A stable combustion system for deep peak regulation of a power plant boiler

Abstract

The present application relates to a kind of stable combustion system for power plant boiler depth peak shaving, including four corner tangential boiler (1), it is characterized in that, the four corner tangential boiler (1) includes upper air chamber (1.1) and lower air chamber (1.2), the main pulverized coal burner (1.3) is equipped in the upper air chamber (1.1), the main pulverized coal burner (1.3) is connected to furnace front powder pipe, the pulverized coal self-stabilizing burner (1.5) with precombustion chamber (1.4) is equipped in the lower air chamber (1.2), the pulverized coal self-stabilizing burner (1.5) inlet is connected to furnace front powder pipe, the inlet of the upper air chamber (1.1) and lower air chamber (1.2) is respectively equipped with air chamber air door.The present application utilizes the high-temperature flame generated by the pulverized coal self-stabilizing burner with precombustion chamber to assist combustion adjacent upper layer of pulverized coal, so that the pulverized coal enters the furnace in active combustion state, to improve the oil-free stable combustion capability of the boiler, with the beneficial effects of good coal quality adaptability, fast response, strong stable combustion capability and no need to invest other combustion-supporting fuel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of boiler combustion technology, in particular to a thermal power plant boiler combustion peak shaving technology, and more particularly to a stable combustion method and equipment for deep peak shaving of a power plant boiler. BACKGROUND

[0002] For a long time, the construction of China's thermal power market has promoted the sustained growth of power supply, and the grid connection and sustainable and healthy development of hydropower, wind power and solar photovoltaic power generation, and the proportion gradually increases. As of the end of 2018, the total installed capacity of the country reached 1.9 billion kilowatts, of which the proportion of renewable energy such as hydropower, nuclear power and wind power in the total installed capacity of power increased to nearly 40%, and the proportion of thermal power gradually decreased to 60%, and the gap is still further narrowed. The survival space of thermal power units is further compressed, and the utilization hours and load rate of units have decreased year by year.

[0003] According to the situation, how to meet the unit peak shaving capacity becomes a thorny problem, but compared with new energy, coal-fired power has good peak shaving performance. However, when the boiler is deeply peak shaved, the original burner is difficult to ensure the stable combustion of the boiler. In order to realize stable combustion, the whole combustion system of the boiler must be transformed, which includes the transformation of the burner.

[0004] The current burner transformation technology includes plasma ignition technology, micro-oil ignition technology and oxygen-enriched ignition technology. The above technologies need to be combined with long-time input of auxiliary fuel (energy) other than coal powder during operation, which does not meet the requirements of relevant regulations, so a new stable combustion technology is needed to fill this gap. SUMMARY

[0005] The present application provides a stable combustion system for deep peak shaving of a power plant boiler, which has good coal quality adaptability, fast response, strong stable combustion capacity and does not need to input other combustion-supporting fuels.

[0006] The present application is realized by the following technical scheme, which provides a stable combustion system for deep peak shaving of a power plant boiler, including a four-corner tangential boiler, the four-corner tangential boiler includes an upper air chamber and a lower air chamber, a main pulverized coal burner is arranged in the upper air chamber, the main pulverized coal burner is connected to a front furnace powder pipe, a pulverized coal self-stable burner with a pre-combustion chamber is arranged in the lower air chamber, the inlet of the pulverized coal self-stable burner is connected to the front furnace powder pipe, and air chamber dampers are installed at the inlets of the upper air chamber and the lower air chamber.

[0007] After the above scheme is adopted, the pulverized coal pre-combustion chamber installed below the main pulverized coal burner is preheated to form a high-temperature cavity, and the pulverized coal entering the high-temperature cavity is ignited. At the same time, under the action of rotating jet entrainment, high-temperature gas is generated in the pre-combustion chamber, which is used to ignite the pulverized coal in the lower air chamber, so that the pulverized coal in the lower air chamber is ignited and burned, and the stable combustion of the boiler is realized.

[0008] The high-temperature backflow area of the flue gas is locally formed in the warm chamber, the high-temperature flue gas continuously backflows to the backflow area, and the primary air and the pulverized coal mixture is continuously heated to make the primary air and the pulverized coal mixture burn fiercely and generate high-temperature flame (1500 DEG C). The low-temperature pulverized coal gas flow near the upper main pulverized coal nozzle enters the furnace at a certain angle alpha and continuously exchanges heat with the high-temperature flame, the upper low-temperature pulverized coal gas flow is ignited in advance, the pulverized coal enters the furnace in an active combustion state, is not affected by the coal quality and the surrounding furnace temperature fluctuation, and the boiler coal powder is prevented from being extinguished due to the low heat load of the furnace, so that the boiler can realize load regulation without stopping the furnace (the minimum load is 20-30% of the rated load), and the deep load regulation capacity of the thermal power unit is enhanced.

[0009] As preferred, the stable combustion nozzle of the main pulverized coal burner can swing within a certain angle alpha, and the angle alpha is not more than 10 DEG around the axis.

[0010] As preferred, the pulverized coal self-stable combustion device is provided with an auxiliary stable combustion nozzle, and the inlet of the auxiliary stable combustion nozzle is connected to the front pulverized coal pipe.

[0011] As above, the high-temperature flame generated by the pulverized coal self-stable combustion device with a pre-combustion chamber is used to assist the combustion of the adjacent upper layer of pulverized coal, the pulverized coal enters the furnace in an active combustion state, the oil-free stable combustion capacity of the boiler is improved, the coal quality adaptability is good, the response is fast, the stable combustion capacity is strong, and other combustion-supporting fuels are not needed. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a schematic diagram of the stable combustion principle of the present application;

[0013] Figure 2 It is a schematic diagram of the overall arrangement structure of the boiler in the present application;

[0014] Figure 3 It is Figure 2 It is a schematic diagram of the structure in the A direction;

[0015] Figure 4 It is Figure 2 It is a schematic diagram of the structure in the B direction;

[0016] The drawings show:

[0017] 1, four corner tangential boiler, 1.1, upper air chamber, 1.2, lower air chamber, 1.3, main pulverized coal burner, 1.4, pre-combustion chamber, 1.5, pulverized coal self-stable combustion device. DETAILED DESCRIPTION

[0018] In order to clearly illustrate the technical features of the present application, the present application will be further described below in combination with the drawings and through specific embodiments.

[0019] For example, Figures 1 to 4As shown in the figure, a stable combustion system for deep peak shaving of a power plant boiler is provided, which comprises a tangentially fired boiler 1, the tangentially fired boiler 1 comprising an upper air chamber 1.1 and a lower air chamber 1.2, the upper air chamber 1.1 being provided with a main pulverized coal burner 1.3 connected to a front pulverized coal pipe, the lower air chamber 1.2 being provided with a self-stable burner 1.5 with a pre-combustion chamber 1.4, the self-stable burner 1.5 being connected to the front pulverized coal pipe at the inlet, and air chamber dampers being installed at the inlets of the upper air chamber 1.1 and the lower air chamber 1.2.

[0020] The main pulverized coal burner 1.3 is provided with a stable combustion nozzle, and the self-stable burner 1.5 is provided with an auxiliary stable combustion nozzle.

[0021] In the embodiment, the stable combustion nozzle of the main pulverized coal burner 1.3 can swing within an angle α, the angle α being not more than 10° around the axis, and the self-stable burner 1.5 is provided with an auxiliary stable combustion nozzle connected to the front pulverized coal pipe at the inlet.

[0022] Finally, it should be noted that the above examples and descriptions are not limited to the above embodiments, and the technical features not described in the present application can be realized by or using the prior art, which will not be described herein; the above embodiments and drawings are only used to illustrate the technical solutions of the present application and are not a limitation on the present application, and the present application has been described in detail with reference to the preferred embodiments, and those skilled in the art should understand that the changes, modifications, additions or replacements made by those skilled in the art within the essential scope of the present application do not deviate from the purpose of the present application, and should also belong to the protection scope of the claims of the present application.

Claims

1. A stable combustion system for deep load following of a power plant boiler, comprising a tangentially fired boiler (1), characterized in that, The quadrilateral tangential boiler (1) comprises an upper air chamber (1.1) and a lower air chamber (1.2), the upper air chamber (1.1) is internally provided with a main pulverized coal burner (1.3), the main pulverized coal burner (1.3) is connected to a front furnace pulverized coal pipe, the lower air chamber (1.2) is internally provided with a pulverized coal self-stabilizing burner (1.5) with a pre-combustion chamber (1.4), the pulverized coal self-stabilizing burner (1.5) inlet is connected to the front furnace pulverized coal pipe, and the upper air chamber (1.1) and the lower air chamber (1.2) are respectively provided with air chamber dampers at the entrances.

2. The system for stable combustion of a power plant boiler for deep load following according to claim 1, characterized in that, The stable combustion nozzle of the main pulverized coal burner (1.3) can swing within a certain angle α, and the angle α is not more than 10° around the axis.

3. The system for stable combustion of a power plant boiler for deep load following according to claim 1, characterized in that, The pulverized coal self-stabilizing burner (1.5) is provided with an auxiliary stable combustion nozzle, and the inlet of the auxiliary stable combustion nozzle is connected to the front furnace pulverized coal pipe.

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