UNIT OPERATING PROCEDURE
INTRODUCTION
:
The procedures included in this section are of basic nature, intended to serve as a guide in following proper sequence and precautions during initial stages of operation. Since the Heat Recovery Steam generator is only a part of the overall plant which must operate in unison, specific and detailed values are to be incorporated to refine the procedure after sufficient experience is gained and the opportunity to fine tune the controlled to confirm with actual operating requirements and characteristics. Reference should be made to respective Manufacturers instructions regarding pre!operational and operational procedures for auxiliary equipment. equipment. PREOPERATING PROCEDURES Clean – up : "efore initial startup with the admission of #T exhaust gas and prior to each subsequent cold start $ up , after maintenance has been done on the unit , it should be inspected and cleaned both internally and externally. %ll foreign material should be removed from pressure parts. %ny grating ,pipe lines, electric conduit etc. that might restrict normal expansion of the unit, should be cleared. %ll personnel should be cleared from the hot gas path inside the HRS# and %ccess doors closed. Chemical cleaning : Specific procedures for al&ali boil out are given separately. Blowing seam lines : 'rior to starting up a new unit or restarting an older unit following ma(or pressure parts repairs, the main steam line should be steam blown to remove scale and foreign matter. This should be done after chemical cleaning and prior to setting safety valves. )etailed procedures for steam line blowing is given separately. Seing o! sa!e" #al#es :
Setting of safety valves is carried out next. Col$ sa% up P%epa%aion !o% se%#ice : *nsure that the unit has been chemically cleaned, that the steam lines have been blown, that the safety valves have been set and that the unit has been filled to the start!up level with properly treated feed water.
*nsure that all instruments instruments are calibrated calibrated and all instrumentation instrumentation,, control control system s ystemss and interloc&s interloc&s have been chec&ed and are available for service. *nsure that all!mechanical equipment have been chec&ed and are available for service. *nsure *nsure that that the feed feed water water system system,, equipm equipment ent have have been been chec&e chec&ed d and is availa available ble fore fore operat operation ion.. +t is recommended that during start!up , the feed water be controlled remote $ manually until sufficient flow is established. *nsure that feed water quality is as per the recommendation . *nsure that the #T exhaust system has been chec&ed and is available for service. *nsure proper operation of #T# , its compressor compressor cleanness, cleanness, +# opening, opening, its steam water in(ection in(ection , divertor opening opening , to deliver deliver the required #T* gas flow at specified gas temperature and composition. )eviation if any shall be informed to "H*- for review of further course of action. +t is assumed that smooth manual and remote operation of guillotine gate and divertor damper at HRS# inlet has been chec&ed and is available for service. *nsure that S system of HRS# has been chec&ed as per "urner / 0 M and is available for service.
+f the HRS# has been recent recently ly filled filled up with with feed feed water water or stored stored as per recommen recommended ded preser preservat vation ion procedures, the following steps 1 2 to 3 4 can be s&ipped and step 5 to be followed directly. 2. /pen the the entire entire vent and and drain valves valves of of economi6e economi6ers, rs, evaporato evaporators rs and the the drum. drum. 7. Slowly fill fill the economi6 economi6ers ers and evapora evaporators tors using using the cold cold boiler feed feed water water up to start!up start!up level. level. +f cold boiler feed water is not available and hot boiler is to be used. The temperature difference of metal and water should not be more than 89 deg :. 8. :lose all the the drain drain valves valves except except SH drain drain valves valves after after 5 minutes. minutes. 3. ;hen ;hen the water level level in drum reache reachess the start!up start!up level, level, vent vent valves valves of economi6 economi6er er are to be closed after ensuring that there is no air in the system. 5. ;a ;ater ter level in drum drum can be ad(usted ad(usted to start!up start!up level level with the help of of respective respective emergen emergency cy drain 1intermittent blow drain valves4. 'urge the HRS# as per <'% < '% requirements.
/R %S'*:T T/ "* T%?*< :%R* /. ariation in temperature during start!up or shutdown causes stresses in the boiler components, particularly in the drum and can cause damage to the drum if the rate of temperature rise @ pressure rise is very high. )uring the initial start up of new unit, it is recommended that a relatively slow rate of pressure increase be allowed in order to allow sufficient time for chec&ing expansion movem movement entss and to permi permitt the operator operatorss to becom becomee familia familiarr with the charac character terist istics ics of the unit and its auxiliaries. Sa% up p%oce$u%e A
)+*RT*R )+*RT*R )%M'*R /'*<+<# B 2. 7. 8. 3. 5. C.
*nsure *nsure #uillo #uillotin tinee damp damper er is is opene opened. d. *nsure *nsure any of the the scanne scannerr fan is runn running ing.. HRS# HRS# drum drum leve levell not not low low. HRS# HRS# lev level not not hig high. h. %ll burner burner trip valves valves are closed closed.. #T is is ru running.
&RSG TRIP INTER'OC(S DESCRIPTION S' NO 2 Supplementary firing trip on gas pressure ery low 7 Supplementary firing trip on gas pressure ery high 8 HRS# HRS# trip trip on scan scanne nerr air air pres pressu sure re very very low low 7@8 7@8.. /nl /nly y sup suppl plem emen enta tary ry
SETTING 9.95 ?g@:m 7 2.D ?g@:m 7
firing trip is provided. )ivertor will trip with both scanner air fans not 3 5
available. HRS# trip on drum level very low HRS# trip on drum level very high
EF G5 F
C E D
HRS# trip on #T8 trip Start permissive for gas supply pressure )rum -e -evel 'e 'ermissi ssive fo for )i )iverto rtor da damper op opening to towards rds HR HRS#
8 ?g@:m7 C9 F
Col$ sa%up in GT mo$e: The #T load shall be ad(usted such that the #T exhaust temperature is less than 399 deg : and open divertor damper towards HRS#, as per start!up curve.
Hold the #T at the above load. )uring the warming up period, maintain the drum water level. +nitially water level will raise and continuous blow down, if required, emergency blow down also can be used to maintain water level in sight in the water level guage glass. :ontinue warming up at this rate till steaming starts. %fter warming up, increase rate of flow of gases through the HRS#, as per the start!up curve, by opening the divertor damper more towards HRS#. Steaming will start with resultant increase in drum pressure. Regarding the startup, vent controls the pressure rise. :lose the drum vents when continuos flow of steam is established and drum pressure is around 7.9 &g @ cm7 1g4. ;hile the unit is heating up, frequent chec&s of the expansion movements of drum, vents, hanger rods and columns also restrain in vents and drain lines should be made. Maintain drum water level at normal. %d(ust the feed water supply to the unit as necessary to maintain normal water level. eed water control should be placed on automatic as soon as possible and practicable after continuos feed water flow has been established. %s drum pressure increases, progressively ad(ust the main stream line start up vent ensuring drum water level and rate of pressure rise are within limits. /pen the divertor damper completely towards HRS# as and when startup curve dictates. +ncrease #T load gradually up to full load 1 88.DG M; at ambient temperature of 8D deg :4 ensuring that steam pressure, temperature and flow rates do not exceed the values given in startup curve. The position of the divertor damper shall be maintained as per startup curve. :hec& all operating instruments and controls and ensure their correctness in unfired mode of operation. %ny deviations to be informed to "H*- 1T4. +ntroduction of supplementary firing B or introduction of S system, the following instructions @ operations shall be carefully followed. #T load minimum $ 88.DG M; and #T exhaust flow of 282.222 &g @ sec and #T exhaust temp. of 53G deg : at an ambient temperature of 8D deg :. however in case of operational limitations on #as Turbine loading, supplementary firing can be introduced with HRS# steam flow rates of 59 tph or more. )ivertor damper shall be fully open towards HRS#. eed water temperature entering economi6er shall be less than 28D deg :. The #T and HRS# fuel are naphtha and "ombay high %ssociated gas resply. Start S system by opening the isolation valve of the burner system in case of "ombay High %ssociated gas. ;hile starting the fuel control valve shall be corresponding to the minimum flow condition. This fuel pressure shall be &ept at minimum when the burner elements are being brought into service. The fuel pressure at burner shall not exceed 9.C &g @ cm7 1g4 for "ombay high associated gas @ reformed gas 1minimum pressure4 while bringing the S system in to service. The value may require refinement based on trial operation. =pward revision shall however be with the approval of "H*-. urther increase in firing shall be gradually till the steam generates reaches the rated parameters and not exceeding M:R steam flow. The flue gas temperature after the duct burner and the superheated metal temp. shall be periodically, particularly when load on HRS# is raised. +n case the flue gas temperature exceeds DE5 deg : or the superheated metal temp. exceeds 3G9 deg : the firing rate control shall become stayput and control changed over to manual.
Reasons for increase in gas @ metal temperature shall be chec&ed before putting bac& the firing s ystem on auto. +n case firing rate shall be restricted such that the gas @ metal temp. is within acceptable limit specified above. #T load may be reduced to the required level 1 but in any case not less than 75 F load4 after reaching the reqd. steam generation at full load but not exceeding M:R steam generation with #T* temp. %lways above steam outlet temp. )uring this period of #T load reduction , supplementary firing shall be constant and shall be increased , even if the steam output decreases. iring rate may be increased gradually to meet steam demand 1 but not exceeding M:R steam generation4 ensuring the gas temp. and metal temp. do not exceed the above values. Sufficient care shall be ta&en to ensure steam generation not less than 59 tph at any point of S mode operation. &OT STARTUP IN GT )ODE : * A+TER , &OURS O+ S&UTDO-N.
/pen the divertor damper and guillotine gate at HRS# inlet. 'urge the HRS# as per <'% requirements. Reduce the #T load such that the #T exhaust temp. is less than 399 deg : %d(ust divertor damper position as per startup curve matching residual drain pressure with cold startup curve. %fter ensuring continuous steam flow through superheated, #T load shall be increased gradually to reach 88.DG M;. )ivertor damper shall be fully open towards HRS#. *nsure that the rate of increase of steam generation, steam pressure and temperature are within limits. +ntroduce S system to increase the steam generation. or introducing the S system, inststructions @ operations specified under startup procedure shall be strictly adhered to.
Shuing $own : The following procedure is for normalA shutdown. This is based on the assumption that the unit is operating and it is intended to reduce the pressure to 6ero and cool the unit completely. Stop supplementary firing. Slowly close deviator damper towards HRS#. This reduces the gas flow thorough HRS#. %llow the pressure to drop with reduction in load to accelerate cooling. The load reduction should be slow enough to ensure that the HRS# cooling rate is not more than 299 deg : per hour. /nce the pressure drops by 7 &g @ cm7 below the normal operating pressure close the main steam stop valve and the divertor.
Eme%genc" p%oce$u%es : 'ow wae% le#el:
+f the water level falls out of sight in the water level gauge, due to failure of feed water supply or some other fault, except in the case of momentary fluctuations that might occur with extraordinary changes in load, appropriate action should be ta&en at once to stop supplementary firing, if S system is in service and also to close the divertor damper towards HRS# . +n case of )ifficulties in closing the divertor damper within the normal closing time, #T shall be tripped. +f someone in the authority, who is familiar with the circumstances and guide to the emergency and positively certain that the water level can be restored immediately without damaging the unit is available, he can ta&e the decision to &eep the divertor damper in an intermediate position so that only a limited gas flow passes through the HRS# after ensuring that S system is not in service.
+f feed water has become available, gradually re!establish the level in the drum. +f feed water is not available fast close divertor damper towards the HRS#, if HRS# is in #T mode, seal air fan and scanner air fan shall be &ept in operation. +f tube failure is suspected reduce the steam pressure gradually by opening the main steam line drain. /pen the drum vent when the pressure drops below 2.5 &g@cm7 and drain the unit following normal draining procedure once pressure drops to atmospheric pressure. )etermine the cause of low water level and examine the unit for the effects of possible overheating such as lea&s and distortion of pressure parts. Repair any lea&s. %fter the repairs, hydrostatically test the unit at wor&ing pressure before putting the unit bac& in service.
&igh wae% le#el B
%bnormally high water level should be avoided as it may lead to moisture carryover. +f the water level rises above the recommended normal operating range, proceed as followsB 2. Reduce the water level immediately by opening the emergency blow down valves. 7. Reduce the steaming rate, if necessary and place feed water control on manual. +f water carryover should occur, as indicated by rapid fluctuations in the outlet steam temperature, proceed as followsB 8. Reduce the steam rate. 3. +f the water level is abnormally high, reduce the level by opening the emergency blow down valves and place feed water control on manual. 5. +nvestigate the water conditions 1 al&alinity and solids4 C. +nvestigate the water condition of the drum as soon as opportunity is there. Tube failuresB The following instructions regarding tube failures are of a general nature. +t must be understood that conditions may arise which will require exercise of (udgement by the operators. Trip S system once a tube failure is suspected.
%fter the unit is cooled enough to permit a man to enter it, ma&e a thorough inspection of pressure parts for any indication of damage resulting from loss of water level. Report the tube failure and operated data to "H*- in the format enclosed elsewhere in the / 0 M. after necessary reports have been made apply a hydrostatic test and obtain the approval of proper authorities before putting the unit bac& in service.
E#apo%ao% u/es :
+n case of a lea& or tube failure, which does not involve a serious drain on the feed water supply, the water level should be maintained, and the unit ta&en out in normal manner. +f the tube failure results in a loss of steam as great that water level cannot be maintained with the feed water supply available, use the method outlined below B
2. :lose the diverter damper towards HRS# to isolate it from #T. 7. Shut off feed water to the unit. 8. %fter the unit is cooled enough to permit a man to enter it, ma&e a thorough inspection of damage resulting from water level. %fter necessary repairs have been made, apply a hydrostatic test and obtain the approval of proper authorities before putting bac& the unit in service.
Economi0e% :
%n economi6er tube lea& can be detected by sound and increased feed water requirements. The lea& should be investigated at the earliest possible time and the unit shut down in a normal manner. ;ater lea&s in economi6er can cause considerable corrosion damage to ad(acent tubes. %ny decision to continue operation with &nown lea&s should be made with this in mind.
-al1 $own chec12 o!! lis :
/ne of the most important benefits of a I wal& down chec&! off I of an unit is derived from the operator &eeping his eyes and ears open for any unusual condition and reporting his findings to his supervisor. 'otential damage to equipment can be avoided if abnormal conditions are detected in time.
The following are some of the items that an operator should be loo&ing for B 2. 7. 8. 3.
-oo& foe any unusual traces of water on the floor or lea&ing from casing (oints. -oo& for valve and valve pac&ing lea&s. "e on the loo&!out for any unusual condition 1discoloration, hot spots etc. 4 on boiler casing. :hec& for unusual noises, overheating of bearings and for adequate lubrication of all motors and driven equipment.
The !ollowing a%e he some speci!ic iems ha shoul$ /e o/se%#e$ a leas once a $a":
2. 7. 8. 3.
-oo& for lea&s in gauge glasses and water column. :hec& for bro&en observation port glasses. :hec& for bro&en seal air and gas pipe hoses. -oo& for lea&age of gases through casing (oints.
The !ollowing mo%e e3ensi#e chec1ing shoul$ /e $one a leas once a wee1 :
2. -isten for lea&ing safety valves. 7. -oo& for non!operating equipments. 8. Trail operates non!operating stand!by equipment. Du%ing e#e%" sa%up !%om col$:
2. :hec& for proper expansions of HRS# to ensure no hang!ups to occur.
7. :hec& spring hangers on boiler support and on steam lines for proper functioning.
&EAT TRANS+ER SUR+ACE DETAI'S
SECTION S='*RH*%T*R
*%'/R%T/R *:/
T4PE S*RR%T*) 0 S/-+) S'+R%- +<<*) '-%+< 0 S*RR%T*) +<<*) T="* S*RR%T*) +<<*) S*RR%T*) +<<*)
TUBE SI5E 52.9 J 8.C
AREA * S67 ). 2999
52.9 J 8.C
E9C5
8D.2 J 8.C 8D.2 J 8.C
22C5 2C39
S%*TK %-*S -/:%T+/<
M%?*
S*T 'R*SS=R* ?#@SL:M 1#4
"H*-
/'*< 89.9
:-/S* 7D.5
"H*-
89.C
7G.2
"H*-
89.G
7G.3
"H*-
75.C
7G.3
"H*-
7C.8
75.9
-/:%T+/<
M%?*
TK'*
M=H
"H*-
S*T'R*SS=R* ?#@SL:M 1#4 75.9
ST*%M )R=M %-* 2 ST*%M )R=M %-* ++ ST*%M )R=M %-* +++ ST*%M )R=M %-* + ST*%M )R=M %-* ++
S%*TK R*-+* %-*S
;%T*R -**- #%=#*S -/:%T+/< M%?* ST*%M )R=M ! -/:%ST*%M )R=M !R*M/T* ST*%M )R=M ! *-*:TR/<+: :") T%
"H*K%R;%K =S% K%R;%K =S% -*:/<
2G29 !?
+S+"+-+TK 1MM4 CDC
<=M"*RS
M/)*-
T;/
TK'* 93EG 1RH4
!
/<*
!
G58
/<*
EC7
/<*
%L=%R+%< 8999 !
STEA) GENERATION UNIT UNIT DESCRIPTION B The heat recovery Steam #enerator 1HRS#4 is a hori6ontal, natural circulation, single drum, single pressure, fired, water tube boiler. +t is designed to generate steam quantities as furnished in the predicted operation. eed water temperature is 28D deg :. SA'IENT +EATURES : The Heat recovery Steam #enerator 1HRS#4 consists of the following main components . Screen and components Superheated and components *vaporator and components *conomi6er and components Ma&eup water heater and components %ttemperator *xpansion (oints Supplementary iring system Steel chimney SCREEN AND CO)PONENTS B Screen is the first heat transfer surface arranged in the direction of the gas flow. Two numbers of screen modules are located immediately after the )uct "urner. Superheater is located after the screen module. The high temperature gases leaving duct burner enter screen module and then Superheater. Screen module contains two rows of plain tubes. The screen module is connected to drum by means of riser at top and to common feeder by means of individual feeders at bottom. )etails of the screen system are as follows. Tu/es in a mo$ule :
2. 7. 8. 3. 5.
Tube /uter )iameter , 52.9 mm Tube Thic&ness , 8.C mm in specification B 'lain tubes Tube Material B S% 728 T22 Tube type plain tubes
&ea$e%s /utside diameter Thic&ness Material
Top 72G.2 75.9 S% 885 '27
Rise% u/es
2. 'ipe si6e 7.
25G x 29 four S% 29C #r"
In$i#i$ual !ee$e%s
2. 'ipe si6e 7.
25G J 27.5 Two S% 29C #r"
Boom 72G.2 23.7
SUPER&EATER AND CO)PONENTS
Superheater is the second heat transfer surface arranged in the direction of gas flow. Superheater is constructed of modules consisting of spiral finned tubes welded to top and bottom headers , two rows per module. The Superheater is designed for single pass flow on the gas side as well as on the tube side. +nterconnection of modules are by multiple 2D9 degrees bent pipes of similar material as header. The superheater modules are equipped with low point 2 drains for a fully drainable design. The superheater outlet is equipped with a vent for start up. The inlet and outlet piping are selected based on steam design pressure and design temperature. )etails of the superheater system are as follows B Main steam line
B
2. 'ipe si6e 39C.3 J 77.7 mm 7. Material S% 885 '77
Tubes in a module B SH ++
SH +
Tube outside diameter Tube thic&ness Tube length
52.9 8.C 29999
52.9 8.C 29999
in specification Type B )ensity Height Thic&ness
Solid 229 27.5 2.75
Serrated 799 27.5 2.75
Tube material in material
S%728T77 S%739 T' 39G
S%728T77
Top headers 2. /utside diameter x thic& 7. Material
72G.2 x 87.9 S%885 '77
72G.2x87.9 S%885 '77
"ottom headers 2. /utside diameter x thic& 7. Material
72G.2 x 27.E S% 885 '77
72G.2 x 27.E S% 885 ' 77
fins @ m mm mm
)rum to SH lin& 2. 'ipe si6e 7.
25G x 29.9 mm Six S% 29C #R. " 25G x 27.5 mm six S% 885 '77 39C. J 77.7 mm one S% 885 ' 77
E8APORATOR AND CO)PONENTS – CIRCU'ATION S4STE)
*vaporator is the third heat transfer surface arranged in the direction of the gas flow. +n the circulation system, the heated feed water from *conomi6er goes to the steam drum. The boiler water from the steam drum flows to the common feed header through a large downcomer and is distributed to the bottom headers of the evaporators through the individual feeders. Steam water mixture generated in the evaporator tubes, due to heat transfer from the gas turbine exhaust, flows bac& to the drum through the riser tubes. The saturated steam is separated by the centrifugal separators and final scrubbers placed inside the drum. The separated boiler water is ricirculated through the downcomer, common feeder, individual feeders, and evaporator tubes and risers. The saturated steam flows to the Main stea m line. )etails system are as followsB Steam )rum 1TK'+:%-4 2. 7. 8. 3. 5.
N
+nner diameter Thic&ness Material +nternals +nternals material
Tubes in a moduleB 2. Tube /uter )iameter 7. Tube Thic&ness 8. in specification
2D7D.D 1 E74 mm 8D mm 1min4 S% 525 #r. E9 "affle Screen and centrifugal seperators :arbon Steel
52.9 mm 8.C mm
Module no Type )ensity fins @ m Height mm Thic&ness mm
98 to 95
9C to 23
Tube material in Material
S% 729 #r %2 +S 528 #r. *))
Serrated fins 279 27.5 2.75
799 27.5 2.75
Top and bottom Headers 2. /utside )iameter x thic& 7. Material
72G.2 x 23.7 S% 29C #r "
)own comer 2. 7. 8. 3.
'ipe si6e
39C.3 x 87 T;/ S% 29C #r : 'lain, gas touched
:ommon feeders 2. 7. 8. 3.
'ipe si6e
39C.3 x 87 T;/ S% 29C #r : 'lain, gas touched
*:/
2. /utside )iameter mm 7. Thic&ness mm 8. Material Tubes in a module 2. Tube /uter )iameter 7. Tube Thic&ness 8. in specification B
Top 72G.2 77.78 S% 29C #r. "
8D.2 8.C
Module
92 to 97 CD Serrated tube 2D9 27.5 2.75
Tube material in material
S% 729 #r. %2 +S 528 #r. *))
:onnecting -in&s rom To 'ipe si6e mm Material
"ottom 72G.2 23.79 S% 29C #r. "
inlet feed pump economi6er 25G x 29, 2 no S% 29C #r."
outlet economi6er drum 25G x 29, 2 no S% 29C #r."
CROSS O8ER PIPES :
2. 7. 8.
'ipe si6e
25G x 29.9 /<* per module S% 29C #r :
M=H is the fifth heat transfer surface arranged in the direction of the gas flow. The M=H is constructed of modules , consisting of spiral finned tubes welded to the top and bottom headers, two rows per modules. The M=H is designed for single pass flow on the gas side and multipass flow on the tube si de. The M=H modules are equipped with high point 2 vents and low point 2 drain for a I fully drainable design.
The modules shall be interconnected with multiple 2D9 degrease bent tubes of similar material as headers.
Top and bottom headers
2. /utside )iameter mm 7. Thic&ness mm 8. Material Tubes in a module 2. Tube /uter )iameter 7. Tube Thic&ness 3. in specification B
Top 72G.2 77.78 S% 827 ' 82C 8D.2 8.C
Module
92 to 97 CD Serrated tube 289 25.G 2.75
Tube material in material
S% 728 T' 82C S% 739 T' 82C
:onnecting -in&s rom To 'ipe si6e mm Material
"ottom 72G.2 27.E9 S% 827 ' 82C
inlet feed pump economi6er 25G x 29, 2 no S% 728 T' 82C
outlet economi6er drum 25G x 29, 2 no S% 739 T' 82C
:R/SS /*R '+'*S 2. 7.
'ipe si6e
25G x 29.9 /<* per module
%TT*M'*R%T/R Spray attemperator is utili6ed to control the final steam temperature to 8D5 deg : . for this application an attemperator is used after the superheater. The attemperator piping is furnished and is designed with an internal sleeve for the first 8 m down stream of the spra y no66le to protect against thermal shoc&. *J'%/+
:H+M<*K The #T exhaust gases, after passing through all the heat transfer surfaces are discharged into the atmosphere at the safe height through a C9 m high steel chimney of dia 8.5 m . The chimney externally insulated to a safe height for personnel protection.
SA+ET4 PRECAUTIONS Safety is everyones business. ;hile at "H*- boilers have been operating safely over decades, this sections purpose is to draw the operators attention of the necessary precautions to be ta&en for the safe operation and maintenance of HRS#. "y observing these simple precautions one can have safe and happy operations of the HRS# throughout the life period.
;hen HRS# are in operation, never touch an exposed piece of process pipe or tubing without first testing for temperature. )o not touch the HRS# casing while in operation without ma&ing sure that the temperature of the surface is tolerable to the human s&in. ;%R<+<#B )+S:/-/=R*) :%S+<# %R*% +S +<)+:T+* / H/T S'/TS :%=S*) "K +=RK %<) *J:*SS+* )%M%#* T/ HRS# 'R*SS=R* '%RTS. M/T/R /'*R%T*) %-* S*TT+<# 1%:T%=T/R4 %R* T/ "* )/<* %S '*R / 0 M %<) SH%--
+
)*%R%T/RB +f the dearator is not proper, it will reduce its outlet temperature and increased oxygen content in feed water. +t is not desirable for proper HRS# operation. +f need to be chec&ed during operation and the design values are to be maintained particularly when #T or S system is fired with fuel oil to avoid bac& end corrosion.
)/S+<# SKST*MB The dosing system including blow down :.".). and +.".). system should be available for service prior to start up procedure.
DO9s PREPARATION O+ &RSG +OR STARTUP • •
• • • • • •
• • • •
:hec& and remove any foreign material from HRS#. *nsure all manholes, access doors and openings in the HRS# ducting area are securely closed. Remove any restrictions for free expansions of HRS# module expansion and drum. They should be free to expand in lateral direction. *nsure proper functioning of all interloc&s and protections of HRS#, all auxiliaries, dampers and valves. *nsure availability of seal air, scanner air, instrument air, power, chemicals, cooling water etc. ?eep 0 operate all vents and drains as specified in unit operating procedure. :hec& up and &eep ready the supplementary fuel systems. :hec& up correct functioning of all mechanical equipment and associated instrumentation. :hec& 2990 tightness of divertor damper towards HRS# as well as "ypass Stac& side and confirm with the remote and local indications. ?eep all dampers in air and gas system in start up condition. ill the HRS# up to the start up water level. *nsure bloc& valve upstream of spray control station and spray control is in fully closed condition. amiliari6e with operation and maintenance.
START UP O+ &RSG – UN+IRED )ODE *CO'D START.
:hec& that no HRS# trip condition exists. #T to run in appropriate condition to purge the HRS# limiting the #%S temperature as indicted in #T supplier @ logic @ <'% requirement. 'urge the HRS# for a time duration as specified in <'%. %fter purge completion, ensure #T exhaust gas temperature is less than 399 deg. : for startup. %dmit the #T exhaust gas as per startup curve, by suitably operating the divertor damper to HRS#. %ll air vents to be closed at 7 &g@s q.cm1g4 1 except startup vent4. "ring the HRS# to the rated steam condition as per startup curve by suitably throttling the startup vent. Ta&ing more time the one specified in startup curve is better. SH and )*SH drains to be closed only after closing of all vents with five minutes delay, after well establishing steam flow through superheater. :harge derator and admit rated feed water temperature to HRS# 28D deg. : for continuos operation. :hec& the free expansion of drum, Superheater, evaporator module economi6er and M=H. )rum level control and superheater steam temperature control to be ta&en on %uto mode after reaching rated parameters. /n drum level low down trip, if the divertor damper is not closing towards HRS# within the stipulated time, the #T shall be tripped.
DO9S
amiliari6e with the operation and maintenance manual of duct burner. *nsure readiness of selected fuel systems. :hec& the igniters and scanners for the corresponding fuel. *nsure all interloc&s and protections to be in operation, to trip or stay put @ decrease firing corresponding to SH metal temp. gas temp and fuel pressure as per the control scheme.
BO)BA4 &IG& ASSOCIATED GAS
?eep #T load at minimum of 75 F. raise steam generation to its full in unfired mode at rated pressure. *nsure )ivertor )amper 299 F open position towards HRS# both through indication and physical verification. +ntroduce burners. The fuel pressure at burner shall not exceed 9.9E &g.cm7 1g4 for Refinery gas and "ombay high associated gas while bringing the S system in to service. #radually increase the firing rate, not exceeding 8F M:R steam generation per minute, limited to the maximum steam output of 29D.9 tph at #T load of 88.DG M monitoring continuously the followingB 2. SH!MTM not to exceed 3G9 deg. : in any case. 7. Main steam temperature not to exceed 8D5 deg.: 8. lue gas steam temperature not to exceed DE5 deg.: 3. uel gas pressure alarm and trip set values. DO9S
or further increase in steam output to meet steam demand, increase the #T load to meet the required steam generation, &eeping the supplementary heat input constant. However, in #T mode with Refinery gas @ "ombay high associated gas firing, the maximum steam output shall not exceed 29D.9 tph. *nsure that all the gas runners are in clean condition and in service b y seeing through the view ports. lame shape has to be observed frequently for proper combustion and hence the flame length. /n fuel gas pressure high alarm, reduce the fuel!firing rate by 29F of the instantaneous value and control shall become stay put and changed over to manual. GENERA'
:hec& and control boiler water, feed water and s team conditions as recommended. ?eep drum level and SH temperature controls in auto during supplementary firing.
NOR)A' REDUCTION O+ BOI'ER 'OAD
Reduce the load in step of 7.5F per minute for load down to 59 F M:R. Reduce supplementary firing accordingly. :hec& and ta&e the controls on manual at a point where better control can be obtained manually.
NOR)A' S&UT DO-N TO CO'D
Shutdown supplementary firing at appropriate time. Reduce the load gradually below 59F M:R. 29F per minute with one minute hold up time for every 29F load reduction.
:hec& the normal drum level and maintain. ;hen the pressure is 7&g@cm7 open all vents. Stop scanner air fan when gas temperature after duct burner reaches C9deg.:. /pen SH 0 )*SH drain valves and evaporator and economi6er vent valves. )o not open evaporator, economi6er 0 M=H valves.
DON9T9S UN+IRED )ODE :
)o not continue HRS# operation if the drum water level is near low low condition. )o not purge HRS# with gas temperature above <'% @#T supplier recommendation. Till HRS# startup parameters reaching the nominal shown in startup curve. *xhaust gas temp. should not be increased beyond 399 deg.:. )o not increase the rate of steam pressure and temperature than recommended value as per startup curve. eed water temperature not below 28D deg.:. SUPP'E)ENTAR4 +IRING )ODE :
HRSG#3 BMS LOGIC
'OGICS +OR PURGING •
'ilot MT should be closed.
•
Main gas MT closed.
•
%ll burner "Ts closed.
•
Scanner air pressure o&.
•
Seal air pressure o&.
•
Showing no flame.
•
Main gas pressure o&.
•
*mergency trip '" is not operated.
•
Main gas pressure is not very low and not very high.
•
Scanner air pressure is not very low and any scanner air fan running feedbac&.
•
'urge not completed.
•
-oss of all fuel trip should not be there.
•
=nit flame failure should not be there.
•
*xternal trip signal should not be there.
/nce all the above conditions are satisfied, select -/:%- or R*M/T* 1selector switch in the hardware console4 in the control room and accordingly, press ST%RT '=R#* '" in local "MS panel or in the control room.
'OSS O+ A'' +UE' TRIP con$iions : •
%ll pilot "Ts closed.
•
'ilot MT closed.
•
%ll main gas "Ts closed.
•
Main gas MT closed.
•
%ny scanner is showing flame for 29 secs.1assuming gas passing4
ETERNA' TRIP con$iions : •
#T should be running.
•
#) open towards HRS#.
•
)rum level not very low.
•
)rum level not very high.
UNIT +'A)E +AI'URE TRIP con$iions : %ll burners unsuccessful start or trip.
BURNER UNSUCCESS+U' START ; TRIP con$iions : •
'articular burner "T opened.
•
"urner trial time elapsed.
•
'OGICS +OR BURNER STARTING :
PI'OT )T8 ; BT8 OPENING : •
MT should not be there.
•
'articular burner "T ready. 2. pilot manual valve open. 7. 'ilot burner stop '" not pressed. 8. iring mode selected. 3. Select local or remote in the hardware selector switch.
P&I'OSOP&4: 'ress start '" for any particular pilot burner. •
Same burner "T ready will come.
•
/nce "T ready comes , pilot MT will open.
•
/nce pilot MT open feedbac& is received, '-: will give command for opening "T within 29 secs.
)AIN GAS )T8 < BT8 OPENING : •
Main gas pressure o&.
•
Main gas manual valve open.
•
Main gas vent valve closed.
•
firing mode selected.
•
%ny burner pilot on or burner on 1for 7 nd burner4.
•
: in minimum position or any burner in service.
•
MT should not be there.
•
Main gas pressure not very low and not very high.
•
"urner stop '" not operated.
"urner unsuccessful start@trip should not be there. +ntroduction of supplementary firing shall be at #T. "ase load or at loads with corresponding steam generation not less than 59 tph. )o not exceed SH metal temp. of 3G9 deg :. )o not reduce the #T load 75F %ssociated with steam generation not below 59 tph. )o not move away from 299 F open position of divertor damper towards boiler when S system on. )o not put on manual. The superheater steams temp. :ontrol 0 water level control. )o not &eep the fuel flow control valves above specified minimum position while introducing S system for startup. )o not operate S system beyond specified capacities. )o not operate HRS# beyond specified capacity. S&UT DO-N
)o not open vents1except startup vent4 and drain. /perate seal air fan and scanner air fan for cooling the glass 0 scanner. )o not start closing divertor damper towards HRS# until supplementary firing is fully shutdown.
-ATER 8O'U)E O+ 8ARIOUS SECTIONS O+ &RSG S='*RH*%T*R %<) :/M'/<*
