Rotation control method for ultrafiltration system

Abstract

The invention belongs to the technical field of nuclear power plant seawater desalination, and particularly relates to an ultrafiltration system rotation control method. Liquid level control is to directly set liquid level related starting conditions so as to control equipment, during use, an ENpin is firstly assigned to TRUE, a control module works in an automatic mode, an MODE pin is assigned to FALSE, a control mode is determined to be liquid level control, an SW pin is directly connected with a liquid level variable, an SWL pin is connected with a manually set shutdown liquid level, and an SWM pin is connected with a manually set liquid level for starting one piece of equipment. The SWH pin is connected with a manually set liquid level for starting two devices, the SWHH pin is connected with a manually set liquid level for starting three devices, and the OUTinput pin determines different working modes for outputting control signals. The problems that a traditional method is complicated and inconvenient to read and maintain are solved, debugging is easy, sharing of different projects is facilitated, the project logic structure is clear, and the readability, reliability and universality of the rotation control logic of the seawater desalination ultrafiltration system are enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of seawater desalination in nuclear power plants, and in particular relates to a rotation control method for an ultrafiltration system. Background Art

[0002] Ultrafiltration is a pressurized membrane separation technology, that is, under a certain pressure, small molecular solutes and solvents are allowed to pass through a special membrane with a certain pore size, while large molecular solutes cannot pass through and remain on one side of the membrane, thereby partially purifying the large molecular substances. The micropores of the ultrafiltration membrane are less than 0.01 microns, which can filter out harmful substances such as bacteria, rust, colloids, etc. in the water, and retain the original trace elements and minerals in the water. It is now widely used in the fields of chemical industry, pharmaceuticals, food processing, seawater desalination, etc.

[0003] Tianwan Nuclear Power Steam Energy Project has 15 sets of ultrafiltration systems for desalination, which are connected in parallel by mother pipes and divided into 3 groups, with 5 sets in each group. The design output of a single ultrafiltration device is 290m 3 / h, the recovery rate of the ultrafiltration system is 90%. The ultrafiltration device is backwashed approximately every 30 minutes (adjustable), and the backwashing time depends on the quality of the influent water, generally 60 seconds. After running for a certain period of time (generally 24 hours), TMC backwashing needs to be started.

[0004] In order to ensure the stable operation of the system, the operating time of each reverse osmosis device is required to be roughly equal. If the above functions are realized according to the traditional configuration method, the control logic structure will be extremely complex, which is not convenient for system configuration, debugging and subsequent maintenance. In order to solve the above problems and effectively improve the reliability of the operation and maintenance of the control logic of the ultrafiltration system, it is necessary to design a new rotation control method for the ultrafiltration system. Summary of the invention

[0005] The purpose of the present invention is to provide an ultrafiltration system rotation control method, enhance the nuclear power plant owner and operator's rotation control of ultrafiltration and other systems in seawater desalination, solve the problems of traditional set methods being complicated, inconvenient to read and maintain, etc., easy to debug, convenient for sharing of different projects, clear project logic structure, and enhance the readability, reliability and versatility of the seawater desalination ultrafiltration system rotation control logic.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for rotating control of an ultrafiltration system, wherein liquid level control is to directly set liquid level related start conditions to control equipment. When in use, the EN_ pin is first assigned a value of TRUE, and the control module works in automatic mode. The MODE pin is assigned a value of FALSE, and the control mode is determined to be liquid level control. The SW pin is directly connected to the liquid level variable, the SW_L pin is connected to the manually set shutdown liquid level, the SW_M pin is connected to the manually set start level of one device, the SW_H pin is connected to the manually set start level of two devices, and the SW_HH pin is connected to the manually set start level of three devices. The OUT_ input pin determines different working modes of the output control signal. When the value is assigned to FALSE, the XX_CONTROL_OUT set signal is reset when the XX_RUN operation feedback signal arrives. The control module determines whether the equipment needs to be started and the quantity according to the input SW variable and the set start limit values ​​SW_L, SW_M, and SW_H, and then performs logical operations according to the equipment operation status and operation time to determine which equipment is specifically started.

[0008] Digital control is to control the number of devices running according to manual settings or calculation assignments. When in use, first assign the MODE pin to TRUE, and automatically determine the number of devices put into operation through the value of the NUM pin, and the remaining READY devices enter the standby state for preparation for operation; when the XX_RUN_LONGTIME signal is received, the control module automatically determines the operating status of the standby equipment according to the SIGN setting method. When the standby equipment has no faults and no maintenance, the device with the least number of startups among the standby devices is determined according to the rotation control logic, and the XX_CONTROL_OUT command is output. Then the device startup is controlled according to the set OUT_select pulse or level method, ensuring that all devices are started in rotation to avoid failures caused by long-term operation of a single device.

[0009] Liquid level control is used for rotation switching control of the three pumps.

[0010] If there are no two operating conditions, the preset value is 9999999.

[0011] If there are no three operating conditions, the preset value is 9999999.

[0012] Use the XX_RUN_LONGTIME pin and set the OUT_ input pin to TRUE.

[0013] The SIGN input pin determines whether the device has started up by rising edge detection or level detection, thereby changing the rotation word. Under normal working conditions, it is assigned a value of TRUE.

[0014] When a device needs to be started according to the liquid level signal, the control module automatically determines the operating status of all devices according to the SIGN setting method. When the device P1_RUN is in a stopped state and the last time it was started by P2_RUN, it automatically outputs the P1_CONTROL_OUT command and the RUN_Number and TURN_Number information; when the device P1_RUN is in a stopped state and the last time it was started by P1_RUN, it automatically outputs the P2_CONTROL_OUT command and the RUN_Number and TURN_Number information. The output P1 / P2_CONTROL_OUT command then controls the device startup according to the set OUT_select pulse or level.

[0015] Digital control is used for rotation switching control of group equipment within 6 sets.

[0016] The beneficial effects achieved by the present invention are:

[0017] The present invention is applicable to various application manufacturers, and the application scenarios in the project include pump / fan standby automatic start-up, rotation switching between ultrafiltration sets, constant pressure water supply, 1-in-1-standby automatic dispensing system, yin-yang mixed bed 3-in-1-standby switching, etc. Graphical programming language is used to simplify the system configuration structure, which is convenient for operators to operate and view. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the module pin diagram; Figure 2 This is a logic diagram of the algorithm. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] The present invention adopts graphical language programming and is encapsulated into a signal acquisition control module, which has functions such as system enablement, control mode, data acquisition, and logic processing. The ready, running, and shutdown command signals of up to 6 devices to be controlled are collected in real time, and logical processing is performed according to the set control mode to control the automatic start and stop or timed switching of the control equipment. The module has a variety of application scenarios and can be selected according to specific needs: the liquid level can be directly set to realize the automatic rotation start and stop of the water pump in a simple 2 (or 1) use and 1 standby working condition, and it has the functions of timed switching and fault skipping; the number of starts can be set to realize the automatic rotation start and stop of motors and equipment in various working conditions such as multiple use and multiple standby between 6 devices; simple logic can be used to realize the rotation control of equipment queue-jumping start, conditional start and stop, etc. Considering the versatility and stability of the system, the module needs to collect the ready signal of the device to be controlled, and the signal requirements include its remote control status, fault-free status, and maintenance-free status.

[0021] Table 1 Module pin definition table

[0022]

[0023]

[0024] The rotary control module has two major working modes: automatic and prohibited. The automatic mode is further divided into two working modes: liquid level and digital control.

[0025] Liquid level control: The liquid level control method is to directly set the liquid level and other related starting conditions to control the equipment. It is mostly used for the rotation switching control of water pumps within 3 units.

[0026] When using, first assign the EN_ pin to TRUE, the control module works in automatic mode, assign the MODE pin to FALSE, determine that the control mode is liquid level control, the SW pin is directly connected to the liquid level variable, the SW_L pin is connected to the manually set shutdown liquid level, the SW_M pin is connected to the manually set liquid level for starting one device, the SW_H pin is connected to the manually set liquid level for starting two devices (if there are no two operating conditions, a sufficiently large value should be preset here, such as 9999999), and the SW_HH pin is connected to the manually set liquid level for starting three devices (if there are no three operating conditions, a sufficiently large value should be preset here, such as 9999999). The 'OUT_' input pin determines the different working modes of the output control signal. When assigned to FALSE, the 'XX_CONTROL_OUT' set signal will be reset when the 'XX_RUN' operation feedback signal arrives.

[0027] If the 'XX_RUN_LONGTIME' pin is used, the 'OUT_' input pin must be assigned a value of TRUE. The 'SIGN' input pin determines the method (rising edge detection / level detection) used to determine that the device has completed startup and thus change the rotation word. In general, it is assigned a value of 'TRUE'.

[0028] The control module determines whether the device needs to be started and the number according to the input SW variables and the set start limits SW_L, SW_M, and SW_H values, and then performs logical operations based on the device's operating status and operating time to determine which device to start. For example, when a device needs to be started based on the liquid level signal, the control module will automatically determine the operating status of all devices according to the 'SIGN' setting method. When the device P1_RUN is in a stopped state and the last start was P2_RUN, the module automatically outputs the P1_CONTROL_OUT command and RUN_Number, TURN_Number information; when the device P1_RUN is in a stopped state and the last start was P1_RUN, the module automatically outputs the P2_CONTROL_OUT command and RUN_Number, TURN_Number information. The output P1 / P2_CONTROL_OUT command then controls the device startup according to the set 'OUT_' selection of pulses or levels.

[0029] Digital control: Control the equipment according to the manual setting (or calculation assignment) of the running quantity, mostly used for the rotation switching control of the group equipment within 6 sets. When using, first assign the MODE pin to TRUE, and automatically determine the number of devices put into operation through the value of the NUM pin, and the remaining ready (READY) devices enter the standby state for commissioning. When the 'XX_RUN_LONGTIME' signal is received, the control module automatically determines the operating status of the standby equipment according to the 'SIGN' setting method. When the standby equipment has no faults and no maintenance, according to the rotation control logic, determine the device with the least number of startups among the standby equipment, output the XX_CONTROL_OUT command, and then control the device startup according to the set 'OUT_' selection of pulses or levels, to ensure that all devices are started in rotation, and avoid the long-term operation of a single device that is prone to failure.

Claims

1. A method for controlling rotation of an ultrafiltration system, characterized in that: Liquid level control is to directly set the liquid level related start conditions to control the equipment. When in use, first assign the EN_ pin to TRUE, the control module works in automatic mode, the MODE pin is assigned to FALSE, and the control mode is determined to be liquid level control. The SW pin is directly connected to the liquid level variable, the SW_L pin is connected to the manually set shutdown liquid level, the SW_M pin is connected to the manually set start level of one device, the SW_H pin is connected to the manually set start level of two devices, and the SW_HH pin is connected to the manually set start level of three devices. The OUT_ input pin determines the different working modes of the output control signal. When the value is assigned to FALSE, the XX_CONTROL_OUT set signal is reset when the XX_RUN operation feedback signal arrives; the control module determines whether the equipment needs to be started and the quantity according to the input SW variables and the set start limits SW_L, SW_M, and SW_H values, and then performs logical operations according to the equipment operation status and operation time to determine which specific equipment to start; Digital control is to control the number of devices running according to manual settings or calculation assignments. When in use, first assign the MODE pin to TRUE, and automatically determine the number of devices put into operation through the value of the NUM pin, and the remaining READY devices enter the standby state for preparation for operation; when the XX_RUN_LONGTIME signal is received, the control module automatically determines the operating status of the standby equipment according to the SIGN setting method. When the standby equipment has no faults and no maintenance, the device with the least number of startups among the standby devices is determined according to the rotation control logic, and the XX_CONTROL_OUT command is output. Then the device startup is controlled according to the set OUT_select pulse or level method, ensuring that all devices are started in rotation to avoid failures caused by long-term operation of a single device.

2. The ultrafiltration system rotation control method according to claim 1, characterized in that: Liquid level control is used for rotation switching control of the three pumps.

3. The ultrafiltration system rotation control method according to claim 1, characterized in that: If there are no two operating conditions, the preset value is 9999999.

4. The ultrafiltration system rotation control method according to claim 1, characterized in that: If there are no three operating conditions, the preset value is 9999999.

5. The ultrafiltration system rotation control method according to claim 1, characterized in that: Use the XX_RUN_LONGTIME pin and set the OUT_ input pin to TRUE.

6. The ultrafiltration system rotation control method according to claim 1, characterized in that: The SIGN input pin determines whether the device has started up by rising edge detection or level detection, thereby changing the rotation word. Under normal working conditions, it is assigned a value of TRUE.

7. The ultrafiltration system rotation control method according to claim 1, characterized in that: When a device needs to be started according to the liquid level signal, the control module automatically determines the operating status of all devices according to the SIGN setting method. When the device P1_RUN is in a stopped state and the last time it was started by P2_RUN, it automatically outputs the P1_CONTROL_OUT command and the RUN_Number and TURN_Number information; when the device P1_RUN is in a stopped state and the last time it was started by P1_RUN, it automatically outputs the P2_CONTROL_OUT command and the RUN_Number and TURN_Number information. The output P1 / P2_CONTROL_OUT command then controls the device startup according to the set OUT_select pulse or level.

8. The ultrafiltration system rotation control method according to claim 1, characterized in that: Digital control is used for rotation switching control of group equipment within 6 sets.

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