Boiler water pressure test control method

Abstract

The invention relates to the technical field of water pressure tests, in particular to a boiler water pressure test control method, which comprises a DCS (Distributed Control System) main controller and comprises the following steps: firstly, checking equipment and preparing water; then, the DCS main controller controls to close valves corresponding to all the units where the boilers to be subjected to the hydrostatic test are located; next, the DCS main controller controls to open corresponding steam turbine side drain valves and boiler side air release valves at all positions; the DCS main controller starts a steam feed pump, and when water is fed to all air valves and water continuously overflows, all boiler side air release valves are sequentially closed; continuously feeding water and boosting pressure; after the test pressure is reached, maintaining the test pressure for 20 minutes, and after no abnormity exists, reducing the pressure in the boiler to the working pressure; water supply and pressurization of the steam feed pump are controlled by the DSC main controller, so that the water pressure test work is simplified and programmed, the workload of operators is reduced to a great extent, and the phenomenon of pressure overshoot is effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of water pressure testing, in particular to a boiler water pressure testing control method. Background Art

[0002] After a major or minor overhaul of the boiler or after an inspection of a partial heating surface, a routine water pressure test must be carried out, and the test pressure is equal to the maximum allowable working pressure of the boiler. In order to avoid excessive water pressure and pressure overshoot during the water pressure test, the operating personnel need to manually operate the equipment. According to actual work on site, during the water pressure test, due to concerns that the pressure will rise too quickly and exceed the target value due to equipment operation, each time the equipment is operated, the operator will stop and wait for half a day to observe the pressure changes before proceeding to the next step. The operation process is slow and cumbersome, and takes up a lot of energy of the operating personnel. Summary of the invention

[0003] In view of the deficiencies in the prior art, the object of the present invention is to provide a boiler water pressure test control method which replaces a large amount of manual operations by operators, realizes automatic control, simplifies and programs the repair work.

[0004] The technical solution adopted by the present invention to solve its technical problem is: A boiler water pressure test control method includes a DCS main controller, and the steps are as follows: S1, preparation: check the equipment to ensure that the boiler and its ancillary equipment are in good condition; confirm that the valves of the steam-water system meet the requirements of the water pressure test and are in the correct position, and that the actuators of the regulating valves, isolation valves and drain valves are tested normally; prepare water, and the water temperature should be maintained at 50°C~70°C to ensure that the water quality is qualified; S2, close valves: The DCS main controller controls to close all valves corresponding to the boiler units to be tested for water pressure, including the high-pressure main steam valve on the turbine side, the high-pressure bypass valve, the high-pressure cylinder exhaust check valve, the medium-pressure main steam valve, the turbine bypass valve, and the electric drain valve, so as to isolate the boiler steam-water system from the turbine; S3, open valves: The DCS main controller controls the opening of the corresponding steam turbine side drain valves and boiler side air release valves in various positions to prepare for boiler water supply; S4, water supply and exhaust: The DCS main controller starts the steam-driven water supply pump to control the water supply speed. When water overflows continuously from each air valve, the air valves on the sides of each boiler are closed in sequence. S5, pressure boost: After all the boiler side air valves are closed, the DCS main controller controls the steam-driven feedwater pump to continue to supply water and boost pressure; S6, pressure maintenance: After reaching the test pressure, maintain the test pressure for 20 minutes. If there is no abnormality, the DCS main controller controls the opening of the electric drain valve to reduce the pressure in the boiler to the working pressure.

[0005] Preferably, a further technical solution of the present invention is: Preferably, in step S1, the target pressure value of the water pressure test, the pressure increasing speed in each stage and the upper limit value of the speed of the steam-driven water feed pump are set in advance according to the boiler to be subjected to the water pressure test; correspondingly, when the pressure is increased in step S5, the DCS main controller adjusts the speed of the steam-driven water feed pump accordingly based on the pressure value monitored by the pressure transmitter without exceeding the upper limit value of the speed of the steam-driven water feed pump, so as to control the pressure increasing speed.

[0006] Preferably, the pressure boosting speed in each stage includes: a first stage pressure boosting speed, when the pressure is less than or equal to 3MPa, the pressure boosting speed is less than or equal to 0.1MPa / min; a second stage pressure boosting speed, when the pressure is greater than 3MPa and less than or equal to 10MPa, the pressure boosting speed is less than or equal to 0.2MPa / min; a third stage pressure boosting speed, when the pressure is greater than 10MPa, the pressure boosting speed is less than or equal to 0.15MPa / min.

[0007] Preferably, the DCS main controller is connected to a display screen.

[0008] Preferably, the DCS main controller is connected to an alarm.

[0009] Compared with the prior art, the present invention adopting the above technical solution has the following outstanding features: By controlling the water supply and pressurization of the steam-driven water supply pump through the DSC main controller, the water pressure test work is simplified and programmed, which greatly reduces the workload of the operating personnel and effectively avoids the pressure overshoot phenomenon; it avoids the situation where each time the equipment is operated, it stops for a period of time to wait and observe the pressure change, thus shortening the overall time of the boiler water pressure test; through this method, the labor cost and time cost are effectively saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a flow chart of a boiler water pressure test control method according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the connection structure of the DCS main controller in an embodiment of the present invention. DETAILED DESCRIPTION

[0011] The present invention is further described below in conjunction with specific embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0012] like Figure 1 As shown, this embodiment provides a boiler water pressure test control method, including a DCS main controller and a display screen connected to the DCS main controller, and the steps are as follows: A boiler water pressure test control method includes a DCS main controller, and the steps are as follows: S1, preparation work: check the equipment to ensure that the boiler and its ancillary equipment are in good condition; confirm that the valves of the steam-water system meet the requirements of the water pressure test and are in the correct position, and that the actuators of the regulating valves, isolation valves and drain valves are tested normally; prepare to use water, and the water temperature should be maintained at 50°C~70°C to ensure that the water quality is qualified; at the same time, according to the boiler to be tested for water pressure, set the water pressure test target pressure value, the pressure increase speed in each stage and the upper limit of the speed of the steam-driven feed water pump in advance.

[0013] In this embodiment, three stages are provided, and the pressure boosting speed in each stage includes: the pressure boosting speed in the first stage is less than or equal to 0.1MPa / min when the pressure is less than or equal to 3MPa; the pressure boosting speed in the second stage is less than or equal to 0.2MPa / min when the pressure is greater than 3MPa and less than or equal to 10MPa; the pressure boosting speed in the third stage is less than or equal to 0.15MPa / min when the pressure is greater than 10MPa.

[0014] S2, close valves: The DCS main controller controls the closing of all valves corresponding to the boiler units to be tested for water pressure, including the high-pressure main steam valve on the turbine side, the high-pressure bypass valve, the high-pressure cylinder exhaust check valve, the medium-pressure main steam valve, the turbine bypass valve, and the electric drain valve, so as to isolate the boiler steam-water system from the turbine.

[0015] S3, open valves: The DCS main controller controls the opening of the corresponding steam turbine side drain valves and boiler side air release valves at various positions to prepare for the boiler water supply.

[0016] S4, water supply and exhaust: The DCS main controller starts the steam-driven water supply pump to control the water supply speed. When water overflows continuously from each air valve during water supply, the side air valves of each boiler are closed in turn.

[0017] S5, boosting pressure: After all the boiler side air valves are closed, the DCS main controller controls the steam-driven feedwater pump to continue to supply water and boost pressure. When boosting pressure, the DCS main controller monitors the pressure value through the pressure gauge, and then boosts pressure at the first stage boosting speed, the second stage boosting speed or the third stage boosting speed. Under the premise of not exceeding the upper limit of the water pump speed, the speed of the steam-driven feedwater pump is adjusted accordingly to control the actual boosting speed to meet the boosting speed requirements of each stage.

[0018] During the pressure boosting process, the operator can control the speed of the steam-driven water supply pump through the DCS main controller.

[0019] S6, pressure maintenance: After reaching the test pressure, maintain the test pressure for 20 minutes. If there is no abnormality, the DCS main controller controls the opening of the electric drain valve to reduce the pressure in the boiler to the working pressure.

[0020] The DCS main controller is connected to the pressure transmitter and temperature sensor to display the water pressure and water temperature in real time on the display; the DCS main controller is equipped with a memory, and the actual time and actual pressure value, actual time and actual temperature value are stored in the memory at each preset storage time interval for later reference.

[0021] The DCS main controller is connected to an alarm; the DCS main controller is pre-programmed with a normal temperature threshold and a normal pressure threshold. When the water pressure exceeds the normal pressure threshold, or the water temperature exceeds the normal temperature threshold, the DCS main controller controls the alarm to notify the staff in time.

[0022] The present invention controls the water supply and pressurization of the steam-driven water supply pump through the DSC main controller, so that the water pressure test work is simplified and programmed, which greatly reduces the workload of the operating personnel and effectively avoids the pressure overshoot phenomenon; it avoids the situation where each time the equipment is operated, it stops for a period of time to wait and observe the pressure change, effectively reduces the invalid waiting time, and thus achieves the purpose of saving labor cost and time cost.

[0023] The above description is only the preferred embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made by using the contents of the present invention specification and its drawings are included in the scope of rights of the present invention.

Claims

1. A boiler water pressure test control method, characterized in that: Including the DCS main controller, the steps are as follows: S1, preparation: check the equipment to ensure that the boiler and its ancillary equipment are in good condition; confirm that the valves of the steam-water system meet the requirements of the water pressure test and are in the correct position, and that the actuators of the regulating valves, isolation valves and drain valves are tested normally; prepare water, and the water temperature should be maintained at 50°C~70°C to ensure that the water quality is qualified; S2, close valves: The DCS main controller controls to close all valves corresponding to the boiler units to be tested for water pressure, including the high-pressure main steam valve on the turbine side, the high-pressure bypass valve, the high-pressure cylinder exhaust check valve, the medium-pressure main steam valve, the turbine bypass valve, and the electric drain valve, so as to isolate the boiler steam-water system from the turbine; S3, open valves: The DCS main controller controls the opening of the corresponding steam turbine side drain valves and boiler side air release valves in various positions to prepare for boiler water supply; S4, water supply and exhaust: The DCS main controller starts the steam-driven water supply pump to control the water supply speed. When water overflows continuously from each air valve, the air valves on the sides of each boiler are closed in sequence. S5, pressure boost: After all the boiler side air valves are closed, the DCS main controller controls the steam-driven feedwater pump to continue to supply water and boost pressure; S6, pressure maintenance: After reaching the test pressure, maintain the test pressure for 20 minutes. If there is no abnormality, the DCS main controller controls the opening of the electric drain valve to reduce the pressure in the boiler to the working pressure.

2. The boiler water pressure test control method according to claim 1, characterized in that: In step S1, according to the boiler to be subjected to the hydraulic pressure test, the target pressure value of the hydraulic pressure test, the pressure increase speed in each stage and the upper limit of the speed of the steam-driven feed water pump are set in advance; correspondingly, when increasing the pressure in step S5, the DCS main controller adjusts the speed of the steam-driven feed water pump accordingly based on the pressure value monitored by the pressure transmitter without exceeding the upper limit of the speed of the steam-driven feed water pump, so as to control the pressure increase speed.

3. The boiler water pressure test control method according to claim 2, characterized in that: The boost speeds at each stage include: The pressure increase rate in the first stage is less than or equal to 0.1 MPa / min when the pressure is less than or equal to 3 MPa. ‌ The pressure increase rate in the second stage is less than or equal to 0.2MPa / min when the pressure is greater than 3MPa and less than or equal to 10MPa; The third stage pressure increase rate, when the pressure is greater than 10MPa, the pressure increase rate is less than or equal to 0.15MPa / min.

4. The boiler water pressure test control method according to claim 2, characterized in that: The DCS main controller is connected with a display screen.

5. The boiler water pressure test control method according to claim 1, characterized in that: The DCS main controller is connected to an alarm.

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