A device and method for increasing the inlet temperature of a CFB boiler separator

Abstract

The invention discloses a device and method for increasing the inlet temperature of a CFB boiler separator. The device comprises a combustion chamber and a feeding device. The combustion chamber is arranged below a horizontal flue of the separator, and the top of the combustion chamber is connected with the horizontal flue of the separator. The feeding device comprises a dropping pipe and a feeding air duct. The dropping pipe is arranged on the side of the combustion chamber, and the outlet of the dropping pipe faces the inner side of the combustion chamber. The inlet of the dropping pipe is connected with the outlet of the feeding device, and the dropping pipe is connected with the feeding air duct. A temperature measuring device is arranged in the combustion zone of the combustion chamber. An air distribution device is arranged at the bottom of the combustion chamber, and the air distribution device is connected with a fluidizing fan. Fuel is burned in the combustion chamber, and heat is continuously output from the combustion chamber to the flue of the separator, so as to increase the temperature of the separator inlet and help to keep the temperature of the separator inlet at the SNCR reaction window temperature, thereby improving the SNCR reaction efficiency and reducing the SNCR reducing agent consumption. The outlet of the dropping pipe faces the inner side of the combustion chamber, which is beneficial for directly transporting the fuel to the combustion zone.

Description

Technical Field

[0001] The invention belongs to the technical field of circulating fluidized bed boilers, and in particular relates to a device and a method for increasing the inlet temperature of a CFB boiler separator. Background Art

[0002] Circulating fluidized bed (CFB) boilers generally use SNCR to remove NOx from flue gas. The SNCR reaction temperature window is 850-1050℃. The characteristics of CFB boilers make the cyclone separator just in the SNCR reaction temperature window, making its SNCR denitrification efficiency high, up to about 80%. However, with the surplus of domestic power production in recent years, the number of operating hours of thermal power plant units has decreased year by year, and the boiler has been in low-load operation for a long time. When running at low load, the temperature in the CFB boiler reactor is below 850℃, or even lower to below 700℃. The reduction of separator temperature, on the one hand, leads to a decrease in SNCR denitrification efficiency, or even termination of the reaction, excessive environmental emissions, and affects the corporate image; on the other hand, the reduction in reaction efficiency leads to a significant increase in reducing agent consumption and a significant increase in denitrification operation costs. The problem of excessive NOx at low load in CFB boilers has become the first problem that affects whether thermal power plants can smoothly participate in peak load regulation. At present, there is still no effective means to solve this problem. Some power plants have to add SCR denitrification facilities, which requires huge investment; some power plants add strong oxidant denitrification facilities, but this technology has great side effects and has been banned in some areas. The technology that can control the temperature stability of SNCR reactors will greatly improve the comprehensive efficiency of SNCR denitrification and reduce the denitrification cost of CFB boilers. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a device and method for increasing the inlet temperature of a CFB boiler separator, wherein when the boiler load is reduced and the inlet temperature of the separator is lower than the SNCR reaction window temperature, the inlet temperature of the separator is increased by putting the device into operation, thereby increasing the efficiency of the SNCR denitration reaction.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is a device for increasing the inlet temperature of a CFB boiler separator, comprising a combustion chamber and a feeding device; the combustion chamber is arranged below the horizontal flue of the separator, and the top of the combustion chamber is connected to the horizontal flue of the separator; the feeding device comprises a drop pipe and a material-broadening air duct, the drop pipe is arranged on the side of the combustion chamber, the outlet of the drop pipe faces the inside of the combustion chamber, the inlet of the drop pipe is connected to the outlet of the feeding device, the drop pipe is connected to the material-broadening air duct, and a temperature measuring device is provided in the combustion zone of the combustion chamber; an air distribution device and a slag dropping pipe are provided at the bottom of the combustion chamber, the slag dropping pipe leads to the outside of the combustion chamber, and the air distribution device is connected to a fluidizing fan.

[0005] The feeding device adopts a coal feeder, and the discharge port of the coal feeder is connected to the drop pipe through a conveying pipeline.

[0006] The inlet of the slag falling pipe is arranged at the horizontal center of the air distribution device, and the outlet of the slag falling pipe is connected to a slag cooler.

[0007] The drop pipe is obliquely inserted into the combustion chamber. The drop pipe is made of high-temperature resistant metal. The upper end of the drop pipe is connected to the material broadcasting air duct.

[0008] Steel plates are welded around the combustion chamber, a first thermal insulation layer and a first fire-resistant layer are arranged on the inner wall of the combustion chamber, and grab nails are welded on the inner side of the steel plate to assist in fixing the first thermal insulation layer and the first fire-resistant layer.

[0009] A wind chamber is arranged below the air distribution device, the wind chamber is connected to the air distribution device, and a second heat-insulating layer and a second fire-resistant layer are arranged above the air distribution device.

[0010] A pressure measuring device is arranged in the wind chamber, and the wind chamber is connected to a fluidizing air duct, on which a regulating valve is arranged.

[0011] A method for increasing the inlet temperature of a CFB boiler separator by using the device of the present invention. When the boiler load is reduced and the separator temperature is lower than the SNCR reaction window temperature, a feeding device supplies fuel to a combustion chamber through a drop pipe. The solid fuel entering the combustion chamber is automatically burned under the action of high-temperature flue gas. Fluidized air passes through a wind chamber and blows heat to a horizontal flue and enters the separator, thereby increasing the inlet temperature of the separator.

[0012] When the boiler is started, the fluidizing fan is started before the primary fan is started and the pressure in the wind chamber is maintained above 10kPa; when the boiler is shut down, the fluidizing fan is shut down after the primary fan is shut down.

[0013] By adjusting the output power of the fluidizing fan and the output of the feeding device, the heat generated in the combustion chamber can be adjusted in real time.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: the fuel is burned in the combustion chamber, and heat is continuously output from the combustion chamber to the flue of the separator, thereby increasing the temperature of the separator inlet and helping to maintain the temperature of the separator inlet at the SNCR reaction window temperature, thereby improving the SNCR reaction efficiency and reducing the SNCR reducing agent consumption; the drop pipe is connected to a feeding air duct, and the outlet of the drop pipe faces the inner side of the combustion chamber, which is conducive to directly transporting the fuel to the combustion zone; a temperature measuring device is arranged in the combustion zone to reflect the real-time temperature of the combustion chamber and provide temperature parameters for operation; the device requires few auxiliary equipment, and the device described in the present invention can also be used as a staged oxygen supply device for a boiler.

[0015] Based on the device described in the present invention, when the boiler is in low-load operation and the separator temperature is lower than the SNCR reaction temperature window, it is helpful to flexibly control the boiler heat distribution, increase the separator inlet temperature, improve the SNCR reaction efficiency, and reduce the SNCR reducing agent consumption; when the device described in the present invention can be used as a staged oxygen supply device for the boiler, it increases the staged combustion effect of the boiler, improves the burnout rate of the fuel, improves the boiler efficiency, and reduces the original NOx emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The figure is a schematic diagram of an overall arrangement of the device of the present invention that can be implemented on a CFB boiler.

[0018] Figure 2 The present invention is a schematic cross-sectional view of an implementable structure of the device.

[0019] Figure 3 It is a cross-sectional schematic diagram of another direction of an implementable structure of the device of the present invention.

[0020] Figure 4 The bottom schematic diagram of an implementable structure of the device described in the present invention.

[0021] In the attached drawings, 1-furnace; 2-combustion chamber; 3-separator; 4-slag cooler; 5-fluidizing fan; 6-furnace coal feeder; 7-coal feeder; 201-steel plate; 202-first insulation layer; 203-first refractory layer; 204-grabbing nails; 205-wind chamber; 206-slag dropping pipe; 207-second insulation layer; 208-second refractory layer; 209-wind hood; 210-pressure measuring device; 211-temperature measuring device; 212-fluidizing air duct; 213-feeding pipe; 214-feeding air duct; 215-feeding pipeline; 216-air distribution device, 217-regulating valve. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0023] A device for increasing the inlet temperature of a CFB boiler separator comprises a combustion chamber 2 and a feeding device; the combustion chamber 2 is arranged below the horizontal flue of the separator, and the top of the combustion chamber 2 is connected to the horizontal flue of the separator; the feeding device comprises a drop pipe 213 and a material-spreading air duct 214, the drop pipe 213 is arranged on the side of the combustion chamber 2, the outlet of the drop pipe 213 faces the inside of the combustion chamber 2, the inlet of the drop pipe 213 is connected to the outlet of the feeding device, the drop pipe 213 is connected to the material-spreading air duct 214, and the combustion zone of the combustion chamber 2 is provided with a temperature measuring device 211; the bottom of the combustion chamber 2 is provided with an air distribution device 216 and a slag dropping pipe 206, the slag dropping pipe 206 is connected to the outside of the combustion chamber, and the air distribution device 216 is connected to a fluidizing fan 5.

[0024] The feeding device adopts a coal feeder 7 , and the discharge port of the coal feeder 7 is connected to the drop pipe 213 through a conveying pipeline 215 .

[0025] The inlet of the slag dropping pipe 206 is arranged at the horizontal center of the air distribution device 216 , and the outlet of the slag dropping pipe 206 is connected to the slag cooler 4 .

[0026] The material dropping pipe 213 is obliquely inserted into the combustion chamber 2 . The material dropping pipe 213 is made of high temperature resistant metal. The upper end of the material dropping pipe 213 is connected to the material broadcasting air duct 214 .

[0027] refer to Figure 1 to Figure 4 A device for increasing the inlet temperature of a low-load separator of a CFB boiler is arranged between a furnace 1 and a separator 3 of a CFB boiler, is set below the inlet flue of each separator, and is connected to the horizontal flue of the separator; it includes a combustion chamber 2 and a drop pipe 213; an air distribution device 216 and a slag drop pipe 206 are arranged at the bottom of the combustion chamber 2, the inlet of the slag drop pipe 206 is arranged at the horizontal center of the air distribution device 216, a drop pipe is arranged on the side of the combustion chamber 2, the outlet of the drop pipe 213 faces the inside of the combustion chamber 2, the drop pipe 213 is connected to a material spreading air duct 214 and a feeding device, the inlet of the air distribution device is connected to a fluidizing fan 5, the slag drop pipe 206 is connected to a slag cooler 4, and a temperature measuring device 211 is arranged in the combustion zone of the combustion chamber 2.

[0028] The feeding device adopts a coal feeder 7, and the coal feeder 7 is connected to the drop pipe 213 through a feeding pipe 215;

[0029] like Figure 2 and Figure 3 As shown, the combustion chamber 2 is welded with steel plates 201 on all sides, the inner wall of the combustion chamber 2 is provided with a first thermal insulation layer and a first fire-resistant layer, and grabbing nails 204 are welded on the inner side of the steel plate 201 to assist in fixing the first thermal insulation layer 202 and the first fire-resistant layer 203. The first thermal insulation layer 202 is laid with thermal insulation plastic, and the first fire-resistant layer 203 is laid with fire-resistant plastic.

[0030] The combustion chamber is arranged below the horizontal flue of the separator, and the top of the combustion chamber is connected to the horizontal flue. A wind chamber 205 is arranged below the combustion chamber 2, and the wind chamber 205 is connected to the air distribution device 216. A second insulation layer 207 and a second refractory layer 208 are arranged above the air distribution device 216. The second insulation layer 207 is laid with insulation castables, and the second refractory layer 208 is laid with refractory castables. The airflow enters the air distribution device 216 from the wind chamber 205 and then enters the combustion chamber 2.

[0031] The wind chamber 205 is arranged at the lower part of the combustion chamber 2, and the wind chamber 205 and the combustion chamber 2 are separated by the air distribution device 216. The air flow enters the combustion chamber 2 from the wind chamber 205 through the air distribution device 216. The thermal insulation castable 207 and the refractory castable 208 are poured in sequence on the upper part of the air distribution device 216.

[0032] The material drop pipe 213 tilts into the combustion chamber 2, and the discharge port of the material drop pipe 213 is close to the center of the combustion chamber 2. The material drop pipe 213 is made of high temperature resistant metal and is welded and fixed to the steel plate 201. The upper end of the material drop pipe 213 is connected to the material broadcasting air duct 214, and the material broadcasting air broadcasts the fuel through the material drop pipe 213 into the combustion chamber 2.

[0033] The combustion chamber 2 is welded around steel plates 201. The combustion chamber is arranged below the horizontal flue of the separator and connected to the bottom of the horizontal flue. The combustion chamber has no top cover and communicates with the horizontal flue.

[0034] The drop pipe 213 is obliquely inserted into the combustion chamber 2. The drop pipe 213 is made of high temperature resistant metal and welded to the steel plate 201 outside the combustion chamber. The upper end of the drop pipe 213 is connected to the material spreading air duct 214, and the fuel is spread into the combustion chamber 2 through the drop pipe 213 by the coal spreading air.

[0035] The slag dropping pipe 206 is installed at the intersection of the vertical and horizontal center lines of the air distribution device 216. The lower end of the slag dropping pipe 216 is connected to the boiler slag cooler 4, and the slag particles in the combustion chamber 2 are discharged through the slag dropping pipe 206.

[0036] A method for increasing the inlet temperature of a low-load separator of a CFB boiler is based on a device for increasing the inlet temperature of a low-load separator of a CFB boiler. When the boiler load is reduced and the separator temperature is lower than the SNCR reaction window greenhouse, the coal feeder 7 of the device is started, and the solid fuel entering the combustion chamber 2 is automatically burned under the action of high-temperature flue gas. At the same time, the heat is blown to the horizontal flue by the wind chamber 205 and enters the separator 3, the separator temperature is increased, and the coal feeding amount of the furnace is reduced. This process transfers part of the boiler heat from the furnace 1 to the separator 3, so that the temperature of the SNCR reactor is increased.

[0037] When the boiler is started, the fluidizing fan 5 is started before the primary fan is started and the pressure in the wind chamber 205 is maintained above 10 kPa; when the boiler is shut down, the vulcanizing fan 5 is shut down after the primary fan is shut down, which can effectively prevent the circulating ash from entering the wind chamber 205 from the horizontal flue.

[0038] The air volume entering the combustion chamber 2 can be adjusted by the regulating door 217 installed on the fluidizing air duct 212 to ensure that the solid fuel entering the combustion chamber 2 is in a fluidized state.

[0039] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A device for increasing the inlet temperature of a CFB boiler separator, characterized in that: The invention comprises a combustion chamber (2) and a feeding device; the combustion chamber (2) is arranged below the horizontal flue of the separator, and the top of the combustion chamber (2) is connected to the horizontal flue of the separator; the feeding device comprises a dropping pipe (213) and a feeding air duct (214); the dropping pipe (213) is arranged on the side of the combustion chamber (2), the outlet of the dropping pipe (213) faces the inside of the combustion chamber (2), the inlet of the dropping pipe (213) is connected to the outlet of the feeding device, the dropping pipe (213) is connected to the feeding air duct (214), and the combustion zone of the combustion chamber (2) is provided with a temperature measuring device (211); An air distribution device (216) and a slag dropping pipe (206) are provided at the bottom of the combustion chamber (2); the slag dropping pipe (206) leads to the outside of the combustion chamber; the air distribution device (216) is connected to a fluidizing fan (5); the feeding device adopts a coal feeder (7); the discharge port of the coal feeder (7) is connected to the dropping pipe (213) via a conveying pipe (215); a wind chamber (205) is provided below the air distribution device (216); the wind chamber (205) is connected to the air distribution device (216); and a second thermal insulation layer (207) and a second refractory layer (208) are provided above the air distribution device (216).

2. The device for increasing the inlet temperature of a CFB boiler separator according to claim 1, characterized in that: The inlet of the slag dropping pipe (206) is arranged at the horizontal center of the air distribution device (216), and the outlet of the slag dropping pipe (206) is connected to the slag cooler (4).

3. The device for increasing the inlet temperature of a CFB boiler separator according to claim 1, characterized in that: The material dropping pipe (213) is obliquely inserted into the combustion chamber (2); the material dropping pipe (213) is made of high temperature resistant metal; and the upper end of the material dropping pipe (213) is connected to the material broadcasting air duct (214).

4. The device for increasing the inlet temperature of a CFB boiler separator according to claim 1, characterized in that: The combustion chamber (2) is welded around steel plates (201), a first thermal insulation layer and a first fire-resistant layer are arranged on the inner wall of the combustion chamber (2), and gripping nails (204) are welded on the inner side surface of the steel plates (201) to assist in fixing the first thermal insulation layer (202) and the first fire-resistant layer (203).

5. The device for increasing the inlet temperature of a CFB boiler separator according to claim 1, characterized in that: A pressure measuring device (210) is provided in the wind chamber (205). The wind chamber (205) is connected to a fluidizing air duct (212). A regulating valve (217) is provided on the fluidizing air duct (212).

6. A method for increasing the inlet temperature of a CFB boiler separator using the device of claim 1, characterized in that: When the boiler load is reduced and the separator temperature is lower than the SNCR reaction window temperature, the feeding device supplies fuel to the combustion chamber (2) through the drop pipe (213). The solid fuel entering the combustion chamber (2) is automatically burned under the action of the high-temperature flue gas. The fluidizing air passes through the wind chamber (205) and blows the heat to the horizontal flue and enters the separator (3), thereby increasing the temperature at the inlet of the separator (3).

7. The method for increasing the inlet temperature of a CFB boiler separator according to claim 6, characterized in that: When the boiler is started, the fluidizing fan (5) is started before the primary fan is started and the pressure in the wind chamber (205) is maintained at above 10 kPa; when the boiler is shut down, the fluidizing fan (5) is shut down after the primary fan is shut down.

8. The method for increasing the inlet temperature of a CFB boiler separator according to claim 6, characterized in that: By adjusting the output power of the fluidizing fan (5) and the output of the feeding device, the heat generated in the combustion chamber (2) is adjusted in real time.

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