REFRACTORY DRYING

Required conditions:1. Boiler is to be made ready for light up after shutdown.2. No L.C is pending for light up.3. All manholes, peepholes are to be kept closed.4. Confirm supply to ID/FD fans and Mills.5. AST Header is to be in charged condition.6. Availability of RSBs is to be ensured.7. Healthiness of Mill O/L temperature readings is to be checked.

DRYING PROCEDURE:1. Boiler interlocking (General) to be simulated for starting mills.2. Simulate sec. Air temp > min contact.3. Start both series of Fans.4. Charge corresponding SCAPHs.5. Start the available mills in presence of maintenance staff and local staff.

Check lub oil system and mill healthiness.6. Keep airflow at 30% MCR (about 250 T/hr) and air temperature at SCAPH O/L

to the max possible extent.7. Start boiler feeding through Boiler Feed Pump with deaerated water at 70ºC.8. After ensuring normal working Drum level, BOILER to be lighted up with one

oil burner with minimum oil flow. Cut in another oil burner preferably in combination of A and C or B and D

9. Raise the Mill O/L temperature from 60 ºC to 120 ºC at the rate of 15 ºC /hr by raising the firing rate gradually and with the help of hot air.

10. Change the combination of OB’s once in 4 hrs.11. Frequently check for any oil leak or fire at local.12. RSB is to be operated with AST source once in 4 hrs.13. Raise the mill O/L temp from 120 to 200ºC at the rate of 20ºC/hr and

maintain at 200 ºC for 8 hrs. With the use of hot air/cold air dampers if necessary.

14. During refractory drying operation, close the air vents/drains on steam side as per the standard norms.

15. Stop mills one by one.16. Normalize the simulations done.17. Raise the oil flow for steam parameter raising as per the normal procedure

for Turbine rolling, synchronizing and load raising as per the schedule.