A cross-load regulating concentrated-lean separation type combustion device

Abstract

The present invention discloses a cross-load regulated light-dense separation combustion device, wherein the outlet of the primary air duct is connected with the inlet of the coal mill, and the outlet of the coal mill is connected with the inlet of the furnace through the primary air powder pipe, and a separation partition, a light-phase primary air powder inlet amount control baffle and a plurality of light-dense separation guide blocks are arranged in the primary air powder pipe, and a primary air exhaust gas outlet is arranged at the bottom of the primary air powder pipe, wherein the separation partition, the light-phase primary air powder inlet amount control baffle and the primary air exhaust gas outlet are distributed in sequence from top to bottom, one end shaft of the light-phase primary air powder inlet amount control baffle is connected to the bottom of the primary air powder pipe, one end of the lead screw is inserted into the primary air powder pipe and connected to the lower surface of the light-phase primary air powder inlet amount control baffle, and a stepping motor is connected to the other end of the lead screw, and the lead screw is driven to rise, fall and stop by the stepping motor. The device can realize safe, stable and optimized operation of the burner under different loads.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection of power plants and relates to a cross-load regulating concentrated-lean separation type combustion device. Background Art

[0002] With my country's increasing emphasis on energy conservation and emissions reduction, coupled with the continuous advancement of renewable energy utilization, higher requirements are being placed on the load regulation performance, low-load stable combustion capabilities, and optimized cross-load operation of power plant coal-fired boilers. Therefore, when renovating existing burners and designing new ones, it is crucial to prioritize low-load stable combustion of pulverized coal and optimize the combustion process. This aims to achieve stable, safe, efficient, and low-pollution combustion across a wide load range, ensuring the proper operation of the boiler unit during peak-shaving operations. Currently, one of the mainstream approaches to achieving this goal is pulverized coal concentration-lean separation technology.

[0003] However, when a pulverized coal burner operates under different loads, the amount of pulverized coal carried by the primary air varies under different loads. If the primary air volume is not changed, the primary air excess air coefficient will change, causing the main combustion zone to fail to operate under optimal conditions. While affecting the combustion structure within the boiler, it also undermines the original design's suppression of nitrogen oxide formation and worsens the burner's low-pollution performance. If the primary air volume is changed, the flow rate of the primary air-pulverized coal mixture in the primary air duct will change. At this time, the separation effect deviates from the original design concept, causing the rich-lean separation ratio to deviate from the original design value, which also causes the burner to fail to operate under optimal conditions. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a cross-load adjustable rich-lean separation type combustion device, which can achieve safe, stable and optimized operation of the burner under different loads.

[0005] To achieve the above-mentioned object, the cross-load regulating thick-lean separation type combustion device of the present invention comprises a primary air duct, a coal mill, a primary air powder pipe, a furnace, a lead screw and a stepping motor;

[0006] The outlet of the primary air duct is connected with the inlet of the coal mill, and the outlet of the coal mill is connected with the inlet of the furnace through the primary air powder pipe. The primary air powder pipe is provided with a separation baffle, a light phase primary air powder inlet amount control baffle and a number of thick and thin separation guide blocks. The bottom of the primary air powder pipe is provided with a primary air exhaust gas outlet, wherein the separation baffle, the light phase primary air powder inlet amount control baffle and the primary air exhaust gas outlet are distributed in sequence from top to bottom, one end shaft of the light phase primary air powder inlet amount control baffle is connected to the bottom of the primary air powder pipe, one end of the lead screw is inserted into the primary air powder pipe and connected to the lower surface of the light phase primary air powder inlet amount control baffle, and the stepper motor is connected to the other end of the lead screw, and the lead screw is driven to rise, fall and stop moving by the stepper motor.

[0007] A primary air-powder mixture flow rate detector is provided at the center of the primary air-powder pipe inlet.

[0008] A thick and thin phase primary air and powder mixture flow rate detector is provided at the outlet of the primary air and powder pipe.

[0009] It also includes a control system, the input end of the control system is connected to the output end of the primary air-powder mixture flow rate detector and the output end of the thick and thin phase primary air-powder mixture flow rate detector, and the output end of the control system is connected to the input end of the stepping motor.

[0010] The control end of the stepper motor is connected to the control system via wireless communication.

[0011] The output shaft of the stepper motor is controlled to rotate counterclockwise, clockwise or stop rotating to control the height of the part of the lead screw located in the primary air powder tube, and then the flow rate of the primary air exhaust gas at the primary air exhaust gas outlet is controlled.

[0012] The length of the baffle for controlling the amount of light phase primary air powder entering the furnace is 2 / 3 of the height of the primary air powder pipe.

[0013] The primary air exhaust gas outlet is connected to the inlet of the coal mill through the primary air exhaust gas conveying pipe.

[0014] The present invention has the following beneficial effects:

[0015] The cross-load regulating thick-lean separation combustion device described in the present invention is operated in a specific manner. When the boiler unit is running at full load, the burner itself works in the optimal state of the design. At this time, the opening of the damper for controlling the amount of light-phase primary air powder entering the furnace is zero. The working state of this device is the same as that of the traditional thick-lean separation combustion device. When the boiler load decreases, the damper for controlling the amount of light-phase primary air powder entering the furnace is opened, so that part of the light-phase primary air exhaust gas returns to the pulverizer through the primary air exhaust gas conveying pipe to carry coal powder, ensuring that the flow rate in the primary air powder pipe is the same as the design flow rate when the primary air flow rate is low under low load. It is equivalent to maintaining the designed thick and thin separation ability. At the same time, the excess primary air exhaust gas required to achieve the thick and thin separation of coal powder is circulated again, and the excess air coefficient that does not enter the furnace to affect the main combustion area is ensured, ensuring the expected optimized combustion state. While ensuring the thick and thin separation effect of primary air powder under a wide load range, the amount of oxygen brought into the furnace by the primary air of the main combustion area under different loads is maintained, ensuring that the air organization of combustion in the furnace under different loads is similar to the designed working conditions, providing protection for the ignition of coal powder airflow and low NOx combustion, and realizing stable, safe, efficient and environmentally friendly combustion under a wide load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Among them, 1 is the coal mill, 2 is the primary air-powder mixture flow rate detector, 3 is the control system, 4 is the thick and thin phase primary air-powder mixture flow rate detector, 5 is the furnace, 6 is the primary air duct, 7 is the primary air exhaust gas conveying pipe, 8 is the screw, 9 is the stepping motor, 10 is the thick and thin separation guide block, 11 is the separation partition, 12 is the light phase primary air powder inlet amount control baffle, and 13 is the primary air powder pipe. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0019] The accompanying drawings illustrate schematic diagrams of the structures of the disclosed embodiments of the present invention. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0020] refer to Figure 1 The cross-load regulating, dense-lean separation combustion device of the present invention comprises a coal mill 1, a primary air-powder mixture flow rate detector 2, a control system 3, a dense-lean phase primary air-powder mixture flow rate detector 4, a furnace 5, a primary air duct 6, a primary air exhaust gas conveying pipe 7, a lead screw 8, a stepping motor 9, a dense-lean separation guide block 10, a separation partition 11, a lean phase primary air-powder feeding amount control baffle 12, and a primary air-powder pipe 13;

[0021] The outlet of the primary air duct 6 is connected to the inlet of the coal mill 1, and the outlet of the coal mill 1 is connected to the inlet of the furnace 5 through the primary air powder pipe 13. A primary air powder mixture flow rate detector 2 is provided at the center of the inlet of the primary air powder pipe 13, and a thick and thin phase primary air powder mixture flow rate detector 4 is provided at the outlet of the primary air powder pipe 13. A separation partition 11, a light phase primary air powder inlet amount control baffle 12 and a number of thick and thin separation guide blocks 10 are provided in the primary air powder pipe 13. A primary air exhaust gas outlet is provided at the bottom of the primary air powder pipe 13, wherein the separation The partition plate 11, the light phase primary air powder entering the furnace amount control baffle 12 and the primary air exhaust gas outlet are distributed in sequence from top to bottom. One end axis of the light phase primary air powder entering the furnace amount control baffle 12 is connected to the bottom of the primary air powder tube 13. One end of the lead screw 8 is inserted into the primary air powder tube 13 and then connected to the lower surface of the light phase primary air powder entering the furnace amount control baffle 12. The stepper motor 9 is connected to the other end of the lead screw 8. The stepper motor 9 controls the height of the lead screw 8 inserted into the primary air powder tube 13 to control the flow rate of the primary air exhaust gas at the primary air exhaust gas outlet.

[0022] The primary air exhaust gas outlet is connected to the inlet of the coal mill 1 through the primary air exhaust gas conveying pipe 7.

[0023] The input end of the control system 3 is connected to the output end of the primary air-powder mixture flow rate detector 2 and the output end of the thick and thin phase primary air-powder mixture flow rate detector 4, and the output end of the control system 3 is connected to the input end of the stepper motor 9, wherein the control end of the stepper motor 9 is connected to the control system 3 by wireless communication to control the output shaft of the stepper motor 9 to rotate counterclockwise, clockwise or stop rotating, so as to control the height of the part of the screw 8 located in the primary air-powder tube 13, to control the inclination angle of the baffle 12 of the light phase primary air powder entering the furnace, and then control the flow rate of the primary air exhaust gas at the primary air exhaust gas outlet. It should be noted that when the light phase primary air powder entering the furnace control baffle 12 is in a horizontal state, it can ensure that no light phase primary air exhaust gas enters the primary air exhaust gas conveying pipe 7.

[0024] The length of the baffle 12 for controlling the amount of light phase primary air powder entering the furnace is 2 / 3 of the height of the primary air powder pipe 13.

[0025] The working principle of the present invention is:

[0026] First, based on the historical operating experience data of the boiler, the optimized light-rich separation ratio under different loads, the light-rich phase primary air powder velocity entering the furnace 5, and the excess air coefficient of the primary air powder are obtained. During actual operation, according to different load requirements, the opening of the light-rich phase primary air powder entering the furnace is controlled by the measurement results of the primary air powder mixture flow rate detector 2 and the light-rich phase primary air powder mixture flow rate detector 4.

[0027] When the boiler unit is running at full load, the burner itself works in the optimal designed state. At this time, the opening of the baffle 12 controlling the amount of light-phase primary air powder entering the furnace is zero. The working state of the present invention is the same as that of the traditional light-phase separation combustion device.

[0028] When the boiler load decreases, taking 50% load as an example, the light-phase primary air powder inlet control damper 12 is opened at this time, so that part of the light-phase primary air exhaust gas returns to the pulverizer 1 through the primary air exhaust gas conveying pipe 7, carrying coal powder. It is ensured that the flow rate in the primary air powder pipe 13 is equivalent to the design flow rate when the primary air flow rate is low under low load, and the designed thick and thin separation capacity is maintained. At the same time, the excess primary air exhaust gas required to achieve the thick and thin separation of coal powder is circulated again, and does not enter the furnace 5 to affect the excess air coefficient of the main combustion area, ensuring that the combustion is in the expected optimized state. Therefore, the present invention can ensure the thick and thin separation effect of the primary air powder under a wide load range, and at the same time can maintain the amount of oxygen brought into the furnace 5 by the primary air of the main combustion area under different loads, ensuring that the air organization of the combustion in the furnace 5 under different loads is similar to the design working conditions, providing protection for the ignition of the coal powder airflow and low NOx combustion, and achieving stable, safe, efficient and environmentally friendly combustion under a wide load.

[0029] It should also be noted that the relationship between the opening of the damper 12 for controlling the amount of primary air and powder fed into the furnace and the boiler or burner load is not linear. To achieve optimal results with this invention, in practice, the opening of the damper 12 for controlling the amount of primary air and powder fed into the furnace must be determined based on the actual operating performance of the boiler under different loads. This opening will serve as a benchmark for subsequent optimization and automatic adjustment of the combustion device.

[0030] In summary, the present invention can adapt to the thick and thin phase separation ratio of the primary air-powder mixture under wide load conditions and the amount of oxygen brought into the furnace 5 by the primary air under the expected separation ratio. On the premise of effectively realizing thick and thin combustion, it improves the combustion stability, maintains the optimized excess air coefficient in the main burner area, reduces the generation of pollutants such as NOx, and realizes safe, stable, efficient and low-pollution operation of the boiler under a wide load through automatic adjustment of the burner under different loads.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A cross-load regulating rich-lean separation type combustion device, characterized in that: It includes a primary air duct (6), a coal mill (1), a primary air powder pipe (13), a furnace (5), a lead screw (8) and a stepping motor (9); The outlet of the primary air duct (6) is connected to the inlet of the coal mill (1), and the outlet of the coal mill (1) is connected to the inlet of the furnace (5) through the primary air powder pipe (13). The primary air powder pipe (13) is provided with a separation partition (11), a light phase primary air powder inlet amount control baffle (12) and a plurality of thick and thin separation guide blocks (10). The bottom of the primary air powder pipe (13) is provided with a primary air exhaust gas outlet. The baffle (12) and the primary air exhaust gas outlet are sequentially distributed from top to bottom. One end of the baffle (12) for controlling the amount of light-phase primary air powder entering the furnace is connected to the bottom of the primary air powder pipe (13). One end of the lead screw (8) is inserted into the primary air powder pipe (13) and then connected to the lower surface of the baffle (12) for controlling the amount of light-phase primary air powder entering the furnace. A stepper motor (9) is connected to the other end of the lead screw (8). The stepper motor drives the lead screw (8) to rise, fall and stop. A primary air-powder mixture flow rate detector (2) is provided at the center of the inlet of the primary air-powder pipe (13); A dense and light phase primary air-powder mixture flow rate detector (4) is provided at the outlet of the primary air-powder pipe (13); The invention also includes a control system (3), wherein the input end of the control system (3) is connected to the output end of the primary air-powder mixture flow rate detector (2) and the output end of the thick-light phase primary air-powder mixture flow rate detector (4), and the output end of the control system (3) is connected to the input end of the stepping motor (9).

2. The cross-load adjustment rich-lean separation type combustion device according to claim 1, characterized in that: The control end of the stepping motor (9) is connected to the control system (3) via wireless communication.

3. The cross-load adjustment rich-lean separation type combustion device according to claim 1, characterized in that: in, The output shaft of the stepping motor (9) is controlled to rotate counterclockwise, clockwise or stop rotating to control the height of the portion of the lead screw (8) located in the primary air powder tube (13), thereby controlling the flow rate of the primary air exhaust gas at the primary air exhaust gas outlet.

4. The cross-load adjustment rich-lean separation type combustion device according to claim 1, characterized in that: The length of the baffle (12) for controlling the amount of light-phase primary air powder entering the furnace is 2 / 3 of the height of the primary air powder pipe (13).

5. The cross-load adjustment rich-lean separation type combustion device according to claim 1, characterized in that: The primary air exhaust gas outlet is connected to the inlet of the coal mill (1) through a primary air exhaust gas conveying pipe (7).

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