A flour making system and method

Abstract

The present invention relates to a pulverizing system and method. The system is mounted in a boiler system and comprises: an air-powder-homogenizing coal mill, which is connected to the boiler system through a plurality of coal-powder pipelines; a coal-powder concentration regulating valve, a coal-powder flow regulating valve, a coal-powder concentration detection sensor and a coal-powder flow detection device are sequentially installed on each coal-powder pipeline from the end close to the air-powder-homogenizing coal mill to the end of the boiler system; an industrial computer is equipped with a control system, which is connected to the air-powder-homogenizing coal mill, the coal-powder concentration regulating valve, the coal-powder flow regulating valve, the coal-powder concentration detection sensor, the coal-powder flow detection device, and the furnace flame detection sensor, the flue gas fly ash carbon content detection sensor, and the flue gas NO detection sensor in the boiler system. X The detection sensor is electrically connected to the flue gas CO detection sensor. By comparing the target values ​​of the industrial computer, combined with the coal powder concentration, flow detection signals and coal quality conditions on each coal powder pipeline, instructions are issued to each actuator, reducing the air-powder deviation in each coal powder pipeline and achieving refined control.

Description

Technical Field

[0001] The present invention relates to the technical field of flour milling equipment, and more particularly to a flour milling system and method. Background Art

[0002] The coal mill and several coal powder pipelines connected to it constitute the pulverizing system, which is responsible for grinding the raw coal into coal powder of qualified fineness and transporting it to the boiler for combustion. The primary air and raw coal enter the coal mill at the same time. The primary air carries the ground coal powder in the coal mill into the coal powder separator. After the coarse and fine powder are separated, the primary air continues to carry the coal powder into the coal powder pipeline until it enters the boiler. In order to improve the combustion efficiency of the boiler and the safety of boiler operation, the coal powder fineness, coal powder concentration and coal powder flow rate in each coal powder pipeline are required to be as consistent as possible.

[0003] After a lot of experiments and research, the inventor found that the deviation of air-powder in the existing pulverizing system coal pipeline is very large, among which the deviation of coal quantity, coal fineness and coal concentration are very large, and the deviation of more than ±30% is very common, and some even exceed ±50%. Boiler coking, pipe burst, uneven temperature field, high carbon content in fly ash, and large NOx generation are all directly related to the air-powder deviation, so the homogenization of air-powder in the pulverizing system is crucial to improving the economy and safety of boiler operation.

[0004] At present, the pulverizing system is generally an extensive pulverizing system, which can only control the total output of each coal mill, the total amount of primary air, the overall control of coal powder fineness, and the overall control of coal powder uniformity, but cannot achieve fine control of the state of the air-powder mixture in each coal powder pipeline.

[0005] After a lot of experiments and studies, the inventor found that the reason why the state of the air-powder mixture cannot be finely controlled is that the coal mill failed to fully homogenize the air-powder mixture. The traditional coal mill only focuses on the ability to grind raw coal into coal powder, and there is no design structure for homogenizing the air-powder mixture. In particular, the medium-speed coal mill itself has a structure that causes serious unevenness of the air-powder. Therefore, when the air-powder mixture reaches the outlet of the coal mill, there are large deviations in both the coal powder concentration and the coal powder fineness. On the other hand, the coal powder pipeline can only control the primary air flow rate through the adjustable shrinkage hole. Even if the real-time detection of the coal powder concentration is achieved, the study found that the coal powder concentration has deviations, and there is no way to adjust the concentration of the coal powder. A large amount of experimental data shows that the deviation of the air powder in the coal powder pipeline of the existing pulverizing system is very large, among which the deviation of the coal powder amount, the deviation of the coal powder fineness, and the deviation of the coal powder concentration are all very large. The deviation of more than ±30% is very common, and some even exceed ±50%. Boiler coking, tube burst, uneven temperature field, high carbon content in fly ash, and large NOx generation are all directly related to air-powder deviation, so fine control of the air-powder mixture state is crucial to improving the economy and safety of boiler operation.

[0006] Therefore, how to provide a powder making system to achieve fine control of the state of the air-powder mixture is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] To this end, an object of the present invention is to propose a pulverizing system to solve the problem that the state of the air-powder mixture cannot be finely controlled in the prior art, resulting in large deviations of the air-powder in each coal powder pipeline, which in turn leads to poor economy and safety of boiler operation.

[0008] The present invention provides a powder making system, which is mounted in a boiler system and comprises:

[0009] Air-powder homogenizing coal mill, which is connected to the boiler system through multiple coal powder pipelines; each coal powder pipeline is sequentially installed with a coal powder concentration regulating valve, a coal powder flow regulating valve, a coal powder concentration detection sensor and a coal powder flow detection device from the end close to the air-powder homogenizing coal mill to the end of the boiler system;

[0010] And the industrial computer, which is equipped with a control system, which is connected with the air-powder homogenizing pulverizer, the pulverized coal concentration regulating valve, the pulverized coal flow regulating valve, the pulverized coal concentration detection sensor, the pulverized coal flow detection device, and the furnace flame detection sensor, flue gas fly ash carbon content detection sensor, flue gas NO X The detection sensor is electrically connected to the flue gas CO detection sensor.

[0011] It can be seen from the above technical solutions that compared with the prior art, the present invention discloses a pulverizing system, which can obtain the flame combustion conditions, flue gas fly ash carbon content, NO X and CO content information; and compared with the target value in the control system, combined with the coal powder concentration detection and coal powder flow detection signals on each coal powder pipeline and the coal quality conditions, a command is issued to the air-powder homogenizing pulverizer to control the fineness of the coal powder. At the same time, a command is issued to the coal powder concentration regulating valve and the coal powder flow regulating valve to adjust the air-powder state in each coal powder pipeline. Through multiple detection, comparison and adjustment, a closed-loop control is formed, so that the boiler system tends to the optimal combustion state; thereby reducing the air-powder deviation in each coal powder pipeline, achieving refined control, and ensuring the economy and safety of boiler operation.

[0012] Furthermore, the air-powder homogenizing coal mill comprises:

[0013] A coal mill housing, a discharge port is provided on the top of the coal mill housing, one end of the coal powder pipeline is connected to the discharge port, and a primary air duct connected to the discharge port is provided on the bottom side wall of the coal mill housing;

[0014] A material powder conveying assembly, which passes through the center of the top of the coal mill housing and is inserted into the coal mill housing, and is communicated with the interior of the coal mill housing;

[0015] A powder grinding assembly, which is rotatably connected to the bottom of the coal mill housing and is arranged opposite to the powder conveying assembly;

[0016] The powder homogenizing assembly includes a driving mechanism and a homogenizing rotor. The driving mechanism is arranged on the top of the coal mill housing. The homogenizing rotor is arranged in the coal mill housing and arranged opposite to the powder grinding assembly. The driving mechanism drives the homogenizing rotor to rotate and sleeve on the powder conveying assembly. The bottom and side wall of the homogenizing rotor are respectively formed with an air inlet and an air outlet. The driving mechanism is electrically connected to the industrial control machine.

[0017] And a central air inlet component, one end of which is connected to the primary air duct, and the other end is an air outlet end, which is bent and inserted into the coal mill housing and connected to the powder conveying component.

[0018] Thus, by utilizing the powder grinding assembly arranged opposite to the powder conveying assembly, the powder can be fully ground and the powder particle size can be reduced; by utilizing the central air inlet assembly, a portion of the primary air can be directly fed into the powder conveying assembly, and a portion of the primary air can be blown to the center of the powder grinding assembly through the powder conveying assembly, thereby improving the uneven primary air entering the mill and weakening the uneven wind-powder problem caused by the uneven primary air entering the mill; by utilizing the homogenizing rotor, the wind-powder mixture in the coal mill housing can be homogenized, and the homogenized wind-powder mixture can be fed into the annular area between the homogenizing rotor and the coal mill housing, and the wind-powder mixture can be further homogenized, so that the wind-powder mixture can achieve the effect of being fully mixed and homogenized. The coal mill with the wind-powder homogenization function of the present invention has a reasonable structural design, can perform coarse and fine separation of coal powder, and can also perform homogenization on the wind-powder mixture, and has a good wind-powder homogenization effect, effectively reducing the wind-powder deviation in the coal powder pipeline, improving the combustion efficiency and operation safety of the boiler, and has a good application prospect.

[0019] Furthermore, the central air inlet assembly includes an air inlet pipe, an air sleeve and a regulating valve. One end of the air inlet pipe is connected to the primary air pipe, and the other end is connected to the side wall of the air sleeve to form an integral body. The air sleeve and one end of the air inlet pipe are bent and inserted into the coal mill housing, and the air sleeve is sleeved and fixed to the lower end of the material powder conveying assembly. The regulating valve is arranged on the air inlet pipe, and the regulating valve is electrically connected to the industrial control machine. Thus, the air inlet pipe can be used to allow part of the primary air to directly enter the center of the coal mill, and part of the primary air can be blown to the center of the material powder grinding assembly through the air sleeve, thereby improving the uneven condition of primary air entering the mill and weakening the uneven wind and powder problem caused by the uneven primary air entering the mill. The regulating valve can be used to adjust the ventilation volume according to the actual operating conditions.

[0020] Furthermore, the homogenizing rotor includes a central tube, a cone, blades, a bottom ring and a choke, and a driving mechanism drives the central tube to rotate and be sleeved on the powder conveying assembly; the cone includes an upper plate and a lower plate, the upper plate is a circular table with a hole in the middle, and the lower plate is an inverted circular table with a hole in the middle, and the edges of the upper plate and the lower plate on one side opposite to each other are fixedly connected, and the upper plate and the lower plate are both fixedly sleeved on the outside of the central tube; there are multiple blades, and the multiple blades are evenly arranged on the same circumferential surface along the side wall of the central tube, and the tops of the multiple blades are fixedly connected to the bottom end surface of the lower plate, the bottom ring is fixed to the outside of the lower ends of the multiple blades, and an air inlet is formed in the middle of the bottom ring, and multiple air outlets are formed between the multiple blades, the lower plate and the bottom ring, and the choke is fixed at the air outlet to change the air outlet direction and air outlet area.

[0021] When the homogenizing rotor rotates at a constant speed, the air-powder mixture will be driven by the homogenizing rotor and sucked into the small chamber formed by multiple blades through the air inlet at the bottom, and rotate with the small chamber. At the same time, the air-powder mixture will also move from bottom to top and from inside to outside, and be discharged through the side air outlet. The setting of the wind baffle can further change the outlet structure and size of the air outlet, so that the movement state of the air-powder mixture when discharged from the small chamber is different, so as to achieve the effect of sufficient mixing and homogenization.

[0022] Furthermore, the wind blocking blocks are fixedly filled at intervals at the inner upper end of the air outlet and are fixedly connected to the lower plate and the blades on both sides, and the area difference between any two adjacent air outlets is 10% to 25%;

[0023] Or the air outlets are divided into ~ groups, each group of air outlets includes multiple adjacent air outlets, and each group of air outlets is fixedly filled with wind blocks at the inner upper end in turn, the wind blocks are fixedly connected to the lower plate and the blades on both sides, the height of each group of air outlets increases gradually and the area difference between any two adjacent air outlets is 10% to 25%.

[0024] The first solution is to adjust the size of the air outlet by setting a wind blocking block, so that the air outlet area of ​​adjacent air outlets can be changed, so that the movement state of the air-powder mixture when discharged from the small chamber is different, so as to achieve the effect of sufficient mixing and homogenization.

[0025] Specifically,

[0026]

[0027] By adopting the second scheme, the stability of the rotation of the homogenizing rotor is ensured through regular structural adjustment of the homogenizing rotor. The gradually increasing height of the air outlet makes the air outlet area of ​​each air outlet in each group of air outlets different, but the total air outlet area between groups is the same, thereby forming a relatively stable wind-dust mixing vortex zone, so that the wind-powder mixture can be better mixed and homogenized.

[0028] Furthermore, the homogenizing rotor also includes a plurality of blade wings, and the blade wings are asymmetrical and fixed on the outside of the wind block on different circumferences. The blade wings can further disturb the annular airflow area formed between the homogenizing rotor and the coal mill housing outside the air outlet, thereby further improving the wind and powder homogenization effect in the annular area.

[0029] Furthermore, each pulverized coal concentration regulating valve comprises:

[0030] The shell is vertically fixed between the air-powder homogenizing pulverizer and the pulverized coal pipeline, with an air-powder mixture inlet formed at its bottom and an air-powder mixture outlet formed at its top, and a pulverized coal concentration regulating chamber formed between the air-powder mixture inlet and the air-powder mixture outlet;

[0031] A driving part, the side wall of the housing is connected with the driving part, and the driving part is electrically connected to the industrial control machine;

[0032] The shaft and the side wall of the housing are provided with a bearing seat in a direction perpendicular to the driving part; one end of the shaft is driven by the driving part to rotate in the bearing seat;

[0033] And valve plates, two groups of valve plates are installed on the shaft, and the two groups of valve plates can be opened and closed in the coal powder concentration regulating chamber to form a cut-off area to change the cut-off area in the coal powder concentration regulating chamber.

[0034] The drive shaft rotates through the drive unit, driving the two valve plates to open and close to form a cutoff area in the coal powder concentration regulating chamber, so as to change the cutoff area in the coal powder concentration regulating chamber, thereby changing the coal powder concentration in the coal powder pipeline.

[0035] Furthermore, the driving part includes: a driving motor, a screw, a driving frame and a driving gear; the driving motor is fixed to the side of the shell through a bracket; its output end is connected to the screw; the driving frame is a rectangular frame structure, and two sets of racks are staggered on the two inner walls opposite to each other in the vertical direction, and the two sets of driving gears are respectively meshed and driven with the two sets of racks; the two sets of driving gears are connected to one end of the shaft; a threaded hole is provided at the bottom of the driving frame, and the screw cooperates with the thread in the threaded hole for transmission, wherein the driving motor is electrically connected to the industrial control machine; the shaft includes a first shaft rod and a second shaft rod, one end of the first shaft rod is formed as a whole with the first valve plate, the second shaft rod is in the shape of a shaft sleeve, which is hinged to the other end of the first shaft rod, the other end of the first shaft rod is connected with the first driving gear, the second shaft rod is formed as a whole with the second valve plate, and its end is connected with the second driving gear; the first driving gear and the second driving gear are respectively meshed with a set of racks, so as to drive the first valve plate and the second valve plate to open and close through the first shaft rod and the second shaft rod to change the size of the interception area; the first valve plate and the second valve plate are of the same length, and an isosceles triangle is formed in the open state with the shaft as the center.

[0036] As a result, the drive motor drives the screw to rotate, and the screw drives the drive frame to move up and down in a straight line. When the drive frame moves downward, the rack engages with the drive gear, driving the drive gear to rotate. The two sets of drive gears rotate in opposite directions, one rotates clockwise and the other rotates counterclockwise, thereby driving the two sets of valve plates to rotate in opposite directions, and the flow cross-sectional area in the shell changes accordingly.

[0037] Furthermore, the outer walls of the first driving gear and the second driving gear both include a cylindrical section and a toothed section, the root circles of the cylindrical section and the toothed section coincide, and the cylindrical section accounts for 50%-55% of the circumference of the root circle of the toothed section; the width of each set of racks is half the width of the inner wall of the frame of the driving frame. This is used to adjust the matching clearance between the driving gear and the rack; the cylindrical section of the driving gear contacts the frame without the rack, which can ensure the matching clearance between the rack and the driving gear, prevent the clearance from being too large, and cause the valve plate connected to the driving gear to vibrate, thereby reducing the vibration frequency of the valve plate, ensuring its normal operation, and thus extending its service life.

[0038] Another object of the present invention is to provide a powder making method based on the above powder making system, wherein the control system carried by the industrial computer receives the feedback from the boiler system on the flame combustion status in the furnace, the carbon content of the flue gas fly ash, and the NO X and CO content information; and compared with the target value in the control system, combined with the coal powder concentration detection and coal powder flow detection signals on each coal powder pipeline and the coal quality, issued instructions to the air-powder homogenizing mill to control the fineness of the coal powder, and issued instructions to the coal powder concentration regulating valve and coal powder flow regulating valve to adjust the air-powder state in each coal powder pipeline. Through multiple detections, comparisons and adjustments, a closed-loop control is formed to make the boiler system tend to the optimal combustion state. As a result, the air-powder deviation in each coal powder pipeline is reduced, and refined control is achieved, ensuring the economy and safety of boiler operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0040] Figure 1 The accompanying drawing is a schematic structural diagram of a flour making system provided by the present invention;

[0041] Figure 2 The attached figure is a schematic diagram of the structure of a coal mill with air-powder homogenization;

[0042] Figure 3 The accompanying drawing is a flow trajectory diagram of the internal airflow of the air-powder homogenizing coal mill provided by the present invention;

[0043] Figure 4 The attached figure is a schematic diagram of the structure of the central air inlet assembly;

[0044] Figure 5 The attached figure is a cross-sectional view of the homogenizing rotor (with the wind block and blade wings removed);

[0045] Figure 6 The accompanying drawing is a front view of the homogenizing rotor in the structural form of the first embodiment;

[0046] Figure 7 The attached picture is Figure 6 A perspective view of the accompanying drawings;

[0047] Figure 8 The attached picture is Figure 6 A bottom view of the accompanying drawing;

[0048] Fig. 9 The accompanying drawing is a front view of the homogenizing rotor in the second embodiment structure;

[0049] Fig.10 The attached picture is Fig. 9 A perspective view of the accompanying drawings;

[0050] Fig.11 The attached picture is Fig. 9 A bottom view of the accompanying drawing;

[0051] Fig.12 The accompanying drawing is a front view of the homogenizing rotor in the third embodiment structure;

[0052] Fig.13 The attached picture is Fig.12 A perspective view of the accompanying drawings;

[0053] Fig.14 The attached picture is Fig.12 A bottom view of the accompanying drawing;

[0054] Fig.15 The accompanying drawing is a side view of the pulverized coal concentration regulating valve;

[0055] Fig.16 The attached figure is Fig.15 AA cross-section diagram;

[0056] Fig.17 The attached figure is Fig.16 BB cross-section diagram;

[0057] Fig.18 The accompanying drawing shows a schematic diagram of the connection relationship between the shaft, valve plate, drive gear, rack and drive frame;

[0058] Fig.19The accompanying drawing shows a schematic diagram of the connection relationship between the first shaft rod, the second shaft rod, the first valve plate, the second valve plate, the first driving gear and the second driving gear;

[0059] Fig. 20 The attached figure is a schematic diagram of the working state of the pulverized coal concentration regulating valve in the open state (i.e., a schematic diagram of the principle);

[0060] In the figure: 10- boiler system, 11- flame detection sensor, 12- flue gas fly ash carbon content detection sensor, 13- flue gas NO X Detection sensor, 14-flue gas CO detection sensor, 20-air powder homogenization coal mill, 21-coal mill housing, 211-discharge port, 22-primary air duct, 23-powder conveying assembly, 24-powder grinding assembly, 241-grinding disc mechanism, 242-grinding roller mechanism, 243-spring loading mechanism, 25-powder homogenization assembly, 251-driving mechanism, 252-homogenizing rotor, 2521-air inlet, 2522-air outlet, 2523-center tube, 2524-cone, 25241-upper plate, 25242-lower plate, 2525-blade, 2526-bottom ring, 2527-wind block, 25271-A block, 25272-B block, 25273-C block, 252 8-blade wing, 26-central air inlet assembly, 261-air inlet pipe, 262-air sleeve, 263-regulating valve, 264-wear-resistant guard plate, 30-coal powder concentration regulating valve, 31-housing, 311-bearing seat, 32-driving unit, 321-driving motor, 322-screw, 323-driving frame, 324-driving gear, 3241-first driving gear, 3242-second driving gear, 325-rack, 33-shaft, 331-first shaft rod, 332-second shaft rod, 34-valve plate, 341-first valve plate, 342-second valve plate, 40-coal powder flow regulating valve, 50-coal powder concentration detection sensor, 60-coal powder flow detection device, 70-industrial computer, L-coal powder pipeline. DETAILED DESCRIPTION

[0061] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0062] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0064] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0066] See attached Figure 1 The present invention provides a powder making system, which is mounted in a boiler system 10, and includes:

[0067] The air-powder-homogenizing coal mill 20 is connected to the boiler system 10 through a plurality of coal powder pipelines L; each coal powder pipeline L is sequentially installed with a coal powder concentration regulating valve 30, a coal powder flow regulating valve 40, a coal powder concentration detection sensor 50 and a coal powder flow detection device 60 from the end close to the air-powder-homogenizing coal mill 20 to the end of the boiler system 10;

[0068] and an industrial computer 70, which is equipped with a control system, which is connected with the air-powder homogenizing pulverizer 20, the pulverized coal concentration regulating valve 30, the pulverized coal flow regulating valve 40, the pulverized coal concentration detection sensor 50, the pulverized coal flow detection device 60, and the furnace flame detection sensor 11, the flue gas fly ash carbon content detection sensor 12, and the flue gas NO X The detection sensor 13 and the flue gas CO detection sensor 14 are electrically connected.

[0069] The present invention discloses a pulverizing system, which obtains the flame combustion status, flue gas fly ash carbon content, NO X and CO content information; and compared with the target value in the control system, combined with the coal powder concentration detection and coal powder flow detection signals on each coal powder pipeline and the coal quality conditions, a command is issued to the air-powder homogenizing pulverizer to control the fineness of the coal powder. At the same time, a command is issued to the coal powder concentration regulating valve and the coal powder flow regulating valve to adjust the air-powder state in each coal powder pipeline. Through multiple detection, comparison and adjustment, a closed-loop control is formed, so that the boiler system tends to the optimal combustion state; thereby reducing the air-powder deviation in each coal powder pipeline, achieving refined control, and ensuring the economy and safety of boiler operation.

[0070] Among them, the control system carried by the industrial computer can adopt the YF-20 powder making control system; the various detection elements in the boiler system are devices equipped in the existing boiler system, the flame detection sensor in the furnace can adopt any one of the ultraviolet flame detector, visible light flame detector or infrared flame detector, the flue gas fly ash carbon content detection sensor can adopt the FAD-300 type, the flue gas NO X The detection sensor may adopt any existing model, and the flue gas CO detection sensor may adopt the COM-200 model.

[0071] The pulverized coal flow regulating valve adopts a pulverized coal pipeline resistance regulating device in patent document 20182042736.1. The pulverized coal pipeline resistance regulating device can make real-time adjustments according to the resistance conditions in the pulverized coal pipeline to ensure that the resistance deviation in each pulverized coal pipeline is within the allowable range, thereby adjusting the pulverized coal flow in each pulverized coal pipeline. The industrial computer is electrically connected to its electric actuator.

[0072] The coal powder concentration detection sensor can use the DKND-B type coal powder concentration velocity online monitoring. The detection process is: install three sensor probes on the cross section of the primary air powder pipeline, and the part of the probe inserted into the pipeline forms a 120-degree angle distribution. The probe in the pipeline is insulated from the pipeline wall. When the charged coal powder flows through the probe, the sensor will be able to effectively receive the charge migration signal in the area near the probe, and the processed signal can reflect the size of the coal powder concentration. The probe of the coal powder concentration detection sensor is made of a special material with high wear resistance, high charge induction sensitivity, and a very long service life. The sensor is also equipped with a sealed waterproof shell and a cable connector to ensure the stability of the sensor. The coal powder concentration detection sensor is distributed at 120 degrees to ensure that the detection can cover the entire pipeline section to reduce the impact of unstable coal powder flow distribution on the detection results. The three sensors lead out three signals, and the three signals are transmitted to the industrial computer through three coaxial cables.

[0073] The pulverized coal flow rate detection device may adopt an existing BR-MODEL50 pulverized coal flow rate monitor-dust flow meter, or may adopt a venturi tube to measure wind speed, and calculate the pulverized coal flow rate in combination with the concentration measured by the pulverized coal concentration sensor, or may adopt other methods to achieve it.

[0074] See attached Figure 2-5 The air-powder homogenizing coal mill 20 comprises:

[0075] A coal mill housing 21, a discharge port 211 is provided on the top of the coal mill housing 21, one end of the coal powder pipeline L is connected to the discharge port 211, and a primary air duct 22 connected to the bottom side wall of the coal mill housing 21 is provided;

[0076] A powder conveying assembly 23, which passes through the center of the top of the coal mill housing 21 and is inserted into the coal mill housing 21, and is communicated with the interior of the coal mill housing 21;

[0077] A powder grinding assembly 24, which is rotatably connected to the bottom of the coal mill housing 21 and is disposed opposite to the powder conveying assembly 23;

[0078] The powder homogenizing assembly 25 includes a driving mechanism 251 and a homogenizing rotor 252. The driving mechanism 251 is disposed on the top of the coal mill housing 21. The homogenizing rotor 252 is disposed in the coal mill housing 21 and arranged opposite to the powder grinding assembly 24. The driving mechanism 251 drives the homogenizing rotor 252 to rotate and sleeve on the powder conveying assembly 23. An air inlet 2521 and an air outlet 2522 are respectively formed on the bottom and side wall of the homogenizing rotor 252. The driving mechanism 251 is electrically connected to the industrial computer 70.

[0079] And a central air inlet assembly 26 , one end of which is connected to the primary air duct 22 , and the other end of which is an air outlet end, which is bent and inserted into the coal mill housing 21 and connected to the powder conveying assembly 23 .

[0080] Among them, the powder grinding assembly adopts the existing structure, which may include a grinding disc mechanism, a grinding roller mechanism and a spring loading mechanism. The grinding disc mechanism is rotatably connected to the bottom of the coal mill shell, and is arranged opposite to the coal drop pipe outlet and the homogenizing rotor. One end of the grinding roller mechanism is fixed to the side wall of the coal mill shell by a limiting rod, and the other end abuts against the top of the grinding disc mechanism. One end of the spring loading mechanism is inserted into the side wall of the coal mill shell and abuts against the grinding roller mechanism.

[0081] See attached Figure 4 The central air inlet assembly 26 includes an air inlet pipe 261, an air sleeve 262 and a regulating valve 263. One end of the air inlet pipe 261 is connected to the primary air duct 22, and the other end is connected to the side wall of the air sleeve 262 to form a whole; the air sleeve 262 and one end of the air inlet pipe 261 are bent and inserted into the coal mill housing 21, and the air sleeve 262 is sleeved and fixed on the lower end of the powder conveying assembly 23; the regulating valve 263 is arranged on the air inlet pipe 261, and the regulating valve 263 is electrically connected to the industrial computer 70.

[0082] Advantageously, the central air inlet assembly further includes a wear-resistant guard plate, the cross section of which is semicircular, and the wear-resistant guard plate is fixed to the bottom of the other end of the air inlet pipe and corresponds to the position of the wind flow direction in the coal mill housing. The beneficial effect of the above technical solution is that the airflow formed when the air-powder mixture moves from bottom to top causes serious scouring and wear on the bottom of the air inlet pipe, and the wear-resistant guard plate can protect the air inlet pipe. The wear-resistant guard plate is made of wear-resistant material, such as wear-resistant steel plate.

[0083] See attached Figure 5-14In one embodiment of the present invention, the homogenizing rotor 252 includes a central tube 2523, a cone 2524, blades 2525, a bottom ring 2526 and a wind block 2527. The driving mechanism 251 drives the central tube 2523 to rotate and sleeve on the powder conveying assembly 23; the cone 2524 includes an upper plate 25241 and a lower plate 25242. The upper plate 25241 is a round table with a hole in the middle, and the lower plate 25242 is a rounded table with a hole in the middle. The upper plate 25241 and the lower plate 25242 are fixedly connected on one side edge opposite to each other. The upper plate 25241 and the lower plate 25242 are both fixedly sleeved. The central tube 2523 is outside; there are multiple blades 2525, and the multiple blades 2525 are evenly arranged on the same circumference along the side wall of the central tube 2523, and the tops of the multiple blades 2525 are fixedly connected to the bottom end surface of the lower plate 25242, the bottom ring 2526 is fixed to the outer side of the lower end of the multiple blades 2525, and the middle of the bottom ring 2526 forms an air inlet 2521, and multiple air outlets 2522 are formed between the multiple blades 2525, the lower plate 25242 and the bottom ring 2526. The wind block 2527 is fixed at the air outlet 2522 to change the wind direction and air outlet area of ​​the air outlet 2522. The blades can be 16 to 36.

[0084] In another embodiment of the present invention, the wind blocking blocks 2527 are fixedly filled at intervals at the inner upper end of the air outlet 2522, and are fixedly connected to the lower plate 25242 and the blades 2525 on both sides, and the area difference between any two adjacent air outlets 2522 is 10% to 25%;

[0085] In some other embodiments of the present invention, the air outlets 2522 are divided into 4 to 6 groups, each group of air outlets 2522 includes a plurality of adjacent air outlets 2522, and each group of air outlets 2522 is sequentially fixed with wind blocking blocks 2527 at the inner upper end, the wind blocking blocks 2527 are fixedly connected to the lower plate 25242 and the blades 2525 on both sides, the height of each group of air outlets 2522 increases gradually and the area difference between any two adjacent air outlets 2522 is 10% to 25%.

[0086] In the embodiments of the present invention, see the attached Figure 6-8The wind-blocking block includes a block A 25271, a block B 25272 and a block C 25273. The block C 25273 is a vertically arranged triangular prism, the top of which is fixed on the lower plate, and the bottom is fixed on the bottom ring to change the wind direction and the wind area of ​​the air outlet, and one of the vertical edges of the block C 25273 faces the air outlet channel, and the side corresponding to the vertical edge facing the air outlet channel is arc-shaped; the block A 25271 is a vertically arranged triangular prism, the top of which is fixed on the lower plate, and the bottom is fixed on the bottom ring to change the wind direction and the wind area of ​​the air outlet, and one side of the block A 25271 is fixedly connected to the blade; the block B 25272 is arranged in a mirror image with the block A 25271, and the block C 25273, the block A 25271 and the block B 25272 are arranged in sequence, and one or more air outlets are separated between each group of the block C 25273, the block A 25271 and the block B 25272. The beneficial effect of adopting the above technical scheme is that block C 25273 can not only effectively change the area of ​​the air outlet, but also change the air outlet direction along the side of the triangular prism, so that it can mix the wind and powder mixture and improve the homogenization effect. Since block A 25271, block B 25272 and block C 25273 are arranged at different positions of the small chamber, and the widths of block A 25271, block B 25272 and block C 25273 are also different from each other, different interception effects can be produced on the small chamber, thereby making the movement state of the wind and powder mixture different when it is discharged from the small chamber, thereby achieving the effect of sufficient mixing and homogenization.

[0087] In the embodiments of the present invention, see the attached Figure 9-14 In actual use, you can choose to use C block 25273, A block 25271, B block 25272 alone, or you can use C block 25273, A block 25271, B block 25272 in combination, the purpose is to change the outlet structure and area of ​​the air outlet, so that the air-powder mixture has different motion states when it is discharged from the air outlet channel, so as to achieve a fully mixed and homogenized effect. Further, the side area of ​​C block 25273, A block 25271, B block 25272 facing the air outlet is 10% to 25% of the area of ​​the air outlet.

[0088] Advantageously, the homogenizing rotor 252 further includes blade wings 2528 , and the blade wings 2528 are multiple, and the multiple blade wings 2528 are asymmetrical and fixed on the outside of the wind blocking block 2527 on different circumferences.

[0089] In one embodiment of the present invention, see the attached Figure 15-19 Each pulverized coal concentration regulating valve 30 comprises:

[0090] The shell 31 is vertically fixed between the air-powder homogenizing pulverizer 20 and the pulverized coal pipeline L, with an air-powder mixture inlet formed at its bottom and an air-powder mixture outlet formed at its top, and a pulverized coal concentration regulating chamber formed between the air-powder mixture inlet and the air-powder mixture outlet;

[0091] A driving part 32 is connected to the side wall of the housing 31 , and the driving part 32 is electrically connected to the industrial computer 70 ;

[0092] The shaft 33 and the side wall of the housing 31 are provided with a bearing seat 311 in a direction perpendicular to the driving part 32; one end of the shaft 33 is driven by the driving part 32 to rotate in the bearing seat 311;

[0093] And valve plates 34, two groups of valve plates 34 are installed on the shaft 33, and the two groups of valve plates 34 can be opened and closed in the coal powder concentration regulating chamber to form a cut-off area to change the cut-off area in the coal powder concentration regulating chamber.

[0094] The air-powder mixture inlet of the shell is rectangular, and the air-powder mixture outlet is circular; it is convenient to connect to the coal powder pipeline.

[0095] See attached Fig.16 The driving part 32 includes: a driving motor 321, a screw rod 322, a driving frame 323 and a driving gear 324; the driving motor 321 is fixed to the side of the shell 31 through a bracket; its output end is connected to the screw rod 322; the driving frame 323 is a rectangular frame structure, and two sets of racks 325 are arranged on the two inner walls opposite to each other in the vertical direction, and the two sets of driving gears 324 are respectively meshed and driven with the two sets of racks 325; the two sets of driving gears 324 are connected to one end of the shaft 33; a threaded hole is provided at the bottom of the driving frame 323, and the screw rod 322 is matched with the thread in the threaded hole for transmission, wherein the driving motor 321 is electrically connected to the industrial computer 70; the shaft 33 includes a first shaft rod 331 and a second shaft rod 332, One end of the first shaft rod 331 is integrated with the first valve plate 341, and the second shaft rod 332 is in the shape of a shaft sleeve, which is hinged to the other end of the first shaft rod 331. The other end of the first shaft rod 331 is connected to the first driving gear 3241, and the second shaft rod 332 is integrated with the second valve plate 342, and its end is connected to the second driving gear 3242; the first driving gear 3241 and the second driving gear 3242 respectively correspond to a group of racks 325 for meshing, so as to drive the first valve plate 341 and the second valve plate 342 to open and close through the first shaft rod 331 and the second shaft rod 332 to change the size of the intercepting area; the first valve plate 341 and the second valve plate 342 have the same length, and form an isosceles triangle in the open state with the shaft 33 as the center.

[0096] See attached Figure 18-19The outer walls of the first driving gear 3241 and the second driving gear 3242 include a cylindrical section and a toothed section. The root circles of the cylindrical section and the toothed section coincide with each other, and the cylindrical section occupies 50%-55% of the circumferential length of the root circle of the toothed section. The width of each set of racks 325 is half the width of the inner wall of the frame of the driving frame 323.

[0097] See attached Fig. 20 The adjustment of the coal powder concentration regulating valve is as follows: the air-powder mixture enters from the air-powder mixture inlet and moves vertically upward, the first valve plate and the second valve plate together form an isosceles triangle cut-off body in the coal powder concentration regulating chamber, and the primary air will bypass the cut-off body when it meets the isosceles triangle cut-off body and continue to move upward from both sides of the cut-off body; when the coal powder particles move to the isosceles triangle cut-off body area, due to the effect of inertia, they will continue to enter the isosceles triangle cut-off body in the original direction, and in the cut-off body, due to the loss of the carrying effect of the primary air and the effect of their own gravity, the coal powder particles accelerate to fall downward, and when falling out of the cut-off body, the downward speed of the coal powder particles overcomes the primary wind resistance and falls back to the coal mill; thereby, the coal powder concentration at the outlet of the air-powder mixture is lower than the concentration at the inlet.

[0098] The powder making method of the present invention is that the control system carried by the industrial computer receives the flame combustion status in the furnace, the carbon content of the flue gas fly ash, and the NO X and CO content information; and compared with the target value in the control system, combined with the coal powder concentration detection and coal powder flow detection signals on each coal powder pipeline as well as the coal quality conditions, a command is issued to the air-powder homogenizing pulverizer to control the fineness of the coal powder. At the same time, a command is issued to the coal powder concentration regulating valve and the coal powder flow regulating valve to adjust the air-powder state in each coal powder pipeline. Through multiple detection, comparison and adjustment, a closed-loop control is formed to make the boiler system tend to the optimal combustion state.

[0099] The coal quality condition (see Table 1, which gives examples of parameters of two types of coal powder) means that different coal qualities and types have different parameters when they are tested in the factory. These data are stored in the control system. According to different coal qualities and outputs, the industrial computer controls the homogenizing rotor speed (controls the drive mechanism) and wind speed (adjusts the regulating valve in the central air inlet assembly) with different strategies.

[0100] Table 1 Coal quality parameter examples:

[0101]

[0102]

[0103] Since the current pulverizing system cannot achieve fine control of the state of the air-powder mixture, it does not pay attention to the perception of the combustion state of the boiler. Therefore, the current pulverizing system is not organically integrated with the boiler and cannot automatically perceive the combustion state of the boiler. In order to further improve the economy and safety of boiler operation, the pulverizing system is organically integrated with the boiler to achieve automatic perception of the boiler combustion state and fine control of the air-powder mixture entering the furnace. Usually, this control process requires multiple iterations to find the optimal state of the regulating unit (air-powder homogenizing pulverizer, coal powder concentration regulating valve and air-powder flow regulating valve). The industrial computer records the adjustment process and results of each working condition. The next time the same working condition is encountered, multiple iterations are omitted, and each regulating unit is directly adjusted to the optimal state, thereby improving the response speed of the pulverizing system.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0105] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A flour making system, characterized in that: It is installed in a boiler system (10) and includes: an air-powder homogenizing coal mill (20), the air-powder homogenizing coal mill (20) being connected to a boiler system (10) via a plurality of coal powder pipelines (L); a coal powder concentration regulating valve (30), a coal powder flow regulating valve (40), a coal powder concentration detection sensor (50) and a coal powder flow detection device (60) being installed in sequence on each coal powder pipeline (L) from an end close to the air-powder homogenizing coal mill (20) to an end close to the boiler system (10); and an industrial control computer (70), wherein the industrial control computer (70) is equipped with a control system, which is connected to the air-powder homogenizing coal mill (20), the coal powder concentration regulating valve (30), the coal powder flow regulating valve (40), the coal powder concentration detection sensor (50), the coal powder flow detection device (60), and the furnace flame detection sensor (11), the flue gas fly ash carbon content detection sensor (12), and the flue gas NO X The detection sensor (13) and the flue gas CO detection sensor (14) are electrically connected; The air-powder homogenizing coal mill (20) comprises: A coal mill housing (21), wherein a discharge port (211) is provided at the top of the coal mill housing (21), one end of the pulverized coal pipeline (L) is connected to the discharge port (211), and a primary air duct (22) connected to the bottom side wall of the coal mill housing (21) is provided; a powder conveying assembly (23), the powder conveying assembly (23) passing through the center of the top of the coal mill housing (21), inserted into the coal mill housing (21), and communicating with the interior of the coal mill housing (21); a powder grinding assembly (24), the powder grinding assembly (24) being rotatably connected to the bottom of the coal mill housing (21) and being arranged opposite to the powder conveying assembly (23); a powder homogenizing assembly (25), the powder homogenizing assembly (25) comprising a driving mechanism (251) and a homogenizing rotor (252); the driving mechanism (251) is arranged on the top of the coal mill housing (21); the homogenizing rotor (252) is arranged in the coal mill housing (21) and is arranged opposite to the powder grinding assembly (24); the driving mechanism (251) drives the homogenizing rotor (252) to rotate and sleeve on the powder conveying assembly (23); an air inlet (2521) and an air outlet (2522) are respectively formed on the bottom and side wall of the homogenizing rotor (252); the driving mechanism (251) is electrically connected to the industrial computer (70); and a central air inlet assembly (26), one end of the central air inlet assembly (26) being in communication with the primary air duct (22), and the other end being an air outlet end, which is bent and inserted into the coal mill housing (21) and is in communication with the powder conveying assembly (23); The central air inlet assembly (26) comprises an air inlet pipe (261), an air sleeve (262) and a regulating valve (263); one end of the air inlet pipe (261) is in communication with the primary air pipe (22), and the other end is in communication with the side wall of the air sleeve (262) to form an integral body; the air sleeve (262) and one end of the air inlet pipe (261) are bent and inserted into the coal mill housing (21), and the air sleeve (262) is sleeved and fixed to the lower end of the material powder conveying assembly (23); the regulating valve (263) is arranged on the air inlet pipe (261), and the regulating valve (263) is electrically connected to the industrial computer (70); The homogenizing rotor (252) comprises a central tube (2523), a cone (2524), blades (2525), a bottom ring (2526) and a wind block (2527); the driving mechanism (251) drives the central tube (2523) to rotate and sleeve on the powder conveying assembly (23); the cone (2524) comprises an upper plate (25241) and a lower plate (25242); the upper plate (25241) is a rounded table with a hole in the middle; the lower plate (25242) is a chamfered table with a hole in the middle; the upper plate (25241) and the lower plate (25242) are fixedly connected at opposite side edges; the upper plate (25241) and the lower plate (25242) are both fixedly sleeved on the central tube (252 3) outside; there are a plurality of blades (2525), and the plurality of blades (2525) are evenly arranged on the same circumferential surface along the side wall of the central tube (2523), and the tops of the plurality of blades (2525) are fixedly connected to the bottom end surface of the lower plate (25242), the bottom ring (2526) is fixed to the outside of the lower ends of the plurality of blades (2525), and an air inlet (2521) is formed in the middle of the bottom ring (2526), ​​and a plurality of air outlets (2522) are formed between the plurality of blades (2525), the lower plate (25242) and the bottom ring (2526), ​​and the wind blocking block (2527) is fixed at the air outlet (2522) to change the air outlet direction and air outlet area of ​​the air outlet (2522).

2. A flour milling system according to claim 1, characterized in that: The wind blocking blocks (2527) are fixedly filled at intervals at the inner upper ends of the air outlets (2522), and are fixedly connected to the lower plate (25242) and the blades (2525) on both sides, and the area difference between any two adjacent air outlets (2522) is 10% to 25%; Or the air outlets (2522) are 4 to 6 groups, each group of the air outlets (2522) includes a plurality of adjacent air outlets (2522), and each group of the air outlets (2522) is sequentially fixedly filled with the wind blocking blocks (2527) at the inner upper end, the wind blocking blocks (2527) are fixedly connected to the lower plate (25242) and the blades (2525) on both sides, the height of each group of the air outlets (2522) increases gradually, and the area difference between any two adjacent air outlets (2522) is 10% to 25%.

3. A flour milling system according to claim 1, characterized in that: The homogenizing rotor (252) further comprises blade wings (2528), the blade wings (2528) being multiple, and the multiple blade wings (2528) are asymmetrical and fixed on the outside of the wind blocking block (2527) on different circumferences.

4. A flour milling system according to claim 1, characterized in that: Each of the pulverized coal concentration regulating valves (30) comprises: A shell (31), the shell (31) being vertically fixed between the air-powder homogenizing coal mill (20) and the coal powder pipeline (L), the bottom of the shell (31) forming an air-powder mixture inlet, the top of the shell (31) forming an air-powder mixture outlet, and a coal powder concentration adjustment chamber being formed between the air-powder mixture inlet and the air-powder mixture outlet; A driving unit (32), the driving unit (32) being connected to a side wall of the housing (31), the driving unit (32) being electrically connected to the industrial computer (70); A shaft (33), a bearing seat (311) is arranged on a side wall of the housing (31) in a direction perpendicular to the driving portion (32); one end of the shaft (33) is driven by the driving portion (32) to rotate in the bearing seat (311); and valve plates (34), wherein two groups of valve plates (34) are mounted on the shaft (33), and the two groups of valve plates (34) can be opened and closed in the coal powder concentration regulating chamber to form a cut-off area, so as to change the cut-off area in the coal powder concentration regulating chamber.

5. A flour milling system according to claim 4, characterized in that: The driving part (32) comprises: a driving motor (321), a screw rod (322), a driving frame (323) and a driving gear (324); the driving motor (321) is fixed to the side of the housing (31) through a bracket; the output end of the driving motor (321) is connected to the screw rod (322) in a power manner; the driving frame (323) is a rectangular frame structure, and two sets of racks (325) are arranged staggered on two inner walls opposite to each other in the vertical direction, and the two sets of driving gears (324) and the two sets of racks (325) are respectively meshed and driven; the two sets of driving gears (324) are connected to one end of the shaft (33); a threaded hole is provided at the bottom of the driving frame (323), and the screw rod (322) is matched with the thread in the threaded hole for transmission, wherein the driving motor (321) is electrically connected to the industrial computer (70); the shaft (33) comprises a first shaft rod (331) and a second shaft rod (332), One end of the first shaft (331) is integrally formed with the first valve plate (341); the second shaft (332) is in the shape of a shaft sleeve and is hinged to the other end of the first shaft (331); the other end of the first shaft (331) is connected to a first driving gear (3241); the second shaft (332) is integrally formed with the second valve plate (342), and the end of the second shaft is connected to a second driving gear (3242); the first driving gear (3241) and the second driving gear (3242) respectively mesh with a group of racks (325) to drive the first valve plate (341) and the second valve plate (342) to open and close through the first shaft (331) and the second shaft (332) to change the size of the interception area; the first valve plate (341) and the second valve plate (342) are of the same length and form an isosceles triangle with the shaft (33) as the center in the open state.

6. A flour milling system according to claim 5, characterized in that: The outer walls of the first driving gear (3241) and the second driving gear (3242) both comprise a cylindrical section and a toothed section, the cylindrical section coincides with the tooth root circle of the toothed section, and the cylindrical section occupies 50%-55% of the circumferential length of the tooth root circle of the toothed section; the width of each group of the racks (325) is half the width of the inner wall of the frame of the driving frame (323).

7. A flour making method based on the flour making system according to any one of claims 1 to 6, characterized in that: The control system equipped with the industrial computer receives feedback from the boiler system on the flame combustion status, flue gas fly ash carbon content, NO X and CO content information; and compared with the target value in the control system, combined with the coal powder concentration detection and coal powder flow detection signals on each coal powder pipeline as well as the coal quality conditions, a command is issued to the air-powder homogenizing pulverizer to control the fineness of the coal powder. At the same time, a command is issued to the coal powder concentration regulating valve and the coal powder flow regulating valve to adjust the air-powder state in each coal powder pipeline. Through multiple detection, comparison and adjustment, a closed-loop control is formed to make the boiler system tend to the optimal combustion state.

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