Steam-injection boiler low-nitrogen burner cooling air system provided with air pre-heater

Abstract

The utility model relates to the technical field of steam-injection boilers for oil fields, in particular to a steam-injection boiler low-nitrogen burner cooling air system provided with an air pre-heater, which comprises a low-nitrogen burner, a high-pressure fan, the air pre-heater, a chimney, a steam-injection boiler combustion chamber, a hot air duct and a fan. The low-nitrogen combustor is mounted at the front end of a combustion chamber of the steam-injection boiler; the cooling circulating air mechanism is connected with the front wall of the boiler; the cooling circulating air mechanism is of an annular structure and is provided with a high-pressure inlet and a low-pressure outlet. High-pressure cooling air is introduced to cool the front wall of the boiler, waste heat is recycled, heat conduction is blocked, and the low-nitrogen combustor runs more safely and reliably. High-pressure cooling air is introduced to resist damage of backflow high-temperature flue gas in the furnace to a fire observation channel, an ignition channel and a fire detection channel, and it is ensured that electrical elements such as a flame detector and an ignition electrode normally work at the working environment temperature meeting the use requirement, and the service life of the electrical elements is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of steam injection boilers for oil fields, in particular to a low-nitrogen burner cooling air system for a steam injection boiler equipped with an air preheater. Background Art

[0002] In order to implement the national policies of energy conservation, consumption reduction and emission reduction, the steam injection boilers for oil fields used in thermal oil recovery are constantly undergoing technological innovation. The steam injection boiler system equipped with an air preheater can not only recover the heat of flue gas, reduce the flue gas discharge temperature, improve the boiler efficiency, but also increase the temperature of the combustion-supporting air of the burner, make the combustion more complete, reduce the incomplete combustion loss, thereby increasing the thermal efficiency. The low-nitrogen transformation of the burner enables the flue gas emissions to meet the national environmental protection policy requirements for oxide emissions.

[0003] The low-nitrogen burner of the steam injection boiler realizes low-nitrogen flue gas emissions through a combination of various nitrogen reduction technologies. Among them, the FGR (flue gas internal circulation) technology has the problems of high temperature on the front wall of the boiler, condensation water and soot corrosion in the burner viewing channel, ignition channel and flame detector channel while effectively reducing nitrogen. Defects such as frequent failures and shortened service life of electrical components such as flame detectors and ignition electrodes due to the influence of high-temperature flue gas are inevitable. Summary of the Utility Model

[0004] The purpose of the utility model is to solve the above-mentioned disadvantages existing in the prior art, and to propose a low-nitrogen burner cooling air system for a steam injection boiler equipped with an air preheater.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A low-nitrogen burner cooling air system for a steam injection boiler equipped with an air preheater, comprising a low-nitrogen burner, a high-pressure blower, an air preheater, a chimney, and a steam injection boiler combustion chamber. The low-nitrogen burner body is integrated with a cooling circulation air mechanism. The low-nitrogen burner is installed at the front end of the steam injection boiler combustion chamber, and the cooling circulation air mechanism is connected to the front wall of the boiler.

[0007] The cooling circulation air mechanism is of a ring structure, and is provided with two interfaces, a high-pressure inlet and a low-pressure outlet. The positions where the two interfaces are led out are (as close as possible) close and provided with a partition plate. The diameters of the two interfaces are preferably DN25, DN32, DN40, DN50 and other specifications. The cross-sectional area of the cooling circulation air mechanism is 2-6 times the cross-sectional area of the interface diameter.

[0008] The high-pressure inlet is connected to the air inlet of the low-nitrogen burner through an equal-diameter high-pressure pipeline, and branch pipelines leading to the ignition channel, the flame detector channel, and the viewing channel are connected in parallel on the high-pressure pipeline.

[0009] A cut-off valve is connected in series on each branch pipeline, and the diameter of each branch pipeline is 1 / 2-1 / 3 of the diameter of the high-pressure pipeline.

[0010] Specifically, the diameter of the low-pressure outlet is usually the same as that of the high-pressure inlet. The diameter of the low-pressure pipeline is the same as that of the low-pressure outlet.

[0011] Specifically, a wavy detour mechanism is arranged in the annular cavity of the cooling circulating air structure.

[0012] Specifically, the lower end of the air preheater is connected to the boiler smoke box at the tail of the combustion chamber of the steam injection boiler, the upper end interface of the air preheater is connected to the chimney, and the chimney is connected to the boiler smoke box through the internal connecting flue of the air preheater;

[0013] The hot air duct connects the air preheater and the axial flow fan in series, and an electric duct damper is connected in series on the hot air duct.

[0014] Specifically, the hot air duct and the fresh air duct are connected in parallel to the air supply duct, and a fresh air filtering device and an electric duct damper connected in series are respectively arranged along the inlet of the fresh air duct.

[0015] Specifically, the air supply duct is connected to the inlet of the high-pressure fan, and the high-pressure fan is equipped with a powerful fan with an adjustable air supply pressure up to 0.62 - 1.0 MPa.

[0016] Specifically, a temperature sensing device is installed near the inlet of the high-pressure fan on the air supply duct to detect the change in the temperature of the combustion-supporting air, and a pressure sensing device is installed at the air inlet interface of the low-nitrogen burner.

[0017] The design scheme proposed by the present utility model has the following beneficial effects during the application process:

[0018] 1. Introducing high-pressure cooling air to cool down the front wall of the boiler, recover waste heat, and block heat conduction, making the operation of the low-nitrogen burner safer and more reliable.

[0019] 2. Introducing high-pressure cooling air to counteract the damage caused by the high-temperature flue gas flowing back in the furnace to the viewing channel, ignition channel, and flame detector channel, ensuring that electrical components such as flame detectors and ignition electrodes can work normally and extend their service life under the working environment temperature that meets the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the process flow block diagram of the present utility model;

[0021] Figure 2 is the structural schematic diagram of the present utility model;

[0022] Figure 3 is the structural schematic diagram of the cooling circulating air mechanism of the present utility model.

[0023] In the figure: 110, low-nitrogen burner; 120, high-pressure blower; 130, air preheater; 140, chimney; 150, steam injection boiler combustion chamber; 1110, cooling circulation air mechanism; 1111, spacer; 1112, high-pressure inlet; 1113, low-pressure outlet; 112, ignition channel; 113, flame detector channel; 114, viewing fire channel; 115, high-pressure pipeline; 116, low-pressure pipeline; 117, pressure sensing device; 121, air supply duct; 122, temperature sensing device; 123, fresh air filtering device; 124, fresh air duct; 131, axial flow fan; 132, hot air duct; 151, boiler smoke box; 16, electric air duct damper; 17, cut-off valve. Detailed implementation mode

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] Refer to Figures 1-3 , a cooling air system for a low-nitrogen burner of a steam injection boiler equipped with an air preheater, comprising a low-nitrogen burner 110, a high-pressure blower 120, an air preheater 130, a chimney 140, and a steam injection boiler combustion chamber 150;

[0026] The low-nitrogen burner 110 body is integrated with a cooling circulation air mechanism 1110. The low-nitrogen burner 110 is installed at the front end of the steam injection boiler combustion chamber 150, and the cooling circulation air mechanism 1110 is connected to the front wall of the boiler;

[0027] The cooling circulation air mechanism 1110 is of a ring structure, and is provided with two interfaces, a high-pressure inlet 1112 and a low-pressure outlet 1113. The lead-out positions of the two interfaces are close (as close as possible) and are provided with a spacer 1111. The nominal diameters of the interfaces are preferably DN25, DN32, DN40, DN50 and other specifications. The cross-sectional area of the cooling circulation air mechanism 1110 is 2-6 times the cross-sectional area of the nominal diameter of the interface.

[0028] The high-pressure inlet 1112 is connected to the air inlet of the low-nitrogen burner 110 through an equal-diameter high-pressure pipeline 115. Branch pipelines leading to the ignition channel 112, the flame detector channel 113, and the viewing fire channel 114 are connected in parallel on the high-pressure pipeline 115. A cut-off valve 17 is connected in series on each branch pipeline. The nominal diameter of each branch pipeline is 1 / 2-1 / 3 of the nominal diameter of the high-pressure pipeline 115, and is preferably DN8, DN15, DN20 and other specifications.

[0029] For example, when the high-pressure pipeline 115 is a DN40 pipeline, usually the nominal diameter of the branch pipeline of the viewing fire channel 114 is selected as DN8, and the nominal diameters of the branch pipelines of the ignition channel 112 and the flame detector channel 113 are selected as DN15.

[0030] It should be further noted that the diameter of the low-pressure outlet 1113 is usually the same as that of the high-pressure inlet 1112, and the diameter of the low-pressure pipeline 116 is the same as that of the low-pressure outlet 1113.

[0031] It should be further noted that a wavy detour mechanism is arranged in the annular cavity of the cooling circulating air structure 1110 to enhance the heat exchange effect.

[0032] It should be further noted that the lower end of the air preheater 130 is connected to the boiler smoke box 151 at the tail of the combustion chamber 150 of the steam injection boiler, the upper end interface of the air preheater 130 is connected to the chimney 140, and the chimney 140 is communicated with the boiler smoke box 151 through the internal connecting flue of the air preheater 130;

[0033] The hot air duct 132 connects the air preheater 130 and the axial flow fan 131 in series, and an electric duct damper 16 is connected in series on the hot air duct 132.

[0034] It should be further noted that the hot air duct 132 and the fresh air duct 124 are connected in parallel to the air supply duct 121, and a fresh air filtering device 123 and an electric duct damper 16 connected in series are respectively arranged along the inlet of the fresh air duct 124;

[0035] It should be further noted that the air supply duct 121 is connected to the inlet of the high-pressure fan 120, and the high-pressure fan is equipped with a powerful fan with an adjustable air supply pressure of up to 0.62 - 1.0 MPa.

[0036] It should be further noted that a temperature sensing device 122 is installed near the inlet of the high-pressure fan 120 on the air supply duct 121 to detect the change in the temperature of the combustion-supporting air;

[0037] A pressure sensing device 117 is installed at the air inlet interface of the low-nitrogen burner 110 to detect the change in the pressure of the combustion-supporting air.

[0038] Working principle:

[0039] Generally, the electric duct damper 16 connected in series on the hot air duct 132 is in a fully open state, and the electric duct damper 16 connected in series on the fresh air duct 124 is in a fully closed state. At this time, the air preheater 130 is in a fully operational state, the temperature of the combustion-supporting hot air in the system is the highest, and the pressure of the combustion-supporting air is the lowest; the ambient fresh air passes through the air preheater 130 and is then transported to the air supply duct 121 through the hot air duct 132 and the axial flow fan 131 to provide hot combustion-supporting air for the low-nitrogen burner, making the combustion more complete, reducing the loss of incomplete combustion, and thus increasing the thermal efficiency.

[0040] Further, in order to meet the actual requirements for the pressure and temperature of the combustion-supporting air, according to the feedback values of the pressure and temperature of the combustion-supporting air, the temperature and pressure of the combustion-supporting air can be adjusted by synchronously adjusting the opening degree of the electric duct damper 16 connected in series on the fresh air duct 124 and the hot air duct 132. At this time, the air preheater is in a semi-operating state.

[0041] Furthermore, when the opening degree of the electric duct damper 16 on the hot air duct 132 is in the fully closed state and the electric duct damper 16 on the fresh air duct 124 is in the fully open state, at this time, the air preheater is in the non-operating state, the combustion-supporting air is the ambient fresh air with high oxygen content, the system combustion-supporting air pressure is the maximum, and the ambient fresh air passes through the fresh air filter device 123 and is then transported to the air supply duct 121 through the fresh air duct 124 to provide normal-temperature combustion-supporting air for the low-nitrogen burner.

[0042] Specifically, regardless of the state of the air preheater 130, the temperature of the system combustion-supporting air is much lower than the high-temperature zones formed by the conduction of the high-temperature flue gas on the front wall of the boiler and each part of the low-nitrogen burner 110 body, and it can continuously provide high-pressure cooling air with the same pressure as the combustion-supporting air pressure for the cooling circulation air mechanism 1110, the ignition channel 112, the flame detection channel 113, the fire viewing channel 114, etc.

[0043] Part of the cooling air enters through the high-pressure inlet 1112 along the annular cavity of the cooling circulation air mechanism 1110 after entering through a part of the high-pressure pipeline 115, takes away the heat conducted from the front wall of the boiler, and then is led out from the low-pressure outlet 1113, and is connected to the air supply duct 121 through the low-pressure pipeline 116. A cut-off valve 17 is connected in series on the low-pressure pipeline 116; part of it is respectively led to the ignition channel 112, the flame detection channel 113, and the fire viewing channel 114 through the branch pipelines connected in parallel to the high-pressure pipeline 115 to resist the invasion of the hot flue gas from the combustion chamber and block the heat conduction of each channel, thereby ensuring the normal operation of electrical components such as flame detectors and ignition electrodes at the working environment temperature that meets the use requirements.

[0044] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A cooling air system for a low - nitrogen burner of a steam - injection boiler with an air pre - heater, comprising a low - nitrogen burner (110), a high - pressure fan (120), an air pre - heater (130), a chimney (140), a steam - injection boiler combustion chamber (150), a hot - air duct (132), and a fan, characterized in that: The body of the low-nitrogen burner (110) is integrated with a cooling circulation air mechanism (1110). After the low-nitrogen burner (110) is installed, the cooling circulation air mechanism (1110) is connected to the front wall of the boiler.

2. The cooling air system of the steam-injected boiler low-nitrogen burner configured with an air preheater according to claim 1, wherein: The cooling circulation air mechanism (1110) is of a ring structure. There are two interfaces, a high-pressure inlet (1112) and a low-pressure outlet (1113), arranged on the cooling circulation air mechanism (1110). The leading positions of the high-pressure inlet (1112) and the low-pressure outlet (1113) are close to each other, and a spacer plate (1111) is arranged between the high-pressure inlet (1112) and the low-pressure outlet (1113).

3. The cooling air system of the steam-injected boiler low-nitrogen burner configured with an air preheater according to claim 2, characterized in that: The cross-sectional area of the cooling circulation air mechanism (1110) is 2 - 6 times the cross-sectional area of the interface diameter.

4. A cooling air system for a low-nitrogen burner of a steam-injected boiler configured with an air preheater according to claim 3, characterized in that: The high-pressure inlet (1112) is connected to the air inlet of the low-nitrogen burner (110) through an equal-diameter high-pressure pipeline (115). Branch pipelines leading to the ignition channel (112), the flame detector channel (113), and the fire viewing channel (114) are connected in parallel on the high-pressure pipeline (115). A cut-off valve (17) is connected in series on each branch pipeline, and the diameter of each branch pipeline is 1 / 2 - 1 / 3 of the diameter of the high-pressure pipeline (115); The low-pressure outlet (1113) is connected to the air inlet of the fan through a low-pressure pipeline (116). A cut-off valve (17) is connected in series on the low-pressure pipeline (116).

5. The cooling air system of the steam injection boiler low-nitrogen burner with an air preheater according to claim 4, characterized in that: A pressure sensing device (117) is installed at the air inlet interface of the low-nitrogen burner (110); A temperature sensing device (122) is installed near the inlet of the high-pressure fan (120) in the air supply air duct (121).

6. The cooling air system of the steam injection boiler low-nitrogen burner configured with an air preheater according to claim 5, wherein: An electric air duct baffle (16) is connected in series on the hot air duct (132). A fresh air filtering device (123) and an electric air duct baffle (16) connected in series are respectively arranged along the inlet of the fresh air duct (124).

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