Safety Operating Procedures for Boiler Operators

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Safety Operating Procedures for Boiler Operators 1. Operations for adding chemicals during boiler heating? 1.1 Dissolve the chemicals in hot water, then add the total amount of chemicals to the boiler drum at once. Before adding the chemicals, adjust the water level to the low mark; after adding them, raise the water level to the highest mark before starting the heating process. Be careful not to add solid medicine into the furnace. ? 1.2 During the boiler cleaning process, water samples from the boiler should be taken at the blowdown points located in the drum and the lower water wall collectors, in order to monitor changes in the alkalinity and phosphate levels of the boiler water. Samples should be taken before and after blowdown; by the end of the cleaning process, there should be no further changes in the alkalinity and phosphate levels of the boiler water. ? 1.3 The boiler cooking period is 3 days: on the first day, it is cooked at a gauge pressure of 0.1 MPa for 24 hours; on the second day, it is cooked at a gauge pressure of 0.2–0.3 MPa for 24 hours; and on the third day, it is cooked at a gauge pressure of 0.1 MPa for 24 hours. ? 1.4. Stop sludge discharge two days before starting to boil the furnace; on the third day, carry out sludge discharge every two hours during the last shift. ? 1.5. After the boiler is shut down, close the smoke and air dampers within 4 hours. ? 1.6. After the boiler is shut down for 4 hours, open the smoke and air dampers to allow natural ventilation for cooling. ? 1.7. Six hours after the ceasefire, once the temperature of the boiler water drops below 50°C, all of the water can be drained from the boiler. ? 1.8: After the boiler water has been drained, fill it up again, then drain it once more to rinse it. ? 2. Water injection into the boiler and piping system? 2.1. Open the drain valve of the steam drum? 2.2. The water inlet temperature should not be too high; the temperature difference between the water temperature and the wall temperature of the boiler drum should not exceed 50°C. ? 2.3 During the water injection process, inspections should be intensified; any leaks detected must be addressed promptly. Additionally, the automatic water level control system and the high/low water level alarms should be checked to ensure their reliable operation. ? 2.4 When the water level rises to the lowest level, suspend water supply and observe whether there is any change in the water level; if there is a change, identify the cause immediately. No abnormalities detected; water supply can be resumed to raise the water level to normal levels. ? 2.5 When filling the hot water boiler with water, stop pouring water once water is seen in the drain valve ； When filling the water supply network, water is injected from the return pipe using a make-up pump, while venting is done at the highest point of the network; once water can be drained from there, the network is fully filled. The circulation pump can be started, and firing can proceed only once the circulation pressure is stable. ? 3. Ignition procedure? 3.1. Open the flue damper and start the fan to provide mechanical ventilation for 5–10 minutes. ? 3.2 Light the ignition torch and keep it burning brightly; position it just below the nozzle of the oil gun, open the oil supply valve, and ignite it carefully. ? 3.3 Adjust the throttle and air supply volume according to the combustion conditions to ensure stable combustion. ? 3.4 Once the flame is stable, the combustion is normal, and the furnace temperature has risen, remove the ignition rod. ? 3.5 The ignition speed should not be too rapid; especially in boilers with a large water capacity and poor water circulation, the furnace temperature should rise more slowly. ? 3.6 If a fire breaks out, the cause should be analyzed to eliminate the fault. After forced ventilation for 5–10 minutes, ignite the fire, taking great care to prevent deflagration accidents. ? 3.7. Closely monitor changes in water level. Properly enhance ventilation and combustion, and begin increasing pressure or temperature. ? 3.8 If ignition does not occur, the ignition gas supply should be cut off immediately, forced ventilation should be applied for 5–10 minutes again, and then ignition attempted once more. ? 4. Boiler pressure/temperature increase operation? 4.1. For steam boilers, when the pressure reaches 0.05–1 MPa gauge pressure, flush the water level gauge. ? 4.2 When the pressure rises to 0.1–0.15 MPa gauge pressure, flush the pressure gauge’s trap to prevent malfunction due to blockage by dirt. ? 4.3 When the pressure rises to 0.15–0.2 MPa gauge pressure, close the vent on the upper drum. ? 4.4 When the steam pressure rises to 0.2–0.3 MPa gauge pressure, check that there are no leaks, and tighten any loose screws on access holes, manholes, and flange connections. When operating, turn sideways, and the length of the wrench used should not exceed 20 times the diameter of the screw. ? 4.5 When the steam pressure rises to 0.3–0.4 MPa gauge pressure, perform a drain from the lower part; when the water level drops as a result of this drainage, the feed water valve should be opened to replenish water. ? 4.6: When the temperature of the hot water heater rises to 20°C, it is necessary to perform a drain and water mixing operation once, and the pressure gauge should also be flushed. The normal account opening heating process must last no less than 4 hours. ? 5. Pipe warming operations for steam boilers? 5.1. First, open all drain valves on the steam pipes to remove the water that has accumulated and condensed inside the pipes. ? 5.2 Slowly open the main steam valve of the boiler until it is fully open; then close it half a turn to prevent it from getting stuck due to thermal expansion. ? 5.3 Once dry steam is observed being discharged from the drain valve, the pipe warming process can be completed, and the drain valve should be closed. ? 5.4 During the pipe heating process, it is necessary to check the condition of the pipe supports and expansion joints. If any abnormalities are detected, heating should be stopped to identify the cause; the fault must be resolved before continuing with the heating process. ? 6. Operation of connecting boilers together? 6.1 Boilers can be connected together only when the steam pressure in them is 0.05–0.1 MPa lower than that in the steam main, and when the water level is at the normal level. ? 6.2 After the main steam valve is slowly opened to full position, it should be turned half a turn to prevent it from getting stuck due to thermal expansion; finally, close the drain valve. ? 7. Steam supply operation for steam boilers? Open the main steam valve slowly; once no abnormal noises are heard in the steam pipes, then open the valve further. If there is a knocking sound in the pipeline, the pipeline drain valve should be opened wider; once all the condensed water has been drained, the main steam valve can be opened again to supply steam. ? 8. Drainage operation of steam boilers? 8.1 First, slightly open the slow-opening valve to preheat the pipeline between the two valves; once there is no sound of shock, open it fully. Then open the quick-opening valve a little to preheat the drainage pipeline. Without any sound of shock, close the quick-opening valve fully several times to carry out drainage. After drainage is complete, first close the quick-opening valve, and then close the slow-opening valve. ? 8.2 When two or more boilers share a single blowdown main, it is strictly prohibited to blow down both boilers simultaneously. Also pay attention to leakage. ? 9. Handling of water shortage incidents? 9.1. If the water level indicated by the gauge is below the lowest safe level and the water level is still visible, the gauge should be flushed to determine the actual level of water. ? 9.2, Manually increase the water supply volume. ? 9.3 After the above treatments, if the water level continues to drop, the furnace should be shut down immediately. Close the main steam valve and continue to feed water to the boiler. ? 9.4. In the event of severe water shortage, water should not be supplied to the boiler. It should be handled in accordance with the emergency shutdown procedures. And report it promptly to the relevant leadership. ? 10. Handling of full-water accidents? 10.1. Immediately close the feedwater valve, and open the economizer recirculation valve or the bypass flue. ? 10.2: Open the sewage valve and increase the water discharge rate, but pay attention to the water level indicated by the gauge to prevent water shortage due to excessive discharge. ? 10.3. Close the air dampers to reduce the amount of oil (gas) and airflow. ? 10.4. Open the drain valves on the main steam valve, steam cylinders, and steam header. ? 10.5. Once the water level returns to normal, resume normal combustion. ? 11. Handling of simultaneous boiling of steam and water? 11.1. Fully open the surface blowdown valves on the upper boiler drum; at the same time, bottom blowdown can be carried out appropriately. Increase the feed water supply to maintain a normal water level, thereby reducing the salt content in the boiler. ? 11.2. Open the drain valves on the superheater, steam pipelines, and steam distribution cylinders. ? 11.3 Effective measures should be taken to improve the quality of the boiler water, and the frequency of analyses of the boiler water should be increased. The boiler load shall not be increased until the quality of the boiler water improves. ? 12. Handling of steam boiler tube rupture accidents? 12.1. In the event of a minor rupture in the boiler tubes, and provided that the water level in the boiler can remain normal and the crack is not likely to expand rapidly, it is necessary to increase the water supply, operate the boiler at reduced load, and immediately activate the backup boiler. Once the backup boiler is started up and operating normally, the boiler can then be shut down as per standard procedures. If several boilers are supplying heat in parallel, this boiler should be isolated from the steam main before being shut down normally. ? 12.2 In the event of a furnace tube rupture and a rapid drop in water level and steam pressure, the furnace should be shut down urgently. If the water level is below the minimum level or is not visible, be sure to supply water into the furnace; however, keep the exhaust fan running until all smoke and steam have been removed, after which stop it. ? 12.3 After shutting down the furnace, close the main steam valve immediately. ? 13. Handling of tube rupture accidents in hot water boilers? 13.1. Once a tube rupture occurs in a hot water boiler, the boiler should be shut down immediately. ? 13.2. Start the water pump to circulate water and continue feeding it; stop the water supply once the temperature of the boiler water drops below 50°C. ? 14. Handling of secondary combustion accidents in flue ducts? 14.1. Immediately stop feeding fuel to the furnace and shut it down urgently. ? 14.2 Close the flue air supply baffles and all access doors; ventilation is strictly prohibited. ? 14.3. Use steam injection into the flue for fire extinguishing, or CO2 fire extinguishers. ? 14.4 After the accident is resolved, carefully inspect the equipment; if nothing is abnormal, ventilate it for about 5–10 minutes first, then start it up according to the operating procedures, reignite it, and resume operation. ? 15. Handling of combustion chamber furnace wall damage incidents? Once overheating of the furnace’s outer shielding is detected, the furnace should be stopped immediately for inspection; if the furnace wall is damaged, it must be repaired right away. ? 16. Handling of power outage incidents? 16.1. Immediately shut down the burner and open the economizer recirculation valve. ? 16.2 Immediately close the main valve of the steam header and clean the oil system. ? 16.3 Determine the cause of the power outage and the time required for restoration, and prepare for restarting the furnace. ? 17. Handling of vaporization accidents in hot water boilers? 17.1. When signs of a vaporization accident occur, immediately reduce the heat load on the boiler, that is, adjust the flame to a smaller size. ? 17.2. Investigate and analyze the causes of vaporization accidents, and take corresponding measures, primarily by increasing water supply and reducing combustion. ? 17.3 If there is still no improvement after reducing the heat load and increasing water supply, the furnace should be shut down urgently. ? 18. Handling of boiler fire extinguishment accidents? 18.1. Upon detecting a fire, immediately close the oil (steam) valves and open the bypass circulation valves (make sure this does not affect the normal operation of the furnace). ? 18.2. After the fan has been running for 5–10 minutes, stop it and close the smoke and air dampers. ? 18.3 If the circulating water pump also stops operating, the boiler water level should be checked, and any vaporized steam should be removed promptly. ? 18.4 Analyze the causes of the fire and take corresponding measures. ? 19. Operations for emergency shutdown of the furnace? 19.1. When operating a single furnace and an emergency shutdown is required, increase the flow rate of the circulation valve, close the oil (gas) supply valves, and immediately shut off the heat supply. ? 19.2 If other furnaces are operating in parallel, the furnace under operation should be subject to enhanced adjustment and monitoring. ? 19.3 If there is a backup furnace, it should be started immediately to ensure heat supply and put it into operation.