Mechanical Hazards - Boiler Safety

1. BOILER SAFETY A PON.RATHNAVEL PRESENTATION

2. OUTLINE • Understanding Boiler • Boiler Hazards • Boiler Accidents in India • Safety Precautions

3. UNDERSTANDING BOILER Boiler is a closed vessel in which water is heated by combustion of fuels or heat from other sources

4. UNDERSTANDING BOILER A boiler is a steel pressure vessel in which water under pressure is converted into steam by the application of combustion. In other words, it is simply a heat exchanger which uses radiant heat and hot flue gases, liberated from burning fuel, to generate steam and hot water for heating and processing loads

5. UNDERSTANDING BOILER

6. UNDERSTANDING BOILER Burner Combustion Space Convection Section Stack Air FansControls & Accessories

7. HAZARDS • A Risk of Explosion • High Pressure steam • Combustion Gases • Chemicals • Moving Machinery • Hot Surfaces

8. BOILER ACCIDENTS • 01 November 2017Feroze Gandhi Thermal Power Station, Unchahar, Uttar Pradesh 43 died, 124 injured • 07 May 2020Nevyeli Lignite Corporation, Neyveli, Tamil Nadu 7 dead, 25 injured • 30 June 2020Nevyeli Lignite Corporation, Neyveli, Tamil Nadu 16 dead, 43 injured

9. SAFETY PRECAUTIONS • Safety Training and Communication • Maintaining Boiler Log • Water Level Control • Water Treatment • Safety Valves • Burner Control System

10. SAFETY PRECAUTIONS • Priming and Carry Over • Component Safety • Protective Clothing • Fire & Chemical Safety • Lockout and Tagout • Accident Reporting System

11. Safety Training & Communication Boiler operation information is communicated to the boiler operator trained in safety and operationDuty ChecklistCommunication during Shift Takeover

12. Boiler Log The boiler room log lists boiler operation data that can be used to increase boiler safety and efficiency as well as identifying a potential malfunction 8 hour/24 hour logs

13. Water Level The Normal Operating Water Level (NOWL) should be approximately in the middle of the gauge glass.

14. Water Level Try cocks are used to determine the boiler water level if the gauge glass is not functional.

15. Water Level The water column is blown down first and then the gauge glass to remove any sediment. Water should enter the gauge glass quickly when the gauge glass blowdown valve is closed.

16. Water Treatment Water must be treated for safety. Minerals can cause a build up of deposits and cause overheating of boiler parts. Demineralisation or Desalination is normally done in situ.

17. Safety Valve The spring-loaded pop-off safety valve pops open when steam pressure exceeds the MAWP.

18. Safety Valve Safety valves are routinely tested to ensure proper operation and must be serviced by an authorized manufacturer representative.

19. Burner Control System The safety devices are all wired through a burner controller. This will shutdown the fuel supply to the burner. When testing the flame scanner, the flame scanner sensor is covered to simulate a flame failure.

20. Carryover & Priming Boiler water carry-over is the contamination of the steam with boiler-water solidsPriming is the carryover of varying amounts of droplets of water in the steam (foam and mist), which lowers the energy efficiency of the steam and leads to the deposit of salt crystals on the super heaters and in the turbines.Carryover occurs when a high boiler water level causes water particles to be carried into steam lines. Periodic check against prevention of priming and carryover is necessary

21. Component Safety During a bottom blowdown, the boiler should be under light load and the water level should be at the NOWL.

22. Component Safety Steam valves are opened slowly and gloves are worn to prevent burns.

23. Component Safety Manhole and handhole covers are removed to provide access to boiler parts during a boiler inspection. Their operation demands paramount importance to safety precautions

24. Component Safety Pumps should be checked periodically to ensure proper bearing temperatures and checked for any unusual vibration. Do not wear loose clothing around moving parts.

25. Component Safety Steam traps are checked for proper operation when determining the cause of a steambound feedwater pump.

26. Protective Clothing A face shield along with safety glasses provides eye protection when working with feedwater chemicals. Full Body Apron or shielded PPE is also in common use these days.

27. Fire & Chemical Safety A fire safety plan includes the locations of fire alarms, fire extinguishers, the main electrical breaker, fire main, and exits for each area of the facility.

28. Fire & Chemical Safety Containers that contain hazardous materials must be labeled, tagged, or marked.

29. Lockout/Tagout Lockouts and tagouts are applied to equipment to prevent injury from energized circuits and equipment operation during maintenance and repair.

30. Accident Reports An accident report details facts about an accident in the facility and is required for insurance claims.

31. Boiler Inspection as a Tradition All internal surfaces are exposed and cleaned prior to the boiler inspection. Boiler inspection should be done at least once in 6 months by a certified boiler inspector