Common faults and treatment of Suzhou steam boiler recovery
Common failures and treatment methods of steam boiler recycling are as follows:
First, boiler overpressure accident
1, the phenomenon of boiler overpressure
⑴Vapor pressure rises sharply, exceeding the allowable working pressure, the pressure is still rising after the pressure gauge pointer exceeds the "red line" safety valve.
时 When the overpressure interlock protection device is activated, an overpressure alarm signal should be issued to stop air supply, air induction and coal supply.
(3) The steam temperature increases and the steam flow rate decreases.
2. Handling of boiler overpressure
减弱 Quickly weaken the combustion and manually open the safety valve or air release valve.
⑵Increase the feed water, and at the same time strengthen the drainage in the lower drum (at this time, pay attention to maintaining the normal water level of the boiler) to reduce the boiler water temperature and thereby reduce the boiler drum pressure.
(3) If the safety valve fails or all the pressure gauges are damaged, the furnace should be stopped immediately, and the safety valve and pressure gauge should be repaired before boosting.
时 When the boiler is over-pressured and endangers safe operation, pressure reduction measures should be taken, but it is strictly prohibited to reduce the pressure too fast.
严重 After the severe overpressure of the boiler is eliminated, the boiler shall be shut down to conduct internal and external inspections of the boiler, and deformation, leakage, etc. caused by the overpressure shall be eliminated, and unqualified safety accessories shall be repaired.
Second, the boiler water shortage accident
1, the phenomenon of boiler water shortage
⑴The water level is below the minimum safe water level line, or the water level is not visible, and the glass tube (board) of the water level meter is white.
⑵The two-color water level meter has all the gas-phase indicating colors.
(3) The low and high water level alarms generate a low water level alarm signal.
⑷ Low water level interlocking device, when the water level is lower than the specified value, the blower, induced draft fan and grate reducer motor should stop running.
汽 The superheater steam temperature rises sharply, which is higher than the normal outlet steam temperature.
⑹The boiler exhaust temperature rises.
⑺The feed water flow rate is less than the steam flow rate. If the water shortage is caused by the rupture of the furnace tube or economizer tube, the opposite phenomenon will occur.
时 When the water shortage is severe, you can smell the burnt smell.
时 When water shortage is severe, red hot water wall tubes can be seen from the furnace door.
时 When the water shortage is severe, the furnace tube may rupture. At this time, a blasting sound can be heard, and steam and smoke will be emitted from the furnace door and the fire door.
2. Treatment of boiler water shortage
⑴If the water shortage is judged to be serious, the boiler must be stopped urgently. It is strictly forbidden to blindly feed water to the boiler.
⑵If the water shortage is judged by “calling water”, reduce fuel, blow air, induce wind, and feed water slowly.
Third, the boiler full of water accident
1, the phenomenon of boiler full of water
⑴The water level is higher than the maximum allowable line, or the water level is not visible, and the color inside the glass tube (plate) of the water level meter is dark.
⑵The two-color water level gauge shows the color of all water phases.
(3) High and low water level alarms generate high water level alarm signals.
温度 The temperature of superheated steam drops obviously.
⑸The feed water flow is abnormally larger than the steam flow.
A large amount of water is stored in the sub-cylinder, and the trap operates violently.
⑺In severe cases, steam carries a lot of water, the salt content increases, water hammer sounds occur in the steam pipeline, and steam drips from the connecting flange.
2. Treatment of boiler full water
Rinse the water gauge to determine if it is slightly full or severely full. Method: First close the water level meter, the water connection pipe cock, and then open the drain cock. If you can see that the water level line drops from above, it indicates that it is slightly full of water.
If it is severely full of water, emergency shutdown measures will be taken.
Fourth, the boiler soda-water common accident
1.Boiler steam and water co-bending phenomenon
水 The water level in the water level table fluctuates sharply, and the water level line is blurred.
The alkalinity and salt content of the shabu-shabu seriously exceeded the standards.
(3) The steam carries a large amount of water, the steam quality decreases, and the steam temperature at the superheater outlet decreases.
水 Water hammer occurred in the steam pipeline, and steam leakage occurred at the flange connection.
2.Boiler steam and water co-boiler treatment
⑴ Reduce combustion, close the main steam valve, reduce boiler evaporation, reduce load and maintain stability.
开启 Fully open the surface drain valve (continuous drain valve) of the upper pot, and drain the bottom of the pot properly. At the same time, increase the water supply to reduce the alkalinity and salt content of the pot water. At this time, attention should be paid to the protection of water level control.
(3) For boilers treated with dosing in the pot, dosing should be stopped.
⑷ Open the traps on the superheater, steam pipes, and sub-cylinder.
⑸ Maintain the boiler water level slightly below the normal water level.
⑹Notify the water treatment personnel to take measures to ensure the supply of qualified demineralized water.
Increase the number of boiler water sampling tests, and then switch to normal operation until the boiler water is qualified.
增大 It is strictly forbidden to increase the boiler load before the boiler water quality is improved. After the accident is eliminated, the water level meter should be flushed in time.
V. Boiler tube burst accident
1.The phenomenon of boiler tube burst
The sound of soda spray can be heard when the pipe is burst, and there is obvious blasting sound in severe cases.
The furnace hearth changes from negative pressure combustion to positive pressure combustion, and a large amount of smoke and steam is ejected from the door hole and air leakage of the furnace wall.
(3) The feed water flow is abnormal and is greater than the steam flow.
⑷Although the feedwater is increased, the water level is often difficult to maintain and the vapor pressure is reduced.
降低 The temperature of the exhaust smoke decreases, and the color of the smoke becomes white.
Oven hearth temperature drops, and even extinguishes fire.
⑺Induced fan load increases and current increases.
水 There is water flowing from the bottom of the boiler, and there is wet ash in the ash slag hopper.
2. Handling of boiler tube bursts
Oven tube rupture and leakage are not serious and can maintain water level. When the accident does not expand, the load can be reduced for a short period of time to maintain operation, and the standby furnace is stopped before the furnace is started.
When the furnace tube is broken and the water level cannot be maintained, the furnace should be stopped immediately, but the induced draft fan should not be stopped, and the boiler should be continued to be watered to reduce the temperature of the tube wall so that the accident will not be expanded.
(3) If the tube is burst due to lack of water in the boiler or overheating of the tube wall, the furnace should be stopped immediately, and water supply to the boiler is strictly forbidden.
⑷If there are several boilers supplying steam side by side, the main steam pipe of the accident boiler should be cut off from the steam main pipe.
Six, superheater tube blasting accident
1.Blasting of superheater tube
附近 Sound or blasting sound of steam near the superheater.
⑵The steam flow is abnormally decreased, and the flow is abnormally smaller than the feed water flow.
(3) The furnace negative pressure decreases or becomes positive pressure. In severe cases, steam and smoke are emitted from the furnace door and the fire hole.
后 The temperature of the flue gas after the superheater is abnormally reduced or the difference between the flue gas temperature before and after the superheater increases.
严重 When the damage is serious, the boiler steam pressure drops.
⑹The smoke exhaust temperature drops significantly, and the color of the smoke from the chimney becomes gray or white.
⑺Induced fan load increases and current increases.
2. Handling of superheater tube blasting
轻微 The superheater tube ruptures slightly, which can reduce the load properly and maintain the operation for a short time. At this time, the leakage should be closely monitored, and at the same time, the standby boiler should be started quickly. If the fault situation worsens during the monitoring process, the furnace should be stopped as soon as possible.
时 When the superheater tube is severely broken, the furnace must be stopped immediately.
Seven, economizer tube blasting accident
1. Economizer tube blasting and phenomena
⑴The boiler water level drops, and the feed water flow is abnormally larger than the steam flow.
泄漏 There is a sound of leakage near the economizer, and the gap between the furnace wall and the lower flue door leaks steam.
(3) The temperature of the exhaust smoke decreases, and the smoke color becomes white.
湿 There is wet ash in the ash hopper at the lower part of the economizer, and water flows downward in severe cases.
⑸The smoke resistance increases, the sound of the induced draft fan is abnormal, and the motor flow increases.
2. Handling of economizer tube blasting
⑴ For non-separable economizers, if the boiler can maintain the normal water level, the water supply can be increased, and all water discharge valves and recirculation pipe valves should be closed to maintain short-term operation. After the standby boiler is put into operation, the furnace is stopped for maintenance . If the accident expands and the water level cannot be maintained, the furnace should be stopped immediately.
⑵ For separable economizers, the bypass flue baffle should be opened, the flue baffle closed, and the economizer suspended. At the same time, the bypass water pipe valve of the economizer was opened to continue to feed water to the boiler. After the smoke and water are reliably isolated, immediately drain the water in the economizer and open the air valve or lift the safety valve. If the flue baffle is tight, maintenance can be carried out under conditions that can ensure personal safety, and operation can be resumed, otherwise the furnace should be stopped for maintenance.
Eight, boiler water hammer accident
1.The phenomenon of boiler water hammer
⑴ There is a certain rhythmic impact sound at the boiler and pipeline, sometimes loud, accompanied by strong vibration of the water supply pipeline or steam pipeline.
⑵The pointer of the pressure gauge swings back and forth, consistent with the frequency of the sound of vibration.
(3) When the water hammer is severe, it may cause various connecting components, such as cracks in flanges, welds, and damage to valves.
2. Handling of water hammer in steam pipelines
⑴ Reduce the steam supply and close the main steam valve if necessary.
⑵ Open the traps on the superheater header and the steam pipe for drainage.
(3) The water level in the drum is too high, and the sewage should be properly drained to maintain the normal water level.
⑷ Strengthen water treatment to ensure the quality of feed water and boiler water to avoid co-transpiration of soda and water.
After the water hammer is removed, check the condition of the pipes, pipe racks, flanges, etc. If there is no damage, reheat the pipe for steam supply once.
3. Treatment of water hammer in water supply pipeline
⑴Open the air valve on the water supply pipe to remove air or steam.
⑵ Enable the standby water supply pipeline to continue to feed water to the boiler. If there is no backup pipeline, the corresponding measures shall be taken to deal with the faulty pipeline.
(3) Check the feed water pump and feed water check valve, and repair it if there is any problem.
⑷ Keep the temperature of the feed water balanced.
Nine, deformation of the heating surface
1.Phenomena of heating surface deformation
变形 The deformation of the water-cooled wall pipe can be seen directly from the fire door or furnace door. When accompanied by water shortage, the red-curved water-wall pipe can be seen.
⑵ For the hearth of a horizontal internal combustion boiler, you can see from the front and rear observation holes that the wall of the hearth is protruding and deformed to the fire side.
2.Deformation of heating surface
⑴The boiler is severely deficient in water, and the heating surface has to be cooled by the boiler water and deformed by overheating.
不良 Poor design structure. If the local circulation flow rate is too low, the stagnation will cause the wall temperature to exceed the allowable temperature and deform.
(3) Incorrect installation prevents the pressured parts from expanding freely.
⑷Unqualified water quality, thick scale and excessive slag.
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