Air & flue gas system
- 1. AIR AND GAS SYSTEM
- 2. INTRODUCTION BoilerCombustion Air Flue Gases • Air needed for combustion • Flue are needed to be evacuated • Losses due to flow need to be overcome Fuel
- 3. … … … … … … … … … … … … Coal Coal Bunker Mill Forced Draft Fan Primary Air Duct Secondary Air Duct Primary Air Fan Cold Primary Air Fan Hot Primary Air Fan Coal Piping Burner Coal, Primary & Secondary Air Flow Diagram
- 4. FD Fan Duct APH Duct Furnace Duct APHBack pass ESP ID Fan Chimney Duct Duct DRAUGHT SYSTEM PRESSURE VARIATION Pressure drop calculation in air & gas path and its comparison with design value. Assessment of ID and FD fan power as a function of furnace pressure.
- 5. MAJOR COMPONENTS Forced Draft Fan Induced Draft Fan Primary Air Fan Seal Air Fan Air Heater Steam Coil Air Pre heater Scanner Cooling Air Fan Ducting Damper
- 6. Impeller casing Suction casing Moving Blade Regulating Mechanism Bearing Gas flow 28 MOVING BLADE1 ARM FOR MOVING BLADE SHAFT2 4 STOPPER PLATE FOR PACKING5 OPERATING PLATE6 PISTON7 ROTOR8 NUT FOR PISTON9 10 MOVING BLADE SHAFT 11 SLEEVE 12 V-PACKING (MV-TYPE) 13 COVER FOR MOVING BLADE 14 15 BUSH FOR MOVING BLADE ARM 16 17 PISTON RING 18 19 BOLT 20 BOLT 21 SET SCREW 23 24 SET SCREW 25 PARALLEL PIN 26 RETAINING RING 27 28 O-RING 29 BOLT 30 BALANCING WEIGHT 31 SET SCREW 32 CYLINDER COVER33 34 HUB DUST COVER35 36 SLIDING PIECE37 38 SLIDING PIECE (PIN TYPE) 39 40 41 45 SLEEVE O-RING O-RING BOLT BUSH FOR ARM WITH PIN NUT FOR MOVING BLADE SHAFT RETAINING RING WASHER HYDRAULIC CYLINDER BUSH FOR MOVING BLADE SHAFT SUPPORT BEARING LINKAGE MECHANISM 42 O RING 43 O-RING 74 BUSH 75 SET SCREW 77 SET SCREW 25 16 38 22 U-NUT 28 MOVING BLADE1 ARM FOR MOVING BLADE SHAFT2 4 STOPPER PLATE FOR PACKING5 OPERATING PLATE6 PISTON7 ROTOR8 NUT FOR PISTON9 10 MOVING BLADE SHAFT 11 SLEEVE 12 V-PACKING (MV-TYPE) 13 COVER FOR MOVING BLADE 14 15 BUSH FOR MOVING BLADE ARM 16 17 PISTON RING 18 19 BOLT 20 BOLT 21 SET SCREW 23 24 SET SCREW 25 PARALLEL PIN 26 RETAINING RING 27 28 O-RING 29 BOLT 30 BALANCING WEIGHT 31 SET SCREW 32 CYLINDER COVER33 34 HUB DUST COVER35 36 SLIDING PIECE37 38 SLIDING PIECE (PIN TYPE) 39 40 41 45 SLEEVE O-RING O-RING BOLT BUSH FOR ARM WITH PIN NUT FOR MOVING BLADE SHAFT RETAINING RING WASHER HYDRAULIC CYLINDER BUSH FOR MOVING BLADE SHAFT SUPPORT BEARING LINKAGE MECHANISM 42 O RING 43 O-RING 74 BUSH 75 SET SCREW 77 SET SCREW 25 16 38 22 U-NUT Rotor Shaft Moving Blade Coupling Inner casing Overall fan construction and flowpath Diffuser Rear casing
- 8. Construction Rotor and Moving Blade
- 14. Soot Blowers in RAPH
- 15. Fire detection probe Provision is there to detect AH fire by detecting the abnormal temperature increase inside RAPH Thermocouples are installed at the Secondary Air side for detecting the abnormal temperature rise and alarm accordingly Water Washing Facility Air heater elements can be water washed during a overhaul by water washing system Water used: Service Water Water Pressure: 5.20 kpa g Quantity/ hr (approx): 318 m3/hr
- 17. Seal Air Fan Type Centrifugal Make TLT India Limited Number 2X100% Capacity 1000 m3/min Motor rating 132KW/4 pole Suction source Cold PA duct Head developed 5500mm(Static) Lubrication type Grease Sealing air is required to seal the mill gearbox internals from PF dust. It is used in the following location:- Roller Journal Grinding Table Rotary Separator
- 18. GA of seal air fan
- 19. GA of seal air fan
- 20. Flame Scanner Cooling Air Fan As the name suggests, flame scanner cooling air fan required to supply the cooling air to flame scanner. There are 2X 100% flame scanner cooling air fan, one AC and one DC driven.
- 21. GA of scanner air fan
- 22. GA of scanner air fan
- 23. SCAPH Contd. The purpose of SCAPH is to heat the secondary air during the initial firing condition to prevent acid corrosion of air heater elements due to low flue gas temperature. It is located at the discharge side of FD fan. SCAPH overall dimension (mm) 8287X7392X1066 Tube material Carbon steel (SA 179 seamless) Tube dimension (mm) 25.4ODX2.79 thk Fins (mm) G type spiral fins (50.4 od X0.4 thk) Fins material Carbon steel IS512/513 Header size 250NBX6525LGX9.3thk Header Material SA106 gr. B
- 24. Ducts and dampers Air and flue gas ducting system has the following major components 1. Ducting of rectangular, square or circular cross section with external stiffeners and internal bracings 2. Expansion Joints ( Non-metallic / Fabric type or Metallic type ) 3. Dampers 4. Guide vanes 5. Aerofoils 6. Access Doors 7. Duct Insulation 8. Duct supports ( Slings, Springs and Bearings) 9. Anchors/Guides ( Based on support philosophy )
- 25. A typical view of a duct section Access Door Aerofoil Expansion joint Support
- 26. • Classification • Air Duct : Inlet air Duct carrying cold air to FD Fans and PA Fans, Outlet duct from FD and PA fans to Air-preheater ( APH ) inlet.Tempering Air Duct from PA Discharge to Mill Inlet.Hot air duct from Air-preheater ( APH ) to Boiler. Generally it is made of 5mm thick carbon steel ( IS 2062 or ASTM A36 or equivalent ) • Flue/Gas Duct : Boiler Outlet duct from Economiser outlet to APH inlet , • APH Outlet to ESP inlet, ESP outlet to ID Fan inlet , ID Fan outlet to Stack ( Chimney ) . Generally it is made of 6 mm thick carbon steel ( IS 2062 or ASTM A36 or equivalent )
- 27. • DAMPERS: • Functions : Main function of Dampers in Flues & Duct System is either to control the flow of air /gas or to isolate the particular path of Flues & Duct System for maintenance of equipments placed on that particular path. • TYPE OF DAMPERS : 1. CONTROL DAMPERS :These dampers are of Louver type construction and are used to control the flow of air /gas. For higher sealing SEAL AIR is provided. 2. ON/OFF or ISOLATION DAMPERS: These dampers are also of Louver type construction and are used to isolate the system with lesser sealing efficiency ( 95%) , however SEAL AIR should be provided for better sealing. 3. GUILLOTINE DAMPERS : It is quick acting damper of Blade type construction with sealing efficiency as 99.9%.This is provided at places where complete isolation is required for maintenance purpose.
- 28. Thank You