Integrated system and method of middle storage type hot air pulverized coal feeding meagre coal boiler

Abstract

The invention relates to the technical field of thermal power generation, and discloses an integrated system and method for a middle storage type hot air pulverized coal feeding meagre coal boiler, in the system, the output end of a bituminous coal pulverizing unit and the output end of a meagre coal pulverizing unit are correspondingly connected with the input end of a bituminous coal pulverized coal feeder and the input end of a meagre coal pulverized coal feeder respectively; the output ends of the bituminous coal powder feeder and the meagre coal powder feeder are respectively connected to the hearth; the bituminous coal powder feeder and the meagre coal powder feeder are respectively provided with a temperature control pipeline, one end of the air temperature control system is connected to the bituminous coal powder feeder through the temperature control pipeline, and the other end of the air temperature control system is connected to the meagre coal powder feeder through the temperature control pipeline. The air temperature control system is connected with the bituminous coal pulverized coal feeder and the meagre coal pulverized coal feeder through the temperature control pipeline, the temperature of hot air fed into the hearth can be accurately controlled according to different coal types and operation working conditions, the appropriate hot air temperature is beneficial to safe and stable ignition and combustion of pulverized coal of different coal qualities, the combustion process is optimized, the combustion efficiency is improved, and the energy consumption is reduced. And incomplete combustion loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power generation, and in particular to an integrated system and method for a central storage type hot air pulverized coal boiler. Background Art

[0002] In the power industry, lean coal boilers with intermediate storage pulverizing systems are a common type of power generation equipment. These boilers typically utilize a ball mill for pulverizing coal and an oil gun for boiler startup and combustion support.

[0003] Lean coal has low volatility and poor burnout properties, making its combustion stability severely limited in boilers operating under deep peak-shaving conditions. Specifically, under deep peak-shaving conditions, the boiler cannot rely on its own combustion characteristics to maintain stable combustion, and must rely on fuel ignition to start and stop the boiler or maintain stable combustion during operation. This situation has directly led to a significant increase in operating costs. For example, a single 300MW lean-coal boiler unit, under the current frequent start-stop peak-shaving operation mode, experiences as many as 20 cold-state starts and stops annually, each of which consumes a large amount of fuel, bringing the annual fuel consumption to nearly 1,000 tons.

[0004] At the same time, lean coal boilers have significant shortcomings in their deep peak-shaving capabilities. Currently, their deep peak-shaving capabilities only reach approximately 45%-50% of the rated unit load. With the development of the power market, frequent unit starts and stops and deep peak-shaving have become the norm. This low deep peak-shaving capability severely restricts the flexibility and competitiveness of boiler units in the power market.

[0005] Among existing flexibility improvement technologies, burner fuel-assisted combustion is commonly used to enhance the flexibility of lean coal boilers. However, this technique not only further increases fuel consumption but also has limited effect on improving deep peak-shaving capacity, and the boiler's stable combustion performance under low-load conditions remains poor.

[0006] Traditional technologies, designed to improve boiler flexibility, primarily adjust combustion by increasing the number of oil guns or optimizing air distribution. However, these methods are merely local optimization measures and do not fundamentally address the core issues of central-storage lean-coal boilers, such as poor flexibility, high oil consumption, and the inability to quickly switch between coal types using raw coal compartment technology. These issues severely restrict the efficient operation of lean-coal boilers in the face of frequent unit starts and stops and the normalization of deep peak load regulation. A new technical solution is urgently needed to overcome this predicament and enhance the flexibility and economic efficiency of lean-coal boilers with central-storage pulverizing systems. Summary of the Invention

[0007] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide an integrated system and method for a central storage type hot air pulverized coal boiler, so as to solve the technical problems of poor flexibility, high fuel consumption and inability to use raw coal separation technology to achieve rapid switching of coal types in central storage type lean coal boilers.

[0008] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides an integrated system for a central storage type hot air pulverized lean coal boiler, comprising a bituminous coal pulverizing unit, a lean coal pulverizing unit, a bituminous coal pulverizer, a lean coal pulverizer, and an air temperature control system; The output ends of the bituminous coal pulverizing unit and the lean coal pulverizing unit are respectively connected to the input ends of the bituminous coal pulverizing feeder and the lean coal pulverizing feeder; the output ends of the bituminous coal pulverizing feeder and the lean coal pulverizing feeder are respectively connected to the furnace; The bituminous coal pulverizer and the lean coal pulverizer are respectively provided with temperature control pipelines. One end of the air temperature control system is connected to the bituminous coal pulverizer through the temperature control pipeline, and the other end is connected to the lean coal pulverizer through the temperature control pipeline.

[0009] Preferably, the bituminous coal pulverizing unit includes a bituminous coal pulverizing bin, a first raw coal bin, a second raw coal bin, a first steel ball mill and a second steel ball mill; The input end of the first raw coal bin is used to input bituminous coal, and the output end of the first raw coal bin is connected to the input end of the first ball mill; The input end of the second raw coal bin is used to input bituminous coal, and the output end of the second raw coal bin is connected to the input end of the second steel ball mill; The output ends of the first and second steel ball coal mills are respectively connected to the input end of the bituminous coal powder bin, and the output end of the bituminous coal powder bin is connected to the input end of the bituminous coal pulverizer.

[0010] Preferably, the lean coal pulverizing unit includes a lean coal pulverizing bin, a third raw coal bin, a fourth raw coal bin, a third steel ball mill and a fourth steel ball mill; The input end of the third raw coal bin is used to input lean coal, and the output end of the third raw coal bin is connected to the input end of the third ball mill; The input end of the fourth raw coal bin is used to input lean coal, and the output end of the fourth raw coal bin is connected to the input end of the fourth ball mill; The output ends of the third and fourth steel ball coal mills are respectively connected to the input end of the lean coal powder bin, and the output end of the lean coal powder bin is connected to the input end of the lean coal powder feeder.

[0011] Furthermore, the integrated system also includes a powder conveying auger, the input end of which is connected to the bituminous coal powder making system near the furnace, and the output end of which is connected to the bituminous coal powder bin or the lean coal powder bin.

[0012] Preferably, the air temperature control system includes a first air temperature control pipeline and a second air temperature control pipeline; An isolation door is provided between the first air temperature control pipeline and the second air temperature control pipeline to isolate hot air of different temperatures on both sides; The input end of the first air temperature control pipeline is used to input cold air, and the output end of the first air temperature control pipeline is connected to the bituminous coal pulverizer through the temperature control pipeline; The input end of the second air temperature control pipeline is used to input cold air, and the output end of the second air temperature control pipeline is connected to the lean coal pulverizer through the temperature control pipeline.

[0013] Furthermore, the first air temperature control pipeline is provided with a first heating module for heating the cold air entering the first air temperature control pipeline; the second air temperature control pipeline is provided with a second heating module for heating the cold air entering the second air temperature control pipeline.

[0014] Furthermore, a cold air communication pipe is provided between the first air temperature control pipe and the second air temperature control pipe; A plurality of cold air regulating pipelines are further provided between the cold air connecting pipe and the first air temperature control pipeline; The input ends of the plurality of cold air regulating pipelines are connected to the cold air connecting pipe, and the output ends of the plurality of cold air regulating pipelines are connected to the output end of the first heating module.

[0015] Furthermore, a first blower is provided at the input end of the first air temperature control pipeline, and the first temperature rising module includes a first air preheater and a steam heater; The input end of the first blower is used to input cold air, and the output end of the first blower is connected to the bituminous coal pulverizer through a temperature control pipeline after passing through the first air preheater and the steam heater in sequence; One end of the cold air connection pipe is arranged at the output end of the first air blower; Output ends of a plurality of cold air conditioning pipelines are connected to an output end of the steam heater.

[0016] Furthermore, a second air blower is provided at the input end of the second air temperature control pipeline, and the second temperature rising module includes a second air preheater; The input end of the second blower is used to input cold air, and the output end of the second blower is connected to the lean coal feeder through a temperature control pipeline after passing through the second air preheater; One end of the cold air connecting pipe is arranged at the output end of the second air blower.

[0017] In a second aspect, the present invention further provides a method for using an integrated system for a central storage type hot air pulverized coal boiler. The integrated system for a central storage type hot air pulverized coal boiler described above includes the following steps: High volatile bituminous coal is transported to the bituminous coal pulverizer through the bituminous coal pulverizing unit; high calorific value lean coal is transported to the lean coal pulverizer through the lean coal pulverizing unit; The air temperature control system inputs cold air, and heats the pulverized coal in the bituminous coal feeder and the lean coal feeder respectively through temperature regulation in the air temperature control system and transports them to the furnace.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides an integrated system for a central storage type hot air pulverized lean coal boiler, which provides a bituminous coal pulverizing unit and a lean coal pulverizing unit, corresponding to a bituminous coal pulverizer and a lean coal pulverizer, respectively. According to different operating conditions and needs, zoning pulverization of coal types can be achieved, thereby improving the utilization efficiency of coal resources and avoiding the impact of tight supply or price fluctuations of a single type of coal on operating costs. The air temperature control system is connected to the bituminous coal pulverizer and the lean coal pulverizer through temperature control pipelines, and can accurately control the hot air temperature for conveying coal powder according to different coal types and operating conditions. The appropriate hot air temperature contributes to the safe and stable ignition and combustion of different types of coal powder, optimizes the combustion process, improves combustion efficiency, and reduces incomplete combustion losses.

[0019] Furthermore, two parallel pulverizing paths are set up, namely the first raw coal bin and the first ball mill, and the second raw coal bin and the second ball mill, so that the two ball mills can grind and pulverize bituminous coal at the same time, greatly increasing the bituminous coal processing capacity per unit time. Compared with a single mill system, the pulverizing efficiency of bituminous coal is significantly improved, and bituminous coal powder that meets the combustion requirements of boilers can be prepared more quickly. Furthermore, by setting up two parallel pulverizing lines—one for the third raw coal bunker and the third ball mill, and the other for the fourth raw coal bunker and the fourth ball mill—lean coal can be ground simultaneously. This parallel model significantly increases the amount of lean coal processed per unit time. Compared to pulverizing with a single pulverizer, it significantly speeds up the preparation of lean coal, effectively improving pulverizing efficiency and more quickly meeting boiler demand for lean coal.

[0020] Furthermore, the pulverized coal conveying auger is connected to the adjacent furnace's bituminous coal pulverization system, allowing the pulverized coal resources of different furnaces to be allocated and shared with each other. If there is no pulverized coal in the boiler pulverized coal bin, the adjacent furnace can first grind the bituminous coal pulverized coal and then use the pulverized coal conveying auger to transport it to the bituminous coal pulverized coal bin of the main furnace. Then, the hot air heated by the steam heater and the plasma device can be used for direct oil-free ignition. If the bituminous coal or lean coal pulverizing unit of the main furnace fails, the pulverizing capacity is insufficient, or there is excess pulverized coal in the adjacent furnace, the pulverized coal from the adjacent furnace can also be transported to the bituminous coal pulverized coal bin or lean coal pulverized coal bin of the main furnace via the pulverized coal conveying auger, avoiding resource waste and improving the utilization efficiency of the pulverized coal resources of the entire power plant.

[0021] Furthermore, the first and second air temperature control lines are connected to the bituminous coal pulverizer and lean coal pulverizer, respectively, and each is equipped with a heating and temperature control module. This enables the system to precisely control the temperature of the hot air conveying the pulverized coal, based on the different combustion characteristics of bituminous and lean coal. For bituminous coal, which has high volatility and is easily ignited, a relatively low and appropriate hot air temperature is provided to ensure safe combustion. For lean coal, which has low volatility and poor burnout, a higher temperature hot air is provided to promote ignition and combustion, thereby improving combustion efficiency and reducing losses from incomplete combustion.

[0022] Furthermore, the cold air connection pipe and several cold air conditioning pipes provide additional dimensions for temperature regulation in the first air temperature control pipe. After the first heating module heats the cold air, the cold air in the cold air connection pipe is introduced to the output of the first heating module through the cold air conditioning pipe, allowing for further fine-tuning of the heated air temperature.

[0023] Furthermore, the first air preheater is arranged after the output end of the first blower, and can use the waste heat of the flue gas at the tail end of the boiler to preliminarily heat the cold air. This process recycles the waste heat of the flue gas that would otherwise be wasted, reducing the energy consumption of the subsequent steam heater, improving the thermal energy utilization efficiency of the entire system, reducing energy waste, and lowering operating costs. When the boiler is started and ignited in a cold state, the air preheater cannot heat the cold air normally. At this time, the steam heater is first used to heat the cold air for conveying pulverized coal to the plasma burner for cold ignition; when the boiler is operating normally, the first air preheater is used to heat the cold air, the steam heater is disabled, and the cold air regulating pipeline is used to adjust the hot air temperature to prevent premature ignition of the bituminous coal pulverized coal due to excessive temperature, thereby ensuring stable operation of the boiler.

[0024] Furthermore, the second air preheater uses the waste heat of the flue gas at the tail end of the boiler to heat the cold air, recovering the heat that would have been lost and using it to increase the air temperature, significantly reducing energy waste, improving the overall energy utilization efficiency of the system, and reducing operating costs.

[0025] The present invention also provides a method for using an integrated system of a central storage type hot air pulverized lean coal boiler. High volatile bituminous coal has a high volatile content, a low ignition temperature, and a fast combustion speed. The air temperature control system provides a relatively low and precise hot air temperature for the bituminous coal pulverizer, which can enable the bituminous coal to quickly reach the ignition point and burn stably after entering the furnace, avoiding problems such as premature precipitation and ignition of bituminous coal volatiles or even deflagration due to excessively high temperature, thereby improving the combustion safety of bituminous coal. High calorific value lean coal has low volatile matter and poor burnability, and requires higher temperature hot air to promote its ignition and full combustion. The system provides suitable high-temperature hot air for the lean coal pulverizer, which can improve the ignition conditions of the lean coal, accelerate the combustion reaction speed, make the lean coal burn more fully in the furnace, reduce the loss of unburned carbon, and improve combustion efficiency. The air temperature control system of the present invention can quickly adjust the hot air temperature according to the combustion conditions of the coal powder, and adapt to the changes in coal quality in a timely manner. The precise temperature control can make the coal powder burn under the optimal conditions, solve the problem that the hot air temperature cannot simultaneously meet the safety of bituminous coal combustion and the stability of lean coal combustion, and improve the flexibility of the lean coal boiler unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of an integrated system of a central storage type hot air pulverized coal boiler according to an embodiment of the present invention; In the figure: 1. Bituminous coal pulverized bunker; 2. Lean coal pulverized bunker; 3. First raw coal bunker; 4. Second raw coal bunker; 5. Third raw coal bunker; 6. Fourth raw coal bunker; 7. First ball mill; 8. Second ball mill; 9. Third ball mill; 10. Fourth ball mill; 11. Pulverized coal conveying auger; 12. First blower; 13. Second blower; 14. First air preheater; 15. Second air preheater; 16. Steam heater; 17. Isolation door; 18. Bituminous coal pulverized feeder; 19. Lean coal pulverized feeder; 20. First cold air regulating door; 21. Second cold air regulating door; 22. Cold air connecting pipe. DETAILED DESCRIPTION

[0027] 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide an integrated system and method for a central storage type hot air pulverized coal boiler to solve the technical problems of poor flexibility, high fuel consumption and inability to use raw coal separation technology to achieve rapid switching of coal types in central storage type lean coal boilers.

[0029] The present invention is described in further detail below with reference to the accompanying drawings: See also Figure 1 In one embodiment of the present invention, an integrated system of a central storage type hot air pulverized lean coal boiler is provided, comprising a bituminous coal pulverizing unit, a lean coal pulverizing unit, a bituminous coal pulverizing feeder 18, a lean coal pulverizing feeder 19 and an air temperature control system; the output ends of the bituminous coal pulverizing unit and the lean coal pulverizing unit are respectively connected to the input ends of the bituminous coal pulverizing feeder 18 and the lean coal pulverizing feeder 19; the output ends of the bituminous coal pulverizing feeder 18 and the lean coal pulverizing feeder 19 are respectively connected to the furnace; the bituminous coal pulverizing feeder 18 and the lean coal pulverizing feeder 19 are respectively provided with a temperature control pipeline, one end of the air temperature control system is connected to the bituminous coal pulverizing feeder 18 through the temperature control pipeline, and the other end is connected to the lean coal pulverizing feeder 19 through the temperature control pipeline.

[0030] Specifically, the bituminous coal pulverizing unit includes a bituminous coal powder bin 1, a first raw coal bin 3, a second raw coal bin 4, a first steel ball mill 7 and a second steel ball mill 8; the input end of the first raw coal bin 3 is used to input bituminous coal, and the output end of the first raw coal bin 3 is connected to the input end of the first steel ball mill 7; the input end of the second raw coal bin 4 is used to input bituminous coal, and the output end of the second raw coal bin 4 is connected to the input end of the second steel ball mill 8; the output ends of the first steel ball mill 7 and the second steel ball mill 8 are respectively connected to the input end of the bituminous coal powder bin 1, and the output end of the bituminous coal powder bin 1 is connected to the input end of the bituminous coal pulverizer 18.

[0031] Specifically, the lean coal pulverizing unit includes a lean coal powder bin 2, a third raw coal bin 5, a fourth raw coal bin 6, a third steel ball mill 9 and a fourth steel ball mill 10; the input end of the third raw coal bin 5 is used to input lean coal, and the output end of the third raw coal bin 5 is connected to the input end of the third steel ball mill 9; the input end of the fourth raw coal bin 6 is used to input lean coal, and the output end of the fourth raw coal bin 6 is connected to the input end of the fourth steel ball mill 10; the output ends of the third steel ball mill 9 and the fourth steel ball mill 10 are respectively connected to the input end of the lean coal powder bin 2, and the output end of the lean coal powder bin 2 is connected to the input end of the lean coal pulverizer 19.

[0032] The integrated system further includes a powder conveying auger 11 , the input end of which is connected to the bituminous coal pulverizing system near the furnace, and the output end of which is connected to the bituminous coal pulverizing bin 1 or the lean coal pulverizing bin 2 .

[0033] In this embodiment, after the system is modified, the bituminous coal powder can be first ground in the adjacent furnace, and the bituminous coal powder can be supplied to the bituminous coal powder bin 1 using the powder conveying auger 11. After the powder level rises, the air and smoke system is put into operation.

[0034] Specifically, the air temperature control system includes a first air temperature control pipeline and a second air temperature control pipeline; An isolation door 17 is provided between the first air temperature control pipeline and the second air temperature control pipeline; The input end of the first air temperature control pipeline is used to input cold air, and the output end of the first air temperature control pipeline is connected to the bituminous coal feeder 18 through a temperature control pipeline; The input end of the second air temperature control pipeline is used to input cold air, and the output end of the second air temperature control pipeline is connected to the lean coal feeder 19 through a temperature control pipeline; The first air temperature control pipeline is provided with a first heating module for heating the cold air entering the first air temperature control pipeline; the second air temperature control pipeline is provided with a second heating module for heating the cold air entering the second air temperature control pipeline.

[0035] Among them, a cold air communication pipe 22 is also provided between the first air temperature control pipe and the second air temperature control pipe; Several cold air regulating pipelines are also provided between the cold air connecting pipe 22 and the first air temperature control pipeline; The input ends of the plurality of cold air regulating pipelines are connected to the cold air connecting pipe 22, and the output ends of the plurality of cold air regulating pipelines are connected to the output end of the first heating module.

[0036] Among them, a first air blower 12 is provided at the input end of the first air temperature control pipeline, and the first temperature rising module includes a first air preheater 14 and a steam heater 16; The input end of the first blower 12 is used to input cold air, and the output end of the first blower 12 is connected to the bituminous coal pulverizer 18 through a temperature control pipeline after passing through the first air preheater 14 and the steam heater 16 in sequence; One end of the cold air connection pipe 22 is arranged at the output end of the first air blower 12; The output ends of the plurality of cold air conditioning pipelines are connected to the output end of the steam heater 16 .

[0037] Among them, a second air blower 13 is provided at the input end of the second air temperature control pipeline, and the second temperature rising module includes a second air preheater 15; The input end of the second blower 13 is used to input cold air, and the output end of the second blower 13 is connected to the lean coal feeder 19 through a temperature control pipeline after passing through the second air preheater 15; One end of the cold air connection pipe 22 is arranged at the output end of the second air blower 13 .

[0038] In this embodiment, the plurality of cold air regulating pipelines include a first cold air regulating pipeline and a second cold air regulating pipeline; a first cold air regulating door 20 is provided on the first cold air regulating pipeline, and a second cold air regulating door 21 is provided on the second cold air regulating pipeline.

[0039] In this embodiment, the burner is transformed into a plasma burner so that plasma ignition and combustion support can be used during the ignition and deep peak regulation process of the boiler to achieve the purpose of saving oil.

[0040] In this embodiment, an isolation door 17 is installed between the first and second air temperature control lines, preventing interference between the temperature control of the first and second air temperature control lines. A cold air communication pipe 22, installed between the first and second air temperature control lines, is connected and equipped with a cold air blending control valve to reduce the temperature of the first air temperature control line for delivery to the bituminous coal pulverizer 18. A steam heater is installed within the first air temperature control line to increase the primary air temperature during cold start ignition, allowing for direct plasma ignition of the pulverized coal.

[0041] This embodiment utilizes coal storage and grinding in separate bins, plasma ignition, and coordinated air temperature control technology to achieve efficient peak load regulation and economical operation for lean coal-fired boilers. A dynamic cold / hot primary air blending circuit is designed to ensure safe bituminous coal pulverization and operation. This application reduces cold start-up and shutdown, as well as fuel oil consumption, by over 95%, extending the load regulation range to 25%-100%, significantly improving economic efficiency and safety.

[0042] In summary, the present invention provides an integrated system for a central storage type hot air pulverized lean coal boiler, which corresponds to a bituminous coal pulverizing unit and a lean coal pulverizing unit respectively by setting a bituminous coal pulverizing unit and a lean coal pulverizing unit. According to different operating conditions and needs, zoning pulverization of coal types can be achieved, the utilization efficiency of coal resources can be improved, and the impact of tight supply or price fluctuations of a single type of coal on operating costs can be avoided. The air temperature control system is connected to the bituminous coal pulverizer and the lean coal pulverizer through temperature control pipelines, and can accurately control the temperature of the hot air sent to the furnace according to different coal types and operating conditions. The appropriate hot air temperature helps the coal powder to ignite and burn safely and stably, optimize the combustion process, improve combustion efficiency, and reduce incomplete combustion losses. The system transforms the lean coal boiler into a plasma burner, which corresponds to the burner installed on the bituminous coal pulverizer, for cold oil-free ignition and stable combustion.

[0043] Example 2 This embodiment provides a method for using an integrated system for a central storage type hot air pulverized coal boiler. The method is based on the above-described integrated system for a central storage type hot air pulverized coal boiler, and includes the following steps: The high-volatile bituminous coal is transported to the bituminous coal pulverizing unit 18; the high-calorific-value lean coal is transported to the lean coal pulverizing unit 19; The air temperature control system inputs cold air, and heats the pulverized coal in the bituminous coal feeder 18 and the lean coal feeder 19 to different temperatures through temperature control in the air temperature control system. The heated pulverized coal is transported to the furnace through the bituminous coal feeder 18 and the lean coal feeder 19 respectively.

[0044] In this embodiment, when the boiler is cold-started, the pulverized coal bin 1 is empty. If the temperature is gradually raised by ignition with an oil gun, and the pulverizing system is then started to grind the pulverized coal, and the pulverized coal is added to increase the parameters after the pulverized coal level reaches a certain level, a single cold start-up consumes over 50 tons of oil. Therefore, after the system is modified, the pulverized coal can be ground by the adjacent furnace, and the pulverized coal can be supplied to the pulverized coal bin 1 using the pulverized coal conveying auger 11. After the pulverized coal level rises, the air and smoke system is put into operation, the first and second air blowers 12, 13 are started, the isolation door 17 is closed, the steam heater 16 is put into operation to increase the air temperature of the first air temperature control pipeline, and the plasma and burner in the pulverized coal bin 1 are put into operation, and the pulverized coal is used for cold ignition.

[0045] As the primary air temperature at the air preheater outlet gradually rises, the steam heater 16 in the first air temperature control line can be promptly deactivated. The air temperature in the first air temperature control line is maintained at ≤200°C, and the air-powder mixture temperature is maintained at ≤160°C, through the first and second cold air adjustment doors 20 and 21. Based on the system's secondary air temperature, the first and second ball mills 7 and 8 are started to grind bituminous coal. To ensure safe operation of the bituminous coal pulverizing system, the mill outlet temperature is adjusted to ≤70°C.

[0046] During normal operation, high-volatile bituminous coal is transported to the first raw coal bin 3 and the second raw coal bin 4 and fed into the first steel ball mill 7 and the second steel ball mill 8 to be ground into the bituminous coal and transported to the bituminous coal powder bin 1. Then, the bituminous coal powder is fed into the furnace through the bituminous coal powder feeder 18, thereby achieving the purpose of stable combustion of the boiler; high-calorific value lean coal is transported to the third raw coal bin 5 and the fourth raw coal bin 6 and fed into the third steel ball mill 9 and the fourth steel ball mill 10 to be ground into the bituminous coal and transported to the lean coal powder bin 2. Then, the lean coal powder is fed into the furnace through the lean coal powder feeder 19, thereby achieving the purpose of peak output of the boiler.

[0047] During the deep peak regulation period of the unit, the speed of the lean coal pulverizer 19 is adjusted to the lowest or stopped, and only the bituminous coal pulverizer bin 1 is used to maintain the bituminous coal pulverizer 18 for stable combustion. The load can be deeply adjusted to 25%-30% of the unit's rated output, and plasma can be used for stable combustion when necessary.

[0048] During the high load stage, the speed of the bituminous coal pulverizer 18 can be appropriately reduced and the speed of the lean coal pulverizer 19 can be increased to increase the proportion of high calorific value lean coal entering the furnace and improve the peak output capacity of the unit.

[0049] In summary, the present invention also provides a method for using an integrated system of a central storage type hot air pulverized lean coal boiler, wherein high volatile bituminous coal has a high volatile content, a low ignition temperature, and a fast combustion speed. The air temperature control system provides a relatively low and precise hot air temperature for the bituminous coal pulverizer, which can enable the bituminous coal to quickly reach the ignition point and burn stably after entering the furnace, avoiding problems such as premature ignition or even deflagration caused by excessively high hot air temperature, and improving the combustion efficiency and stability of the bituminous coal. High calorific value lean coal has low volatile matter and poor burnability, and requires higher temperature hot air to promote its ignition and full combustion. The system provides suitable high-temperature hot air for the lean coal pulverizer, which can improve the ignition conditions of the lean coal, accelerate the combustion reaction speed, make the lean coal burn more fully in the furnace, reduce the loss of unburned carbon, and improve the combustion efficiency. The air temperature control system of the present invention can quickly adjust the hot air temperature according to the combustion conditions of the coal powder, and adapt to the changes in coal quality in a timely manner. The precise temperature control can make the coal powder burn under the optimal conditions, solve the problem that the hot air temperature cannot simultaneously meet the safety of bituminous coal combustion and the stability of lean coal combustion, and improve the flexibility of the lean coal boiler unit.

[0050] 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. An integrated system for a central storage hot air pulverized coal boiler, characterized in that: It includes a bituminous coal pulverizing unit, a lean coal pulverizing unit, a bituminous coal pulverizing machine (18), a lean coal pulverizing machine (19), and an air temperature control system; The output ends of the bituminous coal pulverizing unit and the lean coal pulverizing unit are respectively connected to the input ends of the bituminous coal pulverizing feeder (18) and the lean coal pulverizing feeder (19); the output ends of the bituminous coal pulverizing feeder (18) and the lean coal pulverizing feeder (19) are respectively connected to the furnace; The bituminous coal pulverizer (18) and the lean coal pulverizer (19) are respectively provided with temperature control pipelines, one end of the air temperature control system is connected to the bituminous coal pulverizer (18) through the temperature control pipeline, and the other end is connected to the lean coal pulverizer (19) through the temperature control pipeline.

2. The integrated system of a central storage hot air pulverized coal boiler according to claim 1 is characterized in that: The bituminous coal pulverizing unit comprises a bituminous coal pulverizing bin (1), a first raw coal bin (3), a second raw coal bin (4), a first steel ball coal mill (7), and a second steel ball coal mill (8); The input end of the first raw coal bin (3) is used to input bituminous coal, and the output end of the first raw coal bin (3) is connected to the input end of the first steel ball mill (7); The input end of the second raw coal bin (4) is used to input bituminous coal, and the output end of the second raw coal bin (4) is connected to the input end of the second steel ball mill (8); The output ends of the first steel ball coal mill (7) and the second steel ball coal mill (8) are respectively connected to the input end of the bituminous coal powder bin (1), and the output end of the bituminous coal powder bin (1) is connected to the input end of the bituminous coal powder feeder (18).

3. The integrated system of a central storage hot air pulverized coal boiler according to claim 1, characterized in that: The lean coal pulverizing unit comprises a lean coal pulverizing bin (2), a third raw coal bin (5), a fourth raw coal bin (6), a third steel ball coal mill (9), and a fourth steel ball coal mill (10); The input end of the third raw coal bin (5) is used to input lean coal, and the output end of the third raw coal bin (5) is connected to the input end of the third steel ball mill (9); The input end of the fourth raw coal bin (6) is used to input lean coal, and the output end of the fourth raw coal bin (6) is connected to the input end of the fourth steel ball mill (10); The output ends of the third steel ball coal mill (9) and the fourth steel ball coal mill (10) are respectively connected to the input end of the lean coal powder bin (2), and the output end of the lean coal powder bin (2) is connected to the input end of the lean coal powder feeder (19).

4. The integrated system of a central storage hot air pulverized coal boiler according to claim 2 or 3, characterized in that: The integrated system further comprises a powder conveying auger (11), the input end of the powder conveying auger (11) being connected to a bituminous coal pulverizing system near the furnace, and the output end of the powder conveying auger (11) being connected to a bituminous coal pulverizing bin (1) or a lean coal pulverizing bin (2).

5. The integrated system of a central storage hot air pulverized coal boiler according to claim 1, characterized in that: The air temperature control system includes a first air temperature control pipeline and a second air temperature control pipeline; An isolation door (17) is provided between the first air temperature control pipeline and the second air temperature control pipeline; The input end of the first air temperature control pipeline is used to input cold air, and the output end of the first air temperature control pipeline is connected to the bituminous coal pulverizer (18) through the temperature control pipeline; The input end of the second air temperature control pipeline is used to input cold air, and the output end of the second air temperature control pipeline is connected to the lean coal powder feeder (19) through the temperature control pipeline.

6. The integrated system of a central storage hot air pulverized coal boiler according to claim 5, characterized in that: The first air temperature control pipeline is provided with a first heating module for heating the cold air entering the first air temperature control pipeline; the second air temperature control pipeline is provided with a second heating module for heating the cold air entering the second air temperature control pipeline.

7. The integrated system of a central storage hot air pulverized coal boiler according to claim 6, characterized in that: A cold air communication pipe (22) is further provided between the first air temperature control pipe and the second air temperature control pipe; A plurality of cold air regulating pipelines are further provided between the cold air connecting pipe (22) and the first air temperature control pipeline; The input ends of the plurality of cold air regulating pipelines are connected to the cold air connecting pipe (22), and the output ends of the plurality of cold air regulating pipelines are connected to the output end of the first temperature increasing module.

8. The integrated system of a central storage hot air pulverized coal boiler according to claim 7, characterized in that: A first air blower (12) is provided at the input end of the first air temperature control pipeline, and the first temperature raising module includes a first air preheater (14) and a steam heater (16); The input end of the first blower (12) is used to input cold air, and the output end of the first blower (12) is connected to the bituminous coal pulverizer (18) through a temperature control pipeline after passing through the first air preheater (14) and the steam heater (16); One end of the cold air connecting pipe (22) is arranged at the output end of the first air blower (12); The output ends of the plurality of cold air conditioning pipelines are connected to the output end of the steam heater (16).

9. The integrated system of a central storage hot air pulverized coal boiler according to claim 6, characterized in that: A second air blower (13) is provided at the input end of the second air temperature control pipeline, and the second temperature rising module includes a second air preheater (15); The input end of the second air blower (13) is used to input cold air, and the output end of the second air blower (13) is connected to the lean coal powder feeder (19) through a temperature control pipeline after passing through the second air preheater (15); One end of the cold air connecting pipe (22) is arranged at the output end of the second air blower (13).

10. A method for using an integrated system of a central storage hot air pulverized coal boiler, characterized in that: An integrated system for a central storage hot air pulverized coal boiler according to any one of claims 1 to 9 includes the following processes: The high-volatile bituminous coal is transported to the bituminous coal pulverizing machine (18) through the bituminous coal pulverizing unit; the high-calorific-value lean coal is transported to the lean coal pulverizing machine (19) through the lean coal pulverizing unit; The air temperature control system inputs cold air and controls different hot air temperatures through temperature regulation in the air temperature control system, so as to respectively transport the pulverized coal in the bituminous coal feeder (18) and the lean coal feeder (19) into the furnace.

Images