2. 3.
- B.E. MECHANICAL (THIRD YEAR)
- INDUS INSTITUTE OF ENGINEERING &
TECCHNOLOGY,AHMEDABAD.
4. CONTENTS
5. CLASSIFICATION OF POWER PLANTS:
6. THERMAL POWER PLANT:
- A thermal power station is a power plant in which the prime
mover is steam driven. Water is heated, turns into steam and spins
a steam turbine which either drives an electrical generator or does
some other work, like ship propulsion. After it passes through the
turbine, the steam is condensed in a condenser and recycled to
where it was heated; this is known as a Rankine cycle
- Thermal power stations produce electricity by burning fuel in a
boiler to heat water to produce steam. The steam, at tremendous
pressure, flows into a turbine, which spins a generator to produce
electricity. The steam is cooled, condensed back into water, and
returned to the boiler to start the process over.
- Power generated by this power plant covers nearly 60% of all
power. They work with the help of coal, oil, natural gases, waste
heat etc.
7. INTRODUCTIONOFBOILER 8. What is Boiler?
- A boiler is defined as "a closed vessel in which water or other
liquid is heated, steam or vapor is generated, steam is
superheated, or any combination thereof, under pressure or vacuum,
for use external to itself, by the direct application of energy
from the combustion of fuels, from electricity or nuclear
energy."
Boiler INTRODUCTION OF BOILER 9. Boiler According to Indian
Boiler Regulations.
- IBR Steam Boilersmeans any closed vessel exceeding 22.75 liters
in capacity and which is used expressively for generating steam
under pressure and includes anymounting or otherfitting attached to
such vessel, whichis wholly, or partly under pressure when the
steam is shut off.
10. Introduction to Adani Power 660 MW Boiler Description Unit
Value Type Supercritical, Once Through Type, Sliding Pressure,
Single Furnace, New Tangential Type, Single Reheat, Balanced Draft,
Dryed Slag Discharge, Complete Steel Structure, Complete Hanging
Construction, Double Gas Passes.Manufacturer HARBIN BOILER COMPANY,
CHINA Design Code For Pressure Parts ASME, GB9222-88, IBR 11.
7.Low Nox Tangential Burner 6.Burner tiltingfor reheater
steamtemperature control 3.Proven and economic heatingsurface
arrangement 2.Spirally wounded evaporators for safe and
reliableevaporator 5.Economic and safe low load andstartupsystem by
circulating pump 8.Long life and highPerformance mills 4.High
Strength materialapplication Overall View Of Adani Boiler 12.
CRITICAL CONDITION
- CRITICAL is a thermodynamic expressiondescribing the state of a
substance beyond which there is no clear distinction between the
liquid and gaseous phase.
- The critical pressure & temperature for water are
- Pressure = 225.56 Kg / cm2
13. SUPER CRITICALBOILER CYCLE WITH SH, RH &
RegenerationofADANI5 x 660MW 256Kg/cm2 0 100 200 300 400 500 600
540C 568C Steam flow:2225 T/Hr Steam temp: 540 c Steam Pres : 256
kg/cm2 RH pre: 51.6 Kg/cm2 RH Temp: 568c Feed water Temp: 291c
ENTROPY TEMP 14. WHY SUPERCRITICAL PRESSURE
- The purpose of having high inlet steam pressure for turbine can
be inferred from Previous deliberations.
- A Boiler operating at a pressure above critical point is called
SUPERCRITICAL BOILER
- A point where boiling water and dry saturated lines meet so
that associated latent heat is zero, this point is called Critical
Point and occurs at 225 kg/cm2 (abs) 374.15 C temperature.
15. SH DRUM ECO HTR BFP W/WALL DOWN COMER RISERS Natural
Circulation BoilerW/WALL BFP HTR ECO SH SEPERATOR ONCE THROUGH
SYSTEM 16. FLOW DIAGRAM OF SIPAT SUPER-CRITICAL BOILER 17.
Evaporator Wall Construction (1/3)
18. Spiral wall outlet temp at BMCR (front wall) Spiral Wall
Evaporator Configuration of Evaporator panel Spiral wall : Vertical
wall = 3 : 1 Supercritical Boiler Technology 19. spiral wall spiral
wall and windbox WALLOFBOILER 20. 660 MW PLANT BOILER 21. LTSH
COILS ECONOMISER COILS ECONOMISER I/L HEADER ECONOMISERO/L HEADER
22. AIR PREHEATER 23.
- The Air Preheater absorbs waste heat from flue gas, and then
transfers this heat to incoming cold air by means of continuously
rotating heat transfer elements of specially formed metal
plates.
- Air Preheater is in general divided into two types:
24.
- 1) Regenerative APHare also known as storage type heat
exchangers, have an energy storage medium, called the matrix, which
is alternately exposed to the hot and cold fluids. When the hot
flue gases flow through the matrix in the first half of the cycle,
the matrix is heated and the gas is cooled. In the next half of the
cycle when air flows through the matrix, air gets heated and the
matrix is cooled. The cycle repeats itself.
25.
- 2) Recuperative APH,heat is directly transferred from the hot
gases to the air across the heat exchanging surface. They are
commonly tubular, although some plate types are still in use.
Tubular units are essentially counter-flow shell-and-tube heat
exchangers in which the hot gases flow inside the vertical straight
tubes and air flows outside. Baffles are provided to maximize air
contact with the hot tubes.
26. Regenerative Type Air Pre Heater
- Cooling water Consumption 18t/h
- Air temperature at Regenerative APH outlet -
27. General Arrangement of Airpreheater
SA PA FG FG PA TG HouseChimney 28. Air Preheater, main technical
specifications and list of master drawings 29.
- 1General arrangement of Air Preheater.
- 3.Rotor radial seal assembly
- 5.Rotor post and trunnion assembly.
- 6.Hot end and hot intermediate layer elements and element
baskets.
- 7.Cold end element and element basket.
- 8.Rotor housing assembly.
- 9.Hot end primary center section assembly.
- 10. Cold end primary center section assembly.
- 11. Hot end connecting plate assembly.
- 12. Cold end connecting plate assembly.
- 13. Guide bearing assembly.
- 14. Support bearing assembly.
- 15. Static seal assembly (hot end and cold end).
- 16. Axial and by-pass seal assembly.
- 17. Rotor drive assembly.
- 18. Sector plate assembly (hot end and cold end).
- 19. Air seal pipe, observation port and vapor or dust proof
light assembly.
- 20. Stationary water washing device (hot end and cold end) and
fire fighting device
- 21. Special tools and spare parts.
30. Isometric view of Air Preheater 31. AIR PRE-HEATER
OPERATION
- Support bearing/ guide bearing lubricating oil pumps RUNNING
and lubricating oil coolers are CHARGED.
- Bearing temperature NOT HIGH (less than 60oC)
- Electrical supply to APH motor is AVAILABLE.
- Local operation - Isolating valves of air motors are 'OPEN' and
bypass valves of air motor solenoids are 'CLOSED'.
- 'Air motors' lubricating oil level ADEQUATE
- Service air pressure is ADEQUATE (> 5 Kg/cm2)
32.
- Air motors ON indications come on
- Isolating dampers of APHs start opening.
- INSTRUCT local operator to check, locally for any abnormal
sounds from bearings/seals.
- START air heater electrical motor.
- Breaker CLOSED & its indication comes onUCB
- Associated air motor stops.
- Starting current shoots up and comes down to normal load
current.
AIR PRE-HEATER OPERATION 33. AIR PRE-HEATER OPERATION
- Isolating dampers of the air heater remain open.
- Isolating dampers of the other air heater, not in service,
start closing if its air motor is not ON.
- INSTRUCT local operator to check, locally for any abnormal
sounds from bearings/seals.
- There should be no abnormal hunting in air heater amperes meter
readings.
- There should be no abnormal sounds from air pre-heater seals or
bearings.
- Bearing temperatures must be within the normal range (650 C
-750 C)
34. Parameters related to APH
- Oil used : TC 680 cyndol (Bearing)
- EP 320 Parthan (Gear Box)
- Main Motor (Electric driven, AC)
- Stand by motor (Electric driven, AC)
- Motor: N=970rpm , Speed Reducer Assembly O/P: N=0.89 rpm
35. 36. ASHHANDLINGPLANT 37. INTRODUCTION
- Ash is a waste product of coal and solid fuel combustion. It
contains many harmful elements which can contaminate sub-soil water
of water is allowed to seep through ash into soil. Further,
percentage of ash present in Indian coals is large. As a result,
disposal of ash also uses up considerable area of land, which could
otherwise be put to better use.
- Therefore, it is desirable to put ash to use so that the
problem of providing land area for its disposal is solved. All out
efforts are being made for finding uses of ash. Presently, only
negligible amount of total ash produced in the country is put to
use. However, ash being a good landfill material can be used in
bulk in projects like highway construction. This is being done to
as large an extent as possible.
- Pollution Control Regulations have made it mandatory to dispose
ash in dry form only so that harmful elements do not find ingress
in the sub-soil water
38. ASH HANDLINGSYSTEM
- In modern boilers ash is collected in two locations namely (i)
Bottom of the furnace and (ii) in Electrostatic Precipitators (or
Dust Collection Systems). Out of these two fractions generally the
quantity of ash collected in Electrostatic Precipitators (or Dust
Collection Systems) is larger. Ash collected in the Bottom of
Furnace is generally small in quantity and is handled wet, whereas
that collected in Electrostatic Precipitators (or Dust Collection
Systems) is now collected by means of dry handling systems.
39. Silos for collection of FLY-ASH 40. FLY ASH HANDLING
SYSTEM
- The fly ash handling plant will remove fly ash from Electro
static precipitator (ESP) hoppers and transport it to the storage
silos. This will be carried out by pressure pneumatic conveying
system on a continuous, cyclic basis. One boiler unit will be
provided with one pneumatic conveying system for handling fly ash
collected in the ESP hopper. The system layout and the conveying
pipeline configuration will be designed and constructed to enable
evacuation of fly ash at maximum design rate. The output of the
system will be not less than 200% of actual ash amount. The
capacity of each set of system will be 30t/h.
41. ELECTROSTATIC PRECIPATATOR
- It is a device which captures the dust particles from the flue
gas thereby reducing the chimney emission.
Precipitators function by electrostatically charging the dust
particles in the gas stream. The charged particles are then
attracted to and deposited on plates or other collection devices.
When enough dust has accumulated, the collectors are shaken to
dislodge the dust, causing it to fall with the force of gravity to
hoppers below. The dust is then removed by a conveyor system for
disposal or recycling 42. LOCATION OF ESP ESP CHIMNEY APH ECO 43.
Electro Static Precipitator
44. ESP PROCESS STEPS Collectingelectrode, grounded Rapping
mechanism Discharge electrode with Negative high tension (20-60kV)
4.dust collection 4 Dust layer 1 1.Electron emission 2 2.Dust
particle charging 3 3.Migration 5 5.Rapping 45. ESP Flue gas
Emitter coil Gas distribution plate Collector plate 46. ESP
TECHNICAL SPECIFICATIONS Description Unit Value Nos. of Gas Stream
/ ESP Double Nos. of Parallel Path per Stream Nos. 38 Nos. of
electrical fields in series Nos. 5 Total active treatment length
per stream m 3.5 Treatment Time Seconds 15 47. Description Unit
Value Total Number of Electrode Nos. 3192 x 2 Total numbers of
Rappers per Unit Nos. 7 Total Nos. of Transformer Rectifier Unit
Nos. 20 Capacity of Transformer Rectifier Unit Each KVA 1.6A/72 KV
Total No. of Dust Hoppers Nos. 40 48. FUEL OIL SYSTEM 49.
- There are two types of fuels are used for ignition in
combustion chamber.
- 2) Light diesel oil(LDO).
50. HEAVYFUELOIL
- The density of HFO is higher.
- Cost is low compare to the LDO.
- The auxilary steam is mixed for easely flowing through
pipe.
- The storage tank of HFO is 2000 m3
51. BOILER LIGHT-UP
- "HFO" inlet and re-circulation flow start increasing
- "HFO header pressure very low" alarms clear off.
- HFO temperature in the HFO header increases up to 110o C.
- OPEN Ignitor oil trip valve
- Ignitor oil trip valve opens up.
- Ignitor air fans A & B, start automatically.
- Ignitor oil and ignitor air pressure increase up to 23 Kg/cm2
and 400 mm wcl, respectively.
- "Ignitor air to furnace DP low & "Ignitor oil/Atomising air
pressure low" & "Ignitor oil/HFO trip valve closed" alarms
clear off.
- CHECK these parameters are within their operation limits.
- Drum level normal (-60 mm. to 0, preferably on lower
side).
52. BOILER LIGHT-UP
- HFO temp. 110o C . (Min. temp. required is 95o C).
- HFO atomising steam pressure 8.75 Kg/cm2
- Light oil pressure more than 15 Kg/cm2.
- Ignitor atomising air pressure 5 to 7 Kg/cm2
- Wind box pressure between 35 to 40 mm wcl
- ADJUST HFO header pressure set point to 50%(13 Kg/cm2) and
TRANSFER its control to auto.
- HFO pressure controller transfers to auto and modulates to
maintain the set HFO header pressure.
- CLOSE heavy fuel oil re-circulation valve.
- HFO re-circulation flow valve closes.
- HFO re-circulation flow comes to minimum position
53. 54. LIGHTDIESELOIL
- The density of LDO is low.
- Cost is high compare to the HFO.
- The fuel is easely flowing through pipe.
- The storage tank of LDO is 300 m3
55. 56. 57. COAL MILL 58. INTODUCTION
- As coal powder is the most important fuel in the power plant,
the plant owners need coal mill or coal pulverizer to grind the
coal to micro powders. Raw coal (crushed) is fed through hopper at
the top of the coal pulverizer and falls down to grinder ring to be
pressed, crushed and milled into pieces by rollers. After the first
crush, coal powder fall into the second and third layer. The
pumping of the high-pressure centrifugal blower put the outside air
into the coal mill. The coarse coal powder will be brought into the
classifier.
59. TYPES OF MILLS
60. COALMILL 61. A B C D E F ESPPASS A ID-A ID-B PA-B FD-B PA-A
FD-A FURNACE WIND BOX SCAPH SA PA FG SA PA FG SCAPH ESPPASS B
ESPPASS C ESPPASS D WIND BOX ESP I/L X OVER DUCT ESP O/L X OVER
DUCT SA X-OVER DUCT COLD PA HOT PA FLUE GAS COLD SA HOT SA CHIMNEY
MILL LOCATION APH APH MILL 27C 324C 320C 1165C ECO I/L 493C 351C
136C 134C 129C 126C 62. Milling System
- PRE START CHECKS(Typical: Raymond Bowl Mill)Local
- Ensure R.C. Bunker level satisfactory.
- R.C. feeder and mill properly boxed up and no maintenance staff
working.
- Gear box oil level normal.lubricatingoil coolers charged.
- Pulveriser START PERMIT is AVAILABLE. (Boiler total airflow is
< 40% and all burners are HORIZONTAL). Alternatively, if anyone
coal feeder is proven then start permit will come from the proven
feeder.
- Cold air gate 100 % open. Hot air gate closed.
- Seal air valve 100 % open.
- "No unsuccessful start" permissive for pulveriser is ON.
- Mill fire fighting system ready.
63. Milling System
- PRE START CHECKS(Typical: Raymond Bowl Mill)UCB
- Ensure at least one P.A. fan and a seal air fan is in service.
Check the header pressure for both primary and seal air is
normal.
- Check that mill ignition energy is O.K. (Minimum 3 out of 4 gun
nozzle valves in adjacent elevation are open and elevation oil flow
is more than 30% OR adjacent feeder speed is more than 50% and
boiler load is more than 30%.
- Check that mill start permissive as per FSSS are satisfied
- Ensure E.P. zones have been charged (for first mill).
- Get the electrical supply for the mill.
- Inform the local operator to be near mill for start up.
64. Milling System
- Local-Check there is no abnormal sound from mill. Check return
oil flow from upper bearing is satisfactory. Check all the rollers
are rotating and the rate of reject is normal (after the mill is
loaded).
- U.C.B. -Check mill starting time and current. Ensure that they
are normal. Open hot air gate. Warm up the mill.
- Start the RC feeder and load the mill gradually.
- Keep the air flow through mill - 54 T/hr.
- Keep watch on mill differential to avoid mill choking.
- Maintain mill outlet temperature between 75C to 80C.
- As the pressure, temperature of main steam shoots up with coal
firing proper check should be kept on these parameters. (Especially
for first mill).
65. Milling System
- TRANSFER mill feeder and fuel master controller to manual.
- Fuel master and feeder control transfer to manual.
- REDUCE feeder speed to minimum, gradually.
- Coal flow to mill starts coming down.
- Other running feeders start loading up, to maintain boiler
loading, if on auto.
- Hot air gate closes with a time delay of 30 sec approx.
- Mill current and differential pressure start reducing as the
mill becomes empty, gradually.
- EVACUATE the mill reject chamber locally and STOP the
mill.
- Mill temperature comes down to less than 50 0 C.