Boiler
BOILER
Boiler is a closed pressure vessels , which is strongly constructed by steel and iron . When water converts to steam by the application of heat is known as Boiler .
As per IBR rule (Indian boiler Regulation) act 1973 boiler means 22.75 litre and above for generating steam specially is known as Boiler .
MOUNTING
These device gives safety to the Boiler .v MSSV by pass
v Water level Indicator
v Air vent / Drum Vent
v Pressure Gauge
v Temperature Gauge
v Start-up vent
v TCV / Attemperator - Temperature control valve
v Safety Valve
v Blow down valve (1) IBD – Intermittent blow down
(2)CBD- Continuous blow down
v Man hole door
v NRV ( Non-returning valve)
1 MW = 4.1 Ton (Steam)
= 4.5 Ton (Water)
= 1 Ton (Coal)
Atmospheric pressure = 1.033 kg/cm2
Accessories
These device gives efficiency to the boiler
Ø BFP (Boiler feed pump )
Ø Economizer
Ø APH (Air pre heater)
Ø Superheater (1) Primary super heater
(2) Secondary super heater
Draught / Furnace Pressure
Pressure difference between inside the furnace and outside the atmospheric pressure and temperature is known as Draught .
ID Fan & FD Fan Balancing Draught
Boiler Interlock
ID Fan
Ø Drum level above 80%
Ø Drum level below 20%
Ø Draught above +25 MMWC (Millimeters of water column)
Ø Draught below -25 MMWC (Millimeters of water column)
Ø Bearing temperature above 7 mm/sec
PA Fan
ID Fan trip
Bearing temperature 95 0C
Vibration high 7mm/sec
FD Fan
v ID and PA trip
v Bearing temperature high 95 0 C
v Vibration above 7mm/sec
Coal feeder
ü ID, PA, FD Trip
ü Bed temperature above 950 0 C
ü Bed temperature below 450 0 C
DCF (Drag chain feeder)
Valve
MIV – Manually isolation valve
MOV – Motorized valve (Electric)
CV – Control Valve(Instrument Air)
Damper
PCD – Power cylindrical damper(Instrument)
RPC – Regulating power clinder(Instrument)
VFD – Variable frequency drive(Electric)
Bed Material
Silica - 60% and Alumina 40%
Size – 0.86 mm (Minimum) and 2.36 (Maximum)
Silica fusion temperature = 1200 0C to 1400 0 C
Alumina fusion temperature = 400 0 C to 600 0 C
Boiler feed pump (BFP) start permission
1) Suction valve open condition
2) Discharge valve close condition
3) Balancing line and re-circulation line open condition
4) Oil level near DE and NDE side 40% (Servo 46T )
5) Electrical Clearance
6) Deaerator level 50% approx.
Stop
At first discharge valve close then motor stop command .
Trip
A. Deaerator level below 20%
B. ACW (Auxiliaries cooling water) pressure near by BFP 2kg/cm2
C. Motor High current
D. Vibration 9mm/sec
Silica is a hard glassy like mineral that is found dissolved in water due to sand quarts sand stone granatin etc .
a) Dissolved silica (Reactive silica) – Removed at DM Plant
b) Colloidal silica (Unreactive silica) – Removed at RO Plant
c) Particulate silica (Granular silica) – Removed by lime softening
1 Million = 10 Lakh
Water Silica (Sio2)
1. DM Water ------------------ 0.02 Maximum
2. Feed Water----------------- 0.02
3. Boiler Water---------------- 0.5 (Drum Water)
4. Turbine Condensate -------- 0.02
5. Cooling tower -------------- 100 PPM (Parts per million)
6. Drinking Water ------------ 5 to 25
· Proper water treatment .
· Monitoring silica in water .
· Draining blow down
Boiler Blow Down
TDS – Total Dissolved Solid
CBD – Continuous blow down
IBD – Intermittent blow down
PBD – Periodic blow down
EBD – Emergency blow down
Power Plant
Non – Renewable Energy
1) Thermal Power Plant (Coal)
2) Nuclear Power Plant (Uranium 235)
3) Diesel Power Plant (Diesel)
4) Gas fired Power Plant (Gas)
Renewable Energy
1) Hydro electric Power Plant (Water)
2) Solar Power Plant (Sun light)
3) Wind Power Plant (Wind)
4) Geo thermal Power Plant
BFP Work is low pressure water convert to high pressure to supply boiler .
Boiler is a closed vessel in which steam is generated with the help of combustion of fuel .
Also called steam generation . It is a heat exchange .
Act of IBR (Indian Boiler Regulation)
ü Capacity > 22.75 ltr
ü Under wholly & partially pressure (13.5 kg/cm2)
ü Include any mounting and fitting
Indian Boiler Regulation (IBR)
o 1770-75 – James Watt Steam Engine
o 1863 – First Boiler Explosion in Kolkata
o 1864 – Bill passed in Kolkata [ But rules are different to other state , Problem faced]
o 1920 – Discuss about IBR
o 1923 – IBR Act
o 1937 – Modification comity (IBR 1950Act)
o 22 feb , 2005 – Latest Update
Types of Boiler
i. According to Manufacture Trade .
ii. According to Position of tube .
iii. According to Fuel used ( Coal , Oil , Gas)
iv. According to Position of furnace ( External fired , Internal fired)
v. According to Tube content ( Fired , Water)
vi. According to Circulation of water .
vii. According to Operating Pressure .
viii. According to heat source .
ix. According to Combustion .
x. According to Purpose of Utillsation .
Ranking Cycle
Named by William john Rankine prof in Glasgow University .
Fluid continuously evaporated and Condensate .
Critical pressure = 221 bar
Temperature = 374 0 C
Boiler Mounting
Boiler mounting are a set of safety device installed for the safe operation of boiler .
Boiler Accessories
These are the devices which are used as internal parts of a boiler and help in running efficiency . Circulating fluidized bed combustion boiler - CFBC
(1) Coal (2) Water (3) Air
Primary air fan – PA Fan
Air velocity in PA =4.5 meter / second
Induced draft fan – ID Fan
Boiler hot box
Safe Producer
A. Reduce the boiler load by cut off coal .
B. Reduce the air flow up to minimum .
C. Stop all fan by sequence / interlock affair few minute air flow .
D. Close all damper to reduce / stop heat loss .
E. Stop MSSV ( Main steam stop valve)
F. All drain 2 vents are closed condition . (It required , open start up vent to maintain drum pressure)
G. Maintain drum level .
H. Carefully watch all Parameters .
AFBC Boiler light up
Before light up , Pre check should be checked , taking clearance from , mechanical , Electrical & Instrument department . All air vent opened & water side drain closed condition etc .
Bed material
Bed size char coal 250 to 300 mm
Static layer = 100 mm
Bed material = 150 – 200
Size – 1 to 3 mm
Bulk density = 1000 kg/m3
Fusion – 1400 0 C
Char Coal
Size – 20 to 25 mm
GCV – Gross calorific Value
GCV – 6500 to 7500 Calorie / kg
60 to 70 TPH Boiler = 400 kg char coal
Diesel quantity = 400 * 12 / 100
= 48 kg Diesel
400 = 280 kg dry
120 kg Diesel mixed
After 50 0C to 60 0C furnace = FD & ID 5% load position
After 150 to 170 0C furnace = FD & ID 10% or 15% load
PA Fan = 500 MMWC (Millimeters of water column)
Bed Mixing = Maximum FD Fan {Time 10 sec} The normal condition
Before fuel feeding , PA Header pressure should be approximately 900 to 1000 MMWC .
Tagline used charge for Deaerator .
PRDS Valve – Pressure reduce Desuperheater system
HP Dosing (High pressure) – Transfer chemical dosing to boiler drum .
LP Dosing (Low pressure) – Transfer chemical dosing to Deaerator .
CTF – Cooling tower fan
MCW – Main cooling water pump
DCC- Drag chain conveyer
DCDB in DCS control room , DCDB panel . 415 V , 3 PH , 4 wire , 50 HZ , AC input
DC – Distribution Control
VFD – Variable frequency drive
Ohm find temp = Ohm – 100 * 2.6
BFP Fan : - A specific types of pump used to pump feed water in to steam boiler . The water may be freshly supplied or returning condensate produce as a result of the condensation of the steam produce by the boiler .
DMT : - Dimethyl terephthalate (DMT) is an organic compound with the formula C6H4 (COOCH3)2 . It is the Distar formed .
RPM :- RPM is stands for revolution per minute , and it is a unit of measurement that is commonly used to describe the rotational speed of mechanical component . Such a engines electric motor and turbines . The calculation of RPM depend on the type of machinery or device being measured .
ID Fan (-VE) : - Induced draft fan or ID fan are used in system such as steams boiler and thermal oil heater to draw out and removal flue gases from combustion chamber , by creating a vacuum of -VE air pressure (Typically – 10mmhg) .
FD Fan (+VE) : - Forced draft fan , draws air from the atmosphere and forces it into the furnace through a pre heater . These fans are located at the inlet of the boiler to push high pressure fresh air in to combustion chamber , where it mixes with the fuel to produce +VE pressure .
PA Fan : - A PA fan or primary air fan is a type of fan that is used to provide air to the furnace of a power plant . The air is used to help to burn the fuel and create steam , which is then used to generate electricity .
AFBC – Atmospheric fluidized bed combustion . (Up to 30 mw)
WHRB – Waste heat recovery Boiler .
CFBC – Circulating fluidized bed combustion (30 to 250 mw)
PF – Pulverized fired Boiler (250 to 660mw)
DM Plant – Demineralization plant
DMP Impurities in feed water & effect’s of it advantages of impurities removal .
Impurity in feed water :-
a. Undissolved material – Mud (Kachra), Clay (Mati) , Sediment , Sand etc
b. Dissolved Gas – O2 , CO2 , SO2 (Sulfur dioxide)
c. Other materials – Bacteria , Oil , Grease , acid etc
d. Dissolved solid materials – Salt , minerals
Minerals – Calcium , Magnesium , Sodium , Potassium , zinc , Iron .
Calcium – Magnesium Sodium and Potassium
Cal So4 – Sulfate Hardness Scale Corrossion
Cal Co3 – Carbonate
Cal Hco3 – Bicarbonate
Cal Sio3 – Silicate
Cal Nio3 – Nitrate
Cal Clo2 – Chlorite
Harmful effect of Impurities in water
i. Scale
ii. Corrosion & Pitting
iii. Carry over
iv. Priming
v. Foaming
vi. Caustic embrittlement
vii. Mud Deposits
Advantage of Impurities removal
i. Increase life of Boiler
ii. Maintenance cost reduce
iii. Steam generation cost reduce
Demineralization of raw water by Iron excellence process
ION Exchange (1)Cation exchange resing (2) Anion exchange resing built by polymer
SAC – Strong acid Cation
SBA – Strong base Anion
Cation Impurities – Ca+ , Mg+ , Na+
Reaction in SAC
MGSO4 +RH = MGR + H2SO4
CACL2 + RH = CAR + HCL
CACO3 + RH = CAR + H2CO3
CASIO3 +RH = CAR + H2SIO3
H2CO3 = H2O + CO2
H2SO4 + ROH = RSO4 + H2O
HCL + ROM = RCL + H2O
CAR + HCL = CACL2 + RH
MGR + H2SO4 = MGSO4 + RH
RS04 + NAOH = NASO4 +ROH
MB = Mixed bed
Thank You for Read
Best wishes from
Suvendu Singha , Mamata & Nishan Singha (India , Odisha)
Comments
Post a Comment