A pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units

Abstract

The present application discloses a pulverizing coordination system for improving the deep peak-shaving capability of a coal-fired unit, comprising: a first coal mill, a second coal mill, a regulating coal mill, a mixed temperature air supply system, a powder supply system and a boiler; the first coal mill is connected to the boiler through a first powder pipe, and the second coal mill is connected to the boiler through a second powder pipe. The mixed temperature air supply system is connected to the boiler, and a branch at the output end of the mixed temperature air supply system is respectively connected to the input ends of the first coal mill, the second coal mill and the regulating coal mill, and another branch is respectively connected to the first powder pipe and the second powder pipe. The output end of the regulating coal mill is respectively connected to the boiler and the input end of the powder supply system, and one of the passages at the output end of the powder supply system is connected to the boiler, and another passage is respectively connected to the first powder pipe and the second powder pipe. The powder supply system can adjust the concentration in each powder pipe of the coal mill in real time according to different load conditions, improve the uniformity of air and powder between each powder pipe on the same layer, and adjust the powder delivery air temperature in real time.

Description

Technical Field

[0001] The present application relates to the technical field of deep peak regulation of coal-fired units, and specifically to a pulverizing coordination system for improving the deep peak regulation capability of coal-fired units. Background Art

[0002] As the proportion of new energy increases year by year, the safe and stable supply of electricity has been greatly challenged, and the peak-shaving pressure faced by coal-fired units has also increased, which has put forward higher requirements on the depth and speed of peak-shaving of coal-fired units. On the one hand, under deep peak-shaving conditions, there are generally problems such as large deviation of wind and powder in the same layer burner, low wind temperature, delayed ignition, unstable combustion and even fire extinguishing. The commonly used method is to achieve stable combustion by optimizing the burner structure to concentrate the coal powder, but because it cannot solve the problems of large deviation of wind and powder, low wind temperature and inability to adjust the coal powder concentration in real time, the actual application effect is not ideal, and the fixed burner structure cannot adapt to the needs of changing coal types; on the other hand, the rapid change of load during deep peak-shaving will also cause powder supply delays due to the inherent characteristics of the coal mill, which seriously restricts the rapid adjustment of the unit load. There is no mature technical application at present.

[0003] Therefore, how to provide a system to improve the deep peak-shaving capability of coal-fired units is a problem that technical personnel in this field need to solve. Summary of the invention

[0004] The purpose of this application is to provide a pulverizing coordination system with a reasonable process design and capable of improving the deep peak-shaving capability of coal-fired units.

[0005] To achieve the above-mentioned purpose, the present application provides a pulverizing coordination system for improving the deep peak-shaving capability of a coal-fired unit, comprising: a first coal mill, a second coal mill, a regulating coal mill, a mixed temperature air supply system, a powder supply system and a boiler;

[0006] The output end of the first coal mill is connected to the boiler through a first powder pipe, and the output end of the second coal mill is connected to the boiler through a second powder pipe;

[0007] The input end of the mixed temperature air supply system is connected to the boiler, and one of the branches at the output end of the mixed temperature air supply system is respectively connected to the input ends of the first coal mill, the second coal mill and the regulating coal mill; the other branch at the output end of the mixed temperature air supply system is respectively connected to the first powder hose and the second powder hose;

[0008] The output end of the regulating coal mill is respectively connected to the boiler and the input end of the powder supply system, one of the passages at the output end of the powder supply system is connected to the boiler, and the other passage at the output end of the powder supply system is respectively connected to the first powder pipe and the second powder pipe.

[0009] In some embodiments, the mixed temperature air supply system includes: a hot air duct and a cold air duct; the input end of the hot air duct is connected to the boiler, and the output end of the hot air duct is divided into a first hot air duct and a second hot air duct;

[0010] The first hot air pipe is connected to the first coal mill, the second coal mill and the input end of the regulating coal mill respectively; the second hot air pipe is connected to the first powder pipe and the second powder pipe respectively;

[0011] The output end of the cold air duct is divided into a first cold air duct and a second cold air duct; the first cold air duct is connected to the first hot air duct, and the second cold air duct is connected to the second hot air duct to achieve mixed temperature adjustment.

[0012] In some embodiments, the pulverized material supply system includes: a cyclone separator and a pulverized coal bin;

[0013] The output end of the regulating coal mill is connected to the input end of the cyclone separator, the gas output end of the cyclone separator is connected to the boiler, the solid output end of the cyclone separator is connected to the input end of the coal powder bin, and the output end of the coal powder bin is split and provided with a first powder conveying pipe and a second powder conveying pipe, the first powder conveying pipe is connected to the first powder pipe, and the second powder conveying pipe is connected to the second powder pipe.

[0014] In some embodiments, a first screw powder feeder is disposed on the first powder conveying pipe passage, and a second screw powder feeder is disposed on the second powder conveying pipe passage.

[0015] In some embodiments, a first air-powder mixer is provided on the first powder tube, and a second air-powder mixer is provided on the second powder tube;

[0016] The first powder conveying pipe is connected to the first air-powder mixer, and the second powder conveying pipe is connected to the second air-powder mixer.

[0017] In some embodiments, a first air-powder monitoring device is provided on the first powder hose, and a second air-powder monitoring device is provided on the second powder hose.

[0018] In some embodiments, the boiler is connected to an air preheater, and the input end of the hot air duct is connected to the air preheater.

[0019] In some embodiments, a main path gate is provided between the output end of the regulating coal mill and the boiler, and a branch path gate is provided between the output end of the regulating coal mill and the powder supply system.

[0020] In some embodiments, a fan is connected to the input end of the cold air duct.

[0021] In some embodiments, the first hot air duct, the second hot air duct, the first cold air duct and the second cold air duct are all provided with air volume control valves.

[0022] Relative to the above background technology, the present application is provided with a first coal mill, a second coal mill, a regulating coal mill, a mixed temperature air supply system, a powder supply system and a boiler; the output end of the first coal mill is connected to the boiler through a first powder pipe, and the output end of the second coal mill is connected to the boiler through a second powder pipe. The input end of the mixed temperature air supply system is connected to the boiler, a branch of the output end of the mixed temperature air supply system is respectively connected to the input ends of the first coal mill, the second coal mill and the regulating coal mill, and another branch of the output end of the mixed temperature air supply system is respectively connected to the first powder pipe and the second powder pipe. The output end of the regulating coal mill is respectively connected to the boiler and the input end of the powder supply system, and one of the passages at the output end of the powder supply system is connected to the boiler, and another passage at the output end of the powder supply system is respectively connected to the first powder pipe and the second powder pipe. The two passages at the output end of the powder supply system are respectively used to realize the powder filling of the coal mill input end and discharge the exhaust gas carrying coal powder, and the concentration in each powder pipe of the coal mill can be adjusted in real time according to different load conditions. The two branches at the output end of the mixed temperature air supply system are used to meet the basic air supply demand at the input end of the coal mill and the additional air supply demand at the output end of the coal mill, and the temperature of the powder delivery air can be adjusted in real time. Therefore, this system can improve the concentration of coal powder, improve the uniformity of air and powder between each powder pipe on the same layer, increase the powder delivery air temperature, and reduce the primary air rate. It completely solves the problem of unstable combustion in deep adjustment conditions and improves the operating economy of normal load. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the structure of a pulverizing coordination system for improving the deep peak-shaving capability of a coal-fired unit provided in an embodiment of the present application.

[0025] in:

[0026] 1-first coal mill, 2-second coal mill, 3-regulating coal mill, 4-boiler, 5-hot air duct, 51-first hot air duct, 52-second hot air duct, 6-cold air duct, 61-first cold air duct, 62-second cold air duct, 7-cyclone separator, 8-coal powder bin, 81-first spiral powder feeder, 82-second spiral powder feeder, 91-first air-powder mixer, 92-second air-powder mixer, 10-first air-powder monitoring device, 11-second air-powder monitoring device, 12-air preheater, 13-main road plug-in door, 14-branch road plug-in door, 15-fan. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] Reference Manual Attached Figure 1 , attached Figure 1 The schematic diagram of the structure of the pulverizing coordination system for improving the deep peak-shaving capability of the coal-fired unit provided in the embodiment of the present application includes: a first coal mill 1, a second coal mill 2, a regulating coal mill 3, a mixed temperature air supply system, a powder supply system and a boiler 4; the output end of the first coal mill 1 is connected to the boiler 4 through a first powder pipe, and the output end of the second coal mill 2 is connected to the boiler 4 through a second powder pipe. The input end of the mixed temperature air supply system is connected to the boiler 4, and a branch of the output end of the mixed temperature air supply system is respectively connected to the input ends of the first coal mill 1, the second coal mill 2 and the regulating coal mill 3, and another branch of the output end of the mixed temperature air supply system is respectively connected to the first powder pipe and the second powder pipe. The output end of the regulating coal mill 3 is respectively connected to the boiler 4 and the input end of the powder supply system, and one of the passages at the output end of the powder supply system is connected to the boiler 4, and another passage at the output end of the powder supply system is respectively connected to the first powder pipe and the second powder pipe. The two paths at the output end of the powder supply system are used to realize the powder filling at the input end of the coal mill and discharge the exhaust gas carrying coal powder. The concentration in each powder pipe of the coal mill can be adjusted in real time according to different load conditions. The two branches at the output end of the mixed temperature air supply system are used to realize the basic air supply demand at the input end of the coal mill and the additional air supply demand at the output end of the coal mill, and the powder delivery air temperature can be adjusted in real time.

[0030] Therefore, this system can improve the coal powder concentration, improve the air-powder uniformity between powder pipes on the same layer, increase the powder delivery air temperature, reduce the primary air rate and other advantages, completely solving the problem of unstable combustion under deep adjustment conditions and improving the operating economy of normal load.

[0031] Furthermore, the mixed temperature air supply system includes: a hot air duct 5 and a cold air duct 6; the input end of the hot air duct 5 is connected to the boiler 4, and the hot air gas is provided by the boiler 4. At the same time, the output end of the hot air duct 5 is divided and provided with a first hot air duct 51 and a second hot air duct 52; and the input end of the cold air duct 6 is introduced into the cold air gas, and the output end of the cold air duct 6 is divided and provided with a first cold air duct 61 and a second cold air duct 62. Among them, the first hot air duct 51 is respectively connected to the input ends of the first coal mill 1, the second coal mill 2 and the regulating coal mill 3, and the second hot air duct 52 is respectively connected to the first powder hose and the second powder hose; and the first cold air duct 61 is connected to the first hot air duct 51, and the second cold air duct 62 is connected to the second hot air duct 52; by first dividing the hot air and the cold air, and then merging them respectively, it is ensured that the input to the coal mill input and output ends are mixed temperature air. In specific use, the opening of the cold air duct and the hot air duct can be adjusted according to actual needs, and finally the temperature regulation of the powder delivery air is achieved.

[0032] Furthermore, the above-mentioned material distribution and supply system includes: a cyclone separator 7 and a pulverized coal bin 8; the output end of the above-mentioned regulating coal mill 3 is connected to the input end of the cyclone separator 7, the gas output end of the above-mentioned cyclone separator 7 is connected to the boiler 4, the solid output end of the cyclone separator 7 is connected to the input end of the pulverized coal bin 8, and the output end of the above-mentioned pulverized coal bin 8 is divided into a first powder conveying pipe connected to the first powder pipe and a second powder conveying pipe connected to the second powder pipe.

[0033] After the powder delivery wind enters the cyclone separator 7, the exhaust gas of the powder delivery is output to the boiler 4 through the gas output end for combustion, and the qualified coal powder solid is delivered to the powder coal bin 8 from the solid output end due to gravity. Valves are provided between the powder coal bin 8 and the first powder pipe and the second powder pipe. If powder delivery is required, the valve opening is adjusted according to the demand; if powder delivery is not required, the valve is closed, and the coal powder solid is stored in the powder coal bin 8, realizing the powder storage function of the system, avoiding temporary production of coal powder during powder delivery, and reducing the use efficiency of the system.

[0034] Furthermore, the passage of the first powder conveying pipe is provided with a first spiral powder feeder 81, and the passage of the second powder conveying pipe is provided with a second spiral powder feeder 82. The first spiral powder feeder 81 and the second spiral powder feeder 82 can quickly adjust the powder supply amount of the coal mill by increasing or decreasing their own rotation speeds.

[0035] The specific structure and arrangement of the first spiral powder feeder 81 and the second spiral powder feeder 82 may refer to the prior art and will not be described in detail herein.

[0036] Furthermore, the first powder tube is provided with a first air-powder mixer 91 , and the first powder conveying tube is communicated with the first air-powder mixer 91 ; the second powder tube is provided with a second air-powder mixer 92 , and the second powder conveying tube is communicated with the second air-powder mixer 92 .

[0037] The specific structure and arrangement of the first air-powder mixer 91 and the second air-powder mixer 92 may refer to the prior art and will not be described in detail herein.

[0038] Furthermore, the first powder hose is provided with a first air-powder monitoring device 10, and the second powder hose is provided with a second air-powder monitoring device 11. Both the first air-powder monitoring device 10 and the second air-powder monitoring device 11 can detect the air-powder concentration in the powder hose in real time, and feed back the detection results to the user, so that the user can adjust the opening of each ventilation duct and powder duct according to the feedback results.

[0039] The specific structure and configuration of the first air-powder monitoring device 10 and the second air-powder monitoring device 11 can be referred to the prior art, and will not be described in detail herein.

[0040] Furthermore, the boiler 4 is connected to the air preheater 12, and the input end of the hot air duct 5 is connected to the air preheater 12. The air preheater is used to adjust the temperature of the gas input into the hot air duct 5 by using the heat of the boiler 4. The specific structure and setting method of the air preheater 12 can refer to the prior art and will not be described in detail herein.

[0041] Furthermore, a main gate 13 is provided between the output end of the above-mentioned regulating coal mill 3 and the boiler 4, and a branch gate 14 is provided between the output end of the above-mentioned regulating coal mill 3 and the powder supply system. By controlling the opening and closing states of the main gate 13 and the branch gate 14, the switching between various working conditions of the unit is realized.

[0042] Furthermore, a fan 15 is connected to the input end of the cold air duct 6, and the fan 15 is used to provide the cold air gas required in the cold air duct 6 and adjust the amount and temperature of the cold air.

[0043] In one embodiment, the outlet of the fan 15 is divided into two paths, one of which is connected to the air preheater 12 and heated by the air preheater 12, and the other does not pass through the air preheater 12; the two paths are mixed before the coal mill, and the cold air mixing ratio is adjusted by valve control to achieve a suitable powder delivery temperature. Of course, the air preheater 12 can also be equipped with a separate air supply device, which will not be elaborated in this article.

[0044] Furthermore, air volume control valves are provided on the passages of the first hot air duct 51, the second hot air duct 52, the first cold air duct 61 and the second cold air duct 62. The specific location of the air volume control valve can be changed according to actual needs, and this article will not elaborate on it.

[0045] In a specific embodiment of the present application:

[0046] When the system is operated in deep peak load regulation, the main gate 13 at the output end of the coal mill 3 is closed and the branch gate 14 is opened. After the pulverized coal flows through the cyclone separator 7, the exhaust gas is sent to the upper part of the furnace for combustion, and the qualified pulverized coal is collected in the pulverized coal bin 8. According to the pulverized coal concentration data monitored by the first air-powder monitoring device 10 and the second air-powder monitoring device 11 in the powder pipe, the speed of each first spiral powder feeder 81 and the second spiral powder feeder 82 is reasonably adjusted, and the pulverized coal in the pulverized coal bin 8 is respectively sent to the first common coal mill 1 In the first air-powder mixer 91 and the second air-powder mixer 92 of each powder pipe of the second coal mill 2, the coal powder concentration in the powder pipe is increased and the coal powder concentration deviation of each powder pipe of the burner on the same layer is reduced; according to the air volume and air temperature data monitored by the first air-powder monitoring device 10 and the second air-powder monitoring device 11 in the powder pipe, the air volume and air temperature ratio of the first powder pipe and the second powder pipe at the output end of the coal mill input by the second hot air duct 52 and the second cold air duct 62 is reasonably adjusted to ensure that the powder pipe has a higher air temperature and a lower air volume that meet the safety requirements.

[0047] During normal load operation, refer to the deep peak load operation control mode, according to different operating conditions and the combination of coal mills, by reasonably adjusting the rotation speeds of the first spiral powder feeder 81 and the second spiral powder feeder 82, the coal powder in the coal powder bin 8 is respectively sent to the first air-powder mixer 91 and the second air-powder mixer 92 in each powder pipe of the first coal mill 1 and the second coal mill 2 to achieve an economic coal powder concentration and reduce the coal powder concentration deviation of each powder pipe of the same layer burner; reasonably adjust the air volume and air temperature ratio of the first powder pipe and the second powder pipe at the output end of the coal mill input by the second hot air duct 52 and the second cold air duct 62 to ensure that the economic operation air volume and air temperature that meet the safety requirements are in the powder pipe.

[0048] When the load is increased rapidly, the outlet branch gate 14 of the coal mill 3 is closed and the main gate 13 is opened, so that the coal powder of the coal mill directly enters the furnace of the boiler 4. Compared with the operation of the conventional unit, the time for starting the standby coal mill is saved. At the same time, the coal powder in the coal powder bin 8 is sent to each powder pipe of the common coal mill through the first screw powder feeder 81 and the second screw powder feeder 82. Compared with the operation of the conventional unit, an input end for powder delivery is added, which increases the amount of coal powder delivered to the furnace per unit time of the two started coal mills. The combined effect of the two aspects is to increase the amount of coal powder delivered to the furnace in a shorter time and improve the load increase rate.

[0049] When the load is reduced rapidly, the main gate door 13 at the outlet of the coal mill 3 is closed and the branch gate door 14 is opened, and the coal powder of the coal mill is directly stored in the coal powder bin 8. At the same time, the amount of coal powder sent to the common coal mill by the coal powder bin 8 is reduced or the supply of coal powder is stopped, thereby reducing the amount of coal powder sent to the furnace of the boiler 4 per unit time and increasing the load reduction rate.

[0050] In addition, it is foreseeable that increasing the number of conventional coal mills other than the regulating coal mill 3 will also be able to set up the present pulverizing coordinated system. It is only necessary to adaptively increase the connection passages of the mixed temperature air supply system and the powder supply system at both ends of the new coal mill. For example, a third coal mill is set up, and a third powder pipe is set between the third coal mill and the boiler 4. The first branch at the output end of the mixed temperature air supply system is connected to the input ends of the first coal mill 1, the second coal mill 2 and the regulating coal mill 3, and one more branch is connected to the output end of the third coal mill; the other branch at the output end of the mixed temperature air supply system is connected to the first powder pipe and the second powder pipe, and one more branch is connected to the third powder pipe. And the passage at the output end of the powder supply system is connected to the first powder pipe and the second powder pipe respectively, and one more branch is connected to the third powder pipe. As long as the setting principle of this application is followed, the system with an increased number of conventional coal mills is also within the scope of protection, and this article will not expand on it.

[0051] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0052] The above is a detailed introduction to the pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units, characterized in that: include: A first coal mill (1), a second coal mill (2), a regulating coal mill (3), a mixed temperature air supply system, a powder supply system and a boiler (4); The output end of the first coal mill (1) is connected to the boiler (4) through a first powder pipe, and the output end of the second coal mill (2) is connected to the boiler (4) through a second powder pipe; The input end of the mixed temperature air supply system is connected to the boiler (4); one branch of the output end of the mixed temperature air supply system is respectively connected to the input ends of the first coal mill (1), the second coal mill (2) and the regulating coal mill (3); another branch of the output end of the mixed temperature air supply system is respectively connected to the first powder hose and the second powder hose; The output end of the regulating coal mill (3) is respectively connected to the boiler (4) and the input end of the powder supply system, one of the passages at the output end of the powder supply system is connected to the boiler (4), and the other passage at the output end of the powder supply system is respectively connected to the first powder pipe and the second powder pipe; The mixed temperature air supply system comprises: a hot air duct (5) and a cold air duct (6); the input end of the hot air duct (5) is connected to the boiler (4), and the output end of the hot air duct (5) is provided with a first hot air duct (51) and a second hot air duct (52); The first hot air pipe (51) is respectively connected to the input ends of the first coal mill (1), the second coal mill (2) and the regulating coal mill (3); the second hot air pipe (52) is respectively connected to the first powder pipe and the second powder pipe; The output end of the cold air duct (6) is divided into a first cold air duct (61) and a second cold air duct (62); the first cold air duct (61) is connected to the first hot air duct (51), and the second cold air duct (62) is connected to the second hot air duct (52), so as to achieve mixed temperature adjustment; The powder supply system comprises: a cyclone separator (7) and a coal powder bin (8); The output end of the regulating coal mill (3) is connected to the input end of the cyclone separator (7), the gas output end of the cyclone separator (7) is connected to the boiler (4), the solid output end of the cyclone separator (7) is connected to the input end of the pulverized coal bin (8), and the output end of the pulverized coal bin (8) is divided into a first powder conveying pipe and a second powder conveying pipe, the first powder conveying pipe is connected to the first powder pipe, and the second powder conveying pipe is connected to the second powder pipe; The first powder hose is provided with a first air-powder monitoring device (10), and the second powder hose is provided with a second air-powder monitoring device (11).

2. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 1 is characterized in that: A first spiral powder feeder (81) is arranged on the first powder conveying pipe passage, and a second spiral powder feeder (82) is arranged on the second powder conveying pipe passage.

3. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 2 is characterized in that: The first powder hose is provided with a first air-powder mixer (91), and the second powder hose is provided with a second air-powder mixer (92); The first powder conveying pipe is connected to the first air-powder mixer (91), and the second powder conveying pipe is connected to the second air-powder mixer (92).

4. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 1 is characterized in that: The boiler (4) is connected to an air preheater (12), and the input end of the hot air duct (5) is connected to the air preheater (12).

5. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 1 is characterized in that: A main path gate (13) is provided between the output end of the regulating coal mill (3) and the boiler (4), and a branch path gate (14) is provided between the output end of the regulating coal mill (3) and the powder supply system.

6. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 2 is characterized in that: The input end of the cold air duct (6) is connected to a fan (15).

7. The pulverizing coordination system for improving the deep peak-shaving capability of coal-fired units according to claim 2 is characterized in that: The first hot air duct (51), the second hot air duct (52), the first cold air duct (61) and the second cold air duct (62) are all provided with air volume control valves.

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