<, ''h:,''<.o,'''''_' ~ ~/ Ioo LLrt~ :J IS ~ E ... Jz_ ---------- /~ GOVERNMENT KARNATA~A ~ . f ~,) (Dq1:1rtment ofF,lctories Boiiers}, ~ Time _ 2.00 hours Max. Marks - 100 i ( Boiler Op ration Engineers Examination) All Questions carry 4 marks each Subiect: Boiler a d Heat Engines , i I /1 C():;o:cL {~:> ;(}'/?' 91. Ho~v is the teml~~1_~defined, arId how does this tenn affect wt boiler ' desIgn? .- V / / /--- Az. Wha~ is a down comer? ~.\(, \~ - 3 J~I S'3. {, /' .. ' r .... .• /' 'I r ;t \ ~3. What is Combustion and them1al efficiency ~ithe Boiler ..~ .,; f. '< ..' ? Q4·. \Vh~n does a boiler become a high-temperature hot-water (hth\\') unit? ' ' ·;,,<..• ,jQs,.\V~lat is t lt~meaning. or pH in w~ll:~r chemistry? 'l1' ~ ' 7~~. /' -' 06. Vh:,t three: DUrl)OS7CS7 11= c::: b o\' dO\VI~ valve serve? p ,t.(, t--L~- v ~ / A:J.7. In w at manner is the quality ofa weld checked? ffi List the operating precautions needed to prevent furnace ,~xplosionV ~at is the pur ose ofan Economizer~' ~~.y ~ Name the two methods uf analyzing coal? b'~ ' QlJ- ,Namc three scale COllning properties of water? What ar~ the t'NO major \ \. v~ ¥ objections to sC:lI~ in a boiler? ~ / .. ' -<111--.&- ~12: What IS the purpose of · D and ID {<ans? \ 1- . ~Plai n the teon heating val ue 0 r fEeJ? t V / P 'J( tVJ iJ I Jj ;,,,~~Q14..'':hy 'vc ir. s ;>J f11cnt sirnro rta nt [('I' })roperly operating a steam gen~rat0~ or v <;;'ti~·p;? . ~. c ~. Explain the din~~rellce bl (wecn :l rciicfvalvc and an SV What is a safety relief valve? / -Qf6. What arc the comIllon or primary mCJSuremcnts used in controlling boilers? ~ .~hat i~: carry-over, and how is it'callsed;- \~ r'
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?O C) bChhattisgarh Boiler Operation Engineers Examination 2006
fS ( i \e
Time: 3 Hours Boiler Heat Engines Max. Marks : 100
Q-I Tick the correct answer: -i) The first law of thermodynamics states that (20 X J )=20
~ Heat and work are mutually convertible.b. If two bodies are each equal in temperature to a temperature of third body tlley are equal
in temperature to each other.
c. Change of internal energy is proportional to the change oftemperaturr.
d. Heat can not flow from lower temperature to higher temperature without the aid of an
external agency.
ii) Second law of thermodynamics states that
a. Heat and work are mutually convertible.
b. If two bodies are each equal in temperature to a temperature of third body they are equal
in temperature to each other. ~ Z.oa-J.n ~
c. Change of internal energy is proportional to the change of temperature.J Heat cannot flow from [ower temperature to higher temperature without the aid of anexternal·agency.
iii) Zeroth s law of thermodynamics states that
a. Heat and work are mutually convertible.
~ If two bodies are each equal in temperature to a temperature of third body they are equalin temperature to each other.
c. Change of internal energy is proportional to the change of temperatw c.
d. Heat cannot flow from lower temperature to bigher temperature without
the aid of an external agency.
iv) In thermodynamically reversible process when heat interchange is zero, the process isknown as
a. fsopiestic process. t--l:r Adiabatic process
c. lsochoric process d. Isothennal process
v) In thermodynamically reversible process when change in internal energy is zero, the process isknown as
a. lsopiestic process. b. Adiabatic process
c. lsochoric process vcr.- Isothermal processvi) The main purpose of reheating of steam of thermal plant is
a. To increase dryness fraction of steam in LP stage.
b. Reduce the blade erosion and improve blade efficiencies in LP stages.
c. Increase thennal efficiency
~ Above all
vii) For protecting magnetite layer in boiler tubes, the pH of boiler water should be
a. Less than 8. L-@-£etween 8.8 to 9.2.c. More than 9.8 d. None of above
viii) In trisector regenerative Air preheater boiler, PA fan handles the\AI. cold air b. Hot air
c Tempered air of mill outlet d. None of above.
sk ix) Circulation Ratio range of~igh pressure (100-160 Kgf/cm2) utility and industrial boiler isa.50to15 ~14to9
c. g to 4 c. 3tOTx) The amount of nitrogen in coal is determined by:
a. Its proximate analysis;.~ C i H 2,..(; I V M , A-s h c. v_
b. Burning it completely in air;
.v@ Ultimate analysis;d. Burning it in the absence of air;
xi) Swichiome;;u'ic quamity of air is Lilt qUl1l1lity of air required for complete combustion of fuel with
a. Some excess oxygen left. b. No oxygen left unusedc. 50 ex~ air. d. 1QUO/o excess air.
\ xii), Bomb calorimeter is used to determine,_. a. GCV at constant pressure· b. NCV at constant pressure
c. GCV at constant volume d . NCV at constant volume
xiii) Proximate analysis of fuei is determination oJ~cntagc of. C,H,N,S & H20 l U IH~ ®.£ H20,ash and volatile matter
Q. Conly. d. Useful heat evolved.
xiv) lncomplete combustion can be best judged by
a. Smoky chimney exit. b . Excess air in flue gases
c. Measuring C(l in flue gases. d. Measuring C(h in flue gases.
xv) Lignite is
a. Lowest rank coal. b. Highest rank coal.
c. Used in metailurgy of iron d. Comains no moisture
xvi) Hard water may be softened by passing througha. Sodium Silicate b, Lime stone
b. Ion exchange resign d . Sodahexa metaphosphate.
xvii) Drum imemais ofboiier consists of
a. Level switches for high/low level alanns b. Scrubber cyclone separator.- c. Hydrastep d. Downcomer.
xix) The purpose of continuous blow down valve isa. to control water level b. to drain the boiler
c. to maintain TDS d. to remove sludge.
xx) Two gauge glasses often fitted in boiier drum because
a. One is check against the other b. One is reserve
c. It is a legal requirement d. To increase periods between naintenance
Q-2:- Fiii in me blanks of followiIlg :- (20X I)=20
i) The quantity of heat evolved when unit mass volume of fuel is burnt completely is called
itL _ii). The minimum temperature at which fuel must be preheated so that it starts Jurning is
called temperatUre.
iii.) To remove the is the purpose ofa bottom blow down.
iv.) At low pressure boiler. the water wall tube will overheat due to departure from nucleate boiling
when circulation ratio drops to less th~ to__ ,
v.) Bomb calorimeter is used for determining the calorific value of .vi) Anthracite posses calorific value and carbon percentage.
vii) Temporary hardness in water can be removed by _
viii) pH of neutral water is __ '
ix) Formation of ice cube is the process where enrropy .
x) Carnot cycle consists of two adiabatic two reversible process.
xi) Atmospheric air contains __ of oxygen by volume.
xii) Purest fonn of natural water is water.
xiii) Calcium sulphate when present in boiler feed water causes the formation >f in theboiler.
xiv) Analysis involving the estimating of C,H.N,S and ash is called malysis.xv) As per IBR 1950 regulation 29r ,the safety 'valve reset pressure should no: be less than__
but not more than __ below the safety valve set pressure tor safety '/alves having body
bore more than 32 mm and or having a set pressure above 2 bar gauge.
xvi) Deaerator out let feed water dissolved oxygen is limited to >pb
Find the heat rate of plant and coal firing rate if GCY of firing coal is 3800kc1Vkg, .--
v) What are the reasons for PF mill firing and what action should be laken duting mill fire?
Q-3:- .:- Use steam table for solving following questions. (5X4)=20
./ i) Find the enthalpy and internal energy of lkg steam at pressure of 10 kgfJ,:m2 when dryness
- fraction of steam is 0.75.
~I t~~.<' ii) Find the enthalpy and internal energy of 1kg superheated steam at pressure of 10 kgflcm2;/~;.-'t and temperature of230 C. Assume Sp Heat (Cp)i 0.5 for this superheate<J_range.
d } ~ . ;) It:~.\iii) 0 .005 m3 of ~ater is boil~ at 30°C. It is heated ~ti,1 the pressure is 8 ~Jkgflcm2 and'I (l-· dryness 0.9. Fmd the quantity of heat added for achlevmg above steam l}lL-ill ty.
iv) A boiler supplies steam to a turbine at 18 kgflcm2 dry and saturated. From the same boiler
st~l is foo by throttling to a steam engine working at 10 kgllcm L, Determ ine the quality of
stearn entering to steam engine. Assume Cp for superheated range 0.5.
v) If the superheated steam of temperature 200°C at 10 kgllcm2 feeding to a SLeamengine and
Specific enU'opy of this steam is 1.5&49kcaVkg K. If 11lissteam in engine nxpandsAdiabatically to 1.1 kgflcm2. Find the change of enthalpy of steam during expansion.
28. WhajJs the percentage ofSulphur found in most coals :-~.:_l% (b) 3 -7 %
(c) 5 -10 (d) 8 -12
29. On thrott ling a real gas, temparature of the gas :-
'If.. (a) Increases Jl?}' decreases
(c) Remains same (d) Depends upon initial temparature
30. The most ef ficient cycle is: -
~.a( Carnat cycle (b) Rnkine cycle
(c) Otto cycle (d) Diesel cycle
Q-2 Fil l In theblanks fol lowing:- (1 x1)=15
:.:. -..1. The condition of incomplete combustion issensed bymeasuring .•.•.•••.••.2. Heatvalue with products ofcombustion cooled down toinit ial condition
Is called •.•.•.••.••.
3. Good combustion and high efficiency is indicated by high volume of
(30 x1):::30
Max. Marks: '100Boller & Hoat Engines
(8, Lc:;w of cons8rva~ioll cf mess
(b) ~w ofconservation ofen~L_
(c) Lawof conservation ofmomentum
(d) Noneof the above.
8. Drynessfraction represents :l(a) % of mass of steam to mass of water
(b) % of mass of water to massof steam
,_ ,(0) of mass of dry saturated steam to total mass of wet steam
As per JSR, hydraulic test of newly constructed boiler is to be carried out
at 1.5 times the design pressure.
Hydrazine is fed in CEP suction line_
Copper increases the hardness of steels.
Solubility ofTrisodium in water reduces with increase of temperature .
Compression ignition is used in petrol engines.
Magnetite layer is found after deaerator.
A grade coal has lowest GCv. .L-i n 7 _ b~.s.l . - J e ~5 ~ '--', .-PHofneutalwaterlszero. C. PH - 7, b ~v~-:rtulU> ~ .:~c...;d..,
If grindability index of coal is less, the coal is easily grindable. _;.'. , _l ,-Thermal power plant work in the principles of camot cycle. ~.>~.:.:'::,:-\.':':..-:.2--
Turbine is provided with multistage blades to limit the blade speed.
For acceleration of fluid in supersonic velocity range, the nozzle lIsed
must be divergent nozzle.
Give answers of the following :-
1. What is nternal energy?
2. What is regenerative air preheater?
3. What is the purpose of primary air?
4. What is the maximum metal temperature difference permitted in drum?
5. What is all volatile treatment in boiler?
6. What is the chemical composition of carbon steel?
7. What is the chemical composition of SA213T11 ?
8_ What is the chem ical composition of SA213T22 ?
9. Effective disconnection of toiier?
iO. Ageing of Boilers - Assessment of the remanent life of parts ?
Answer briefly any of tile five questicns- 5x2 = 10
1. Define heat?
2. What is the stress corrosion cracking?
3_ What is the purpose of drum in boiler?
4. Mention the type of safety valves us ,d in boiler?
5_ What are the materiais used iti sup,:::rhe2[er and reneater in modem
o. Major types of coal feeding systemvailable in AFBC/CFBC
Boilers are v\.-.l.· -f-.17 and i·\ .•/\·..•.-- d ...-
P. Major attractive feature of eFEC Boiler w.r.f~ emission is
(. r ,· ./-;,,·t.1 Sf f • • ; ;. .1-·>f •
Q. Since heat release rate per unit furnace cross sec~ion isas 10\' as ' hence the max i.11111~1 econOlFica1capacity of a AFDC Boiler get r.estricted t.o ._ to
TPH.
,C • / ,2,'/. (,
ih (''' 'l. .p4L eft iele.'.j by:;:illrl~ of 5l'C.llll hl'low OItmospher.e.
(5) The Ratio of Primary air velocity to Secondary air is
(a) 1 (b) les8 than 1 (c) More than 1 (d) Any value.
(6) Mill fineness for - 200 mesh should be -
(a) 70 (b) 50' (c) 30' (d) 20
(7 )
(8 )
The latent~heat is su~p1ied in a Boiler in -
\.~)/waterwall (b~ Superheater (e) Down comer (d) Rehea;er.\In natural circulation the driving force is due to(a) Force exerted by Drum pres £lure• , .'
.,(j;yPOensity difference ot Steam and wa'ter(c) Pressure of BFP(d) None of the above.
(9) In a boiler Hydrazene is fed in -(a) Main steam line (b) Reheat Steam line(c) CEP Suction line ~dr BF? Suction line.
(10) The critical Pressure for Ste~ater ia-a) 190 Ksc 2~5 Kspc)
275 Ksc (d)25 Ksc.
rise in Econ~miser is-
(a) 50°C (b). 100°C (c) °C (d) JOoC.-;
(b) At the bottom ~f boiler
(d) ,None of the above.
~b·)/~tside furnace
(d) None of the above.
Pent house i~ situated
(a) At the top of boiler(e) Below drum
Down comer is-(a) Inside furnace(e) On water wall surface
i
15.
14.
I.
16.
'(12) Ash fusion temperature is important for(a) Heat transfer in water wall(b) Cold end corrosion
~siag formation
(d) Flow at ash particle in Boiler.
(13) The-maincomoosi tion of Ash ..ealEil is form~c1,,_ :,,-_,-_ , cLi) Iiislde'the···tube··-- ..--- (b) Outside--the tube .(e) On the furnace ~efr~=~tr~ (d) None b the ~bove./
Control stage in the turbine is - I.
(a) Last stage (b) First stage(e) One atage before last state (d) None.
:
.:
17. The value of pressure setting of MS Safety valve is dona-\a) Higher t(.b-r-Lower
\c) Equal (d) None of the above.
18. Three element control is used for-
(a) Spray control ~Drum level control
(e) RH steam temperature control(d) SF? Recirculation control.
19. The Boiler efficiency in Modern Thermal Power Station is
in the range of-
( a ) 60 t (b ) 8 0 ,tc') 9 0 ( d ) 4 0
·20. Volatile matter limits-
(a) Maximum temperature in furnace.(b) Maximum Mill outlet temperature\c) Air temperature to Boiler(d) None of the above .
------Steel<l\\a.be simlpy defined a j an allow of iron and carbonwhich doe not contain more ~aan . carbon •
Hardnes; - of .steel ¥y be- def .nd ' as_6tatict dynamic loads ~nd als. as resistance to
and
Major attractive feature 9f CFBC Beiler w.r.f.•emission is
What is proxim~
Wh3t is thede':lerator?
(xvii) What is materia' for Superheater (mo3t commonly used) ~
(xv)
(xvi)
(xii)
(xiii)
(xiv)
(xi)
What are dl':,ferentmode of heat transfer ?, f \
What is the )~rp06e of deaerator ?
What is th· offc,,', of Bulphurp In coal onperformance • ,
(}Ii) Why rotor heat ',ngis lone in turbine ?
(vii) Why chlorine il added in cooling water?
(viii) What is the cr; :ical)ressure of water ?
(ix) Name different ~I?e of governing in steam turbine ~
x Which cycle ha maximum thermodynamic efficiency workin~betwe~n two ~i~'~n reservoir 1At what press' re 'the hydraulic testof _a Boiler i~carried out af .U' erection on Bite ? I
What do you me; .1 by HGI. of coal ?
Why stres6re:~eving is required for steam headers?
What is normall· percentage of excess air kept in boilefor efficient , mbustion ?
(iii)
(iv)
( v)
s .
T.
since heat release rate per unit urnace cross section isas 10' as henc the m:;\xi:uumconomical
capac
i :y of-a--A-F-B-C--B-o-~-'l-e-r--g-etes .:r icted tc .t
0. TPH.
----,-~. : A'.'_' '_ _.'_'. ·flui•.dizing,~ab~orpt on al10~~_ ,.
Draw a neat schematic layout of Demineraliser Plant 8.explain the working.
Explain with neat sketches:
i) Boiler Safety Valveii) Steam Trap
Draw a neat sketch of Raymond Bowl Mill
explain the INOrkingof all components.
10
10
10·
b) i)
ii)
Draw a schematic layout of Oeaerator, BoilerFeed Pump High Pressure Feed.Water HeatE'lfs.
Explain how cycle effiCiency improveswith feed vvater heaters.
5
5
5. a)Estimate suitable size for a steam pife to carry dl~_140 Kg/Sec. of steam at 100.Kg/em pressure at 400ClC ..4 -Assume a steam velocity of 50 metre/second.
5
(:.~;~-
~'4'
·t
~i::~
~~;J~
~}.,.
\
6.
i
b) Write a note on Soot Blower
c) Write a detail note on annllJaloverhaul of boiler explainin details the inspections testing to be carried out.
. Explain the working of the fOI~Owing : I •
i) 'Nater Sbftenirig Plantii) Mechanical Chemical Deaerationiii) 3 Element Drum Level Control