One Question per Day (December 31)

Operation of the boiler unit must be stopped immediately in any of the following situations: a. When there is a lack of water in the boiler, causing the water level to disappear from the drum gauge. b. When the boiler is full of water, causing the water level to exceed the visible level indicated by the drum level gauge. c. When the furnace tube bursts and the normal water level in the boiler cannot be maintained. d. When all drum level gauges are damaged. e. When secondary combustion occurs in the flue and the temperature of the flue gas in each section rises sharply. f. When the steam and water pipes of the boiler burst, posing a threat to the safety of personnel and equipment. g. When all the pressure gauges on the steam side fail and pressure cannot be monitored

The operation of the boiler unit must be stopped immediately in any of the following situations: 1. When there is a lack of water in the boiler, causing the water level to disappear from the drum level gauge. 2. When the boiler is full of water, causing the water level to exceed the visible level indicated by the drum level gauge. 3. When the furnace tube bursts and the normal water level in the boiler cannot be maintained. 4. When all drum level gauges are damaged. 5. When secondary combustion occurs in the flue and the temperature of the flue gas in each section rises sharply. 6. When the steam and water pipes of the boiler burst, posing a threat to the safety of personnel and equipment. 7. When all the steam-side pressure gauges fail and it is not possible to monitor the pressure.

The boiler should be shut down urgently in any of the following situations: (1) The water level in the drum is below the limit value (a value specified by the manufacturer or based on operational experience, and approved by the plant’s chief engineer)； (2) The drum water level is above the limit value (a value specified by the manufacturer or based on operational experience, and approved by the plant’s chief engineer) ； (3) When all the water level gauges of the boiler are damaged ； (4) Tube explosion; the drum water level cannot be maintained even with increased feedwater and reduced load ； (5) When the main feedwater and steam pipes burst, making it impossible to switch over, thereby threatening the safety of equipment or personnel ； (6) When the main steam pressure exceeds the operating pressure of the safety valve, yet the safety valve does not operate and the exhaust valve to the atmosphere cannot be opened ； (7) Reheat steam interruption ； (8) When the boiler shuts down or the pressure behind the fuel control valve of a fuel-fired boiler drops to an unacceptable level ； (9) When all the induced draft fans, forced draft fans, or rotary air preheaters fail and stop operating ； (10) When an explosion occurs inside the furnace or flue, causing severe damage to the equipment ； (11) In the event of a fire in the boiler room that directly affects the safe operation of the boilers ； (12) When reignition occurs at the boiler tail.

The boiler should be shut down urgently in any of the following situations: (1) The water level in the drum is below the limit value (a value specified by the manufacturer or based on operational experience, and approved by the plant’s chief engineer)； (2) The drum water level is above the limit value (a value specified by the manufacturer or based on operational experience, and approved by the plant’s chief engineer) ； (3) When all the water level gauges of the boiler are damaged ； (4) Tube explosion; the drum water level cannot be maintained even with increased feedwater and reduced load ； (5) When the main feedwater and steam pipes burst, making it impossible to switch over, thereby threatening the safety of equipment or personnel ； (6) When the main steam pressure exceeds the operating pressure of the safety valve, yet the safety valve does not operate and the exhaust valve to the atmosphere cannot be opened ； (7) Reheat steam interruption ； (8) When the boiler shuts down or the pressure behind the fuel control valve of a fuel-fired boiler drops to an unacceptable level ； (9) When all the induced draft fans, forced draft fans, or rotary air preheaters fail and stop operating ； (10) When an explosion occurs inside the furnace or flue, causing severe damage to the equipment ； (11) In the event of a fire in the boiler room that directly affects the safe operation of the boilers ； (12) When reignition occurs at the boiler tail.

Operation of the boiler unit must be stopped immediately in any of the following situations: a. When there is a lack of water in the boiler, causing the water level to disappear from the drum gauge. b. When the boiler is full of water, causing the water level to exceed the visible level indicated by the drum level gauge. c. When the furnace tube bursts and the normal water level in the boiler cannot be maintained. d. When all drum level gauges are damaged. e. When secondary combustion occurs in the flue and the temperature of the flue gas in each section rises sharply. f. When the steam and water pipes of the boiler burst, posing a threat to the safety of personnel and equipment. g. When all the steam-side pressure gauges fail and it is not possible to monitor the pressure.

(1) When the drum water level exceeds the positive and negative limit values. (2) When all the water gauges of the boiler are damaged. (3) When the superheater steam pipes, reheat steam pipes, or main feedwater pipes burst and operation cannot be maintained. (4) When reignition occurs at the rear of the boiler. (5) When all suction and supply fans or rotary air preheaters stop operating. (6) When the reheat steam is interrupted. (7) When an explosion occurs inside the furnace or flue, causing severe damage to the equipment. (8) When the boiler pressure rises to the safety valve operating pressure but it does not activate, and at the same time the high-pressure bypass and vent valves cannot be opened. (9) When the safety door fails to return to its original position after operating, the steam pressure drops and the steam temperature changes to a level not permitted by the turbine. (10) In the event of a fire in the boiler room that directly affects the safe operation of the boilers. (11) When the boiler is extinguished.

(1) When the drum water level exceeds the positive and negative limit values. (2) When all the water gauges of the boiler are damaged. (3) When the superheater steam pipes, reheat steam pipes, or main feedwater pipes burst and operation cannot be maintained. (4) When reignition occurs at the rear of the boiler. (5) When all suction and supply fans or rotary air preheaters stop operating. (6) When the reheat steam is interrupted. (7) When an explosion occurs inside the furnace or flue, causing severe damage to the equipment. (8) When the boiler pressure rises to the safety valve operating pressure but it does not activate, and at the same time the high-pressure bypass and vent valves cannot be opened. (9) When the safety door fails to return to its original position after operating, the steam pressure drops and the steam temperature changes to a level not permitted by the turbine. (10) In the event of a fire in the boiler room that directly affects the safe operation of the boilers. (11) When the boiler is extinguished.

The boiler shall be stopped immediately if any of the following situations occur during operation: (1) The boiler water level is below the lower visible edge of the water gauge； (2) The water supply was continuously increased and other measures were taken, but the water level continued to drop ； (3) The boiler water level exceeds the highest visible level (full water), and the water level cannot be seen even after draining water ； (4) All feed water pumps fail or there is a fault in the feed water system, preventing water from being supplied to the boiler ； (5) The water level gauge or safety valve is completely malfunctioning ； (6) Damage to boiler components, posing a risk to the safety of operators ；

1 When the quality of steam supplied to the boiler is significantly below the standards, and normal conditions cannot be restored despite efforts to make adjustments； 2 The boiler is severely under-watered or severely over-watered ； 3 The boiler is severely overfilled with water ； 4 DC boiler water outage ； 5 The water level gauge is malfunctioning, preventing monitoring of the water level ； 6 When the pressure-bearing components of the boiler leak, such as the main steam pipe, reheat steam pipe, or main feed water pipe bursting ； 7 Reheater steam interruption (except as specified by the manufacturer) ； 8 Furnace flameout ； 9 Severe drop in oil (gas) pressure in the fuel (gas) boiler ； 10 All safety valves fail or the boiler is overpressured ； 11 Thermal instruments and control power supplies are interrupted, preventing the monitoring and adjustment of key operating parameters ； 12 Other situations that pose a serious threat to the safety of personnel and equipment, or for which there are special regulations in the manufacturing plant, such as when leaks in the boiler’s steam and water pipelines threaten the safety of equipment or personnel ； 13 When the boiler is severely coked, it is still difficult to maintain normal operation despite efforts ； 14 When the boiler safety valve is defective and cannot function properly ； 15 When the main steam temperature or reheat steam temperature of the boiler exceeds the operational limits, or when the temperature of the metal walls of the heating surfaces exceeds the allowable values, and normal operation cannot be restored despite making adjustments or reducing the load ； 16 When other serious failures occur that threaten the safe operation of the crew.

① The boiler water level is below the visible lower edge of the water gauge； ② More water was supplied and other measures were taken, but the water level continued to drop ； ③ The boiler water level exceeds the highest visible level (full water), and the water level cannot be seen even after draining water ； ④ All feed water pumps have failed or there is a fault in the feed water system, preventing water from being supplied to the boiler ； ⑤ The water level gauge or safety valve has completely failed ； ⑥ Damage to boiler components poses a risk to the safety of operators ； ⑦ Damage to the combustion equipment, collapse of the furnace walls, or heating up of the boiler framework pose a serious threat to the safe operation of the boiler ； ⑧ Other abnormal conditions endanger the safe operation of the boiler.