【Weekly Topic】Why is it necessary to establish a normal water circulation as soon as possible during boiler startup? (7.10--7.16)

The stronger the water circulation, the faster the steam-water mixture at the outlet of the rising pipe enters, disturbing the water volume and thereby increasing the heat transfer coefficient of the water to the lower wall of the drum. This reduces the temperature difference between the upper and lower walls. Therefore, whether a normal water circulation can be established as soon as possible not only affects the safety of operation of the water wall but also directly influences the magnitude of the temperature difference between the upper and lower walls of the drum. A normal water circulation ensures a uniform and high circulation flow rate within the water wall, thereby cooling the heated surfaces. Measure: Perform regular or continuous drainage from the lower part of the water wall ； Steam heating from adjacent furnace ； At startup, the displacer door can be opened earlier and more widely to increase the combustion rate. Increase the steam generation rate without accelerating the pressure rise ； The slower voltage increase at the start is also beneficial for establishing a normal water circulation as soon as possible

The stronger the water circulation, the faster the steam-water mixture at the outlet of the rising pipe enters, disturbing the water volume and thereby increasing the heat transfer coefficient of the water to the lower wall of the drum. This reduces the temperature difference between the upper and lower walls. Therefore, whether a normal water circulation can be established as soon as possible not only affects the safety of operation of the water wall but also directly influences the magnitude of the temperature difference between the upper and lower walls of the drum. A normal water circulation ensures a uniform and high circulation flow rate within the water wall, thereby cooling the heated surfaces. Measure: Perform regular or continuous drainage from the lower part of the water wall ； Steam heating from adjacent furnace ； At startup, the displacer door can be opened earlier and more widely to increase the combustion rate. Increase the steam generation rate without accelerating the pressure rise ； The slower voltage increase at the start is also beneficial for establishing a normal water circulation as soon as possible

The stronger the water circulation, the faster the steam-water mixture at the outlet of the rising pipe enters, disturbing the water volume and thereby increasing the heat transfer coefficient of the water to the lower wall of the drum. This reduces the temperature difference between the upper and lower walls. Therefore, whether a normal water circulation can be established as soon as possible not only affects the safety of operation of the water wall but also directly influences the magnitude of the temperature difference between the upper and lower walls of the drum. A normal water circulation ensures a uniform and high circulation flow rate within the water wall, thereby cooling the heated surfaces. Measure: Perform regular or continuous drainage from the lower part of the water wall ； Steam heating from adjacent furnace ； At startup, the displacer door can be opened earlier and more widely to increase the combustion rate. Increase the steam generation rate without accelerating the pressure rise ； The slower voltage increase at the start is also beneficial for establishing a normal water circulation as soon as possible

Reply to 1# zgj2405: 1) The water entering the boiler should be deoxygenated and meet the water quality specifications for feedwater after treatment； Power alliance | Cogeneration | Thermal power | Nuclear power | Hydroelectric power | Standards | Energy | Energy conservation: j7 N* S* a6 e3 z (2) The temperature of the feedwater should comply with the requirements specified in the operating procedures. Generally, the temperature of the water supplied to a boiler should differ from the wall temperature of the steam drum by no more than 40 degrees℃ ； (3) The upward water flow speed must be controlled. The magnitude of the temperature difference between the upper and lower walls of the drum is related to the water feeding rate. bbs.cnpou.com, w& f& h9 Y* A( E" A' f$ T Therefore, it is necessary to control the water supply rate properly to prevent the temperature difference across the drum wall from exceeding acceptable levels. Power Union | Protection measures include: (1) Increasing the drainage from the water wall lower header to facilitate the establishment of water circulation ； (2) Maintain stable and uniform combustion ； (3) Install the bottom heating device before ignition. 2. Protection of the drum: A large temperature difference occurs across the drum wall before ignition when water is introduced, and during ignition when pressure is increased. Protection measures include: increasing the water discharge from the lower header of the water wall to facilitate the establishment of water circulation ； (2) Maintain stable and uniform combustion ； (3) Install the bottom heating device before ignition. (3) Control the water inflow rate and temperature in accordance with the regulations ； (4) Strictly control the rate of temperature and pressure increase.

Reply to 1# zgj2405: The stronger the water circulation, the faster the steam-water mixture at the outlet of the rising pipe flows in, disturbing the water volume and thereby increasing the heat transfer coefficient from the water to the lower wall of the drum. This reduces the temperature difference between the upper and lower walls of the drum. Therefore, whether a normal water circulation can be established as soon as possible not only affects the safety of operation of the water wall but also directly influences the magnitude of the temperature difference between the upper and lower walls of the drum. A normal water circulation ensures a uniform and high circulation flow rate within the water wall, thereby cooling the heated surfaces. Measure: Perform regular or continuous drainage from the lower part of the water wall ； Steam heating from adjacent furnace ； At startup, the displacer door can be opened earlier and more widely to increase the combustion rate. Increase the steam generation rate without accelerating the pressure rise ； The slower voltage increase at the start is also beneficial for establishing a normal water circulation as soon as possible

Establishing a water circulation first can prevent temperature differences between the water supply and the furnace tubes, thereby extending the service life of the furnace tubes

A too slow establishment of the water circulation can lead to an increased temperature difference, severe vaporization, and a lack of safety guarantees