Boiler Interlock and Protection

Manish Dhruw Asst Manager 14843 Cpp-540

Boiler Interlock - A Boiler Interlock is an arrangement of heating controls. It ensures the boiler does not fire when there is no demand for heat. Protection of boiler – Boiler protection are provide to detect the abnormal condition by constantly measuring the various parameter under normal and faulty condition. If any abnormality happened trip the boiler to prevent from major damage. Need of Interlocks & Protection

◦ ◦ ◦ ◦

To avoid operational faults To avoid equipments damage. To avoid accidents to individuals. To avoid system disturbances

Master Fuel Trip - it produces trip signal for fuel systems from operation , then trip the boiler out of service away from danger. this relay needs many conditions to operate , these conditions will be found at the following points. • 9. Unit flame failure.  1. Both ID fan trip. • 10. Loss of fuel.  2. Both FD fans trip. • 11. Loss of scanner cooling air (Scanner air  3. Emergency manual trip. pressure250 mm: emergency priority alarm. 4. Level>-250 mm: emergency priority alarm. Furnace pressure 1. Pressure>30 mm of H2O: high priority alarm. 2. Pressure>-30 mm of H2O: high priority alarm. 3. Pressure>50 mm of H2O: emergency priority alarm. 4. Pressure>-50 mm of H2O: emergency priority alarm. MS flow 1. MS flow>200 TPH: high priority alarm. 2. MS flow>450 TPH: emergency priority alarm.

• MS & RH Temperature • 1. MS temperature>5450C: high priority alarm. • 2. MS temperature>5500C: emergency priority alarm. • 3. RH temperature>5450C: high priority alarm. • 4. RH temperature>5500C: emergency priority alarm. • Others • 1. APH flue gas inlet temperature260 Amp: emergency priority alarm. 3. Seal air discharge pressure3.4 kg/cm2. 5. Secondary air temperature>1770C. 6. Total air flow700C: emergency priority alarm. 4. Mill motor front/ rear bearing temperature>750C: high priority alarm. 4. Mill motor winding temperature>1000C: high priority alarm. 5. Mill outlet, roller bearing temperature>900C: high priority alarm. 6. Mill current>60 amp: high priority alarm. 7. Mill inlet PA flow< 50 TPH: high priority alarm. 8. Mill hydraulic pressure>150 kg/cm2: high priority alarm. 9. Mill hydraulic pressure