A disc dehydrator system and its output adjustment method

Abstract

This invention relates to the field of desulfurization technology and discloses a disc dewatering machine system and its output adjustment method. The disc dewatering machine system includes: a thickness gauge to obtain the thickness of the gypsum filter cake; a vacuum pump connected to a steam-water separator; a pressure transmitter to obtain the pressure at the inlet of the steam-water separator; and a distributed control system connected to the vacuum pump via a variable frequency motor. The distributed control system acquires the thickness signal transmitted by the thickness gauge, the pressure signal transmitted by the pressure transmitter, the flue gas flow rate at the inlet of the desulfurization facility, and the SO2 concentration of the raw flue gas at the inlet of the desulfurization facility, and adjusts the output frequency of the variable frequency motor in a timely manner. This application transmits the gypsum filter cake thickness signal, pressure signal, flue gas flow rate at the inlet of the desulfurization facility, and SO2 concentration of the raw flue gas at the inlet of the desulfurization facility to the distributed control system, enabling the disc dewatering machine system to adjust the frequency of the variable frequency motor in a timely manner according to the operating conditions, thereby adjusting the output of the disc dewatering machine system in a timely manner and significantly reducing the energy consumption of the disc dewatering machine system.

Description

Technical Field

[0001] This invention relates to the field of desulfurization technology, specifically to a disc dewatering machine system and its output adjustment method. Background Technology

[0002] Currently, limestone-gypsum wet flue gas desulfurization (FGD) is the mainstream desulfurization process for large-scale coal-fired power units in thermal power plants. Traditional vacuum belt dewatering machines are typically used in this process. The working principle of limestone-gypsum wet FGD is as follows: limestone powder is mixed with water to form a slurry, which reacts with sulfur dioxide to produce calcium sulfate. Once the calcium sulfate reaches a certain saturation level, it crystallizes to form calcium sulfate dihydrate. This calcium sulfate dihydrate is then desulfurized by a vacuum belt dewatering machine to produce calcium sulfate, i.e., gypsum filter cake. The vacuum belt dewatering machine mainly consists of a vacuum system, a belt conveyor system, and a filter cloth cleaning system. The working principle is as follows: under the action of a vacuum pump, a negative pressure environment is created inside the equipment. Sludge is evenly spread on the filter cloth. As the belt moves, the water in the sludge is rapidly extracted under negative pressure, forming a filter cake. The filter cake is peeled off by a scraper at the end of the belt, while the filter cloth is cleaned by the cleaning system and then re-enters the next dewatering process.

[0003] In existing limestone-gypsum wet flue gas desulfurization processes, disc dewatering machines are generally used. Compared with traditional vacuum belt dewatering machines, disc dewatering machines have advantages such as smaller footprint and faster filtration speed. For example, in terms of footprint, the disc dewatering machine occupies approximately 20% of the area of ​​a vacuum belt dewatering machine. Therefore, disc dewatering machines are widely used in the wet desulfurization gypsum dewatering process of flue gas desulfurization in thermal power plants.

[0004] The existing disc dewatering machine mainly consists of a distribution head, filter discs, a tank, and a transmission device. The distribution head is the core structure of the disc dewatering machine, primarily composed of a moving disc and a stationary disc. One side of the moving disc is connected to the connecting branch pipe of the filter disc, and the other side is connected to a vacuum pump through the functional area of ​​the stationary disc, thereby generating a vacuum that allows the desulfurized slurry in the adsorption tank of the filter disc to complete the gypsum dewatering process. The stationary disc consists of three functional areas: a slurry suction area, a drying area, and a discharge backflushing area. The moving and stationary discs of the distribution head remain tightly fitted under the elastic force of the compensation mechanism, sliding relative to each other as the main shaft rotates. This prevents leakage of the fluid medium between the slurry suction area, the drying area, the discharge backflushing area, and the atmosphere, forming relatively independent and sealed chambers. As the main shaft rotates, each hole on the moving disc and the groove on the stationary disc form a connecting channel, switching between the three processes of slurry suction, drying, and discharge backflushing.

[0005] Current disc dewatering machines have the following problems: they can only operate at the mains frequency. Under the new power system, deep peak shaving of coal-fired units has become the new normal, resulting in large load adjustments and long periods of low-load operation. The desulfurization facilities have poor flexibility; for example, disc dewatering machines can only operate at the mains frequency, and the vacuum level can only be maintained between -50 kPa and -70 kPa. Under low-load, low-sulfur conditions, the density of the desulfurization slurry remains low for extended periods. The density control range for the desulfurization slurry in the desulfurization absorption tower is 1080 kg / m³. 3 Up to 1130kg / m 3 When the density of the desulfurization slurry is not less than 1130 kg / m³ 3 At that time, the disc dewatering machine starts dewatering, and when the density of the desulfurization slurry is lower than 1080 kg / m³, the dewatering process continues. 3 At times, the disc dewatering machine is manually shut down. Therefore, under low load and low sulfur content conditions, the output of desulfurized gypsum is relatively small, and the disc dewatering machine can only be frequently started and stopped to adjust the output of the gypsum dewatering equipment. It is impossible to operate under varying conditions according to the unit load, resulting in high energy consumption of the equipment and seriously affecting the energy-saving operation of the desulfurization facility. Summary of the Invention

[0006] In view of this, the present invention provides an improved disc dewatering machine system and output adjustment method to solve the problem that under low load and low sulfur content operating conditions, the output of desulfurized gypsum is small, and the disc dewatering machine can only be frequently started and stopped to adjust the output of the gypsum dewatering equipment. It is impossible to operate under different operating conditions according to the unit load, resulting in high energy consumption of the equipment and seriously affecting the energy-saving operation of the desulfurization facility.

[0007] In a first aspect, the present invention provides a disc dehydrator system, comprising:

[0008] Multiple suction discs are suitable for filtering slurry in a slurry tank to form gypsum filter cake; A thickness gauge is positioned close to the gypsum filter cake on the suction disc; the thickness gauge is suitable for obtaining the thickness of the gypsum filter cake online in real time. The gas-water separator has its inlet connected to the suction disc via a distribution head; A vacuum pump is connected to the top outlet of the steam-water separator; A pressure transmitter is installed near the inlet of the steam-water separator; the pressure transmitter is adapted to obtain the operating pressure value at the inlet of the steam-water separator in real time, as the operating pressure value of the vacuum pump; The distributed control system is signal-connected to both the thickness gauge and the pressure transmitter. The distributed control system is connected to the vacuum pump via a variable frequency motor, which is adapted to change the output frequency to adjust the output of the vacuum pump. The distributed control system is adapted to acquire the thickness signal transmitted by the thickness gauge, the pressure signal transmitted by the pressure transmitter, the flue gas flow rate at the inlet of the desulfurization facility, and the SO2 concentration in the raw flue gas at the inlet of the desulfurization facility in real time, and to change the output frequency of the variable frequency motor as needed. Beneficial effects: This application adopts the above technical solution. First, by setting the existing industrial frequency motor connected to the vacuum pump as a variable frequency motor, the output of the disc dewatering machine system can be adjusted. Then, the thickness of the gypsum filter cake is continuously measured online using a thickness gauge. The gypsum filter cake thickness signal is transmitted to the distributed control system. The pressure signal transmitted by the pressure transmitter, the flue gas flow rate at the inlet of the desulfurization facility, and the SO2 concentration of the raw flue gas at the inlet of the desulfurization facility are also transmitted to the distributed control system. This enables the disc dewatering machine system to adjust the frequency of the variable frequency motor in a timely manner according to the operating conditions, thereby adjusting the output of the disc dewatering machine system in a timely manner, significantly reducing the energy consumption of the disc dewatering machine system, and adapting to the flexible operation and adjustment of desulfurization facilities under the new power system.

[0009] Optionally, the thickness gauge is located above the gypsum filter cake and is perpendicular to the gypsum filter cake.

[0010] Optionally, the allocation header includes: The stationary disc of the disc dewatering machine is fixed concentrically with the stationary disc fixed shaft; an annular groove is provided on the edge of the stationary disc, and the bottom surface of the annular groove is the second sealing surface; fan-shaped vacuum connection holes for the slurry suction area, fan-shaped vacuum connection holes for the drying area, and vacuum connection holes for the backflushing discharge area are arranged around the surface of the stationary disc; the stationary disc of the disc dewatering machine is connected to the inlet of the steam-water separator through vacuum pipes in the vacuum suction area and vacuum pipes on the vacuum side, respectively; The rotating disc dewatering disc is fitted to the stationary disc of the disc dewatering machine under the elastic force of the compensation mechanism. Multiple vacuum connection holes are arranged around the rotating disc near its edge. These vacuum connection holes are adapted to communicate with the fan-shaped vacuum connection holes in the suction zone via vacuum pipes in the non-vacuum side suction zone, and these pipes are also adapted to communicate with the suction disc. Furthermore, the rotating disc vacuum connection holes are adapted to communicate with the fan-shaped vacuum connection holes in the drying zone via vacuum pipes in the non-vacuum side drying zone, and also via vacuum pipes in the backflushing discharge zone. The rotating disc dewatering disc is concentrically fixed to the rotating disc fixed shaft, and slides relative to the stationary disc of the disc dewatering machine as the rotating disc fixed shaft rotates. An annular boss is provided on the edge of the rotating disc dewatering disc. The top surface of the annular boss is a first sealing surface. Simultaneously, the annular boss is fitted to the annular settling tank, and the first sealing surface is sealed to the second sealing surface.

[0011] Optionally, the portion of the rotating disc dehydration disc near its center is fixedly connected to the rotating disc fixed shaft by a plurality of first fixing bolts arranged around it; The stationary disc of the disc dewatering machine is fixedly connected to the stationary disc fixing shaft near the center by a plurality of second fixing bolts arranged around it.

[0012] Optionally, as the fixed shaft of the moving disc rotates, each vacuum connection hole of the moving disc of the disc dewatering machine is connected to the fan-shaped vacuum connection hole of the slurry suction area, the fan-shaped vacuum connection hole of the drying area, and the vacuum connection hole of the backflushing discharge area of ​​the stationary disc of the disc dewatering machine, and the process of slurry suction, drying and backflushing is completed.

[0013] Optionally, a drain port is provided at the bottom of the steam-water separator, the drain port being adapted to discharge filtrate.

[0014] Secondly, the present invention also provides a method for adjusting the output of the disc dehydrator system, comprising: The distributed control system calculates the output frequency of the variable frequency motor according to the following formula (1), and uses the output frequency to control the operation of the variable frequency motor; f = P μ (1) in, f This refers to the output frequency of the variable frequency motor, measured in Hz. P This is the operating pressure value at the inlet of the steam-water separator, in kPa. μThe calibration coefficient was determined through experiments. Beneficial effects: This application adopts the above technical solution, which monitors the operating pressure at the inlet of the steam-water separator in real time and adjusts the output frequency of the variable frequency motor accordingly. This enables the disc dewatering machine system to adjust the frequency of the variable frequency motor based on the operating conditions, thereby adjusting the output of the disc dewatering machine system in a timely manner, significantly reducing the energy consumption of the disc dewatering machine system, and adapting to the flexible operation and adjustment of desulfurization facilities under the new power system.

[0015] Thirdly, the present invention also provides a method for adjusting the output of the disc dehydrator system, comprising: The distributed control system obtains the output of gypsum filter cake according to the following formula (2). λ ; (2) in, λ The output of gypsum filter cake is expressed in t / h. M The thickness of the gypsum filter cake is expressed in cm. θ The output of gypsum filter cake from a single suction disc is given under standard gypsum filter cake thickness, expressed in t / h·disc. τ This refers to the standard thickness of the gypsum filter cake, in cm. N This refers to the number of suction discs, expressed in pieces. The distributed control system obtains the output of gypsum filter cake according to the following formula (3). λ ; (3) in, Q The flue gas flow rate at the inlet of the desulfurization facility is expressed in meters per second (m³). 3 / h; S The concentration of SO2 in the raw flue gas at the inlet of the desulfurization facility, in mg / m³. 3 η is the desulfurization efficiency, expressed as a percentage; K1 is the SO2 conversion coefficient, a constant; K2 is the gypsum purity correction coefficient, a constant. Output frequency of variable frequency motor f With the thickness of the gypsum filter cake M There exists a univariate function correspondence as shown in formula (4); (4) Where A and B are both undetermined coefficients; Formula (5) is obtained from formulas (3) and (4); the distributed control system calibrates the undetermined coefficients A and B according to the following formula (5) and field data; (5) The distributed control system then obtains the output of gypsum filter cake according to formula (3). λThe output frequency of the variable frequency motor is calculated using formula (4), and the operation of the variable frequency motor is controlled by the output frequency. Beneficial effects: This application adopts the above technical solution, and proposes a monitoring method for controlling the thickness of the gypsum filter cake and the output operation index of the disc dewatering machine system. It also proposes a calculation model for the variable frequency control of the variable frequency motor that drives the vacuum pump in the disc dewatering machine system. This realizes the function of adjusting the power of the disc dewatering machine system in a timely manner according to the unit's operating conditions, significantly reducing the energy consumption of the disc dewatering machine system and adapting to the flexible operation and adjustment of desulfurization facilities under the new power system.

[0016] Optionally, the value of K1 is 1.7; the value of K2 is 0.9.

[0017] Optionally, the distributed control system calculates the output of gypsum filter cake under different gypsum filter cake thicknesses according to formula (4), and displays the output of the gypsum filter cake in real time on the display unit of the distributed control system. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a connection diagram of the disc dehydrator system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the main structure of the stationary disc of the disc dewatering machine provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the main structure of the disc dehydration motor provided in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the stationary disc of the disc dewatering machine provided in an embodiment of the present invention. Figure 5 This is a cross-sectional view of the assembly structure of the stationary disc and the moving disc of the disc dewatering machine provided in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Rotary disc dewatering machine moving disc; 2. First sealing surface; 3. Vacuum connection hole of moving disc; 4. First fixing bolt; 5. Moving disc fixing shaft; 6. Rotary disc dewatering machine stationary disc; 7. Second sealing surface; 8. Slurry suction zone fan-shaped vacuum connection hole; 9. Drying zone fan-shaped vacuum connection hole; 10. Backflush discharge zone vacuum connection hole; 11. Second fixing bolt; 12. Stationary disc fixing shaft; 13. Distributor head; 14. Vacuum pipe of non-vacuum side slurry suction zone; 15. Vacuum side vacuum pipe; 16. Vacuum pipe of non-vacuum side drying zone; 17. Vacuum pipe of vacuum side slurry suction zone; 18. Vacuum pipe of non-vacuum side backflush discharge zone; 19. Slurry tank; 20. Slurry suction disc; 21. Thickness gauge; 22. Pressure transmitter; 23. Steam-water separator; 24. Vacuum suction port; 25. Drain port; 26. Vacuum pump; 27. Distributed control system. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Regarding the problems mentioned in the background technology, the applicant, through in-depth analysis and consideration, discovered that: the motor driving the vacuum pump of the disc dewatering machine is an industrial frequency motor, which cannot adjust the power of the disc dewatering machine according to the unit load and the actual output of gypsum. The thickness of the gypsum filter cake in the disc dewatering machine is generally controlled between 1 cm and 2 cm; when the disc dewatering machine is put into operation, the output of each absorbent disc is almost constant and directly proportional to the thickness of the gypsum filter cake, thanks to output calibration. However, in actual operation, there is a lack of means to monitor the thickness of the gypsum filter cake in the disc dewatering machine, making it impossible to effectively measure its thickness. Therefore, this application adds an online filter cake thickness tester to continuously monitor the thickness of the gypsum filter cake online, and transmits the thickness signal of the gypsum filter cake to the desulfurization dispersion control system in real time. This establishes a functional relationship between the thickness of the gypsum filter cake and the output of the disc dewatering machine, thereby controlling the output frequency of the vacuum pump motor to control the output of the disc dewatering machine in a timely manner.

[0023] like Figures 1 to 5 One specific embodiment of the disc dewatering system shown includes: multiple suction discs 20, a thickness gauge 21, a steam-water separator 23, a vacuum pump 26, a pressure transmitter 22, and a distributed control system 27. The distributed control system 27 is also referred to as a desulfurization distributed control system. The suction discs 20 are also referred to as water-absorbing discs. The thickness gauge 21 is also referred to as an online filter cake thickness tester.

[0024] like Figure 1 As shown, multiple suction discs 20 are adapted to filter the slurry in the slurry tank 19 to form a gypsum filter cake. The thickness gauge 21 is positioned close to the gypsum filter cake on the suction discs 20; the thickness gauge 21 is adapted to acquire the thickness of the gypsum filter cake online in real time. The inlet of the steam-water separator 23 is connected to the suction discs 20 via a distribution head 13. The vacuum pump 26 is connected to the top outlet of the steam-water separator 23. The top outlet is also referred to as the vacuum suction port 24. The pressure transmitter 22 is positioned close to the inlet of the steam-water separator 23; the pressure transmitter 22 is adapted to acquire the operating pressure value at the inlet of the steam-water separator 23 in real time, which serves as the operating pressure value of the vacuum pump 26. The distributed control system 27 is signal-connected to the thickness gauge 21 and the pressure transmitter 22. The distributed control system 27 is connected to the vacuum pump 26 through a variable frequency motor. The variable frequency motor is adapted to change the output frequency to adjust the output of the vacuum pump 26. The distributed control system 27 is adapted to acquire the thickness signal transmitted by the thickness gauge 21, the pressure signal transmitted by the pressure transmitter 22, the flue gas flow rate at the inlet of the desulfurization facility, and the SO2 concentration of the raw flue gas at the inlet of the desulfurization facility in real time, and change the output frequency of the variable frequency motor in a timely manner.

[0025] In one specific embodiment, the gas separated in the gas-water separator 23 is drawn away by the vacuum pump 26 through the vacuum suction port 24 at the top.

[0026] Specifically, the thickness gauge 21 is located above the gypsum filter cake, and the thickness gauge 21 is perpendicular to the gypsum filter cake.

[0027] In one specific embodiment, the thickness gauge 21 is located 5 centimeters above the gypsum filter cake.

[0028] Specifically, such as Figures 2 to 5As shown, the distribution head 13 includes: a stationary disc 6 for the disc dewatering machine and a moving disc 1 for the disc dewatering machine. The stationary disc 6 is concentrically fixed to the stationary disc fixed shaft 12; an annular groove is provided on the edge of the stationary disc 6, and the bottom surface of the annular groove is the second sealing surface 7; a fan-shaped vacuum connection hole 8 for the suction zone, a fan-shaped vacuum connection hole 9 for the drying zone, and a vacuum connection hole 10 for the backflushing discharge zone are arranged around the disc surface of the stationary disc 6; the stationary disc 6 is connected to the inlet of the steam-water separator 23 through a vacuum pipe 17 for the vacuum side suction zone and a vacuum pipe 15 for the vacuum side, respectively. The rotating disc dewatering disc 1 is kept in close contact with the stationary disc 6 of the rotating disc dewatering machine under the elastic force of the compensation mechanism; a plurality of rotating disc vacuum connection holes 3 are arranged around the edge of the rotating disc dewatering disc 1; the rotating disc vacuum connection holes 3 are adapted to communicate with the fan-shaped vacuum connection holes 8 of the suction zone through the vacuum pipe 14 of the non-vacuum side suction zone, and the vacuum pipe 14 of the non-vacuum side suction zone is connected to the suction disc 20; the rotating disc vacuum connection holes 3 are adapted to communicate with the fan-shaped vacuum connection holes 9 of the drying zone through the vacuum pipe 16 of the non-vacuum side drying zone. The moving disc vacuum connection hole 3 is adapted to communicate with the backflushing unloading zone vacuum connection hole 10 through the vacuum pipe 18 of the non-vacuum side backflushing unloading zone; the disc dewatering moving disc 1 is concentrically fixed with the moving disc fixed shaft 5, and the disc dewatering moving disc 1 slides relative to the disc dewatering machine stationary disc 6 as the moving disc fixed shaft 5 rotates; an annular boss is provided on the edge of the disc dewatering moving disc 1; the top surface of the annular boss is the first sealing surface 2; while the annular boss is fitted with the annular sink, the first sealing surface 2 is sealed with the second sealing surface 7.

[0029] In one specific implementation, the number of vacuum connection holes 3 on the moving disk can be twelve, evenly distributed around the disk.

[0030] Specifically, such as Figures 2 to 4 As shown, the moving disc 1 of the disc dehydrator is fixedly connected to the moving disc fixed shaft 5 near its center by a plurality of first fixing bolts 4 arranged around it. The stationary disc 6 of the disc dehydrator is fixedly connected to the stationary disc fixed shaft 12 near its center by a plurality of second fixing bolts 11 arranged around it.

[0031] In one specific embodiment, the number of the first fixing bolts 4 can be six, evenly distributed around the perimeter.

[0032] In one specific embodiment, the number of the second fixing bolts 11 can be six, evenly distributed around the perimeter.

[0033] Specifically, as the fixed shaft 5 of the moving disc rotates, each vacuum connection hole 3 of the moving disc 1 of the disc dewatering machine is connected to the fan-shaped vacuum connection hole 8 of the slurry suction area, the fan-shaped vacuum connection hole 9 of the drying area, and the vacuum connection hole 10 of the backflushing discharge area of ​​the stationary disc 6 of the disc dewatering machine, and the process of slurry suction, drying and backflushing is completed.

[0034] Specifically, such as Figure 1 As shown, a drain port 25 is provided at the bottom of the steam-water separator 23, and the drain port 25 is suitable for discharging filtrate.

[0035] In one specific embodiment, the filtrate separated in the steam-water separator 23 is discharged into the filtrate receiving tank through the drain port 25 at the bottom.

[0036] This application also proposes a method for adjusting the output of the disc dehydrator system, including the following steps: The distributed control system 27 calculates the output frequency of the variable frequency motor according to the following formula (1), and uses the output frequency to control the operation of the variable frequency motor; f = P μ (1) in, f This refers to the output frequency of the variable frequency motor, measured in Hz. P This is the operating pressure value at the inlet of steam-water separator 23, in kPa; μ The calibration coefficient was determined through testing. The operating pressure at the inlet of steam-water separator 23 is the operating pressure of the slurry suction zone and drying zone of the disc dewatering machine system.

[0037] This application also proposes a method for adjusting the output of the disc dehydrator system, including: S1, Distributed control system 27 obtains the output of gypsum filter cake according to the following formula (2). λ ; (2) in, λ The output of gypsum filter cake is expressed in t / h. M The thickness of the gypsum filter cake is expressed in cm. θ The output of gypsum filter cake from a single 20mm suction disc is given under standard gypsum filter cake thickness, expressed in t / h·disc. τ This refers to the standard thickness of the gypsum filter cake, in cm. N This refers to the quantity of suction discs 20, expressed in pieces.

[0038] In one specific embodiment, the standard thickness of the gypsum filter cake τ It can be taken as 2cm.

[0039] In one specific embodiment, the number N of the suction discs 20 can be 12.

[0040] S2, Distributed control system 27 obtains the output of gypsum filter cake according to the following formula (3). λ ; (3) in, Q The flue gas flow rate at the inlet of the desulfurization facility is expressed in meters per second (m³). 3 / h; S The concentration of SO2 in the raw flue gas at the inlet of the desulfurization facility, in mg / m³. 3 η represents the desulfurization efficiency as a percentage; K1 is the SO2 conversion coefficient, a constant; K2 is the gypsum purity correction coefficient, a constant. The flue gas flow rate at the inlet of the desulfurization facility is the flow rate value measured under the conditions of a baseline oxygen content of 6%, a temperature of 25°C, an atmospheric pressure of 101 kPa, and without moisture. The SO2 concentration in the raw flue gas at the inlet of the desulfurization facility is the concentration value measured under the conditions of a baseline oxygen content of 6%, a temperature of 25°C, an atmospheric pressure of 101 kPa, and without moisture.

[0041] Output frequency of variable frequency motor f With the thickness of the gypsum filter cake M There exists a univariate function correspondence as shown in formula (4); (4) Where A and B are both undetermined coefficients; S3. Formula (5) is obtained from formula (3) and formula (4); the distributed control system 27 calibrates the undetermined coefficients A and B according to the following formula (5) and field data; (5) It can be seen from the above formula (5) Q S η It is directly proportional to M. When the flue gas flow rate at the inlet of the desulfurization facility... Q The concentration of SO2 in the flue gas at the inlet of the desulfurization facility S and desulfurization efficiency η When the thickness changes, the distributed control system 27 automatically calculates the thickness of the gypsum filter cake. M and the output of gypsum filter cake λ And automatically change the frequency of the variable frequency motor f By matching the optimal frequency, the output of the variable frequency motor that drives the vacuum pump 26 can be adjusted in a timely manner.

[0042] S4, Distributed control system 27 then obtains the output of gypsum filter cake according to formula (3). λ The output frequency of the variable frequency motor is calculated using formula (4), and the output frequency is used to control the operation of the variable frequency motor.

[0043] Specifically, the value of K1 can be 1.7; the value of K2 can be 0.9.

[0044] Specifically, the distributed control system 27 calculates the output of gypsum filter cake under different gypsum filter cake thicknesses according to formula (4), and displays the output of the gypsum filter cake in real time on the display unit of the distributed control system 27.

[0045] This application replaces the existing power frequency motor that drives the vacuum pump in the disc dewatering machine with a variable frequency motor. It proposes a monitoring method to control the thickness of the gypsum filter cake and the output performance of the disc dewatering machine system. It also proposes a calculation model for the variable frequency control of the variable frequency motor that drives the vacuum pump 26 in the disc dewatering machine system. This enables the disc dewatering machine system to adjust its power in a timely manner according to the unit's operating conditions, significantly reducing the energy consumption of the disc dewatering machine system and adapting to the flexible operation and adjustment of desulfurization facilities under the new power system.

[0046] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by this application.

Claims

1. A disc dehydrator system, characterized in that, include: Multiple suction discs (20) are suitable for filtering slurry in slurry tank (19) to form gypsum filter cake; A thickness gauge (21) is positioned close to the gypsum filter cake of the suction disc (20); the thickness gauge (21) is adapted to obtain the thickness of the gypsum filter cake online in real time; The inlet of the steam-water separator (23) is connected to the suction disc (20) via a distribution head (13); A vacuum pump (26) is connected to the top outlet of the steam-water separator (23); A pressure transmitter (22) is installed near the inlet of the steam-water separator (23); the pressure transmitter (22) is adapted to obtain the operating pressure value at the inlet of the steam-water separator (23) in real time, as the operating pressure value of the vacuum pump (26); The distributed control system (27) is connected to the thickness gauge (21) and the pressure transmitter (22) via signals. The distributed control system (27) is connected to the vacuum pump (26) via a variable frequency motor. The variable frequency motor is adapted to change the output frequency to adjust the output of the vacuum pump (26). The distributed control system (27) is adapted to acquire the thickness signal transmitted by the thickness gauge (21), the pressure signal transmitted by the pressure transmitter (22), the flue gas flow rate at the inlet of the desulfurization facility, and the SO2 concentration of the raw flue gas at the inlet of the desulfurization facility in real time, and change the output frequency of the variable frequency motor in a timely manner.

2. The disc dewatering machine system according to claim 1, characterized in that, The thickness gauge (21) is located above the gypsum filter cake and is perpendicular to the gypsum filter cake.

3. The disc dehydrator system according to claim 1, characterized in that, The distribution head (13) includes: The stationary disc (6) of the disc dewatering machine is fixed concentrically with the stationary disc fixed shaft (12); an annular groove is provided on the edge of the stationary disc (6) of the disc dewatering machine, and the bottom surface of the annular groove is the second sealing surface (7); a fan-shaped vacuum connection hole (8) for the slurry suction area, a fan-shaped vacuum connection hole (9) for the drying area, and a vacuum connection hole (10) for the backflushing discharge area are provided around the disc surface of the stationary disc (6) of the disc dewatering machine; the stationary disc (6) of the disc dewatering machine is connected to the inlet of the steam-water separator (23) through the vacuum pipe (17) of the vacuum side slurry suction area and the vacuum pipe (15) of the vacuum side respectively; The rotating disc dewatering disc (1) is fitted to the stationary disc (6) of the disc dewatering machine under the elastic force of the compensation mechanism; multiple rotating disc vacuum connection holes (3) are arranged around the edge of the rotating disc dewatering disc (1); the rotating disc vacuum connection holes (3) are adapted to communicate with the fan-shaped vacuum connection holes (8) of the suction zone through the vacuum pipe (14) of the non-vacuum side suction zone, and the vacuum pipe (14) of the non-vacuum side suction zone is connected to the suction disc (20); the rotating disc vacuum connection holes (3) are adapted to communicate with the fan-shaped vacuum connection holes (9) of the drying zone through the vacuum pipe (16) of the non-vacuum side drying zone. The vacuum connection hole (3) of the moving disc is adapted to be connected to the vacuum connection hole (10) of the backflushing unloading area through the vacuum pipe (18) of the non-vacuum side backflushing unloading area; the moving disc dewatering motor disc (1) is concentrically fixed with the moving disc fixed shaft (5), and the moving disc dewatering motor disc (1) slides relative to the stationary disc (6) of the moving disc dewatering machine as the moving disc fixed shaft (5) rotates; an annular boss is provided on the edge of the moving disc dewatering motor disc (1); the top surface of the annular boss is the first sealing surface (2); while the annular boss is fitted with the annular sink, the first sealing surface (2) is sealed and fitted with the second sealing surface (7).

4. The disc dewatering machine system according to claim 3, characterized in that, The portion of the rotary dehydration motor disc (1) near the center is fixedly connected to the motor disc fixing shaft (5) by a plurality of first fixing bolts (4) arranged around it; The stationary disc (6) of the disc dehydrator is fixedly connected to the stationary disc fixing shaft (12) near the center by a plurality of second fixing bolts (11) arranged around it.

5. The disc dewatering machine system according to claim 3, characterized in that, As the fixed shaft (5) of the moving disc rotates, each moving disc vacuum connection hole (3) of the moving disc of the disc dewatering machine (1) is connected to the fan-shaped vacuum connection hole (8) of the slurry suction area, the fan-shaped vacuum connection hole (9) of the drying area, and the vacuum connection hole (10) of the backflushing discharge area of ​​the stationary disc (6) of the disc dewatering machine, and the process of slurry suction, drying and backflushing is completed.

6. The disc dewatering machine system according to any one of claims 1-5, characterized in that, A drain port (25) is provided at the bottom of the steam-water separator (23), which is suitable for discharging filtrate.

7. A method for adjusting the output of a disc dewatering machine system according to any one of claims 1-6, characterized in that, include: The distributed control system (27) calculates the output frequency of the variable frequency motor according to the following formula (1) and uses the output frequency to control the operation of the variable frequency motor; f = P μ （1） in, f This refers to the output frequency of the variable frequency motor, measured in Hz. P The operating pressure at the inlet of the steam-water separator (23) is in kPa. μ The calibration coefficients are determined through experiments.

8. A method for adjusting the output of a disc dewatering machine system according to any one of claims 1-6, characterized in that, include: The distributed control system (27) obtains the output of gypsum filter cake according to the following formula (2). λ ; （2） in, λ The output of gypsum filter cake is expressed in t / h. M The thickness of the gypsum filter cake is expressed in cm. θ The output of gypsum filter cake from a single suction disc (20) is t / h·piece, given the standard gypsum filter cake thickness. τ This refers to the standard thickness of the gypsum filter cake, in cm. N The number of suction discs (20), in units of pieces; The distributed control system (27) obtains the output of gypsum filter cake according to the following formula (3). λ ; （3） in, Q The flue gas flow rate at the inlet of the desulfurization facility is expressed in meters per second (m³). 3 / h; S The concentration of SO2 in the raw flue gas at the inlet of the desulfurization facility, in mg / m³. 3 η is the desulfurization efficiency, expressed as a percentage; K1 is the SO2 conversion coefficient, a constant; K2 is the gypsum purity correction coefficient, a constant. Output frequency of variable frequency motor f With the thickness of the gypsum filter cake M There exists a univariate function correspondence as shown in formula (4); （4） Where A and B are both undetermined coefficients; Formula (5) is obtained from formulas (3) and (4); the distributed control system (27) calibrates the undetermined coefficients A and B according to the following formula (5) and field data; （5） The distributed control system (27) then obtains the output of gypsum filter cake according to formula (3). λ The output frequency of the variable frequency motor is calculated using formula (4), and the output frequency is used to control the operation of the variable frequency motor.

9. The output adjustment method of the disc dewatering machine system according to claim 8, characterized in that, The value of K1 is 1.7; the value of K2 is 0.

9.

10. The output adjustment method of the disc dewatering machine system according to claim 8, characterized in that, The distributed control system (27) calculates the output of gypsum filter cake under different gypsum filter cake thicknesses according to formula (4), and displays the output of the gypsum filter cake in real time on the display unit of the distributed control system (27).

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