Steam jet vacuumizing control system of condenser

Abstract

The utility model relates to the technical field of condenser vacuumizing, and discloses a condenser steam injection vacuumizing control system which comprises a condenser vacuumizing system, an auxiliary steam header and a power steam pipeline connected to each stage of injection pump. The primary injection pump is arranged on the power steam pipeline; the first condenser is communicated with a discharge port of the first-stage injection pump; the second-stage injection pump and the first-stage injection pump are arranged on different power steam pipelines, a suction inlet of the second-stage injection pump is communicated with the first condenser, and the second-stage injection pump sucks non-condensed gas in the first-stage condenser; the second condenser comprises a second-stage condenser and a third-stage condenser which are connected in series; an exhaust port of the second-stage injection pump is communicated with the second condenser; the third-stage condenser is provided with a condenser cooling water outlet pipe; and the third-stage injection pump is communicated with the second-stage condenser, and an outlet of the third-stage injection pump is communicated with the third-stage condenser. Vacuum of the condenser of the unit can be effectively monitored and controlled through the steam injection vacuum-pumping system, and safe operation and power generation efficiency of the unit are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of condenser vacuuming, in particular to a condenser steam jet vacuuming control system. Background Art

[0002] The vacuum system is an important part of the turbine condenser system. If the uncondensed gas cannot be discharged in time, it will not only occupy the steam side space of the condenser and affect the normal condensation of steam in the turbine exhaust, but also the oxygen and other gases in it will corrode the condenser heat exchange tube bundle and increase the supercooling of the condensate. In addition, oxygen dissolved in the condensate will also affect the quality of the condensate. In particular, when the air-cooled unit is started and operated normally, the volume to be vacuumed is huge, and the back pressure fluctuation of the unit is greatly affected by load changes, ambient temperature, wind speed, and wind direction. Ensuring the tightness and vacuum degree of the unit vacuum system is the key factor for the stable operation of the unit.

[0003] At present, most of the jet pumps in the condenser steam jet vacuum system of most power plants are fixed jet pumps. Under the condition of constant back pressure, the suction volume remains basically unchanged under different load conditions, which will cause over-pumping under low load conditions, that is, too much condenser steam-gas mixture is extracted, the vacuum is too high, and the power steam is wasted; on the other hand, if the vacuum is too high, the low-pressure cylinder exhaust steam will over-expand, which will reduce the efficiency and may even cause the low-pressure cylinder bearing vibration, seriously affecting the safety of the unit. Utility Model Content

[0004] The utility model aims to provide a condenser steam jet vacuum control system.

[0005] To achieve the above object, the utility model provides the following technical solution: a condenser steam jet vacuum pumping control system, including a condenser vacuum pumping system, and further comprising:

[0006] The auxiliary steam header has power steam pipelines connected to various levels of jet pumps, and the power steam pipelines have a first branch, a second branch and a third branch;

[0007] A first-stage jet pump, arranged on the power steam pipeline;

[0008] A first condenser, wherein the discharge port of the first-stage jet pump is connected to the first condenser through a pipeline;

[0009] A secondary jet pump is arranged on the power steam pipeline, and is not in the same pipeline as the primary jet pump. Its suction port is connected to the first condenser through a pipeline, and the secondary jet pump sucks non-condensable gas in the primary condenser; the second condenser includes a secondary condenser and a third condenser arranged in series; the discharge port of the secondary jet pump is connected to the second condenser through a pipeline; the third condenser has a condenser cooling water outlet pipe;

[0010] The three-stage jet pump is connected to the secondary condenser, and the discharge port of the three-stage jet pump is connected to the three-stage condenser through a pipeline. The three-stage jet pump sucks non-condensable gas in the secondary condenser, and the discharge port of the three-stage jet pump is connected to the three-stage condenser through a pipeline.

[0011] According to the utility model, further, each power steam pipeline is provided with a pressure sensor, a temperature sensor and a power steam flow measurement device for signal transmission with an external system, and the monitored data is transmitted to the external system;

[0012] According to the utility model, further, the vacuum pipelines of the jet pumps at each level are also provided with pressure sensors and temperature sensors to monitor the temperature and pressure of the gas flowing in the corresponding vacuum pipelines and transmit the data to an external system.

[0013] According to the utility model, further, the first-stage jet pump vacuum pipeline is also correspondingly provided with a condenser A side vacuum valve and a condenser B side vacuum adjustable valve for adjusting the amount of air sucked from the condenser.

[0014] According to the utility model, further, inlet and outlet electric valves, temperature sensors and pressure sensors are arranged on the cooling water inlet and outlet main pipes of the condenser, and the data are transmitted to the external system.

[0015] According to the utility model, further, a flow measurement device is arranged on the power steam main pipe from the auxiliary steam header to the jet pump, and transmits data to an external system.

[0016] According to the utility model, further, adjustable valves are arranged on the power steam pipelines of each level of the jet pumps to adjust the pressure and flow of the jet pump inlet steam. Pressure sensors and temperature sensors are arranged on the pipelines to transmit data to the external system.

[0017] According to the utility model, further, the three-stage condenser has an exhaust pipeline for exhausting a small amount of non-condensable gas remaining inside the condenser, and an adjustable valve is arranged on the exhaust pipeline.

[0018] Compared with the prior art, the utility model has the following beneficial effects: the control mode of the condenser steam jet vacuum pumping system obtains the pressure and temperature data of each pipeline, which is used to provide the data to the external system, so as to obtain real-time data. According to the preset unit vacuum value, the command is issued in real time to automatically adjust the opening of each adjustable valve of the vacuum pumping system, so as to achieve the purpose of controlling and maintaining the back pressure of the unit. Under different operating conditions of the unit, the condenser steam jet vacuum pumping system and the water ring pump vacuum pumping system can be switched by setting the control logic to ensure the vacuum of the condenser.

[0019] The utility model has a simple structure and is convenient to configure, and can monitor the operating status of the vacuum pumping system of the unit in real time, grasp the operating status of the unit in real time, make judgments on the operating status of the unit and prompt the operating personnel to operate to achieve the optimal state. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a schematic diagram of a condenser steam jet vacuum control system.

[0021] In the figure: 1- condenser, 2- auxiliary steam header, 2.1- power steam pipeline, 2.11- first branch, 2.12- second branch, 2.13- third branch, 3- first-stage jet pump, 4- second-stage jet pump, 5- third-stage jet pump, 6- first condenser, 7- second condenser, 8- pressure sensor, 9- temperature sensor, 10- jet pump power steam regulating valve, 11- power steam flow measuring device, 12- condenser cooling water outlet valve, 13- adjustable valve, 14- condenser A side vacuum valve, 15- condenser B side vacuum valve, 16- condenser cooling water inlet valve. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] See also Figure 1 The utility model provides a technical solution, a condenser steam jet vacuum control system, in order to ensure the reliability of operation under various working conditions, auxiliary steam is used to provide a power steam source for the steam jet vacuum system, two first-level jet pumps 3 are arranged in parallel, respectively connected to the air extraction pipes on the A side and the B side of the condenser, the steam-gas mixture at the discharge port of the first-level jet pump 3 is condensed and heat exchanged through the first condenser 6, the first condenser 6 is used as a first-level condenser, most of the steam is condensed, and the uncondensed steam-gas mixture is sucked by the second-level jet pump 4 and discharged into the second condenser 7, the second condenser 7 includes a second-level condenser and a third-level condenser connected in series with the shell, first discharged into the second-level condenser for condensation, the remaining uncondensed steam-gas mixture is then sucked by the third-level jet pump 5 and discharged into the third-level condenser of the second condenser 7 for condensation, and finally the remaining small amount of non-condensable gas is discharged to the atmosphere through the emptying pipe of the third-level condenser, and the third-level condenser also has a cooling water outlet pipeline, on which a condenser cooling water outlet valve 12 is arranged. The drain of each condenser is returned to the condenser for recovery.

[0024] The first condenser 6 and the second condenser 7 of the vacuum system both have a water inlet for cooling water to enter and a water outlet for cooling water to be discharged. The water supply pipeline connected to the water inlet is provided with a pressure sensor 8, a temperature sensor 9 and a condenser cooling water inlet valve 16. The drainage pipeline connected to the water outlet is provided with a pressure sensor 8, a temperature sensor 9 and a condenser cooling water outlet valve 17. The water inlet and drainage pipelines of the condenser are arranged according to the prior art and will not be described in detail here. The pressure sensor 8 and the temperature sensor 9 monitor the temperature and pressure in the corresponding water inlet pipeline or water outlet pipeline, and transmit the data to an external DCS system.

[0025] Pressure sensors 8 and temperature sensors 9 are also provided on the air extraction pipelines of the jet pumps at each level of the vacuum extraction system. The pressure sensors 8 and temperature sensors 9 are transformed into transmitters for monitoring the temperature and pressure of the liquid in the cooling water pipeline and transmitting the data to an external DCS system. A condenser A side vacuum extraction valve 14 and a condenser B side vacuum extraction valve 15 are also provided on the first-level jet pump air extraction pipeline for adjusting the suction volume. The two vacuum extraction valves can be pneumatic valves or electric valves. When the system is in working state, the condenser A side vacuum extraction valve 14 and the condenser B side vacuum extraction valve 15 are opened, and when not in working state, they are closed.

[0026] The vacuum pumping system also includes an auxiliary steam manifold 2, which has a power steam pipeline 2.1. The power steam pipeline 2.1 is provided with a pressure sensor 8, a temperature sensor 9 and a power steam flow measurement device 11. The internal temperature and pressure of the power steam pipeline 2.1 are monitored by the pressure sensor 8 and the temperature sensor 9. The power steam flow measurement device 11 monitors the steam flow and transmits the data to the DCS system; the steam power steam pipeline 2.1 has a first branch 2.11 connected to the air inlet of the first-stage jet pump 3, a second branch 2.12 connected to the air inlet of the second-stage jet pump 4 and a third branch 2.13 connected to the third-stage jet pump 5, which serve as driving steam for each jet pump; each branch is provided with a pressure sensor 8 and a power steam regulating valve 10, and the pressure sensor 8 transmits the data to the DCS system. The control module reads data from the DCS system and issues instructions through the DCS system and the SIS system (safety instrument system) to control the opening and closing degree of the power steam regulating valve 10 corresponding to each pipeline, and control the steam pressure and flow entering the corresponding jet pump.

[0027] The third-stage condenser of the second condenser 7 of the vacuum pumping system has an exhaust pipeline for exhausting a small amount of non-condensable gas remaining inside it, and an adjustable valve 13 and a check valve (not marked in the figure) are arranged on the condensation exhaust pipeline.

[0028] The real-time data measured by the pressure sensor 8 and the temperature sensor 9 can monitor the unit's condenser vacuum, the pressures and temperatures of the condenser steam vacuum pumping system, and issue real-time instructions to automatically adjust the vacuum pumping system operation to achieve control over maintaining the unit's back pressure.

[0029] The control method of the condenser steam jet vacuum system is to obtain the pressure and temperature data of each pipeline through the set measuring points, and concentrate all point information on the DCS system for processing. The DCS system is an existing technology and will not be described in detail; the condenser steam jet vacuum system control system does not require the setting of a separate control cabinet. The control module reads the measuring point data from the DCS system, controls each valve according to the target back pressure value and the preset value of each level of steam extraction pressure, and adjusts the vacuum system in real time, so as to realize the rapid adjustment of the system air extraction volume according to the changes in unit load and back pressure.

[0030] When the unit is started, the condenser steam jet vacuum system and the standby vacuum pump operate simultaneously to quickly establish the unit vacuum; after the unit is operating normally, the condenser steam jet vacuum system maintains operation and the water ring vacuum pump is shut down as a standby; if the condenser steam jet vacuum system fails and stops operating, the standby vacuum pump is put into operation to maintain the safe operation of the unit.

[0031] When the system is operating normally, the control module automatically collects operating data through the temperature and pressure sensors or transmitters, compares it with the condenser target back pressure value set for the unit, and controls and adjusts the opening of the power steam regulating valves of each level of jet pumps in real time, adjusts the air extraction volume, makes the unit back pressure reach the set value, and ensures safe and stable operation of the unit.

[0032] After the system automatically gives the target value of the condenser back pressure, each actuator starts to adjust. In this link, the exhaust subcooling is introduced as negative feedback, and the appropriate exhaust subcooling is set to ensure the efficient operation of the steam jet vacuum system without over-extraction.

[0033] The specific control scheme is as follows:

[0034] (1) Setting the optimal power steam pressure value of each level of jet pump, and automatically adjusting the opening of the power steam regulating valve of each level of jet pump through the control module during operation, so that the jet pump operates in the optimal state;

[0035] (2) When the unit is started, the cooling water inlet and outlet valves are opened. The control module calculates the system water resistance according to the inlet and outlet water pressure, controls the opening of the cooling water inlet and outlet electric valves, and controls the water inlet flow. After the system cooling water runs normally, the control module sequentially puts the jet pumps of each level into operation;

[0036] (3) By monitoring the inlet and outlet temperatures and pressures of the three-stage jet pump 5, the control module controls and adjusts the opening of the corresponding power steam regulating valve 10 and the adjustable valve 13 provided on the condensate exhaust pipeline to ensure that the second condenser 7 operates at a slightly positive pressure and discharges the last non-condensable gas;

[0037] (4) By monitoring the inlet and outlet temperatures and pressures of the jet pumps at each level, the control module controls and adjusts the opening of the power steam regulating valve 10 of the jet pumps at each level to ensure that the pressure of the condensers at each level operates near the preset optimal value;

[0038] (5) When the unit load changes or the ambient temperature changes, the unit back pressure also changes accordingly. The control module monitors the condenser vacuum value in real time and sends instructions to each regulating mechanism to adjust the air extraction volume to quickly adapt to the changes and maintain the unit back pressure stable.

[0039] (6) When the condenser steam jet vacuum system is cut off, the control module issues a command to start the standby vacuum pump, and at the same time closes the condenser A side vacuum valve 14 and the condenser B side vacuum valve 15, the power steam inlet regulating valve 10 and the adjustable valve 13 of each level of jet pump.

[0040] (7) A standby water ring vacuum pump start-up switching module is provided to enable the selection of dual pumps to be put into operation or to interlock and start only one pump.

[0041] (8) By monitoring the vacuum status of condenser 1, when the vacuum degree is lower than the preset value, the standby water ring vacuum pump is started and the electric door at the vacuum pump inlet is opened.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A condenser steam jet vacuum control system, comprising a condenser vacuum system, characterized in that: Also includes: The auxiliary steam header is connected to the power steam pipelines of the jet pumps at all levels. The power steam pipelines are equipped with pressure sensors, temperature sensors and power steam flow measurement devices for signal transmission with the external system, and transmit the monitored data to the external system; A first-stage jet pump, arranged on the power steam pipeline; A first condenser, wherein the discharge port of the first-stage jet pump is connected to the first condenser through a pipeline; A secondary jet pump is arranged on the power steam pipeline, and is not in the same pipeline as the primary jet pump. Its suction port is connected to the first condenser through a pipeline, and the secondary jet pump sucks non-condensable gas in the primary condenser; The second condenser comprises a secondary condenser and a tertiary condenser which are arranged in series; the discharge port of the secondary jet pump is connected with the secondary condenser through a pipeline; the tertiary condenser has a condenser cooling water outlet pipe; the tertiary jet pump is connected with the secondary condenser, the tertiary jet pump sucks the non-condensable gas in the secondary condenser, and the discharge port of the tertiary jet pump is connected with the tertiary condenser through a pipeline.

2. A condenser steam jet vacuum control system according to claim 1, characterized in that: It also includes a condenser, which has a condenser A side and a condenser B side, and both the condenser A side and the condenser B side are provided with vacuum pipelines; there are two first-stage jet pumps, and the two vacuum pipelines are respectively connected to the suction ports of the corresponding first-stage jet pumps.

3. A condenser steam jet vacuum control system according to claim 2, characterized in that: The vacuum pipelines are also provided with pressure sensors and temperature sensors to monitor the temperature and pressure of the gas flowing in the corresponding vacuum pipelines and transmit the data to an external DCS system.

4. A condenser steam jet vacuum control system according to claim 2, characterized in that: The vacuum pipeline is also provided with a vacuum valve on the condenser A side and an adjustable vacuum valve on the condenser B side for adjusting the suction volume.

5. A condenser steam jet vacuum control system according to claim 1, characterized in that: The three-stage condenser has an exhaust pipeline for exhausting the non-condensable gas inside the condenser, and an adjustable valve is arranged on the exhaust pipeline.

6. The condenser steam jet vacuum control system according to claim 1, characterized in that: The pressure sensor and the temperature sensor are transformed into a transmission device for monitoring the temperature and pressure of the liquid in the cooling water pipeline and transmitting the data to an external DCS system.

7. The condenser steam jet vacuum control system according to claim 1, characterized in that: Each level of the jet pump is provided with a power steam regulating valve for regulating the steam pressure and flow rate at the inlet of each level of the jet pump.

8. The condenser steam jet vacuum control system according to claim 1, characterized in that: The main motive steam pipeline is provided with a motive steam flow measuring device for measuring the total steam consumption of the ejector.

9. The condenser steam jet vacuum control system according to claim 1, characterized in that: The control system is equipped with a control module, and the measurement data is connected to the DCS system. The control module controls the opening of each regulating valve according to the preset value.

10. The condenser steam jet vacuum control system according to claim 1, characterized in that: In the automatic control link, the system introduces the exhaust subcooling as negative feedback to ensure the efficient operation of the steam jet vacuum system without over-extraction.

Images