Four-corner tangential combustion boiler system

Abstract

The utility model relates to a four-corner tangential combustion boiler system which comprises a fuel pretreatment device. A plurality of layers of fuel inlets are respectively formed in four corners of the hearth, are arranged in a four-corner tangential manner, and at least comprise a preheating fuel inlet positioned on the upper layer and a pulverized coal fuel inlet positioned on the lower layer; pretreated fuel treated by the fuel pretreatment device is suitable for being introduced into the preheated fuel inlet. By means of the technical scheme, the combustion stability of the coal-fired boiler under the low load can be improved, and NOx emission can be reduced. According to the scheme, the deep peak regulation potential of the pulverized coal four-corner tangential boiler is excavated, the current peak regulation pressure of China is relieved, and high-proportion new energy power is consumed.

Description

Technical Field

[0001] This utility model relates to the field of combustion equipment technology, and in particular to a four-corner tangential combustion boiler system. Background Technology

[0002] Under the "dual carbon" target, coal-fired power units will undertake the task of supporting a large proportion of renewable energy power generation. The mainstay of my country's coal-fired power units is pulverized coal power plant boilers. Based on my country's energy structure and the proportion of installed capacity on the power grid's power supply side, achieving deep and flexible peak shaving for pulverized coal power plant boilers, so that the power grid can absorb renewable energy power generation to the maximum extent, has become an urgent problem to be solved for pulverized coal power plant boilers.

[0003] However, most existing pulverized coal power plant boilers are of the tangential combustion type, which faces serious technical challenges during peak shaving. Existing tangential combustion boilers struggle to achieve stable operation at low loads. Generally, when the boiler load drops below 50%, the jet velocity at the four corners decreases, making it difficult to form a tangential shape, resulting in poor combustion organization and unstable combustion at low loads, leading to increased NO production. x The steam parameters are too high; in addition, when the load decreases to a certain level, the steam parameters will decrease and fail to meet the turbine inlet steam requirements. Utility Model Content

[0004] To address at least one of the aforementioned technical problems, such as tapping the deep peak-shaving potential of pulverized coal tangential combustion boilers, this utility model proposes a tangential combustion boiler system.

[0005] According to an embodiment of this utility model, a tangential combustion boiler system is proposed, comprising:

[0006] Fuel pretreatment unit; and

[0007] The boiler furnace has multiple fuel inlets at its four corners, arranged in a tangential circle at the four corners.

[0008] in:

[0009] The multi-layer fuel inlet includes at least a preheated fuel inlet at the upper layer and a pulverized coal fuel inlet at the lower layer, and the pretreated fuel processed by the fuel pretreatment device is suitable for being introduced into the preheated fuel inlet.

[0010] Optionally, the boiler system further includes a bottom-supporting air distribution device installed at the bottom of the furnace, wherein the bottom-supporting air is secondary air.

[0011] Optionally, the boiler system further includes multiple secondary air inlets, which are located at the four corners of the furnace, above and below the preheating fuel inlet, and above and below the pulverized coal fuel inlet in the height direction of the furnace; the boiler system also includes tertiary air inlets, located at the four corners of the furnace, and located above the secondary air inlets above the preheating fuel inlet in the height direction of the furnace.

[0012] Optionally, the boiler system further includes a control device, the control device being configured as follows:

[0013] When the boiler load is 50% or above, the preheating fuel inlet and the pulverized coal fuel inlet are put into operation simultaneously;

[0014] When the boiler load is less than 50%, only the preheating fuel inlet is connected while the pulverized coal fuel inlet is not connected, and all secondary air is provided by the bottom air distribution device.

[0015] Optionally, the control device is configured such that when the boiler load is in the range of 20%-50%, only the preheating fuel inlet is engaged while the pulverized coal fuel inlet is not engaged, and all secondary air is provided by the bottom air distribution device.

[0016] Optionally, the bottom-supporting air distribution device is a uniform air distribution device.

[0017] Optionally, the number of fuel pretreatment devices is four, each of which includes a separator, and the gas-solid fuel outlet of each separator is connected to a corresponding preheated fuel inlet.

[0018] Optionally, the number of fuel pretreatment devices is two, respectively arranged on the two side walls or front and rear walls of the furnace. Each fuel pretreatment device includes a separator, and the gas-solid fuel outlet of the separator is simultaneously connected to two corresponding preheated fuel inlets.

[0019] Optionally, the number of fuel pretreatment devices is two, respectively arranged on the two side walls or front and rear walls of the furnace. Each multi-nozzle fuel pretreatment device includes two separators, and the gas-solid fuel outlet of each separator is connected to a corresponding preheated fuel inlet.

[0020] Optionally, in the height direction of the furnace, above the tertiary air, the upper part of the furnace is also provided with a burnout air inlet.

[0021] Based on the above technical solutions, the combustion stability of coal-fired boilers under low loads can be improved, which is also conducive to reducing NOx emissions. These solutions tap into the deep peak-shaving potential of pulverized coal tangential-circular boilers, which is beneficial for alleviating current peak-shaving pressures in my country and absorbing a high proportion of renewable energy power. Attached Figure Description

[0022] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:

[0023] Figure 1 This is a schematic diagram of the air distribution of a tangential combustion boiler system according to an exemplary embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of a bottom-supporting air distribution device according to an exemplary embodiment of the present invention. Detailed Implementation

[0025] The technical solution of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of this utility model with reference to the accompanying drawings is intended to explain the overall inventive concept of this utility model and should not be construed as a limitation thereof.

[0026] Figure 1 This is a schematic diagram of the air distribution of a tangential combustion boiler system according to an exemplary embodiment of the present invention. The boiler system includes a furnace 10 and a fuel pretreatment device (not shown).

[0027] like Figure 1 As shown, the furnace has multiple fuel inlets at its four corners, arranged in a tangential circle. Each fuel inlet includes at least a preheating fuel inlet 22 at the top and a pulverized coal fuel inlet 24 at the bottom. Pretreated fuel, processed by a fuel pretreatment device, is suitable for introduction into the preheating fuel inlet 22. Here, the pulverized coal fuel introduced into the pulverized coal fuel inlet is untreated, while the preheated fuel entering the preheating fuel inlet, processed by the fuel pretreatment device, has a temperature above 800 degrees Celsius.

[0028] like Figure 1 As shown, the boiler system also includes a bottom-supporting air distribution device 30 installed at the bottom of the furnace, wherein the bottom-supporting air is secondary air.

[0029] like Figure 1 As shown, the boiler system also includes multiple secondary air inlets 26, which are located at the four corners of the furnace, on the upper and lower sides of the preheating fuel inlet 22, and on the upper and lower sides of the pulverized coal fuel inlet 24. The boiler system also includes tertiary air inlets 28, which are located at the four corners of the furnace and on the upper side of the secondary air inlet above the preheating fuel inlet in the height direction of the furnace.

[0030] Although not shown, the boiler system may also include a control device configured to:

[0031] When the boiler load is 50% or above, the preheating fuel inlet and the pulverized coal fuel inlet are put into operation simultaneously;

[0032] When the boiler load is less than 50%, for example, when the boiler load is in the range of 20%-50%, only the preheating fuel inlet is put in while the pulverized coal fuel inlet is not put in, and all secondary air is provided by the bottom air distribution device.

[0033] Figure 2 This is a schematic diagram of the structure of a bottom-supporting air distribution device according to an exemplary embodiment of the present invention. Figure 2 As shown, the bottom-supporting air distribution device is a uniform air distribution device. This uniform air distribution device 30 includes a secondary air box 32 and multiple rows of air distribution ducts 34 uniformly drawn from the secondary air box. Each air distribution duct 34 is equipped with an air distribution port or air cap 36 for distributing air into the furnace 10. Figure 2 As can be seen, the air distribution pipes are evenly distributed at the bottom of the furnace.

[0034] In one embodiment, although not shown, the number of fuel pretreatment devices is four, each of which includes a separator, and each separator’s gas-solid fuel outlet is connected to a corresponding preheated fuel inlet.

[0035] In one embodiment, although not shown, there are two fuel pretreatment devices, respectively arranged on two side walls or front and rear walls of the furnace. Each fuel pretreatment device includes a separator, and the gas-solid fuel outlet of the separator is simultaneously connected to two corresponding preheated fuel inlets.

[0036] In one embodiment, although not shown, there are two fuel pretreatment devices, respectively arranged on two side walls or front and rear walls of the furnace. Each multi-nozzle fuel pretreatment device includes two separators, and the gas-solid fuel outlet of each separator is connected to a corresponding preheated fuel inlet.

[0037] In one embodiment, although not shown, a burnout air inlet is also provided at the upper part of the furnace above the tertiary air in the height direction of the furnace.

[0038] Based on the above, a tangentially circular pulverized coal preheating combustion boiler system is proposed. This system replaces the upper fuel nozzle with a high-temperature preheating fuel nozzle. Furthermore, a uniform bottom-supporting air distribution device is installed at the bottom of the furnace. When the boiler operates above 50% load, both the upper preheating fuel nozzle and the lower cold pulverized coal nozzle are used simultaneously, with secondary air entering the furnace through the original secondary air nozzles. When the boiler load drops below 50%, only the upper preheating fuel is used. At this time, due to the reduced secondary air volume, the original secondary air nozzles cannot form an effective tangential circle; therefore, all secondary air enters the furnace uniformly through the bottom-supporting air device. The uniformly distributed secondary air mixes evenly with the preheating fuel, ensuring stable combustion of the preheating fuel. Simultaneously, the combined effect of tertiary air and burnout air reduces NO₂ during combustion. x In addition, the use of upper preheated fuel nozzles raises the flame center, which helps to improve steam parameters under low load.

[0039] The tangential combustion boiler system of this utility model can achieve at least one of the following technical effects:

[0040] 1. Ensure the boiler operates stably at 20% load;

[0041] 2. Ensure reduced NOx emissions under low load conditions;

[0042] 3. Under low load conditions, the upper nozzle is used, and the bottom uniform air distribution and staged air distribution can adjust the steam parameters to ensure the steam parameters under low load conditions.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tangential combustion boiler system, comprising: Fuel pretreatment unit; and The boiler furnace has multiple fuel inlets at its four corners, arranged in a tangential circle at the four corners. Its features are: The multi-layer fuel inlet includes at least a preheated fuel inlet at the upper layer and a pulverized coal fuel inlet at the lower layer, and the pretreated fuel processed by the fuel pretreatment device is suitable for being introduced into the preheated fuel inlet.

2. The boiler system according to claim 1, characterized in that: The boiler system also includes a bottom-supporting air distribution device installed at the bottom of the furnace, wherein the bottom-supporting air is secondary air.

3. The boiler system according to claim 2, characterized in that: The boiler system also includes multiple secondary air inlets. In the height direction of the furnace, at the four corners of the furnace, on the upper and lower sides of the preheating fuel inlet and on the upper and lower sides of the pulverized coal fuel inlet, the secondary air inlets are provided. The boiler system also includes a tertiary air inlet, located at the four corners of the furnace, and positioned above the secondary air inlet above the preheating fuel inlet in the height direction of the furnace.

4. The boiler system according to claim 3, characterized in that: The boiler system also includes a control device, which is configured as follows: When the boiler load is 50% or above, the preheating fuel inlet and the pulverized coal fuel inlet are put into operation simultaneously. When the boiler load is less than 50%, only the preheating fuel inlet is connected while the pulverized coal fuel inlet is not connected, and all secondary air is provided by the bottom air distribution device.

5. The boiler system according to claim 4, characterized in that: The control device is configured such that when the boiler load is within the range of 20%-50%, only the preheating fuel inlet is engaged while the pulverized coal fuel inlet is not engaged, and all secondary air is provided by the bottom air distribution device.

6. The boiler system according to claim 2, characterized in that: The bottom-supporting air distribution device is a uniform air distribution device.

7. The boiler system according to claim 1, characterized in that: The number of fuel pretreatment devices is four, and each fuel pretreatment device includes a separator, with the gas-solid fuel outlet of each separator connected to a corresponding preheated fuel inlet.

8. The boiler system according to claim 1, characterized in that: The number of fuel pretreatment devices is two, which are respectively arranged on the two side walls or front and rear walls of the furnace. Each fuel pretreatment device includes a separator, and the gas-solid fuel outlet of the separator is simultaneously connected to two corresponding preheated fuel inlets.

9. The boiler system according to claim 1, characterized in that: The number of fuel pretreatment devices is two, which are respectively arranged on the two side walls or front and rear walls of the furnace. Each multi-nozzle fuel pretreatment device includes two separators, and the gas-solid fuel outlet of each separator is connected to a corresponding preheated fuel inlet.

10. The boiler system according to claim 3, characterized in that: In the height direction of the furnace, above the tertiary air, the upper part of the furnace is also provided with a burnout air inlet.

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