A control system for main steam automatic grid connection of a waste heat boiler

Abstract

The application discloses a control system for main steam automatic grid connection of a waste heat boiler, which comprises a first steam conveying pipe and a second steam conveying pipe, the first steam conveying pipe and the second steam conveying pipe are connected in series, a superheating unit is arranged on the first steam conveying pipe, and an exhaust unit, a grid connection unit and a pressure relief unit are connected in parallel on the second steam conveying pipe, the exhaust unit comprises a first pressure regulating valve, a first flow meter and a first pressure transmitter which are connected in series, the grid connection unit comprises a second pressure regulating valve, a second flow meter and a second pressure transmitter which are connected in series, the first pressure transmitter and the second pressure transmitter are arranged in the boiler, steam is exhausted from the boiler when the steam is detected to be unqualified, grid connection operation is performed on the steam when the steam is detected to be qualified, and the qualified steam is sent to a conveying pipe network, so that the work pressure of workers is reduced, and the control system has the characteristics of high automation degree and accurate valve control.

Description

Technical Field

[0001] This application relates to the field of boiler grid connection control, and in particular to a control system for automatic grid connection of main steam in a waste heat boiler. Background Technology

[0002] Waste heat boilers are boilers that use the residual heat from industrial waste gas, waste materials, or waste liquid, or the heat from the combustion of combustible substances, to heat water to a certain temperature. They are environmentally friendly equipment that can improve the energy utilization rate of industrial waste and are widely used in people's lives.

[0003] Before the high-temperature steam in the waste heat boiler is connected to the transmission pipeline network, the steam in the waste heat boiler needs to be heated and pressurized. In the early stage of the operation, some steam will be generated whose temperature or pressure values ​​do not reach the predetermined values. This steam cannot be directly connected to the network and transported to the transmission pipeline network. It needs to be discharged directly from the boiler until the temperature and pressure values ​​of the steam reach the predetermined values ​​before the connection operation is carried out and the steam is transported to the transmission pipeline network. In the relevant technology, when discharging unqualified steam and when performing the connection operation, it is necessary to manually monitor the temperature and pressure values ​​of the steam at all times. The work pressure of the staff is high, and there is room for improvement. Summary of the Invention

[0004] To reduce the workload of staff when controlling boiler grid connection, this application provides a control system for automatic grid connection of main steam in waste heat boilers.

[0005] The control system for automatic grid connection of main steam in a waste heat boiler provided in this application adopts the following technical solution:

[0006] A control system for automatic grid connection of main steam in a waste heat boiler includes a first steam delivery pipe and a second steam delivery pipe connected in series. The first steam delivery pipe is equipped with a superheating unit, and the second steam delivery pipe is connected in parallel with an exhaust unit, a grid connection unit, and a pressure relief unit. The exhaust unit includes a first pressure regulating valve, a first flow meter, and a first pressure transmitter connected in series. The grid connection unit includes a second pressure regulating valve, a second flow meter, and a second pressure transmitter connected in series.

[0007] By adopting the above technical solution, after steam passes through the superheating unit to form superheated steam, it will sequentially pass through the first and second pressure transmitters connected in parallel. When the temperature or pressure of the superheated steam is unqualified, the first pressure transmitter will control the first pressure regulating valve to open, allowing the unqualified steam to be discharged from the first pressure regulating valve, while the second pressure regulating valve will close to prevent the unqualified steam from being discharged from the second pressure regulating valve. When the temperature and pressure of the superheated steam are qualified, the second pressure regulating valve will open and the first pressure regulating valve will close, enabling the steam to complete the grid connection operation and be transported to the transmission pipeline network. Controlling the first and second pressure regulating valves through the first and second pressure transmitters facilitates the automatic adjustment of the first and second regulating valves, improving the automation level of the entire control system. This eliminates the need for operators to constantly monitor the pressure gauge readings to manually adjust the first and second pressure regulating valves, reducing the workload of the operators.

[0008] Preferably, both the first pressure regulating valve and the second pressure regulating valve are equipped with a gradient controller.

[0009] By adopting the above technical solution, the gradient controller can control the opening and closing degree of the first pressure regulating valve and the second pressure regulating valve in a gradient manner, thereby controlling the flow rate of steam during discharge and grid connection under different pressure conditions, which is beneficial to improving the stability of the steam flow rate during discharge and after grid connection.

[0010] Preferably, the superheating unit includes a primary superheater.

[0011] By adopting the above technical solution, the first-stage superheater can heat the saturated steam for the first time, thereby increasing the temperature of the saturated steam. This is beneficial in two ways: firstly, it helps to increase the steam temperature so that it can reach a suitable temperature for grid connection; secondly, it helps to increase the air temperature inside the boiler, thereby increasing the gas pressure.

[0012] Preferably, the superheating unit further includes a secondary superheater, which is located downstream of the primary superheater.

[0013] By adopting the above technical solution, the secondary superheater can reheat the superheated steam that has been heated by the primary superheater, which is beneficial to further improve and ensure the temperature of the steam, so that it can reach the appropriate temperature for grid connection, and also has the effect of increasing the internal gas pressure of the boiler.

[0014] Preferably, the superheating unit further includes a water spray desuperheater, which is disposed between the primary superheater and the secondary superheater and faces the secondary superheater.

[0015] By adopting the above technical solution, the water spray desuperheater can prevent the superheater from overheating and thus protect the safety of the high-temperature superheater. At the same time, it can make the steam temperature regulation more sensitive and help reduce thermal deviation.

[0016] Preferably, the pressure relief unit is configured as a pressure relief valve.

[0017] By adopting the above technical solution, the pressure relief valve is designed to be opened when the first pressure regulating valve has difficulty discharging the substandard steam from the boiler, so that it can assist the first pressure regulating valve in sharing the pressure of the substandard steam.

[0018] Preferably, a sampling unit is also connected in parallel to the second steam delivery pipe. The sampling unit includes a sampling tube connected in parallel to the second steam delivery pipe and a first thermometer connected to the sampling tube.

[0019] By adopting the above technical solution, the sampling unit can extract steam from the boiler for sampling at any time during the grid connection operation of the second steam transmission pipe, which is beneficial to constantly detect whether the temperature and pressure of the steam in the boiler meet the grid connection requirements.

[0020] Preferably, a second thermometer is provided downstream of the first steam delivery pipe.

[0021] By adopting the above technical solution, the setting of the second thermometer is beneficial for monitoring the temperature of saturated steam heated by the first and second superheaters. When the steam temperature does not reach the predetermined value, the first and second pressure regulating valves are closed simultaneously, allowing the steam to be heated to a suitable temperature in the boiler before the pressure of the steam in the boiler is detected by the first pressure transmitter. This helps prevent the steam from being discharged through the first pressure regulating valve for a long time, which would make it difficult to raise the temperature of the steam in the boiler, thus ensuring the heating efficiency of the boiler.

[0022] Preferably, both the exhaust unit and the grid connection unit are equipped with a first protection valve, a second protection valve, and a third protection valve.

[0023] By adopting the above technical solution, the setting of the first protection valve, the second protection valve and the third protection valve is beneficial to the manual closure of the valves when the first pressure regulating valve and the second pressure regulating valve in the exhaust unit and the grid connection unit fail, and can also be opened when the first pressure regulating valve or the second pressure regulating valve is unable to release the large pressure inside the boiler, so as to facilitate the sharing of the pressure inside the boiler.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] By utilizing the first and second pressure transmitters in the exhaust unit and grid connection unit, the pressure and temperature of the steam inside the boiler can be monitored autonomously. Based on this data, the first and second pressure regulating valves can be controlled in a gradient manner. This helps to prevent unqualified steam from entering the transportation pipeline network and improves the automation level of the control system, thus reducing the workload of the staff.

[0026] By using a primary superheater, a secondary superheater, and a water spray desuperheater, saturated steam can be heated a second time, and the overheating of the secondary superheater during the heating process can be avoided, which helps to ensure that the appropriate temperature is reached when the steam is connected to the grid.

[0027] By setting up the first and second thermometers, the temperature of steam in the boiler can be monitored in two locations. If the steam temperature in the boiler does not reach the predetermined value, the first and second pressure regulating valves can be closed first to allow the steam to heat up quickly. At the same time, after the boiler is connected to the grid, the steam temperature can be known immediately when sampling and testing the steam. Attached Figure Description

[0028] Figure 1 This embodiment of the application is a schematic diagram illustrating the overall structure of a control system for automatic grid connection of main steam in a waste heat boiler.

[0029] Reference numerals: 1. First steam delivery pipe; 11. Superheating unit; 111. First-stage superheater; 112. Second-stage superheater; 113. Water spray desuperheater; 12. Second thermometer; 2. Second steam delivery pipe; 21. Exhaust unit; 211. First pressure transmitter; 212. First flow meter; 213. First pressure regulating valve; 22. Grid connection unit; 221. Second pressure transmitter; 222. Second flow meter; 223. Second pressure regulating valve; 23. Pressure relief unit; 231. Pressure relief valve; 24. Sampling unit; 241. Sampling tube; 242. First thermometer; 3. Gradient controller; 4. First protection valve; 5. Second protection valve; 6. Third protection valve. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0031] This application discloses a control system for automatic grid connection of main steam in a waste heat boiler.

[0032] Reference Figure 1A control system for automatic grid connection of main steam in a waste heat boiler includes a first steam delivery pipe 1 and a second steam delivery pipe 2. The second steam delivery pipe 2 is connected in series with the first steam delivery pipe 1. A superheating unit 11 is provided on the first steam delivery pipe 1, which can continue to heat the saturated steam. An exhaust unit 21 and a grid connection unit 22 are connected in parallel on the second steam delivery pipe 2. The exhaust unit 21 includes a first pressure transmitter 211 located upstream, a first flow meter 212 located midstream, and a first pressure regulating valve 213 located downstream. The grid connection unit 22 includes a second pressure transmitter 221 located upstream, a second flow meter 222 located midstream, and a second pressure regulating valve 223 located downstream and connected to the delivery network. Gradient controllers 3 are provided on both the first pressure regulating valve 213 and the second pressure regulating valve 223.

[0033] When steam passes through the first steam delivery pipe 1 and is superheated, it enters the second steam delivery pipe 2 and then the first pressure transmitter 211 and the second pressure transmitter 221 connected in parallel. When the output steam pressure is lower than the qualified value, the second pressure transmitter 221 controls the gradient controller 3 to close the second pressure regulating valve 223, and the first pressure transmitter 211 controls the gradient controller 3 to open the first pressure regulating valve 213. As the steam pressure increases, the opening gradually narrows, thereby directly discharging the unqualified steam. When the output steam pressure is greater than or equal to the qualified value, the first pressure transmitter 211 controls the gradient controller 3 to completely close the first pressure regulating valve 213, and the second pressure transmitter 221 controls the gradient controller 3 to open the second pressure regulating valve 223. As the steam pressure increases, the opening gradually widens, thereby transporting the qualified steam into the delivery network. By setting up a first pressure transmitter 211, a second pressure transmitter 221, and a gradient controller 3, the first pressure regulating valve 213 and the second pressure regulating valve 223 can be automatically adjusted, improving the automation level of the entire control system. During the boiler grid connection process, the staff does not need to pay attention to the pressure gauge readings. The opening and closing of the first pressure regulating valve 213 and the second pressure regulating valve 223 can be achieved simply by using the first pressure transmitter 211 and the second pressure transmitter 221, thereby reducing the workload of the staff.

[0034] Reference Figure 1Both the exhaust unit 21 and the grid connection unit 22 are equipped with a first protection valve 4, a second protection valve 5, and a third protection valve 6. Since the structures of the three valves and their connection and positional relationships with their respective units are the same, the first protection valve 4, the second protection valve 5, and the third protection valve 6 in the exhaust unit 21 will be used as an example for explanation. The first protection valve 4 and the second protection valve 5 are connected in parallel with the exhaust unit 21, and the third protection valve 6 is connected in series with the exhaust unit 21. The first protection valve 4 is located upstream of the first pressure transmitter 211, and the second protection valve 5 is located downstream of the first pressure regulating valve 213. By setting the first protection valve 4, the second protection valve 5, and the third protection valve 6, on the one hand, the valves can be manually closed when the first pressure regulating valve 213 and the second pressure regulating valve 223 malfunction. On the other hand, they can also be opened when the first pressure regulating valve 213 or the second pressure regulating valve 223 has difficulty releasing the high-pressure steam inside the boiler, which facilitates the distribution of pressure inside the boiler and improves the safety of the entire control system.

[0035] Reference Figure 1 The superheating unit 11 includes a primary superheater 111, a secondary superheater 112, and a water spray desuperheater 113. The secondary superheater 112 and the water spray desuperheater 113 are both located downstream of the primary superheater 111, and the water spray desuperheater 113 is located between the primary superheater 111 and the secondary superheater 112 and faces the secondary superheater 112. When the saturated steam passes through the primary superheater 111 and the secondary superheater 112, the temperature of the steam can be increased and guaranteed, so that the steam can reach the predetermined temperature for grid connection through two heating processes. At the same time, the water spray desuperheater 113 can prevent the secondary superheater 112 from overheating, thereby protecting the superheater's safe operation at high temperatures. It also helps to reduce thermal deviation and further ensure the stability of the steam temperature.

[0036] Reference Figure 1The second steam delivery pipe 2 is also equipped with a pressure relief unit 23 and a sampling unit 24 connected in parallel. The pressure relief unit 23 is a pressure relief valve 231, which is beneficial to share the discharge of unqualified steam when the first pressure regulating valve 213 has difficulty in discharging the pressure in the boiler. The sampling unit 24 includes a sampling tube 241 and a first thermometer 242 connected to the sampling tube 241. The sampling tube 241 can extract steam from the boiler and take samples at any time after the second steam delivery pipe 2 is connected to the grid. The first thermometer 242 is convenient for monitoring whether the temperature of the steam in the boiler meets the grid connection requirements at any time. A second thermometer 12 is also installed downstream of the first steam delivery pipe 1. The second thermometer 12 can measure the superheat temperature of saturated steam after two heatings. When the temperature of the steam does not reach the predetermined value, the first pressure regulating valve 213 and the second pressure regulating valve 223 are closed at the same time, so that the steam is heated to a suitable temperature in the boiler before the first pressure regulating valve 213 is opened to discharge the unqualified steam in the boiler, thus ensuring the heating efficiency of the boiler.

[0037] The implementation principle of a control system for automatic grid connection of main steam in a waste heat boiler according to an embodiment of this application is as follows: Before the boiler is connected to the grid, unqualified steam generated is heated by the primary superheater 111 and the secondary superheater 112, and then sequentially passes through the first pressure transmitter 211 and the second pressure transmitter 221 connected in parallel. When the first pressure transmitter 211 and the second pressure transmitter 221 detect that the steam pressure is below standard, the second pressure transmitter 221 will normally close the second pressure regulating valve 223, while the first pressure transmitter 211 will drive the gradient controller 3 to open the first pressure regulating valve 213, discharging the unqualified steam from the boiler. As the pressure inside the boiler increases, the first pressure regulating valve 213 will gradually close. When the steam pressure in the boiler reaches standard, the first pressure transmitter 211 will drive the first pressure regulating valve 213 to normally close, while the second pressure transmitter 221 will drive the gradient controller 3 to open the second pressure regulating valve 223, transporting qualified steam from the second steam conveying pipe 2 into the conveying network pipe. By setting up a first pressure transmitter 211, a second pressure transmitter 221, and a gradient controller 3, the first pressure regulating valve 213 and the second pressure regulating valve 223 can be automatically adjusted, improving the automation level of the entire control system. During the boiler grid connection process, the staff does not need to pay attention to the pressure gauge readings. The opening and closing of the first pressure regulating valve 213 and the second pressure regulating valve 223 can be achieved simply by using the first pressure transmitter 211 and the second pressure transmitter 221, thereby reducing the workload of the staff.

[0038] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A control system for automatic grid connection of main steam in a waste heat boiler, characterized in that: It includes a first steam delivery pipe (1) and a second steam delivery pipe (2), which are connected in series. The first steam delivery pipe (1) is provided with a superheating unit (11), and the second steam delivery pipe (2) is connected in parallel with an exhaust unit (21), a grid connection unit (22) and a pressure relief unit (23). The exhaust unit (21) includes a first pressure regulating valve (213), a first flow meter (212) and a first pressure transmitter (211) connected in series. The grid connection unit (22) includes a second pressure regulating valve (223), a second flow meter (222) and a second pressure transmitter (221) connected in series. The pressure relief unit (23) is configured as a pressure relief valve (231); a sampling unit (24) is also connected in parallel on the second steam conveying pipe (2), the sampling unit (24) includes a sampling tube (241) connected in parallel on the second steam conveying pipe (2) and a first thermometer (242) connected on the sampling tube (241); a second thermometer (12) is provided downstream of the first steam conveying pipe (1). The first thermometer (242) is used to monitor whether the temperature of the steam in the boiler meets the grid connection requirements; the second thermometer (12) is used to measure the superheat temperature of the saturated steam after two heating cycles. When the temperature of the steam does not reach the predetermined value, the first pressure regulating valve (213) and the second pressure regulating valve (223) are closed at the same time, so that the steam is heated to a suitable temperature in the boiler before being opened. Gradient controllers (3) are provided on both the first pressure regulating valve (213) and the second pressure regulating valve (223); The superheating unit (11) includes a primary superheater (111); the superheating unit (11) also includes a secondary superheater (112), which is located downstream of the primary superheater (111); the superheating unit (11) also includes a water spray desuperheater (113), which is disposed between the primary superheater (111) and the secondary superheater (112) and faces the secondary superheater (112). When steam passes through the first steam delivery pipe (1) and is superheated, it enters the second steam delivery pipe (2) and then enters the first pressure transmitter (211) and the second pressure transmitter (221) connected in parallel. When the output steam pressure is lower than the qualified value, the second pressure transmitter (221) controls the gradient controller (3) to keep the second pressure regulating valve (223) normally closed, and the first pressure transmitter (211) controls the gradient controller (3) to open the first pressure regulating valve (213). As the steam pressure increases, the opening gradually narrows to discharge the unqualified steam directly. When the output steam pressure is greater than or equal to the qualified value, the first pressure transmitter (211) controls the gradient controller (3) to close the first pressure regulating valve (213) completely, and the second pressure transmitter (221) controls the gradient controller (3) to open the second pressure regulating valve (223). As the steam pressure increases, the opening gradually widens to transport the qualified steam into the delivery network.

2. The control system for automatic grid connection of main steam in a waste heat boiler according to claim 1, characterized in that: Both the exhaust unit (21) and the grid connection unit (22) are equipped with a first protection valve (4), a second protection valve (5) and a third protection valve (6).

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