Thermal Power Station Boilers & Auxiliaries PDF

Thermal Power Station Boilers & Auxiliaries NATIONAL POWER TRAINING INSTITUTE EASTERN REGION CITY CENTRE, DURGAPUR-713216.  INDIAN ENERGY SCENARIO Growth: 1,362 MWe (in 1947) to 1,43,542 MWe (as Nov. 30, 2008) 68308, 55%...

Thermal Power Station Boilers & Auxiliaries NATIONAL POWER TRAINING INSTITUTE EASTERN REGION CITY CENTRE, DURGAPUR-713216.  INDIAN ENERGY SCENARIO Growth: 1,362 MWe (in 1947) to 1,43,542 MWe (as Nov. 30, 2008) 68308, 55% Coal Gas 6158, 5% Oil Hydro 3310, 3% Nuclear 12430, 10% Renewable 1201, 1% 32135, 26% POWER SECTOR GROWTH PROJECTION IN MWe [Source: Central Electricity Authority (CEA)] COAL GAS NUCLEAR HYDRO OTHERS TOTAL Installed 68308 12430 3310 32135 7359 123542 Capacity as on 30 Nov 2005 Total 114490 31430 11100 53810 4970 215800 Capacity by 2012 NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 Introduction Classification 1. General Classification Package & Field Erected Fire tube/Water tube 2. Purpose wise classification Power boiler Utility Boiler for process steam  FIRE TUBE BOILERS Small Boilers :Combustion gases pass through interior of tubes submerged in water to be heated.Furnace may be separate or built into the boiler shell. Sub-Class 1. Dry back type/ Wet back type 2. Oil fired / coal fired 3. Externally fired / internally fired 4. Through tube type/Return tube type 5. Horizontal / Vertical / Inclined NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 Fire Tube Boilers / Sub Classification(Contd.) Other Designs Includes; 1. Simple Vertical Boiler 2. Two Pass Boiler 3. Scotch Marine Boiler 4. Locomotive Type Boiler NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 Water Tube Boilers Power Boilers Utility Boilers LAYOUT PROCESS FLOW DIAGRAM  Classification Of Water Tube Boilers By Type of Circulation: Natural Forced Assisted By Number of Drums Drum less ( Once Through Type) *Single Drum *Mostly used in *Two(Bi-)Drum Power Station/ Industrial Boilers Three(Tri-)Drum Multi-Drum  Fuels Utilized for Different Boilers 1. SOLID FUELS Coal Bagasse,Straw,Fire-wood,other bio-fuels Coke breeze Pet-Coke Washery Rejects/ Middling Municipal Garbage/Manure  Fuels Utilized for Different Boilers 2. LIQUID FUELS Fuel Oil – L.D.O./H.F.O./L.S.H.S./H.S.D. etc Black Liquor ( Pulp Industry Waste) Naphtha 3.GASEOUS FUELS Coke-oven Gas Blast Furnace Gas Corex Gas Bio-Gas Natural Gas  SOLID FUEL FIRING SYSTEMS For Coal Firing 1. Fuel Bed Firing Chain Grate/Renfrew & Oldbury Stoker Traveling Grate Stoker 1. Style 28X Stoker 2.Rotograte Spreader Stoker SOLID FUEL FIRING SYSTEMS(Contd.) For Coal Firing 2.SUSPENSION FIRING (a) Fluidizing Bed Firing 1.Bubbling Fluidizing Bed Firing 2.Atmospheric Fluidizing Bed Firing 3.Circulating Fluidizing Bed Firing 4.Pressurized Fluidizing Bed Firing SOLID FUEL FIRING SYSTEMS(Contd.) (b)Pulverized Coal Firing (P.F.Mills) Direct Firing 1. Front Fired 2.Opposed Fired 3.Downshot Fired ( U-Type / W- Type ) 4.Corner Fired Indirect Firing -- Bin System BURNERS: Laminar / Turbulent / Low-NOx NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 SOLID FUEL FIRING SYSTEMS(Contd.) © For Bagasse Firing Horse Shoe Furnace Dumping Grate Furnace Rotograte Furnace LIQUID FUEL FIRING ARRANGEMENT For Oil Firing Steam Atomized Air Atomized Pressure Atomized For Black Liquor Black Liquor Guns Spraying on Furnace Walls & Burning of Char at Furnace Hearth. NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 GASIOUS FUEL FIRING EQUIPMENT Spud Burners – For High C.V. Gases Scroll Type Burners -- For Low C.V. Gases (such as Blast Furnace Gas) Basic Function of Steam Generators Generation of Steam at specified rate of QUANTITY at a particular Temperature, Pressure & Degree of Superheat / Enthalpy Content Steam Separation , Washing & Drying Up Control of combustion or balancing of rate of Heat Generation & Absorption Minimization of Heat Losses Through Incombustibles / Ash NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 MAJOR PARTS OF BOILERS Furnace – Chemical Energy of Fuel is converted into Thermal/ Heat Energy by Process of Combustion Heat Transfer Zone  TYPES OF FURNACE Refractory Fitted Spaced Tube Partially Water - cooled Tangent Tube Fully Water – cooled Membrane Tube Fully Water – cooled Steam – cooled Furnace Enclosure Oil – Firing Furnace Dry – Bottom Furnace Wet – Bottom / Slag Furnace ARRANGEMENT OF HEATING SURFACE 1. Economizer Tubes – Plain Tube Gilled / Finned Tubes C.I.Sleeve on Steel Tubes Tube Arrangements : (a) Vertical – Used on Recovery Boilers (b) Horizontal – Used on Power / Industrial Boilers TYPES OF ECONOMIZER : Steaming & Non - steaming ARRANGEMENT OF HEATING SURFACE 2. Furnace Walls & Roof Tubes 3. Super heater Tubes DUTYWISE – Primary Secondary & Tertiary Mode of Heat Transfer : Radiant & Convective Steam/ Gas Flow Arrangement: Parallel Counter flow Mixed flow PASSAGEWISE : Single Steam Pass OR More than One Steam Pass  NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 ARRANGEMENT OF HEATING SURFACE Super heater Tubes (Contd.) By Supporting Arrangement: Pendant Inverted Loop Horizontal By Draining Arrangement : Drainable Super heater Non – Drainable By Steam Temperature Control Arrangement: Tilting Burner (No control – adjustment only) Attemperator – Spray type & Drum type ARRANGEMENT OF HEATING SURFACE Reheater Tubes DUTYWISE – Primary Secondary Mode of Heat Transfer : Radiant & Convective Steam/ Gas Flow Arrangement: Parallel Counter flow Mixed flow PASSAGEWISE : Single Steam Pass OR More than One Steam Pass Super heater Tubes (Contd.) By Supporting Arrangement: Pendant Inverted Loop Horizontal By Draining Arrangement : Drainable Super heater Non – Drainable By Steam Temperature Control Arrangement: Tilting Burner (No control – adjustment only) Attemperator – Spraying at INLET (CRH) Gas Proportioning over the parallel path By Gas Recirculation  BOILER DRUM Purpose: Location for separation of dry saturated steam(May be within or outside heat transfer zone) Function: Saturated Steam Separation, Washing , Drying. Boiler may be DRUMLESS(Supercritical/Once through), Single-Drum(Steam Drum), Bi-Drum(Two-Drums)- mud drum{bottom} & steam drum{top} Tri(Three)- drum or Multi drum  AIR PRE HEATER RECUPERATIVE : 1. Plain tube,horizontal ,in-line arrangement ( Air through tube & Gas over the tubes) 2. Vertical,Staggered tube arrangement ( Gas through tubes & Air over the tubes) Finned Tube Steam Air Pre heater – Waste Heat Recovery & Oil Fired Boilers. Regenerative Rotary Air Pre Heater : Bi-Sector Tri-Sector SOOT BLOWER An Aid To On Load Cleaning Of Heating Surfaces SHORT RETRACTIVE TYPE: For furnace wall (Wall De-slagger) LONG RETRACTIVE TYPE :For tube banks ROTARY TYPE BLOWER :For Low Temperature Banks NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 GAS CLEANING DEVICE Mechanical Dust Collector: 1. Cyclone Separator 2. Fabric Filter / Bag House Electrostatic Precipitator(ESP) Flue Gas De-Sulphurisation Unit (FGD) NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 DRAFT SYSTEM NATURAL DRAFT – Only used in small boilers ( Through Chimney) FORCED DRAFT – Only used where gas tight enclosure possible as in Oil Fired Units ( Through F.D.Fans only) INDUCED DRAFT -- Only used with I.D.Fan BALANCED DRAFT – In Power & Large Utility Boilers ( Both I.D.Fan & F.D.Fan are used.) NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 FANS FOR AIR MOVEMENT : F.D.Fan, P.A.Fan, Scanner Air Fan & Seal Air Fan FOR GAS MOVEMENT: I.D.Fan, Booster Fan & Gas Recirculation Fan NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 BOILER MOUNTINGS Safety Valves Stop Valves Blow Down Valve Feed Control Valve / Feed Check Valve Steam / Water Pressure Gauges Drum Level Indicator ( GAUGE GLASS) Hydra step and other C & I Mountings NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 Boiler Supporting Structure ( HOT & COLD ) Galleries, Ladders, Access & Emergency Doors Flue Gas Ducts & Expansion Joints Buck stay , Tie bars , Anchors ,Slings , Hangers. Struss, Beam, Column,Casing & Insulation Station Piping Basic Boiler Design Considerations 1.System Considerations: Location Type of Fuel Used Capacity of Steam Generation Required Steaming Parameters at Outlet (Enthalpy,Temperature,Pressure) Water Source Air Supply Units Fuel Preparation Units Combustible Product Disposal Units Detail Thermal Engineering & Heat Balance NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 Basic Boiler Design Considerations 2.Structural Design & Engineering Consideration DEAD LOAD LIVE LOAD WIND LOAD EARTHQUAKE LOAD EXPANSION PROVISION FOR HOT STRUCTURE SAFETY ARRANGEMENT FOR EXPLOSION / IMPLOSION NATIONAL POWER TRAINING INSTITUTE (EASTERN REGION) CITY CENTRE, DURGAPUR-713216 T h a n k Y O U