A hybrid powder making system

Abstract

This utility model discloses a hybrid pulverizing system, relating to the technical field of pulverizing systems for coal-fired power plant boilers. It includes a direct-fired pulverizing system, a boiler, boiler cold primary air ducts and boiler hot primary air ducts, and a rapid pulverizing supply system. The rapid pulverizing supply system includes a gas-solid separator, a pulverized coal storage bin, a pulverized coal storage pipe, a new pulverized coal airflow pipe, an exhaust gas pipe, a pulverizing supply air duct, a boiler cold primary air bypass, and a boiler hot primary air bypass. The gas-solid separator is connected to the exhaust gas pipe, and its bottom is connected to the pulverized coal storage bin; the pulverized coal storage bin is connected to the pulverizing supply air duct. This utility model improves the unit's load-up response rate while reducing the cost of the pulverizing system, increasing system integration, and reducing the total investment of the power plant.

Description

Technical Field

[0001] This utility model relates to the technical field of pulverizing systems for coal-fired power plant boilers, and more specifically, it is a hybrid pulverizing system. Background Technology

[0002] On March 26, 2025, the National Development and Reform Commission and the National Energy Administration jointly issued the "Implementation Plan for the Special Action to Upgrade the New Generation of Coal-fired Power (2025-2027)" (NDRC Energy

[2025] No. 363), which put forward clear requirements for the load change rate of newly built units and pilot demonstration units of the new generation of coal-fired power. Specifically, the load change rate of newly built pulverized coal boiler units burning bituminous coal should reach 2.2% and 1% of rated power / minute for 50% and above load and 30%-50% load, respectively; the load change rate of new generation coal-fired power pilot demonstration units should reach 4% and 2% of rated power / minute for 50% and above load and 30%-50% load, respectively.

[0003] Currently, the load increase rate of domestic pulverized coal boiler units is generally below 2% of rated power per minute. The industry consensus is that this is mainly due to the large inertial lag of the boiler pulverizing system. After the unit receives the load increase command, the coal feeder increases the belt speed to increase the coal feed rate, and the coal mill increases the grinding load to increase the grinding output. The raw coal falls from the coal bunker to the coal feeder, then falls into the coal mill via the coal feeder belt, and after being ground and dried by the coal mill, it is sent into the furnace for combustion through the pulverized coal conveying pipeline. The whole process takes 5-8 minutes. The response rate of the existing pulverizing system is far from meeting the load increase rate requirements of the new generation of coal-fired power units.

[0004] Meanwhile, existing rapid load-increasing pulverizing systems suffer from complex piping systems, low system integration, and high costs.

[0005] Therefore, it is necessary to develop a hybrid pulverizing system that can effectively solve the problem of large inertia lag in existing direct-blown pulverizing systems, reduce pipeline system investment, and improve system integration. Utility Model Content

[0006] The purpose of this invention is to overcome the problem that the load increase rate of existing coal-fired power units does not meet the requirements of the new generation of coal-fired power units, and that rapid load increase pulverizing systems have problems such as complex piping, low system integration, and high cost. The invention provides a hybrid pulverizing system that improves the load increase response rate of the unit while reducing the cost of the pulverizing system, improving system integration, and reducing the total investment of the power plant.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows: a hybrid pulverizing system, comprising a direct-fired pulverizing system, a boiler, a boiler cold primary air duct, and a boiler hot primary air duct. The direct-fired pulverizing system includes a coal mill, which is connected to the boiler's first burner via the original pulverized coal feeding duct. The boiler cold primary air duct originates from the boiler primary air fan outlet, and the boiler hot primary air duct originates from the boiler air preheater hot primary air outlet. The boiler cold primary air duct and the boiler hot primary air duct are mixed and then connected to the coal mill. The system is characterized by: It also includes a rapid pulverized coal supply system, which comprises a gas-solid separator, a pulverized coal storage bin, a pulverized coal storage pipeline, a new pulverized coal airflow pipeline, a waste gas pipeline, a pulverized coal supply duct, a boiler cold primary air bypass, and a boiler hot primary air bypass. One end of the pulverized coal storage pipeline is connected to the original pulverized coal supply pipeline, and the other end is connected to the gas-solid separator. One end of the new pulverized coal airflow pipeline is connected to the waste gas pipeline and the pulverized coal supply duct, and the other end is connected to the boiler's second burner. The gas-solid separator is connected to the exhaust gas pipeline, and the bottom of the gas-solid separator is connected to the powder storage silo; the powder storage silo is connected to the powder supply air duct. One end of the boiler cold primary air bypass is connected to the coal supply duct, and the other end is connected to the boiler cold primary air pipeline. One end of the boiler hot primary air bypass is connected to the coal supply duct, and the other end is connected to the boiler hot primary air pipeline.

[0008] In the above technical solution, dampers are provided at the connection points of the boiler cold primary air duct and the boiler hot primary air duct, and dampers are provided at the connection points of the original pulverized coal feeding duct and the coal mill, and at the connection points of the original pulverized coal feeding duct and the first burner.

[0009] In the above technical solution, a damper is provided at the connection between the pulverized coal storage silo and the pulverized coal supply duct; a damper is provided at the connection between the pulverized coal storage pipe and the original pulverized coal supply pipe; a damper is provided at the connection between the exhaust gas pipe and the newly added pulverized coal airflow pipe; a damper is provided at the connection between the pulverized coal supply duct and the newly added pulverized coal airflow pipe; dampers are provided at the connection between the boiler cold primary air bypass and the boiler cold primary air pipe, and at the connection between the boiler hot primary air bypass and the boiler hot primary air pipe; and a damper is provided at the connection between the newly added pulverized coal airflow pipe and the boiler's second burner.

[0010] In the above technical solution, the second burner is located above the first burner.

[0011] In the above technical solution, when the unit is running stably at a load of 50% or more, the damper at the connection between the pulverized coal storage pipeline and the original pulverized coal delivery pipeline is opened, the damper at the connection between the exhaust gas pipeline and the new pulverized coal gas flow pipeline is opened, and the damper at the connection between the new pulverized coal gas flow pipeline and the second burner of the boiler is opened. The rapid pulverized coal supply system starts storing pulverized coal, and the exhaust gas from the gas-solid separator is sent to the boiler for combustion through the exhaust gas pipeline and the new pulverized coal gas flow pipeline. When the pulverized coal storage bin reaches the set limit, the damper at the connection between the pulverized coal storage pipeline and the original pulverized coal delivery pipeline is closed, and the damper at the connection between the exhaust gas pipeline and the new pulverized coal gas flow pipeline is closed. When the unit receives a load increase command from the power grid, the dampers at the connection between the pulverized coal storage silo and the pulverized coal supply duct, the dampers at the connection between the boiler cold primary air bypass and the boiler cold primary air duct, the dampers at the connection between the boiler hot primary air bypass and the boiler hot primary air duct, the dampers at the connection between the pulverized coal supply duct and the new pulverized coal airflow duct, and the dampers at the connection between the new pulverized coal airflow duct and the boiler's second burner are opened, and the rapid pulverized coal supply system begins to supply pulverized coal to the boiler. When the pulverized coal storage silo level drops to the set limit, the dampers at the connection between the pulverized coal storage silo and the pulverized coal supply duct, the dampers at the connection between the boiler cold primary air bypass and the boiler cold primary air duct, the dampers at the connection between the boiler hot primary air bypass and the boiler hot primary air duct, the dampers at the connection between the pulverized coal supply duct and the new pulverized coal airflow duct, and the dampers at the connection between the new pulverized coal airflow duct and the boiler's second burner are closed.

[0012] Compared with the prior art, this utility model has the following advantages: 1) This utility model can effectively solve the problem of large inertial lag in the rapid load increase stage of the existing direct-fired pulverizing system, improve the load increase rate response capability of the unit, and meet the rapid load increase rate requirements of the new generation of coal-fired power units.

[0013] 2) This utility model uses a single newly added pulverized coal airflow pipeline and a second burner for both the pulverized coal storage and supply stages; the second burner operates as an exhaust gas burner during the pulverized coal storage process and as a conventional pulverized coal burner during the pulverized coal supply process; the newly added pulverized coal airflow pipeline, together with the exhaust gas pipeline, serves as an exhaust gas air pipeline during the pulverized coal storage process and as a rapid pulverized coal delivery pipeline during the pulverized coal supply process; the exhaust gas air pipeline and the rapid pulverized coal delivery pipeline, as well as the exhaust gas burner and the load-increasing burner, are organically combined to improve system integration and reduce project costs.

[0014] 3) This utility model improves the load increase response rate of the unit while reducing the cost of the pulverizing system, increasing the system integration, and reducing the total investment of the power plant. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the structure of a direct-blown pulverizing system in the prior art.

[0017] Among them, 100-direct-fired pulverizing system, 110-coal mill, 120-original pulverized coal feeding pipeline, 200-boiler, 210-first burner, 220-second burner, 310-boiler cold primary air pipeline, 320-boiler hot primary air pipeline, 400-rapid pulverized coal supply system, 410-gas-solid separator, 420-pulverized coal storage bin, 430-pulverized coal storage pipeline, 440-newly added pulverized coal airflow pipeline, 450-exhaust gas pipeline, 460-pulverized coal supply duct, 471-boiler cold primary air bypass, 472-boiler hot primary air bypass, 500-damper. Detailed Implementation

[0018] The following detailed description, in conjunction with the accompanying drawings, illustrates the implementation of this utility model. However, these descriptions do not constitute a limitation of the present utility model and are merely illustrative. Furthermore, the advantages of this utility model will become clearer and easier to understand through this description.

[0019] like Figure 1 As shown, a hybrid pulverizing system includes a direct-fired pulverizing system 100, a boiler 200, a boiler cold primary air duct 310, and a boiler hot primary air duct 320. The direct-fired pulverizing system 100 includes a coal mill 110, which is connected to the first burner 210 of the boiler 200 via the original coal feeding duct 120. The boiler cold primary air duct 310 originates from the boiler primary air fan outlet, and the boiler hot primary air duct 320 originates from the boiler air preheater hot primary air outlet. The boiler cold primary air duct 310 and the boiler hot primary air duct 320 are mixed and then connected to the coal mill 110. The system is characterized by: It also includes a rapid pulverized coal supply system 400, which includes a gas-solid separator 410, a pulverized coal storage bin 420, a pulverized coal storage pipe 430, a new pulverized coal airflow pipe 440, a waste gas pipe 450, a pulverized coal supply duct 460, a boiler cold primary air bypass 471, and a boiler hot primary air bypass 472. One end of the pulverized coal storage pipe 430 is connected to the original pulverized coal supply pipe 120, and the other end is connected to the gas-solid separator 410. One end of the new pulverized coal airflow pipe 440 is connected to the waste gas pipe 450 and the pulverized coal supply duct 460, and the other end is connected to the second burner 220 of the boiler 200. The gas-solid separator 410 is connected to the exhaust gas pipeline 450, and the bottom of the gas-solid separator 410 is connected to the powder storage bin 420; the powder storage bin 420 is connected to the powder supply air duct 460. One end of the boiler cold primary air bypass 471 is connected to the coal supply duct 460 and the other end is connected to the boiler cold primary air duct 310. One end of the boiler hot primary air bypass 472 is connected to the coal supply duct 460 and the other end is connected to the boiler hot primary air duct 320.

[0020] The boiler cold primary air duct 310 and the boiler hot primary air duct 320 are both equipped with dampers 500 at their connection points. The original pulverized coal feeding duct 120 is also equipped with dampers 500 at its connection points with the coal mill 110 and with the first burner 210.

[0021] A damper 500 is provided at the connection between the pulverized coal storage silo 420 and the pulverized coal supply duct 460. A damper 500 is provided at the connection between the pulverized coal storage pipe 430 and the original pulverized coal supply pipe 120. A damper 500 is provided at the connection between the exhaust gas pipe 450 and the new pulverized coal airflow pipe 440. A damper 500 is provided at the connection between the pulverized coal supply duct 460 and the new pulverized coal airflow pipe 440. A damper 500 is provided at the connection between the boiler cold primary air bypass 471 and the boiler cold primary air pipe 310, and at the connection between the boiler hot primary air bypass 472 and the boiler hot primary air pipe 320. A damper 500 is provided at the connection between the new pulverized coal airflow pipe 440 and the second burner 220 of the boiler 200.

[0022] To control NO in the furnace of boiler 220 x To generate a higher level and improve the response speed when the load increases, the second burner 220 is located above the first burner 210.

[0023] When the unit is running stably at a load of 50% or more, the damper 500 at the connection between the pulverized coal storage pipe 430 and the original pulverized coal delivery pipe 120 is opened, the damper 500 at the connection between the exhaust gas pipe 450 and the new pulverized coal gas flow pipe 440 is opened, and the damper 500 at the connection between the new pulverized coal gas flow pipe 440 and the second burner 220 of the boiler 200 is opened. The rapid pulverized coal supply system 400 starts storing pulverized coal, and the exhaust gas from the gas-solid separator 410 is sent to the boiler 200 for combustion through the exhaust gas pipe 450 and the new pulverized coal gas flow pipe 440. When the material level in the pulverized coal storage bin 420 reaches the set limit, the damper 500 at the connection between the pulverized coal storage pipe 430 and the original pulverized coal delivery pipe 120 is closed, and the damper 500 at the connection between the exhaust gas pipe 450 and the new pulverized coal gas flow pipe 440 is closed. When the unit receives a load increase command from the power grid, the dampers 500 at the connection points of the pulverized coal storage silo 420 and the pulverized coal supply duct 460, the boiler cold primary air bypass 471 and the boiler cold primary air duct 310, the boiler hot primary air bypass 472 and the boiler hot primary air duct 320, the pulverized coal supply duct 460 and the newly added pulverized coal airflow duct 440, and the newly added pulverized coal airflow duct 440 and the second burner 220 of the boiler 200 are opened, and the rapid pulverized coal supply system 400 is activated. Pulverized coal is supplied to boiler 200. When the material level in pulverized coal storage silo 420 drops to the set limit, the damper 500 at the connection between pulverized coal storage silo 420 and pulverized coal supply duct 460, the damper 500 at the connection between boiler cold primary air bypass 471 and boiler cold primary air duct 310, the damper 500 at the connection between boiler hot primary air bypass 472 and boiler hot primary air duct 320, the damper 500 at the connection between pulverized coal supply duct 460 and new pulverized coal airflow duct 440, and the damper 500 at the connection between new pulverized coal airflow duct 440 and the second burner 220 of boiler 200 are closed.

[0024] like Figure 2 As shown, the process flow of the existing direct-fired pulverizing system of the coal-fired unit is as follows: the cold primary air and the hot primary air of the boiler are mixed in a certain proportion to form a hot air flow at a qualified temperature and then enter the coal mill 110. The raw coal in the coal mill 110 is ground, dried by hot air, and screened and separated to form a coal powder flow with qualified particle size, moisture and uniformity. The flow is then sent to the first burner 210 of the furnace of the boiler 200 through the original coal feeding pipeline 120 and injected into the furnace for combustion to release heat.

[0025] This invention couples a rapid powder supply system 400 onto an existing direct-blowing powder pulverizing system. The operating mode of this invention is as follows: 1) Pulverized coal storage: When the unit is running stably at high load (above 50% load), part of the pulverized coal airflow in the original pulverized coal delivery pipe 120 at the outlet of the coal mill 110 is bypassed to the gas-solid separator 410 through the pulverized coal storage pipe 430. After separation by the gas-solid separator 410, the pulverized coal falls into the pulverized coal storage bin 420 at the bottom of the gas-solid separator 410 for storage. The airflow separated by the gas-solid separator 410 (containing a small amount of pulverized coal, <10%) is sent to the second burner 220 of the boiler 200 through the exhaust gas pipe 450 and the newly added pulverized coal airflow pipe 440 and injected into the furnace for combustion. When the material level in the powder storage silo 420 reaches the set limit, the damper 500 at the connection between the powder storage pipeline 430 and the original powder delivery pipeline 120 is closed, completing the powder storage process in the powder storage silo 420. 2) Pulverized coal supply: When the unit receives a load increase command from the power grid, the damper 500 at the connection between the pulverized coal storage bin 420 and the pulverized coal supply duct 460, the damper 500 at the connection between the boiler cold primary air bypass 471 and the boiler cold primary air duct 310, the damper 500 at the connection between the boiler hot primary air bypass 472 and the boiler hot primary air duct 320, the damper 500 at the connection between the pulverized coal supply duct 460 and the newly added pulverized coal airflow duct 440, and the damper 500 at the connection between the newly added pulverized coal airflow duct 440 and the second burner 220 of the boiler 200 are opened; after the boiler cold primary air and boiler hot primary air are mixed in a certain proportion to form a hot air flow of qualified temperature, the pulverized coal stored in the pulverized coal storage bin 420 is sent to the newly added second burner 220 of the boiler 200 through the pulverized coal supply duct 460 and the newly added pulverized coal airflow duct 440 and injected into the furnace for combustion, so as to quickly replenish the heat of the boiler 200; When the material level in the powder storage silo drops to the set limit, powder supply will stop.

[0026] In actual use, the damper 500 at the connection between the powder storage pipe 430 and the original powder delivery pipe 120 enables the connection and isolation between the powder storage pipe 430 and the original powder delivery pipe 120, and also plays a role in adjusting the airflow of the powder storage air.

[0027] The air-coal mixture interface of the gas-solid separator 410 is connected to the coal powder storage pipe 430, the coal powder storage bin 420 at the bottom of the gas-solid separator 410 is connected, and the air-side interface at the top of the gas-solid separator 410 is connected to the exhaust gas pipe 450. The gas-solid separator 410 separates coal powder and airflow through the principle of centrifugal force. The separated coal powder particles fall into the lower coal powder storage bin 420, and the separated airflow (exhaust gas, containing a small amount of coal powder) enters the exhaust gas pipe 450.

[0028] The newly added pulverized coal airflow duct 440 has two functions: one is to serve as a channel for the airflow separated by the gas-solid separator 410 to enter the furnace during pulverized coal storage, together with the exhaust gas duct 450; the other is to serve as a channel for the pulverized coal and the pulverized coal airflow in the pulverized coal storage bin 420 to enter the furnace of the boiler 200, together with the pulverized coal supply duct 460.

[0029] The opening and closing of the damper 500 at the connection between the boiler cold primary air bypass 471 and the boiler cold primary air duct 310, and the damper 500 at the connection between the boiler hot primary air bypass 472 and the boiler hot primary air duct 320, realize the connection and isolation between the boiler cold primary air bypass 471 and the boiler cold primary air duct 310, and the boiler hot primary air bypass 472 and the boiler hot primary air duct 320, and also play a role in adjusting the coal supply air volume and temperature; the coal supply air and the coal powder from the coal storage bin 420 are mixed in the coal supply air duct 460 and then connected to the newly added coal powder airflow duct 440.

[0030] Considering that the number of coal mills matched with boiler units of different capacities varies, one or more coal mills 200 can be selected to be configured with a mixed pulverizing system according to the unit capacity and the target requirements for rapid load increase rate. It is recommended to consider configuring a mixed pulverizing system with at least two coal mills 200, with one coal mill 200 as a spare. This can ensure both the rapid load increase rate and the reliability of the system.

[0031] All other unspecified parts belong to the prior art.

Claims

1. A hybrid pulverizing system, comprising a direct-fired pulverizing system (100), a boiler (200), a boiler cold primary air duct (310), and a boiler hot primary air duct (320), wherein the direct-fired pulverizing system (100) includes a coal mill (110), the coal mill (110) is connected to the first burner (210) of the boiler (200) via a primary pulverizing duct (120), the boiler cold primary air duct (310) originates from the boiler primary air fan outlet, the boiler hot primary air duct (320) originates from the boiler air preheater hot primary air outlet, and the boiler cold primary air duct (310) and boiler hot primary air duct (320) are mixed and then connected to the coal mill (110); characterized in that: It also includes a rapid coal pulverizing system (400), which includes a gas-solid separator (410), a coal storage bin (420), a coal storage pipe (430), a new coal pulverizing airflow pipe (440), a waste gas pipe (450), a coal supply air duct (460), a boiler cold primary air bypass (471), and a boiler hot primary air bypass (472). One end of the coal storage pipe (430) is connected to the original coal supply pipe (120), and the other end is connected to the gas-solid separator (410). One end of the new coal pulverizing airflow pipe (440) is connected to the waste gas pipe (450) and the coal supply air duct (460), and the other end is connected to the second burner (220) of the boiler (200). The gas-solid separator (410) is connected to the exhaust gas pipeline (450), and the bottom of the gas-solid separator (410) is connected to the powder storage bin (420); the powder storage bin (420) is connected to the powder supply air duct (460); One end of the boiler cold primary air bypass (471) is connected to the coal supply duct (460) and the other end is connected to the boiler cold primary air duct (310). One end of the boiler hot primary air bypass (472) is connected to the coal supply duct (460) and the other end is connected to the boiler hot primary air duct (320).

2. The hybrid powder-making system according to claim 1, characterized in that: The boiler cold primary air duct (310) and the boiler hot primary air duct (320) are both equipped with dampers (500) at their connection points. The original pulverized coal duct (120) is also equipped with dampers (500) at the connection points between it and the coal mill (110) and between it and the first burner (210).

3. A hybrid flour milling system according to claim 2, wherein: A damper (500) is provided at the connection between the pulverized coal storage silo (420) and the pulverized coal supply duct (460). A damper (500) is provided at the connection between the pulverized coal storage pipe (430) and the original pulverized coal supply pipe (120). A damper (500) is provided at the connection between the exhaust gas pipe (450) and the new pulverized coal airflow pipe (440). A damper (500) is provided at the connection between the pulverized coal supply duct (460) and the new pulverized coal airflow pipe (440). A damper (500) is provided at the connection between the boiler cold primary air bypass (471) and the boiler cold primary air pipe (310), and at the connection between the boiler hot primary air bypass (472) and the boiler hot primary air pipe (320). A damper (500) is provided at the connection between the new pulverized coal airflow pipe (440) and the second burner (220) of the boiler (200).

4. A hybrid flour milling system according to claim 3, wherein: The second burner (220) is located above the first burner (210).

5. A hybrid flour milling system according to claim 4, wherein: When the unit is running stably at a load of 50%, the damper (500) at the connection between the pulverized coal storage pipe (430) and the original pulverized coal delivery pipe (120) is opened, the damper (500) at the connection between the exhaust gas pipe (450) and the new pulverized coal gas flow pipe (440) is opened, and the damper (500) at the connection between the new pulverized coal gas flow pipe (440) and the second burner (220) of the boiler (200) is opened. The rapid pulverized coal supply system (400) starts storing pulverized coal, and the exhaust gas from the gas-solid separator (410) is sent to the boiler (200) for combustion through the exhaust gas pipe (450) and the new pulverized coal gas flow pipe (440). When the material level in the pulverized coal storage bin (420) reaches the set limit, the damper (500) at the connection between the pulverized coal storage pipe (430) and the original pulverized coal delivery pipe (120) is closed, and the damper (500) at the connection between the exhaust gas pipe (450) and the new pulverized coal gas flow pipe (440) is closed. When the unit receives a load increase command from the power grid, the damper (500) at the connection between the pulverized coal storage silo (420) and the pulverized coal supply duct (460), the damper (500) at the connection between the boiler cold primary air bypass (471) and the boiler cold primary air duct (310), the damper (500) at the connection between the boiler hot primary air bypass (472) and the boiler hot primary air duct (320), the damper (500) at the connection between the pulverized coal supply duct (460) and the newly added pulverized coal airflow duct (440), and the damper (500) at the connection between the newly added pulverized coal airflow duct (440) and the second burner (220) of the boiler (200) are opened, and the rapid pulverized coal supply system (400) begins to supply pulverized coal. The boiler (200) supplies pulverized coal; when the material level in the pulverized coal storage silo (420) drops to the set limit, the damper (500) at the connection between the pulverized coal storage silo (420) and the pulverized coal supply duct (460), the damper (500) at the connection between the boiler cold primary air bypass (471) and the boiler cold primary air duct (310), the damper (500) at the connection between the boiler hot primary air bypass (472) and the boiler hot primary air duct (320), the damper (500) at the connection between the pulverized coal supply duct (460) and the newly added pulverized coal airflow duct (440), and the damper (500) at the connection between the newly added pulverized coal airflow duct (540) and the second burner (220) of the boiler (200) are closed.

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