CN2172404Y - A radial thick-lean swirl pulverized coal burner - Google Patents

Abstract

A radial thick-lean swirling pulverized coal burner, including a thick pulverized coal channel in a cylindrical space, a light pulverized coal channel in an annular space, and a secondary air duct. The dense pulverized coal channel is connected with the furnace and the pulverized coal concentrator through the burner and the dense pulverized coal delivery pipe respectively, and the pulverized coal channel is also connected with the furnace and the pulverized coal concentrator through the burner and the pulverized coal delivery pipe respectively. The burner has high pulverized coal combustion efficiency, stable combustion and low NO _X emissions, and has good adaptability to inferior coal combustion, reduces air pollution, and improves energy utilization.

Description

The utility model relates to a coal powder burner, in particular to a swirl flow coal powder burner.

my country's national conditions are that the oil output is small, and although the coal output is large, the coal types are changeable and the coal quality is poor. In the combustion technology of pulverized coal boilers in the electric power industry, the basic requirements for pulverized coal combustion are high efficiency, stable combustion and low consumption. pollute. First of all, in order to save energy, it is necessary to ensure high-efficiency combustion; secondly, stable combustion, because the quality of coal used in power plants in my country is poor, and the coal types are changeable, and the problem of stable combustion is very prominent, especially in low-load operation. No oil is used to support combustion, which increases the cost of power generation. Furthermore, as people pay more and more attention to environmental issues, the requirement for low pollution of pulverized coal combustion is becoming stronger and stronger. The swirling pulverized coal burner occupies a certain proportion in power station boilers and other pulverized coal combustion applications in my country. It relies on the high-temperature recirculation zone as a stable heat source to make the pulverized coal flow ignite in time and burn stably. After the pulverized coal airflow passes through the cyclone, due to the centrifugal force, the pulverized coal is mostly thrown near the outer surface of the rotating jet, and part of the pulverized coal cannot enter the high-temperature recirculation zone, but can only pass along the edge of the recirculation zone, so that the pulverized coal The concentration distribution does not match the temperature distribution of the gas flow, that is, there is very little coal powder in the high-temperature recirculation zone, but a large amount of coal powder is concentrated in the low-temperature zone near the edge, and no high-temperature and high-concentration zone that is conducive to the stability of the flame is formed. It is beneficial to timely ignition of pulverized coal and stable flame. When low-volatile coal and low-quality coal are used, it is difficult to achieve stable combustion; especially for direct blowing systems, stable combustion cannot be carried out due to high moisture and low temperature in the primary air; low-load stable combustion capability is poor, and often requires a Oil supports combustion. Ordinary swirling pulverized coal burner, the primary and secondary air mix strongly, the temperature peak is high, and the NO _X generation is large. According to the survey, its NO _X is about 500-600PPm, which is about 25% larger than that of the DC burner. The WR-PC burner (Japanese Patent No. 62-233611) developed by Japan Ishikawajima Harima Heavy Industries Co., Ltd. (IHI) only solves the problem of low-load stable combustion, and the operation adjustment is complicated, which is not suitable for my country's national conditions. The swirling flow generator developed by F·W Company of the United States (US patent US4270895) effectively reduces the emission of NO _X , but its swirling secondary air volume only accounts for 5-15% of the total air volume, and it is difficult to form a stable backflow zone; the airflow carrying fine coal particles (i.e., light coal airflow) and the airflow carrying coarse coal particles (i.e., dense coal airflow) enter the furnace in the form of direct flow, relying on the airflow of fine coal particles to ignite the coarse coal particles Draft, poor flame stability.

The purpose of the utility model is to improve the problems existing in the current technology, and provide a radial thick-lean swirl pulverized coal burner with simple structure, high efficiency, stable combustion and low pollution that can realize pulverized coal combustion at the same time.

The utility model radial thick-lean swirl pulverized coal burner includes a thick pulverized coal channel 2, a light pulverized coal channel 3 with an annular space and a secondary air duct 4 with an annular space, the secondary air duct 4 Cyclone 5 is installed in the annular space, and the entrance of dense coal powder channel 2 communicates with the thick coal powder outlet of coal powder concentrator 9 through delivery pipe 7, and its outlet communicates with furnace 1 through burner 12, and light coal powder Channel 3 communicates with the light coal powder outlet of pulverized coal concentrator 9 through delivery pipe 10, and its outlet communicates with furnace 1 through burner 13. It is connected with the secondary air duct 11 and its outlet is connected with the furnace 1. The utility model is characterized in that the thick coal powder channel 2, the light coal powder channel 3 and the secondary air duct 4 are arranged in sequence from the inside to the outside, and the light coal powder channel 3 A cyclone 6 is installed in the annular space.

Compared with the prior art, the structure and principle adopted in the design of this utility model not only overcomes the shortcomings of (IHI) WR-PC burner which is only used for low-load stable combustion and complicated adjustment, but also overcomes the shortcomings of F·W The downside of the company's swirl generators. The utility model simultaneously solves the problems of high efficiency, stable combustion and low NO _X emission of pulverized coal combustion, which has a very positive effect on the high-efficiency and low-pollution utilization of China's unique low-quality coal. The solution to the problem of stable combustion improves the coal type adaptability of pulverized coal boilers and the reliability of low-load operation, ensuring the safety of boiler operation; the solution to the problem of low NO _X emissions reduces air pollution and ensures the living environment of human beings. The low-pollution utilization of coal has important social and economic significance; high-efficiency combustion can improve energy utilization and save energy.

Fig. 1 is an axial sectional schematic diagram of an example of the utility model pulverized coal burner, and Fig. 2 is an axial sectional schematic diagram of another example of the utility model pulverized coal burner.

Below in conjunction with two examples the utility model is described in detail.

Example 1:

As shown in Figure 1: In the figure 1 furnace, 2 thick pulverized coal channel, 3 light pulverized coal channel, 4 secondary air duct, 5 cyclone, 6 cyclone, 7 concentrated pulverized coal airflow conveying pipe, 8 primary air powder conveying Pipeline, 9 concentrators, 10 light coal powder air flow delivery pipes, 11 secondary air ducts, 12 and 13 are burners.

The utility model is realized in the following ways: the pulverized coal air flow sent from the primary air powder transportation pipeline 8 is divided into thick and light pulverized coal airflows with a large difference in pulverized coal concentration through the concentrator 9, and the pulverized coal airflow contains primary pulverized coal airflow. Most of the pulverized coal in the wind powder airflow, the light coal powder airflow only contains a small part of coal powder in the primary wind powder airflow. Concentrated pulverized coal flow passes through the concentrated pulverized coal flow conveying pipe 7 and the concentrating pulverized coal channel 2 and the burner in the inner layer of the burner - the dense pulverized coal flow nozzle 12 enters the furnace 1 in the form of direct current or weak swirling flow, and the light pulverized coal The air flow enters the furnace in the form of a swirling flow through the light coal powder airflow conveying pipe 10 and the light coal powder passage 3 and the swirler 6 and the light coal powder airflow burner 13 outside the thick coal powder airflow burner. After the secondary air passes through the secondary air duct 11, the secondary air duct and the cyclone 5, it is sprayed into the furnace at the outermost layer from the secondary air nozzle. The concentrated coal powder flow enters the high-temperature recirculation zone, adjust the swirl strength of the secondary wind, and make the expansion angle of the light coal powder flow greater than or equal to the expansion angle of the concentrated coal powder flow, so as to ensure that the light coal powder flow and the secondary air flow as much as possible at the initial stage of ignition. Less mixing of dense pulverized coal airflow will form a high-temperature, high-concentration area, which is conducive to coal pulverized ignition and flame stability. Before ignition and at the initial stage of combustion, they are distributed sequentially in the radial direction: thick pulverized coal air flow area, light coal pulverized air flow area, and secondary air area. The formation of NO _X can be effectively suppressed, and the emission of NO _X can be greatly reduced. Select the appropriate secondary air swirl strength to ensure that the light coal powder airflow and secondary air are mixed in time after the concentrated coal powder airflow is ignited, so that the oxygen required for coal powder combustion can be supplied in time; at the same time, the concentrated coal powder airflow will be ignited in time Light coal dust flow. Realize ignition, stable combustion and timely burnout.

In addition, the total primary air rate of the two streams of pulverized coal, thick and thin, is the chemical equivalent ratio of volatile combustion, that is, the total primary air rate is still the conventional design value, which ensures high-efficiency combustion. A center pipe is arranged in the thick pulverized coal passage 2, and an oil gun is arranged in the center pipe, and the end is an expanding cone.

Example 2:

As shown in Figure 2, there are 14 central tubes, 15 annular partitions, 16 swirl secondary air ducts, 17 direct current secondary air ducts, 18 and 19 damper baffles.

The pulverized coal air flow sent from the primary air pulverized pipeline 8 is divided into thick and light pulverized coal airflows with a large difference in pulverized coal concentration through the concentrator 9, and the total primary air rate of the two airflows is a conventional design value. The concentrated pulverized coal flow passes through the concentrated pulverized coal airflow conveying pipe 7 and the dense pulverized coal flow nozzle 12 enters the high-temperature recirculation zone in a direct flow, forming a high temperature and high concentration area that is conducive to stable combustion, and the light pulverized coal flow passes through The light pulverized coal airflow delivery pipe 10, the pulverized coal passage 3, the cyclone 5 and the pulverized coal airflow burner 13 enter the furnace 1 in the form of swirling flow, forming the pulverized coal airflow zone. The improvement of this example is: the secondary air channel 4 is provided with an annular partition 15 to separate the channel into a swirling secondary air duct 16 and a direct current secondary air duct 17, and a cyclone 6 is set in the swirling secondary air duct 16 , the entrances of the swirling secondary air duct 16 and the direct current secondary air duct 17 are respectively provided with adjustable and rotating damper baffles 18 and 19, and the secondary air is divided into swirling secondary air before entering the burner from the secondary air duct. and DC secondary air two parts, the share of the two parts of the wind can be flexibly adjusted by damper baffles 18 and 19, and they enter the furnace 1 through the swirl secondary air pipeline 16 and the DC secondary air pipeline 17 respectively. The swirl intensity of the secondary air can be flexibly adjusted by changing the volume of the secondary air. The central pipe 14 is provided with an oil gun and an expanding cone at the end.

Claims (1)

1, a kind of radially deep or light vortex burner, comprise a thick coal culm passage [2], one has the thin powdered coal passage [3] of annulus and the secondary air channel road [4] that has annulus, cyclone [5] is installed in the annulus in secondary air channel road [4], the inlet of thick coal culm passage [2] is communicated with the thick coal culm outlet of pulverized coal concentrator [9] by carrier pipe [7], its outlet is communicated with burner hearth [1] by nozzles [12], thin powdered coal passage [3] is communicated with the thin powdered coal outlet of pulverized coal concentrator [9] by carrier pipe [10], its outlet is communicated with burner hearth [1] by nozzles [13], the inlet of pulverized coal concentrator [9] connects an air channel [8], the inlet in secondary air channel road [4] is communicated with secondary air duct [11], its outlet is communicated with burner hearth [1], the thick coal culm passage [2] that is characterised in that of the present utility model, thin powdered coal passage [3] and secondary air channel road [4] are arranged in order from inside to outside, and cyclone [6] is installed in the annulus of thin powdered coal passage [3].

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