 12.7 22.23 28.58 34.93 41.28 47.63 53.9824 600 610 9.53 12.7 6.35 9.53 14.27 17.48 24.61 30.96 38.89 46.02 52.37 59.5426 650 660 9.53 12.7 7.92 12.728 700 711 9.53 12.7 7.92 12.7 15.8830 750 762 9.53 12.7 7.92 12.7 15.8832 800 813 9.53 12.7 7.92 12.7 15.88 17.4834 850 864 9.53 12.7 7.92 12.7 15.88 17.4836 900 914 9.53 12.7 7.92 12.7 15.88 19.0538 950 965 9.53 12.740 1000 1016 9.53 12.742 1050 1067 9.53 12.744 1100 1118 9.53 12.746 1150 1168 9.53 12.748 1200 1219 9.53 12.752 1300 1321 9.53 12.754 1350 1372 9.53 12.756 1400 1422 9.53 12.760 1500 1524 9.53 12.7

THICKNESS SCHEDULESDIAMETER

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SELECT A PIPE OF DIAMETER GREATER SELECT A PIPE OF DIAMETER GREATER THAN THE CALCULATED ID.THAN THE CALCULATED ID.

THEN PROCEED TO DO THE THICKNESS THEN PROCEED TO DO THE THICKNESS CALCULATIONCALCULATION

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THICKNESS OF THE PIPE WITH THICKNESS OF THE PIPE WITH SPECIFIED OUTER SPECIFIED OUTER DIAMETERDIAMETER IS CALCULATED USING THE FORMULA as per IS CALCULATED USING THE FORMULA as per

REG 350 OFREG 350 OF IBR IBR (INDIAN BOILER REGULATIONS CODE) (INDIAN BOILER REGULATIONS CODE)

T(MINIMUM) = P*D

(2*S*E+P)+ C

P – DESIGN PRESSURE IN KG/SQCM(G)

D – OUTER DIAMETER OF PIPE in mm

E – WELD JOINT EFFICIENCY FACTOR (1 FOR SEAMLESS PIPES, 0.8-0.95 FOR WELDED PIPES)

S – ALLOWABLE STRESS OF PIPE MATERIAL AS PER ASME SEC IID STANDARD in kg/cm2

C – COROSSION ALLOWANCE –0.75 mm

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THICKNESS OF THE PIPE WITH THICKNESS OF THE PIPE WITH SPECIFIED INNER SPECIFIED INNER DIAMETERDIAMETER IS CALCULATED USING THE FORMULA as per IS CALCULATED USING THE FORMULA as per

REG 350 OFREG 350 OF IBR IBR (INDIAN BOILER REGULATIONS CODE) (INDIAN BOILER REGULATIONS CODE)

T(MINIMUM) = P*d

(2*S*E-P)

+ C


d – INNER DIAMETER OF PIPE in mm



C – COROSSION ALLOWANCE –0.75 mm

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THICKNESS OF THE PIPE WITH THICKNESS OF THE PIPE WITH SPECIFIED OUTER SPECIFIED OUTER DIAMETERDIAMETER IS CALCULATED USING THE FORMULA IS CALCULATED USING THE FORMULA as per as per ASME B31.1ASME B31.1

T(MINIMUM) = P*D

2*(S*E+P*y)+ A


D – OUTER DIAMETER OF PIPE in mm



Y - FACTOR DEPENDING ON THE DESIGN TEMPERATURE, TO BE TAKEN FROM ASME B31.1

A – COROSSION ALLOWANCE –(1 OR 1.6 MM)

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THICKNESS OF THE PIPE WITH THICKNESS OF THE PIPE WITH SPECIFIED INNER SPECIFIED INNER DIAMETERDIAMETER IS CALCULATED USING THE FORMULA IS CALCULATED USING THE FORMULA as per as per ASME B31.1ASME B31.1

T(MINIMUM) = P*d +2*S*E*A+2*P*y*A

2*(S*E+P*y - P)P – DESIGN PRESSURE IN KG/SQCM(G)

d – INNER DIAMETER OF PIPE in mm



Y - FACTOR DEPENDING ON THE DESIGN TEMPERATURE, TO BE TAKEN FROM ASME B31.1

A – COROSSION ALLOWANCE –(1 OR 1.6 MM)

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Y- FACTOR AS PER ASME B 31.1Y- FACTOR AS PER ASME B 31.1Y- FACTOR AS PER ASME B 31.1Y- FACTOR AS PER ASME B 31.1

TEMP 0-482 DEG C – Y = 0.4TEMP 0-482 DEG C – Y = 0.4

AT TEMP 510 DEG C – Y = 0.5AT TEMP 510 DEG C – Y = 0.5

AT TEMP 540 DEG C & ABOVE – Y = 0.7AT TEMP 540 DEG C & ABOVE – Y = 0.7

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BASIS FOR THICKNESS FORMULABASIS FOR THICKNESS FORMULABASIS FOR THICKNESS FORMULABASIS FOR THICKNESS FORMULA

2r

dx

t

tConsider the fluid inside the pipe with pressure ‘p’ acting on a

small length dx of the pipe, h – the hoop stress arising due to the reaction

P*2*r dx = h * 2*t*dx

h = p*r / t

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DESIGN PRESSUREDESIGN PRESSUREDESIGN PRESSUREDESIGN PRESSURE

THE PIPING SYSTEM MUST BE DESIGNED TO SAFELY CONTAIN THE PIPING SYSTEM MUST BE DESIGNED TO SAFELY CONTAIN THE MAXIMUM POSSIBLE PRESSURE.THE MAXIMUM POSSIBLE PRESSURE.

FACTORS SUCH AS FAILURE OF CONTROL DEVICES, EVENTS FACTORS SUCH AS FAILURE OF CONTROL DEVICES, EVENTS LIKE SURGE, SAFETY RELIEF VALVES ETC SHOULD BE LIKE SURGE, SAFETY RELIEF VALVES ETC SHOULD BE CONSIDERED WHILE ARRIVING AT THE DESIGN PRESSURECONSIDERED WHILE ARRIVING AT THE DESIGN PRESSURE

DESIGN PRESSURE IS EXPRESSED IN KG/CMDESIGN PRESSURE IS EXPRESSED IN KG/CM22(G)(G)

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MAIN STEAM – SET PRESSURE OF SAFETY VALVE MAIN STEAM – SET PRESSURE OF SAFETY VALVE AT SUPER HEATER OUTLET.AT SUPER HEATER OUTLET.

HOT REHEAT – LOWEST SET PRESSURE OF SAFETY HOT REHEAT – LOWEST SET PRESSURE OF SAFETY VALVE AT REHEATER OUTLETVALVE AT REHEATER OUTLET

COLD REHEAT – MAXIMUM SET PRESSURE OF COLD REHEAT – MAXIMUM SET PRESSURE OF SAFETY VALVE AT REHEATER INLETSAFETY VALVE AT REHEATER INLET

BOILER FEED DISCHARGE – SHUT OFF HEAD OF AT BOILER FEED DISCHARGE – SHUT OFF HEAD OF AT MAXIMUM PUMP SPEED CORRESPONDING TO MIN MAXIMUM PUMP SPEED CORRESPONDING TO MIN RECIRCULATION FLOW.RECIRCULATION FLOW.

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DESIGN TEMPERATUREDESIGN TEMPERATUREDESIGN TEMPERATUREDESIGN TEMPERATURE

THE PIPING SYSTEM MUST BE DESIGNED FOR THE MAXIMUM THE PIPING SYSTEM MUST BE DESIGNED FOR THE MAXIMUM SUSTAINED TEMPERATURE OF THE MEDIUM.SUSTAINED TEMPERATURE OF THE MEDIUM.

DESIGN TEMPERATURE IS EXPRESSED IN DESIGN TEMPERATURE IS EXPRESSED IN ooCC

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ALLOWABLE STRESS OF THE MATERIALALLOWABLE STRESS OF THE MATERIALALLOWABLE STRESS OF THE MATERIALALLOWABLE STRESS OF THE MATERIAL

ALLOWABLE STRESS FOR THE MATERIAL FOR THE DESIGN ALLOWABLE STRESS FOR THE MATERIAL FOR THE DESIGN TEMPERATURE IS ADOPTED FROM THE ASME SEC IID TEMPERATURE IS ADOPTED FROM THE ASME SEC IID STANDARD. ALLOWABLE STRESS IS EXPRESSED IN KG/CMSTANDARD. ALLOWABLE STRESS IS EXPRESSED IN KG/CM2. 2. THE HOOP STRESS ON THE MATERIAL SHOULD BE LESS THAN THE HOOP STRESS ON THE MATERIAL SHOULD BE LESS THAN THE ALLOWABLE STRESS FOR THE TEMPERATURETHE ALLOWABLE STRESS FOR THE TEMPERATURE

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CRITERIA FOR ALLOWABLE STRESSCRITERIA FOR ALLOWABLE STRESSCRITERIA FOR ALLOWABLE STRESSCRITERIA FOR ALLOWABLE STRESS

ALLOWABLE STRESS IS THE LOWEST ALLOWABLE STRESS IS THE LOWEST OF THE FOLLOWING BELOW CREEP OF THE FOLLOWING BELOW CREEP TEMPERATURETEMPERATURE

Specified minimum tensile strength at room Specified minimum tensile strength at room temperature divided by 3.5temperature divided by 3.5

Tensile strength at service temperature Tensile strength at service temperature divided by 3.5divided by 3.5

2/3 of specified min yield strength at room 2/3 of specified min yield strength at room temperaturetemperature

2/3 of specified yield strength at service 2/3 of specified yield strength at service temperaturetemperature

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CRITERIAL FOR ALLOWABLE STRESSCRITERIAL FOR ALLOWABLE STRESSCRITERIAL FOR ALLOWABLE STRESSCRITERIAL FOR ALLOWABLE STRESS

ALLOWABLE STRESS IS THE LOWEST ALLOWABLE STRESS IS THE LOWEST OF THE FOLLOWING ABOVE CREEP OF THE FOLLOWING ABOVE CREEP TEMPERATURETEMPERATURE

100% of the average stress to produce a 100% of the average stress to produce a creep rate of 0.01% / 1000 hrscreep rate of 0.01% / 1000 hrs

67% of the average stress to cause rupture 67% of the average stress to cause rupture at the end of 100,000 hoursat the end of 100,000 hours

80% of minimum stress to cause rupture at 80% of minimum stress to cause rupture at the end of 100,000 hoursthe end of 100,000 hours

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HOOKE’S LAWHOOKE’S LAWHOOKE’S LAWHOOKE’S LAW

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CREEPCREEPCREEPCREEP

Creep is the term used to describe the Creep is the term used to describe the tendency of a material to deform tendency of a material to deform permanently at higher temperatures. permanently at higher temperatures. Material deformation occurs as a result of Material deformation occurs as a result of long term exposure to levels of stress that long term exposure to levels of stress that are below the yield or ultimate strength of are below the yield or ultimate strength of the material.The rate of this damage is a the material.The rate of this damage is a function of the material properties, function of the material properties, exposure time, exposure temperature and exposure time, exposure temperature and the applied load (stress). the applied load (stress).

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WALL THICKNESS CALCULATIONWALL THICKNESS CALCULATIONWALL THICKNESS CALCULATIONWALL THICKNESS CALCULATION

CALCULATE THE MINIMUM WALL CALCULATE THE MINIMUM WALL THICKNESS (TMIN) FOR THE PIPE FOR THICKNESS (TMIN) FOR THE PIPE FOR THE DESIGN CONDITIONS SUCH AS THE DESIGN CONDITIONS SUCH AS PRESSURE, TEMPERATURE AND PRESSURE, TEMPERATURE AND MATERIAL. DO THE MINIMUM WALL MATERIAL. DO THE MINIMUM WALL THICKNESS CALCULATION AS PER THICKNESS CALCULATION AS PER BOTH IBR AND ASME FORMULA AND BOTH IBR AND ASME FORMULA AND TAKE THE HIGHER VALUE.TAKE THE HIGHER VALUE.

ARRIVE AT THE NOMINAL WALL ARRIVE AT THE NOMINAL WALL THICKNESS (TNOM) BY ADDING THE THICKNESS (TNOM) BY ADDING THE PIPE MANUFACTURER’S TOLERANCE OF PIPE MANUFACTURER’S TOLERANCE OF (-12.5%) ON THE MINIMUM WALL (-12.5%) ON THE MINIMUM WALL THICKNESS – (TNOM = TMIN / 0.875)THICKNESS – (TNOM = TMIN / 0.875)

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WALL THICKNESS CALCULATIONWALL THICKNESS CALCULATIONWALL THICKNESS CALCULATIONWALL THICKNESS CALCULATION

SELECT A PIPE WITH WALL THICKNESS SELECT A PIPE WITH WALL THICKNESS HIGHER THAN THE NOMINAL WALL HIGHER THAN THE NOMINAL WALL THICKNESS, FROM THE ASME B36.10 THICKNESS, FROM THE ASME B36.10 STANDARD OR RATIONALIZED LIST OF STANDARD OR RATIONALIZED LIST OF PIPES.PIPES.

CALCULATE THE ID OF THE SELECTED CALCULATE THE ID OF THE SELECTED PIPE. IF THE ID IS GREATER THAN THE PIPE. IF THE ID IS GREATER THAN THE CALCULATED ID , SELECTION IS OK, CALCULATED ID , SELECTION IS OK, OTHER WISE SELECT THE NEXT HIGHER OTHER WISE SELECT THE NEXT HIGHER OD AND REPEAT THE PIPE THICKNESS OD AND REPEAT THE PIPE THICKNESS CALCULATION.CALCULATION.

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SAMPLE CALCULATIONSAMPLE CALCULATIONSAMPLE CALCULATIONSAMPLE CALCULATION

AUXILIARY STEAM LINE TO SCAPHAUXILIARY STEAM LINE TO SCAPH

FLOW = 32 T/HRFLOW = 32 T/HR

OPERATING PRESSURE = 16 kg/cmOPERATING PRESSURE = 16 kg/cm22(a)(a)

OPERATING TEMPERATURE = 210OPERATING TEMPERATURE = 210ooCC

DESIGN PRESSURE = 20 kg/cmDESIGN PRESSURE = 20 kg/cm22(g)(g)

DESIGN TEMPERATURE = 210DESIGN TEMPERATURE = 210ooCC

MATERIAL = SA106GRBMATERIAL = SA106GRB

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CALCULATION OF IDCALCULATION OF IDCALCULATION OF IDCALCULATION OF ID

THE SATURATION TEMPERATURE THE SATURATION TEMPERATURE CORRESPONDING TO 16 kg/cmCORRESPONDING TO 16 kg/cm22(a) is (a) is 200200ooC. SINCE THE DEGREE OF C. SINCE THE DEGREE OF SUPERHEAT (OPERATING TEMP- SAT SUPERHEAT (OPERATING TEMP- SAT TEMP = 210-200= 10TEMP = 210-200= 10ooC) IS LESS THAN C) IS LESS THAN 2020ooC, THE MAX ALLOWABLE VELOCITY C, THE MAX ALLOWABLE VELOCITY IS 30 m/sIS 30 m/s

SPECIFIC VOLUME CORRESPONDING TO SPECIFIC VOLUME CORRESPONDING TO 16 kg/cm16 kg/cm22(g) AND 210(g) AND 210ooC is 0.12991 MC is 0.12991 M33/KG./KG.

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CALCULATION OF IDCALCULATION OF IDCALCULATION OF IDCALCULATION OF ID

ID = 595*SQRT(flow*spvol/velocity)ID = 595*SQRT(flow*spvol/velocity)

ID = 595*SQRT(32*0.12991/30)

ID = 221.49 mm

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SELECTION OF ODSELECTION OF ODSELECTION OF ODSELECTION OF OD

SELECT NEAREST STANDARD OD SELECT NEAREST STANDARD OD GREATER THAN 221.49 mm, NEAREST GREATER THAN 221.49 mm, NEAREST OD IS 273 mm. OD IS 273 mm.

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ALLOWABLE STRESSALLOWABLE STRESSALLOWABLE STRESSALLOWABLE STRESS

ALLOWABLE STRESS OF SA106GRB ALLOWABLE STRESS OF SA106GRB MATERIAL AT 210MATERIAL AT 210ooC IS 1202.24 kg/cmC IS 1202.24 kg/cm22

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SELECTION OF MINIMUM WALL THICKNESSSELECTION OF MINIMUM WALL THICKNESSSELECTION OF MINIMUM WALL THICKNESSSELECTION OF MINIMUM WALL THICKNESS

T(MINIMUM) = P*D T(MINIMUM) = P*D

(2*S*E+P)(2*S*E+P)+ C

T(MINIMUM) = 20*273

(2*1202.24*1+20)

+ 0.75

AS PER IBR

T(MIN)- IBR = 3.00 mm

T(MINIMUM) = P*D

2*(S*E+P*y)

AS PER ASME

+ A

T(MINIMUM) = 20*273

2*(1202.24*1+20*0.4)+ 1.6 T(MIN) - ASME = 3.86 mm

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SELECTION OF NOMINAL WALL THICKNESSSELECTION OF NOMINAL WALL THICKNESSSELECTION OF NOMINAL WALL THICKNESSSELECTION OF NOMINAL WALL THICKNESS

SELECT THE GREATER VALUE OF THE MINIMUM SELECT THE GREATER VALUE OF THE MINIMUM WALL THICKNESS FROM THE CALCULATIONS WALL THICKNESS FROM THE CALCULATIONS USING IBR AND ASME FORMULAE – USING IBR AND ASME FORMULAE –

TMIN = 3.86 mm (GREATER OF 3.00,3.86)TMIN = 3.86 mm (GREATER OF 3.00,3.86)

TNOM = TMIN / (1- NEGATIVE TOLERANCE) TNOM = TMIN / (1- NEGATIVE TOLERANCE)

NEGATIVE TOLERANCE = 12.5%NEGATIVE TOLERANCE = 12.5%

TNOM = 3.86 / (1-0.125) = 3.86 / 0.875 = 4.41TNOM = 3.86 / (1-0.125) = 3.86 / 0.875 = 4.41

SELECT A PIPE WITH WALL THICKNESS GREATER SELECT A PIPE WITH WALL THICKNESS GREATER THAN 4.41 mm FROM B36.10THAN 4.41 mm FROM B36.10

PIPE WITH WALL THICKNESS 6.35 mm (SCH 10) is PIPE WITH WALL THICKNESS 6.35 mm (SCH 10) is SELECTEDSELECTED

SELECTED PIPE IS OF OD 273 AND WALL SELECTED PIPE IS OF OD 273 AND WALL THICKNESS 6.35 MMTHICKNESS 6.35 MM

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CHECK FOR IDCHECK FOR IDCHECK FOR IDCHECK FOR ID

ID REQUIRED AS PER FORMULA = 221.49 ID REQUIRED AS PER FORMULA = 221.49 mmmm

ID OF SELECTED PIPE OD 273 X 6.35 = ID OF SELECTED PIPE OD 273 X 6.35 = 273 – 2*6.35 = 260.3 mm273 – 2*6.35 = 260.3 mm

260.3 mm > 221.49 mm, HENCE 260.3 mm > 221.49 mm, HENCE SELECTED PIPE IS OK. (ID OF SELECTED SELECTED PIPE IS OK. (ID OF SELECTED PIPE SHOULD BE GREATER THAN PIPE SHOULD BE GREATER THAN CALCULATED ID)CALCULATED ID)

42

PRESSURE DROP CALCULATIONPRESSURE DROP CALCULATIONPRESSURE DROP CALCULATIONPRESSURE DROP CALCULATION

43

PRESSURE LOSS IN STRAIGHT PIPESPRESSURE LOSS IN STRAIGHT PIPESPRESSURE LOSS IN STRAIGHT PIPESPRESSURE LOSS IN STRAIGHT PIPES

PRESSURE LOSS IN PIPES IS GIVEN BY THE PRESSURE LOSS IN PIPES IS GIVEN BY THE DARCY-WEISBACH EQUATIONDARCY-WEISBACH EQUATION

p = ( f*l/d)*(vp = ( f*l/d)*(v22/2g)*(1/10000)* /2g)*(1/10000)* p = Pressure Loss in kg/cmp = Pressure Loss in kg/cm22

f = DARCY FRICTION FACTORf = DARCY FRICTION FACTOR

l = LENGTH OF PIPE IN METRESl = LENGTH OF PIPE IN METRES

d = INNER DIAMETER OF PIPE IN METRESd = INNER DIAMETER OF PIPE IN METRES

v = VELOCITY OF FLUID IN M/Sv = VELOCITY OF FLUID IN M/S

g = ACCELERATION DUE TO GRAVITY In m/sg = ACCELERATION DUE TO GRAVITY In m/s22 – – 9.81 m/s9.81 m/s22

= DENSITY IN kg/m= DENSITY IN kg/m33

44

FRICTION FACTOR FOR PIPESFRICTION FACTOR FOR PIPESFRICTION FACTOR FOR PIPESFRICTION FACTOR FOR PIPES

DARCY FRICTION FACTOR = 4 * MOODY DARCY FRICTION FACTOR = 4 * MOODY FRICTION FACTORFRICTION FACTOR

(mm)

= Absolute Pipe Roughness in mm = 0.05 for Steel Pipe

d = Inner Diameter of Pipe in mm

Re = Reynolds Number

f = Moody Friction Factor

The Barr Equation

89.010 Re

1286.5

71.3log4

1

df

2

89.010 Re

1286.5

71.3log41

df

45

REYNOLDS NUMBERREYNOLDS NUMBERREYNOLDS NUMBERREYNOLDS NUMBER

REYNOLDS NUMBER IS A REYNOLDS NUMBER IS A DIMENSIONLESS NUMBER CALCULATED DIMENSIONLESS NUMBER CALCULATED BY THE FOLLOWING FORMULABY THE FOLLOWING FORMULA

Re = Re = *V*d/*V*d/ = DENSITY OF FLUID IN kg/m= DENSITY OF FLUID IN kg/m33

V = VELOCITY OF FLUID IN m/sV = VELOCITY OF FLUID IN m/s

d = INNER DIA OF PIPE IN mmd = INNER DIA OF PIPE IN mm

= ABSOLUTE VISCOSITY IN CENTIPOISE = ABSOLUTE VISCOSITY IN CENTIPOISE (cP) (CENTIPOISE = VISCOSITY IN KG/M-S (cP) (CENTIPOISE = VISCOSITY IN KG/M-S *1000 )*1000 )

46

REYNOLDS NUMBERREYNOLDS NUMBERREYNOLDS NUMBERREYNOLDS NUMBER

IF THE REYNOLDS NUMBER < 2000, IF THE REYNOLDS NUMBER < 2000, FLOW IS LAMINARFLOW IS LAMINAR

IF THE REYNOLDS NUMBER > 4000 IF THE REYNOLDS NUMBER > 4000 FLOW IS TURBULENTFLOW IS TURBULENT

47

FRICTION FACTOR FOR FITTINGSFRICTION FACTOR FOR FITTINGSFRICTION FACTOR FOR FITTINGSFRICTION FACTOR FOR FITTINGS

THE RESISTANCE TO FLOW OF FLUIDS THE RESISTANCE TO FLOW OF FLUIDS IN FITTINGS IS GIVEN BY A RESISTANCE IN FITTINGS IS GIVEN BY A RESISTANCE FACTOR ‘K’.FACTOR ‘K’.

K = f*(Leq/D)K = f*(Leq/D)

F = DARCY FRICTION FACTORF = DARCY FRICTION FACTOR

Leq = EQUIVALENT LENGTH OF FITTINGLeq = EQUIVALENT LENGTH OF FITTING

D = INNER DIAMETER OF PIPE IN D = INNER DIAMETER OF PIPE IN METRESMETRES

48

(Leq/D) for FITTINGS(Leq/D) for FITTINGS(Leq/D) for FITTINGS(Leq/D) for FITTINGS

(Leq/D) FOR VARIOUS FITTINGS IS (Leq/D) FOR VARIOUS FITTINGS IS OBTAINED FROM CRANES HANDBOOK OBTAINED FROM CRANES HANDBOOK OF FLOW OF FLUIDSOF FLOW OF FLUIDS

FITTING (Leq/D)

ELBOW 14

RUN TEE 20

BRANCH TEE 60

RESISTANCE FACTOR K = f * (Leq/D)

PRESSURE LOSS IN FITTINGS K = f * (Leq/D)

49

RESISTANCE FACTOR DIRECTLY GIVENRESISTANCE FACTOR DIRECTLY GIVENRESISTANCE FACTOR DIRECTLY GIVENRESISTANCE FACTOR DIRECTLY GIVEN

RESISTANCE FACTOR FOR FITTINGS RESISTANCE FACTOR FOR FITTINGS LIKE VALVES CAN BE DIRECTLY LIKE VALVES CAN BE DIRECTLY OBTAINED FROM CATALOGUES OBTAINED FROM CATALOGUES INSTEAD OF (Leq/D) METHODINSTEAD OF (Leq/D) METHOD

FITTING K

GATE VALVE – 10” 0.182

NON RETURN VALVE – 10”

0.98

50


FIND THE PRESSURE DROP IN THE FOLLOWING FIND THE PRESSURE DROP IN THE FOLLOWING PIPE. ALLOWED PRESSURE DROP IS 3 kg/cmPIPE. ALLOWED PRESSURE DROP IS 3 kg/cm22

PIPE SIZE – OD 273 X 28 (ID = 273-2*28 = 217 mm)PIPE SIZE – OD 273 X 28 (ID = 273-2*28 = 217 mm)

FLOW – 150 T/HRFLOW – 150 T/HR

PRESSURE AT OUTLET OF BOILER – 90kg/cmPRESSURE AT OUTLET OF BOILER – 90kg/cm22(a)(a)

TEMPERATURE AT OUTLET OF BOILER – 515 deg CTEMPERATURE AT OUTLET OF BOILER – 515 deg C

SPVOL = 0.03174 mSPVOL = 0.03174 m33/kg/kg

DENSITY = (1/SPVOL) = 25.99 kg/mDENSITY = (1/SPVOL) = 25.99 kg/m33

VISCOSITY = 0.029 cPVISCOSITY = 0.029 cP

51


LENGTH OF PIPE – 65 metresLENGTH OF PIPE – 65 metres

FITTINGS IN THE LINEFITTINGS IN THE LINE

90 deg LR Elbow – 14 Nos90 deg LR Elbow – 14 Nos

Gate Valve – 1 NoGate Valve – 1 No

Run Tee – 2 NosRun Tee – 2 Nos

Flow Nozzle (Fixed Pressure Drop – 0.3 Flow Nozzle (Fixed Pressure Drop – 0.3 kg/cmkg/cm22))

52

CALCULATION OF VELOCITYCALCULATION OF VELOCITYCALCULATION OF VELOCITYCALCULATION OF VELOCITY

VELOCITY OF FLUIDVELOCITY OF FLUID

ID = 595*SQRT(flow*spvol/velocity)

ID2 = 595*595*(flow*spvol/velocity)

velocity = 595*595*(flow*spvol/ID2)

velocity = 595*595*(150*0.03174/2172)

velocity = 43.39 m/s

53

CALCULATION OF REYNOLDS NUMBERCALCULATION OF REYNOLDS NUMBERCALCULATION OF REYNOLDS NUMBERCALCULATION OF REYNOLDS NUMBER

Re = Re = *V*d/*V*d/

Re = 25.99*43.39*217/0.029Re = 25.99*43.39*217/0.029

Re = 8438353Re = 8438353

54

CALCULATION OF MOODY FRICTION FACTORCALCULATION OF MOODY FRICTION FACTORCALCULATION OF MOODY FRICTION FACTORCALCULATION OF MOODY FRICTION FACTOR

f = 1/[-4*log10(0.05/3.71*217 + 5.1286/(8438353)0.89)]2

The Barr Equation

89.010 Re

1286.5

71.3log4

1

df

2

89.010 Re

1286.5

71.3log41

df

f = 1/[-4*log10(6.56*10-5)]2

f = 1/ [-4*- 4.18]2

f = 1/ 279.95

f = 0.00357

Darcy Friction Factor = 4*f = 0.01428

55

TOTAL PRESSURE DROPTOTAL PRESSURE DROPTOTAL PRESSURE DROPTOTAL PRESSURE DROP

PRESSURE DROP IS STRAIGHT PIPE + PRESSURE DROP IS STRAIGHT PIPE + PRESSURE DROP IN PRESSURE DROP IN FITTINGS+PRESSURE DROP IN FITTINGS+PRESSURE DROP IN VALVES+PRESSURE DROP IN FLOW VALVES+PRESSURE DROP IN FLOW NOZZLENOZZLE

56

CALCULATION OF PRESSURE LOSS IN CALCULATION OF PRESSURE LOSS IN STRAIGHTPIPESTRAIGHTPIPE

CALCULATION OF PRESSURE LOSS IN CALCULATION OF PRESSURE LOSS IN STRAIGHTPIPESTRAIGHTPIPE

p = ( f*l/d)*(vp = ( f*l/d)*(v22/2g)* /2g)* *(1/10000)*(1/10000)

p = (0.01428*67/0.217)*(43.39p = (0.01428*67/0.217)*(43.3922/2*9.81)*25.99* /2*9.81)*25.99* (1/10000)(1/10000)

p = 1.06 kg/cmp = 1.06 kg/cm22

57

PRESSURE LOSS IN FITTINGSPRESSURE LOSS IN FITTINGSPRESSURE LOSS IN FITTINGSPRESSURE LOSS IN FITTINGS

90 DEG LR ELBOW = 14 NOS90 DEG LR ELBOW = 14 NOS

RUN TEE = 2 NOSRUN TEE = 2 NOS

Leq/D FOR ONE ELBOW = 14Leq/D FOR ONE ELBOW = 14

Leq/D FOR ONE RUN TEE = 20Leq/D FOR ONE RUN TEE = 20

TOTAL Leq/D FOR FITTINGS = 14*14+2*20 = 236TOTAL Leq/D FOR FITTINGS = 14*14+2*20 = 236

TOTAL RESISTANCE K = f*Leq/DTOTAL RESISTANCE K = f*Leq/D

K = 0.01428*236 = 3.37K = 0.01428*236 = 3.37

FRICTION LOSS = K*(VFRICTION LOSS = K*(V22/2g)* /2g)* *(1/10000)*(1/10000)

FRICTION LOSS = 3.37*(43.39FRICTION LOSS = 3.37*(43.3922/2*9.81)*25.99* (1/10000)/2*9.81)*25.99* (1/10000)

FRICTION LOSS IN FITTINGS = 0.84 kg/cmFRICTION LOSS IN FITTINGS = 0.84 kg/cm22

58

PRESSURE LOSS IN VALVESPRESSURE LOSS IN VALVESPRESSURE LOSS IN VALVESPRESSURE LOSS IN VALVES

RESISTANCE FACTOR FOR GATE VALVE RESISTANCE FACTOR FOR GATE VALVE NB 250 = 0.182NB 250 = 0.182

K = 0.182K = 0.182

FRICTION LOSS = K*(VFRICTION LOSS = K*(V22/2g)* /2g)* *(1/10000)*(1/10000)

FRICTION LOSS = 0.182*(43.39FRICTION LOSS = 0.182*(43.3922/2*9.81)*25.99* (1/10000)/2*9.81)*25.99* (1/10000)

FRICTION LOSS IN GATE VALVE = 0.045 kg/cmFRICTION LOSS IN GATE VALVE = 0.045 kg/cm22

59

PRESSURE LOSS IN FLOW NOZZLEPRESSURE LOSS IN FLOW NOZZLEPRESSURE LOSS IN FLOW NOZZLEPRESSURE LOSS IN FLOW NOZZLE

FRICTION LOSS IN FLOW NOZZLE = 0.3 FRICTION LOSS IN FLOW NOZZLE = 0.3 kg/cmkg/cm2 2

60

TOTAL PRESSURE DROPTOTAL PRESSURE DROPTOTAL PRESSURE DROPTOTAL PRESSURE DROP

PRESSURE DROP IS STRAIGHT PIPE + PRESSURE DROP IN FITTINGS+PRESSURE DROP IN VALVES+PRESSURE DROP IN FLOW NOZZLE

TOTAL PRESSURE DROP = 1.06+0.84+0.05+0.3 = 2.25 kg/cm2

61

CHECK FOR ALLOWED DROPCHECK FOR ALLOWED DROPCHECK FOR ALLOWED DROPCHECK FOR ALLOWED DROP

SINCE TOTAL PRESSURE DROP OF 2.25 SINCE TOTAL PRESSURE DROP OF 2.25 kg/sqcm IS LESS THAN ALLOWED kg/sqcm IS LESS THAN ALLOWED PRESSURE DROP OF 3 kg/sqcm, THE PRESSURE DROP OF 3 kg/sqcm, THE SELECTED PIPE SIZE IS OK.SELECTED PIPE SIZE IS OK.

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Pipe Sizing