A measurement and control device system and method for cyclones in a desulfurization island limestone slurry cyclone

Abstract

The present invention provides a system and method for measuring and controlling cyclones in a desulfurization island limestone slurry cyclone. The system includes a control unit, a vibration measuring device, an underflow flow measuring device, and an inlet electric valve. The control unit includes an input card and an output card. The vibration measuring device and the underflow flow measuring device are both connected to the input card. The inlet electric valve is connected to the output card. The measurement and control method includes a working step and a cyclone switching step. The system can automatically monitor cyclone failures and automatically switch to a normal standby cyclone, effectively reducing user operation intensity and workload, ensuring the quality of the desulfurization island limestone slurry, and resolving the problem of limestone slurry quality being compromised due to cyclone failures in desulfurization island cyclones in power plants.

Description

Technical Field

[0001] The present invention relates to the technical field of cyclones, and in particular to a measurement and control device system and method for cyclones of a limestone slurry cyclone on a desulfurization island. Background Art

[0002] Currently, sulfur dioxide (SO2) generated during coal combustion is a major source of air pollution. Wet limestone-gypsum flue gas desulfurization (FGD) processes, with their proven technology, high reliability, and simple operation, are widely used in thermal power plants. The concentration and fineness of limestone slurry are key factors influencing desulfurization efficiency. Therefore, preparing a high-quality limestone slurry is crucial for improving desulfurization efficiency and reducing SO2 emissions from thermal power plants.

[0003] The limestone slurry in a thermal power plant's wet desulfurization system is crushed to a specific particle size and then mixed with water in a specific proportion to create a slurry of a certain concentration. The limestone is weighed on a weighing conveyor, then conveyed to a ball mill where it is mixed with water for slurry production. The resulting slurry is then stored in a circulating slurry tank and pumped to a cyclone for separation via a slurry circulation pump. The separated overflow slurry is stored in the limestone slurry tank for backup. The underflow slurry, considered unqualified, is returned to the ball mill for further grinding.

[0004] The cyclone is a key device that affects the performance of limestone slurry. Generally, each cyclone is equipped with 4-6 cyclones. Each cyclone inlet has a manual regulating valve for adjustment and isolation. A spare cyclone is reserved for normal operation. Therefore, the current operation control lacks the necessary measurement and adjustment means and mainly relies on on-site manual operation (see "Adjustment of the Limestone Slurry Preparation System of Taishan Power Plant", Gao Xiaochun et al., Guangdong Electric Power, 2006, 19(11):66-68).

[0005] CN2678776U discloses a combined gypsum slurry cyclone, which consists of a distribution valve, a cyclone and corresponding pipelines, wherein the distribution valve (1) consists of a hollow valve body (11) and a hollow sliding valve stem (12), the sliding valve stem being located in the valve body, and an isolation ring (15) being provided in the valve body to divide the cavity in the valve body into two parts, the left side being a cyclone slurry distribution chamber (13), and the right side being a recirculation slurry distribution chamber (14); a gypsum slurry outlet pipe (5) is arranged axially on the wall of the cyclone slurry distribution chamber to lead to each cyclone (4), and a gypsum slurry recirculation outlet (3) is provided on the wall of the recirculation slurry distribution chamber; the blind end of the hollow sliding valve stem is connected to an actuator (2), and the other end is open to face the incoming gypsum slurry flow; a long strip side hole (121) is opened on the wall of the sliding valve stem to connect to the recirculation slurry distribution chamber.

[0006] CN104689929A ​​discloses a limestone cyclone distribution device. The device includes a distribution box connected to the underflow pipe and overflow pipe of the limestone cyclone. An overflow trough and a diversion trough are provided below the distribution box, respectively. A circulation pipe is provided below the overflow trough, a finished product pipe is provided on the side wall of the overflow trough, and a diversion pipe is provided on the diversion box. This device solves the power problem of limestone slurry distribution, saves space, reduces equipment costs, and simultaneously limits the density fluctuation of the finished product slurry to a smaller range, making it easy to promote and practice.

[0007] However, none of the above devices solves the problem of "overflow and coarseness" caused by the blockage of the cyclone bottom flow, which will cause the limestone pulping product to be unqualified and seriously affect the normal operation of the subsequent desulfurization process.

[0008] Therefore, developing a system and method for measuring and controlling the cyclones of the limestone slurry cyclone in the desulfurization island to detect the blockage of the cyclones in time is of great significance for ensuring the quality of the limestone slurry products. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides a measurement and control device system and method for the cyclone of the limestone slurry cyclone on the desulfurization island. By setting a vibration measuring device and an underflow flow measuring device to detect the amplitude and underflow flow of the cyclone, it is accurately judged whether the cyclone is blocked; when the cyclone is detected to be blocked, the cyclone switching step can be automatically started, which effectively reduces the user's operation intensity and workload, and avoids the deterioration of limestone slurry quality caused by "overflow and coarsening".

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In the first aspect, the present invention provides a measurement and control device system for the cyclone of the limestone slurry cyclone on the desulfurization island, wherein the measurement and control device system includes a control unit, a vibration measuring device, an underflow flow measuring device and an inlet electric valve; the control unit includes an input card and an output card; the vibration measuring device and the underflow flow measuring device are both connected to the input card; the inlet electric valve is connected to the output card.

[0012] The vibration measurement device and underflow flow measurement device in the measurement and control system for the limestone slurry cyclone in the desulfurization island described in this invention detect the cyclone's amplitude and underflow flow. Based on these data, a control unit accurately determines whether the cyclone is blocked. If blockage is detected, the control unit adjusts the inlet electric valve to switch the cyclone. This measurement and control system is rationally designed and simple in structure, resolving the issue of limestone slurry quality compromised by desulfurization island cyclone failures in power plants and holds great promise for large-scale application.

[0013] Preferably, the control unit comprises a logical settlement unit.

[0014] Preferably, the input card, the logic settlement unit and the output card are connected in sequence via a control bus.

[0015] Preferably, the control unit includes an IEC61131-3 function module, a real-time operation control module and a hardware module which are sequentially connected to the logic settlement unit.

[0016] Preferably, the vibration measuring device is arranged on the side wall of the cyclone.

[0017] Preferably, the number of the vibration measuring devices is the same as the number of the cyclones.

[0018] Preferably, the underflow flow measuring device comprises an ultrasonic flow measuring device.

[0019] Preferably, the number of the underflow flow measuring devices is the same as the number of the cyclones.

[0020] Preferably, the number of the inlet electric valves is the same as the number of the cyclones.

[0021] The number of the vibration measuring devices and the cyclones in the present invention is the same, and the number of the underflow flow measuring devices and the cyclones is the same. In this way, the amplitude and underflow flow of each cyclone in the desulfurization island limestone slurry cyclone can be monitored separately, and the cyclone blockage can be discovered in time.

[0022] In the second aspect, the present invention also provides a measurement and control method for the cyclones of the limestone slurry cyclone on the desulfurization island. The measurement and control method is carried out using the measurement and control device system for the cyclones of the limestone slurry cyclone on the desulfurization island described in the first aspect; the measurement and control method includes a working step and a cyclone switching step.

[0023] Preferably, the working steps include:

[0024] (1) Start the control unit, load the IEC61131-3 function module and the real-time operation control module, and monitor the amplitude and underflow of the cyclone;

[0025] (2) Determine whether the amplitude of the cyclone has doubled. If not, continue to monitor the amplitude of the cyclone and the underflow rate. If the amplitude of the cyclone has doubled, detect the underflow rate of the cyclone.

[0026] (3) Determine whether the underflow of the cyclone is reduced. If the underflow of the cyclone is reduced, the cyclone switching step is automatically started; if the underflow of the cyclone is not reduced, an alarm is issued and manual confirmation is made to determine whether the cyclone is blocked;

[0027] (4) If the cyclone is blocked, the cyclone switching step is automatically started; if the cyclone is not blocked, the amplitude and underflow of the cyclone are continuously monitored;

[0028] Preferably, the cyclone switching step includes:

[0029] (1') Close the inlet electric valve of the plugged cyclone;

[0030] (2') Open the inlet electric valve of the standby cyclone;

[0031] (3') Determine whether the underflow of the spare cyclone is normal;

[0032] (4') If the underflow rate is not normal, wait and alarm; if the underflow rate is normal, exit the cyclone switching step.

[0033] The measurement and control method for the cyclone of the limestone slurry cyclone on the desulfurization island of the present invention starts the control unit, loads the IEC61131-3 function module and the real-time operation control module, and timely monitors the amplitude and underflow flow of the cyclone; first, the amplitude of the cyclone is judged. If the amplitude has not doubled, it means that the cyclone is normal at this time, and the amplitude and underflow flow of the cyclone are continuously monitored; if the amplitude of the cyclone is doubled, the underflow flow of the cyclone is further detected. If the underflow flow of the cyclone decreases, it means that the cyclone is blocked at this time, and the cyclone switching step is automatically started; if the underflow flow of the cyclone does not decrease, it means that the cyclone condition is uncertain at this time, and an alarm is issued, and manual confirmation is performed to determine whether the cyclone is blocked; if it is confirmed that the cyclone is blocked, the cyclone switching step is automatically started; if the cyclone is not blocked, the amplitude and underflow flow of the cyclone are continuously monitored. The measurement and control method described in the present invention can automatically monitor the cyclone failure and automatically perform the cyclone switching steps, effectively avoiding the problem of "overflow and coarseness" caused by cyclone blockage. The finished limestone pulping product of the desulfurization island is qualified, which is conducive to the normal progress of the subsequent desulfurization process.

[0034] In the cyclone switching step (4') of the present invention, if the underflow rate is not normal, the system waits and issues an alarm, and after the alarm, it is manually confirmed whether the cyclone is blocked; if it is confirmed that the cyclone is blocked, the cyclone switching step is automatically started, and the system automatically switches to another spare cyclone; if the cyclone is not blocked, the amplitude and underflow rate of the cyclone are continuously monitored.

[0035] Preferably, the amplitude doubling in step (2) is an amplitude > 1.5 times the average value of the amplitude in the previous minute, for example, it can be 1.5 times, 1.6 times, 1.8 times, 2 times, 2.3 times or 2.5 times, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0036] Preferably, the underflow rate in step (3) is reduced to an underflow rate < 70% of the average underflow rate in the previous minute, for example, it can be 70%, 60%, 50%, 40% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the measurement and control method includes a working step and a vortex switching step; the working step includes:

[0038] (1) Start the control unit, load the IEC61131-3 function module and the real-time operation control module, and monitor the amplitude and underflow of the cyclone;

[0039] (2) Determine whether the amplitude of the vortex is greater than 1.5 times the average value of the amplitude in the previous minute. If not, continue to monitor the amplitude and underflow of the vortex. If the amplitude of the vortex is greater than 1.5 times the average value of the amplitude in the previous minute, detect the underflow of the vortex.

[0040] (3) Determine whether the underflow of the cyclone is reduced. If the underflow of the cyclone is less than 70% of the average underflow of the previous minute, the cyclone switching step is automatically started; if the underflow of the cyclone is not less than 70% of the average underflow of the previous minute, an alarm is issued and manual confirmation is made to determine whether the cyclone is blocked;

[0041] (4) If the cyclone is blocked, the cyclone switching step is automatically started; if the cyclone is not blocked, the amplitude and underflow of the cyclone are continuously monitored;

[0042] The cyclone switching step includes:

[0043] (1') Close the inlet electric valve of the plugged cyclone;

[0044] (2') Open the inlet electric valve of the standby cyclone;

[0045] (3') Determine whether the underflow of the spare cyclone is normal;

[0046] (4') If the underflow rate is not normal, wait and alarm; if the underflow rate is normal, exit the cyclone switching step.

[0047] Compared with the prior art, the present invention has at least the following beneficial effects:

[0048] (1) The measurement and control system of the cyclone of the limestone slurry cyclone in the desulfurization island provided by the present invention has a simple structure and a reasonable design. It can automatically monitor the failure of the cyclone and automatically switch to the normal spare cyclone, effectively reducing the user's operation intensity and workload;

[0049] (2) The measurement and control method of the cyclone of the desulfurization island limestone slurry cyclone provided by the present invention ensures the quality of the desulfurization island limestone slurry, effectively avoids the problem of limestone slurry quality degradation caused by "overflow and coarseness", and is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural schematic diagram of the measurement and control device system of the cyclone of the desulfurization island limestone slurry cyclone provided in a specific embodiment.

[0051] Figure 2 It is a flow chart of the working steps in the measurement and control method of the cyclone of the limestone slurry cyclone in the desulfurization island provided in the specific implementation manner.

[0052] Figure 3 It is a flow chart of the cyclone switching steps of the cyclone measurement and control method of the desulfurization island limestone slurry cyclone provided in a specific embodiment.

[0053] In the figure: 1-control unit; 201-first vibration measuring device; 202-second vibration measuring device; 203-third vibration measuring device; 301-first underflow flow measuring device; 302-second underflow flow measuring device; 303-third underflow flow measuring device; 401-first inlet electric valve; 402-second inlet electric valve; 403 third inlet electric valve; 5-input card; 6-output card; 7-logic settlement unit; 8-wet ball mill; 9-slurry circulation box; 10-limestone slurry box; 11-pressure measuring device. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0055] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0056] As a specific embodiment of the present invention, a measurement and control device system for the cyclones of the limestone slurry cyclone on the desulfurization island is provided. The measurement and control device system includes three cyclones, and accordingly, includes three vibration measuring devices, three underflow flow measuring devices and three inlet electric valves. The measurement and control device system is set in the desulfurization system of the thermal power plant and is used to monitor the working conditions of the cyclones in the limestone slurry cyclone on the desulfurization island. The structural diagram thereof is shown as follows: Figure 1 shown.

[0057] The measurement and control device system includes a control unit 1, a vibration measuring device, an underflow flow measuring device and an inlet electric valve; the control unit 1 includes an input card 5 and an output card 6; the vibration measuring device and the underflow flow measuring device are both connected to the input card 5; the inlet electric valve is connected to the output card 6.

[0058] The control unit 1 includes a logic settlement unit 7; the input card 5, the logic settlement unit 7 and the output card 6 are connected in sequence through a control bus.

[0059] The control unit 1 includes an IEC61131-3 function module, a real-time operation control module and a hardware module which are sequentially connected to the logic settlement unit 7 .

[0060] The vibration measuring devices are arranged on the side walls of the cyclone, and are respectively a first vibration measuring device 201 , a second vibration measuring device 202 and a third vibration measuring device 203 .

[0061] The underflow flow measuring devices are respectively a first underflow flow measuring device 301 , a second underflow flow measuring device 302 and a third underflow flow measuring device 303 .

[0062] The underflow flow measuring device is an ultrasonic flow measuring device.

[0063] The inlet electric valve includes a first inlet electric valve 401 , a second inlet electric valve 402 and a third inlet electric valve 403 .

[0064] The desulfurization island system in the desulfurization system of a thermal power plant includes a wet ball mill 8, a slurry circulation box 9, a limestone slurry tank 10, and a pressure measuring device 11. The wet ball mill 8, slurry circulation box 9, pressure measuring device 11, cyclone, and limestone slurry tank 10 are connected in sequence.

[0065] The bottom of the cyclone is connected to the wet ball mill 8 and the slurry circulation box 9. The pressure measuring device 11 is connected to the input card 5.

[0066] The workflow of the desulfurization island system within the desulfurization system of a thermal power plant includes:

[0067] The limestone is weighed on a conveyor belt and transported to a wet ball mill 8 where it is mixed with water to form a slurry. The resulting slurry is then stored in a slurry circulation tank 9 and pumped by a slurry circulation pump to a cyclone composed of cyclones for separation. The separated overflow slurry is stored in a limestone slurry tank 10 for backup. The underflow slurry, which is unqualified, is returned to the wet ball mill 8 for further grinding.

[0068] As a specific embodiment of the present invention, a method for measuring and controlling the cyclone of the limestone slurry cyclone on the desulfurization island is also provided. The measuring and controlling method is performed using the measuring and controlling device system of the cyclone of the limestone slurry cyclone on the desulfurization island. The measuring and controlling method includes working steps and cyclone switching steps. The flow chart of the working steps is as follows: Figure 2 The flowchart of the vortex switching steps is shown in Figure 3 shown.

[0069] The working steps include:

[0070] (1) Start the control unit, load the IEC61131-3 function module and the real-time operation control module, and monitor the amplitude and underflow of the cyclone;

[0071] (2) Determine whether the amplitude of the vortex is greater than 1.5 times the average value of the amplitude in the previous minute. If not, continue to monitor the amplitude and underflow of the vortex. If the amplitude of the vortex is greater than 1.5 times the average value of the amplitude in the previous minute, detect the underflow of the vortex.

[0072] (3) Determine whether the underflow of the cyclone is reduced. If the underflow of the cyclone is less than 70% of the average underflow of the previous minute, the cyclone switching step is automatically started; if the underflow of the cyclone is not less than 70% of the average underflow of the previous minute, an alarm is issued and manual confirmation is made to determine whether the cyclone is blocked;

[0073] (4) If the cyclone is blocked, the cyclone switching step is automatically started; if the cyclone is not blocked, the amplitude and underflow of the cyclone are continuously monitored;

[0074] The cyclone switching step includes:

[0075] (1') Close the inlet electric valve of the plugged cyclone;

[0076] (2') Open the inlet electric valve of the standby cyclone;

[0077] (3') Determine whether the underflow of the spare cyclone is normal;

[0078] (4') If the underflow is not normal, wait for 10 seconds and give an alarm. If the underflow is normal, exit the cyclone switching step.

[0079] To sum up, the measurement and control device system for the cyclone of the limestone slurry cyclone on the desulfurization island provided by the present invention has a simple structure and a reasonable design. It can automatically monitor the failure of the cyclone and automatically switch to the normal standby cyclone, effectively reducing the user's operation intensity and workload, ensuring the quality of the limestone slurry on the desulfurization island, and effectively avoiding the problem of deterioration in the quality of the limestone slurry caused by "overflow and coarsening".

[0080] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for measuring and controlling the cyclones of a limestone slurry cyclone in a desulfurization island, characterized in that: The measurement and control method is carried out using the following measurement and control device system for the cyclone of the limestone slurry cyclone on the desulfurization island; The measurement and control device system includes a control unit, a vibration measuring device, an underflow flow measuring device and an inlet electric valve; the control unit includes an input card and an output card; the vibration measuring device and the underflow flow measuring device are both connected to the input card; the inlet electric valve is connected to the output card; The vibration measuring device is arranged on the side wall of the cyclone; The measurement and control method includes a working step and a cyclone switching step; The working steps include: (1) Start the control unit, load the IEC61131-3 function module and the real-time operation control module, and monitor the amplitude and underflow of the cyclone; (2) Determine whether the amplitude of the cyclone has doubled. If not, continue to monitor the amplitude of the cyclone and the underflow rate. If the amplitude of the cyclone has doubled, detect the underflow rate of the cyclone. (3) Determine whether the underflow of the cyclone is reduced. If the underflow of the cyclone is reduced, the cyclone switching step is automatically started; if the underflow of the cyclone is not reduced, an alarm is issued and manual confirmation is made to determine whether the cyclone is blocked; (4) If the cyclone is blocked, the cyclone switching step is automatically started; if the cyclone is not blocked, the amplitude and underflow of the cyclone are continuously monitored; The cyclone switching step includes: (1') Close the inlet electric valve of the plugged cyclone; (2') Open the inlet electric valve of the standby cyclone; (3') Determine whether the underflow of the spare cyclone is normal; (4') If the underflow rate is not normal, wait and alarm; if the underflow rate is normal, exit the cyclone switching step.

2. The measurement and control method according to claim 1, characterized in that: The control unit includes a logical settlement unit.

3. The measurement and control method according to claim 2, characterized in that: The input card, the logic settlement unit and the output card are connected in sequence via a control bus.

4. The measurement and control method according to claim 2, characterized in that: The control unit includes an IEC61131-3 function module, a real-time operation control module and a hardware module which are sequentially connected to the logic settlement unit.

5. The measurement and control method according to claim 1, characterized in that: The number of the vibration measuring devices is the same as the number of the cyclones.

6. The measurement and control method according to claim 1, characterized in that: The underflow flow measuring device includes an ultrasonic flow measuring device.

7. The measurement and control method according to claim 1, characterized in that: The number of the underflow flow measuring devices is the same as the number of the cyclones.

8. The measurement and control method according to claim 1, characterized in that: The number of the inlet electric valves is the same as the number of the cyclones.

9. The measurement and control method according to claim 1, characterized in that: The amplitude doubling in step (2) is an amplitude greater than 1.5 times the average value of the amplitude in the previous minute.

10. The measurement and control method according to claim 1, characterized in that: In step (3), the underflow rate is reduced to underflow rate < 70% of the average underflow rate in the previous minute.

Images