EXAMINATION FOR COMPETENT PERSONS FOR INSPECTION AND CERTIFICATION OF BOILERS - OCTOBER 2015 BOILER DESIGN ENGINEERING

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1 Regn.No. _ Paper- 1 Name: (To be written by the candidate) EXAMINATION FOR COMPETENT PERSONS FOR INSPECTION AND CERTIFICATION OF BOILERS - OCTOBER 2015 BOILER DESIGN ENGINEERING Date: 11/10/2015 Question I Time: 09:30-11:30 Hrs. Marks: x 2 = 10 marks a. b. c. 1) Whether Inspecting authority can inspect a boiler meant for export? 2) What is the form in which he will certify? What is the minimum thickness of the boiler plate allowed by IBR? 1) When a shell is made of more than one ring, how the longitudinal joints of the adjacent rings are placed? 2) In the tube thickness calculations, how the constant "c" varies with the working pressure? 1) Name any three. boiler mounting fittings to be provided essentially in every boiler. 2) In shell type boilers, is it allowed to form the uptakes through ERW process? and cross tubes w en d. What are the limiting criteria for using? 1) Ellipsoidal heads 2) Partial spherical heads e) After how many hours/years the boilers shall be tested for Remnant Life Assessment Organization of its components. Question II 1) The boilers which are operating at a temperature of 400 C (main steam outlet temperature) 2) The boilers which are operating at a temperature of less than 400 C (main steam outlet temperature) Design a Boiler Drum with the following parameters Design Pressure 170 Kg/ Cm 2 Design temperature 354 C Drum inside diameter 1778 mm Drum thickness 155 mm Drum material SA299 Stress values for the Shell plate BOILER DESIGN ENGINEERING 30 marks 1

Temp'iC 300 325 350 375 Stress Value Kg/Cm 2 1454 1420 1380 1309 Hole drilling pattern in the Drum is as per the attached Sketch.

2 Temp'iC Stress Value Kg/Cm Hole drilling pattern in the Drum is as per the attached Sketch. Assume that the down comer pipe and eco inlet connection pipe are self- compensated. Diagonal efficiency need not be considered. a) Calculate the minimum ligament efficiency. b) Calculate the maximum working Pressure for the Drum as per the code. c) Check whether the Down comer Nozzle needs compensation for the given design parameters. DRUM t---1f---etm7ffi----ffh-ffi---ffi---ft'r t---"-tp1.:...:...:01-a(rises )@650Pitch, 17.5-B(lnst tapping)@midleofthepitch f--f-h---f++---f+i--+h-f-h---f++---f++---'i'-j..>..l-a(rises )@650 Pitch t---1f---ffi----ffi.--ffr--flr-ffi----ffi.--fft---"-tp1.:...:...:0 1-A( Rises )@650Pitch -f-1-t h-}++++-ii-+t++_t--"-tp2=.=72-c DownComer@1200Pitch Question III 10 marks 1 Manifold Header with Hemi Spherical dish end for the followingdesign condition. Header Outside diameter =127mm Drum pressure = 56kg/Cm 2 Header Pressure drop before drum=3kg/ Cm 2 Medium Temperature = 271 Degree C Thickness = 18mm Header material = SA234WPC Assume C Value Height = 61.50mm The Hemi Spherical Header dish end is located outside the furnace. Check whether the provided thickness is sufficient. Question IV 30 marks Refer the sketches 1 to 3. The horizontal multi tubular boiler is to be designed for a maximum working pressure of kg/cm 2 Check whether the thickness provided for: (a) Furnace and (b) Shell end plates. Material used for construction temperature is 185 C is conforming to SA 515 Gr.70. The saturation BOILER DESIGN ENGINEERING 2

$MAIN STEAM STOP VALVE :T' 18 REVERSING -rt REAR EN;HAMBER ' +-T PLATE\ a 1 1 ='1-_,_1- : - - - - -. FRONT END Ie 'i 8 1. ---------.- ---- 111 18 Cl._OF ---U-OF ---- _ Cl.OF).$

3 =o t= e I a I:)!1!: cl 370Q I.. aoox4oo.1 (OPENING) SHELL REAR END PLATE 1.PRESSURE GAUGE 2.SAFETY VALVE 3.AUXIUARY VALVE. STlffENER RING 5.MANHOLE 6.MAIN STEAM STOP VALVE :T' 18 REVERSING -rt REAR EN;HAMBER ' +-T PLATE\ a 1 1 ='1-_,_1- : FRONT END Ie 'i Cl._OF ---U-OF ---- _ Cl.OF). _ REVERSING CHAMBER DETAIL - A 2SOO 14mm THK ACCESS PIPE 14mm THK ASH DROP OUT PIPE I!KI <478 SECTIONAL ELEVATION SKETCH 1 FOR QUESTION 4- Co)

4 GUSSET N.W.L or CL BOILER CL OF REVERSING CHAMBER STAY TUBES REVERSING CHAMBER STAY ROD PRESSURE CIRCLE DIAGRAM FOR SHELL REAR END PLATE SKETCH Z. FOR QUESTION 4- BOILER DESIGN ENGINEERING 4

5 GUSSET N.W.L CL or rur(2) CL or BOILER CL or FUR:1 I FURNACE-I STAY TUBES PRESSURE CIRCLE DIAGRAM FOR SHELL FRONT END PLATE SKETCH 3 FOR QUESTION 4- BOILER DESIGN ENGINEERING 5

Question V 20 marks During renovation ofa boiler, the owner was planning to install an integral economizer coil with the tube of size OD 51mm and material SA210Gr Al in the convection pass of the

6 Question V 20 marks During renovation ofa boiler, the owner was planning to install an integral economizer coil with the tube of size OD 51mm and material SA210Gr Al in the convection pass of the boiler. The various tube thicknesses available are 4.5mm, 5mm and 5.2 mm. Previous to the installation the economizer working pressure was 225 KgjCm 2 and the design temp was 345 C. What is the minimum thickness required for the tube and justify. Allowable stress values can be taken from the table below: Ternp'[C Stress Value KgjCm End of Question Paper BOILER DESIGN ENGINEERING 6

BHEL Steam Generators Material Selection Overview by Veerendar Aluvala DM/BHEL/Trichy

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