1. Circulation rate of circulating fluidized bed boiler

Definition: The circulation rate refers to the ratio of the amount of material (mainly ash particles) entering the CFB boiler to the amount of fuel required for combustion in the furnace. It reflects the number and degree of circulation of the material in the furnace.

Influencing factors:

Separator efficiency: The higher the separator efficiency, the more ash particles are recovered and the higher the circulation rate.
Fuel particle size: Small particle size, more fly ash, large circulation rate.
Fuel ash content: High ash content, more ash particles produced, large circulation rate.
Boiler load: Load reduction, flue gas flow rate reduction, circulation rate reduction.

2. Reasons for closing the economizer recirculation door of drum boiler

Closing the recirculation door is to prevent cracks caused by uneven boiler water temperature and uneven heating of the recirculation pipe metal, while ensuring the normal operation of the economizer.

3. Chemical cleaning of new and overhauled boilers

Chemical cleaning is to remove impurities such as grease, iron filings, welding slag, etc. generated during manufacturing, transportation, installation and maintenance to prevent these impurities from damaging the boiler and turbine.
 

4. Boiler blowpipe

Blowpipe is to use the steam generated by the boiler itself to physically clean the steam-water system and remove the residues in the equipment and pipelines that cannot be cleaned by chemical cleaning.

5. Time and temperature regulations for water filling before boiler start-up

The time and temperature for water filling are stipulated to prevent the expansion difference between the drum and the connecting pipe due to uneven heating, causing damage to the equipment.

6. Common maintenance methods for boilers

Wet protection: prevent corrosion by adding chemical agents.
Dry protection: keep dry by drying or placing desiccant.

7. Reasons for deterioration of steam quality

Steam carries water: impurities in boiler water are carried by steam.
Steam dissolves salt: steam dissolves part of the salt under high pressure.

8. Low-temperature corrosion of the tail heating surface

  Since the sulfur in the fuel burns to generate SO3, it combines with the water vapor in the flue gas to generate sulfuric acid vapor, which condenses on the low-temperature heating surface and causes corrosion.

9. Emergency shutdown situations

Including many serious situations such as drum water level exceeding the limit, damage to all water level gauges, pipeline explosion, tail re-combustion, fan shutdown, etc.

10. Reasons for monitoring exhaust gas temperature

Exhaust gas temperature is the main part of boiler heat loss and can reflect the operating status of the boiler, so it needs to be monitored.

11. Pressure increase, pressure relief speed and qualified standards for water pressure test

The speed and qualified standards for pressure increase and pressure relief are specified to ensure the safety of the test process and accurately evaluate the sealing of pressure-bearing parts.

12. Flushing steps for drum water level gauge

The accuracy and cleanliness of the water level gauge are ensured through three steps: water side flushing, steam side flushing and steam-water co-flushing.

13. Reasons for not using water spray cooling for reheat steam temperature regulation

Water spray cooling will reduce the thermal efficiency of the unit and limit the working capacity of the high-pressure cylinder.

14. Steps for reheater water pressure test

The preparation, pressure increase, inspection and pressure reduction process of the reheater water pressure test are described in detail.

15. Main factors affecting wear rate

  Including the flow rate, concentration, particle size, hardness of flue gas materials and the surface shape and hardness of the worn components.

16. Reasons for controlling the bed temperature between 850-950℃

This temperature range can avoid ash melting, improve desulfurization efficiency, reduce nitride generation and alkali metal sublimation.

17. Phenomenon of coking on the bed surface of circulating fluidized bed boiler

Including a sharp increase in bed temperature, a decrease in oxygen content, changes in fan current and other manifestations.

18. Measures to avoid coking during startup

  Including checking the hood opening, controlling the heating rate, ensuring uniform bed temperature, and slowly feeding coal.

19. Factors affecting the load of fluidized bed boilers

Including coal quality, bed temperature, bed pressure, oxygen content and air ratio, feed water temperature and cleanliness of the tail heating surface.

20. Methods for protecting castings during startup

Control temperature changes, furnace pressure changes and coal feeding to ensure the safety of castings.

Through these detailed explanations and supplements, you can have a more comprehensive understanding of the operation, maintenance and care of circulating fluidized bed boilers and drum boilers.