Energy-saving and efficiency-improving security device of combustion system for negative pressure heating furnace and control method thereof

Abstract

The invention discloses a combustion system energy-saving and efficiency-improving security device for a negative pressure heating furnace and a control method thereof. The device comprises a cylinder body, a flue gas inlet and outlet, a square hole, a square flange, a front bearing plate, a bearing cover, a rear bearing, a valve shaft and a baffle of an electric baffle valve, an electric actuator, a bayonet lock, an upper inspection manhole, a lower inspection manhole, a sealing plate, a water collecting tank, a condensate water collecting and discharging assembly, a lifting lug, a flue gas temperature detector, a flue gas oxygen content detector and a flue gas pressure detector. On-line maintenance and replacement of the chimney baffle valve can be achieved without moving the chimney, and the disassembly and assembly work is simple and rapid; the baffle valve adopts the electric adjustment design, the valve opening degree can be adjusted in real time according to smoke exhaust parameters, the operation working condition matched with the heating furnace is optimized, and it is guaranteed that the heating furnace can operate safely, stably and efficiently for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of heating furnaces, and particularly to an energy-saving, efficiency-increasing and safety-guarantee device for a combustion system of a negative-pressure heating furnace and a control method thereof. Background Art

[0002] In the oilfield surface gathering and transportation system, the heating furnace, as the main energy equipment for heating process media, is of crucial significance for the safe, stable and efficient operation of the oil and gas production process in the long term. In actual production, the heating furnace mainly consists of a combustion system, a heat exchange system and a smoke exhaust system. The three affect each other and are closely related. Any change in each part will cause fluctuations in the other two systems. Through long-term engineering practice in the oilfield, a common but often overlooked problem has been found, that is, the problem of rust and jamming of the chimney baffle valve of the negative-pressure heating furnace. The chimney baffle valve can not only optimize the air-fuel ratio and improve the combustion efficiency by adjusting the combustion air volume, but also effectively balance the furnace pressure, stabilize the flow field and temperature field in the furnace, and achieve the effect of protecting the safety of the heating furnace body. However, in actual operation, after several years of operation of most negative-pressure heating furnaces, the baffle valve in the chimney will be jammed due to rust, so that the opening degree can no longer be adjusted, affecting the safe and efficient operation of the heating furnace. It can be seen from this that the average service life of the current heating furnace chimney is usually more than 15 years, while the baffle valve of the chimney is jammed and fails in two or three years, and cannot be replaced online. It can only be replaced together when the chimney is replaced, so that the negative-pressure heating furnace can only operate in a low-efficiency and safety-hazard state in the following more than ten years. This not only increases the gas consumption of oil production, increases the production cost of the enterprise, but also increases the emissions of pollutants, especially nitrogen oxides and carbon dioxide. The long-term operation will cause great pollution and damage to the atmospheric environment. Summary of the Invention

[0003] The purpose of the present invention is to provide an energy-saving, efficiency-increasing and safety-guarantee device for a combustion system of a negative-pressure heating furnace and a control method thereof in view of the deficiencies of the prior art. On the one hand, it aims to ensure that the chimney baffle valve can be used safely and normally for a long time to optimize the operating conditions of the heating furnace, so that the heating furnace can operate safely and efficiently for a long time. On the other hand, when the baffle valve fails to jam or is damaged, it can be conveniently repaired or replaced online, thereby achieving the goal of ensuring the normal production of the heating furnace.

[0004] In a first aspect, the present invention provides an energy-saving, efficiency-enhancing and safety-guarantee device for a combustion system of a negative-pressure heating furnace, comprising: a cylinder body, wherein connecting flanges are installed at both the upper and lower ends of the cylinder body, the lower end is a flue gas inlet, and the upper end is a flue gas outlet; a long and narrow rectangular hole is opened on the cylinder wall in the middle of the cylinder body, and a method flange structure composed of four steel plates is arranged around the rectangular hole on the cylinder wall. The method flange and the front bearing plate are connected by a flange, and a front bearing is fixedly arranged in the middle of the front bearing plate. Pin holes are opened on the side walls of the bearing cover and the front bearing, and the bearing cover and the front bearing are fixed by pins; a circular hole is opened on the cylinder wall opposite to the rectangular hole, a rear bearing is welded outside the circular hole, the valve shaft of the electric baffle valve is fixedly connected with the baffle, the rear end of the valve shaft penetrates into the rear bearing, the front section of the valve shaft is fixed with the electric actuator, and pin holes are opened in the area of the valve shaft between the front bearing and the bearing cover, and the displacement of the valve shaft in the horizontal direction is restricted by installing pins; an upper maintenance manhole is welded on the cylinder wall at the upper part of the cylinder body, and the end of the upper maintenance manhole is connected with an upper maintenance hole sealing plate through a flange; a water collecting trough inclined backward and downward is arranged along the inner side of the cylinder wall above the upper maintenance manhole, a drain hole is opened at the lowest part of the water collecting trough, a condensate collecting pipe is welded on the cylinder wall around the drain hole, a reducing pipe is welded behind the condensate collecting pipe, and a condensate drain pipe with a smaller pipe diameter is welded below the reducing pipe; a lower maintenance manhole is welded on the cylinder wall at the lower part of the cylinder body, and the end of the lower maintenance manhole is connected with a lower maintenance hole sealing plate through a flange; lifting lugs are arranged on both sides of the upper maintenance manhole on the cylinder wall, and a flue gas temperature detector is arranged below the lifting lugs on the cylinder wall; a flue gas oxygen content detector and a flue gas pressure detector are respectively installed on both sides of the lower maintenance manhole on the cylinder wall.

[0005] Further, a method flange structure composed of four steel plates is welded around the rectangular hole on the cylinder wall.

[0006] Further, the valve shaft of the electric baffle valve and the baffle are fixedly connected by welding or pins.

[0007] Further, the front section of the valve shaft and the electric actuator are fixed by threads or pins.

[0008] In a second aspect, the present invention provides a control method for the energy-saving, efficiency-enhancing and safety-guarantee device for the combustion system of the negative-pressure heating furnace described above, comprising:

[0009] The opening degree of the electric baffle valve is controlled by the flue gas oxygen content; when the flue gas oxygen content detector is in normal working condition, the opening degree of the electric baffle valve is controlled by the oxygen content, and at the same time, the control system records the data of the flue gas pressure, flue gas temperature and gas volume in the same period, and through the edge computing function of the control system, sorts out the internal logical relationship between the flue gas oxygen content and the flue gas pressure, flue gas temperature, gas volume and baffle opening degree, so that when the fault data of the flue gas oxygen content detector has a large deviation, relying on the internal logical relationship between the above several parameters, a desired flue gas oxygen content is set to accurately control the opening degree of the electric baffle valve, and finally the goal of matching and optimizing the operating conditions of the heating furnace is achieved.

[0010] Further, the normal state control logic of the flue gas oxygen content detector is as follows:

[0011] Kd = f1(Vgas, φO2jc);

[0012] 0 = f2(Py, Vgas, Kd);

[0013] 0 = f3(Ty, Vgas, Kd);

[0014] Wherein, φO2jc is the oxygen content of the flue gas monitored online; Kd is the opening degree of the baffle valve; Py is the flue gas pressure monitored online; Ty is the flue gas temperature monitored online; Vgas is the gas volume of the fuel gas monitored online, which comes from the data of the burner system.

[0015] Further, the control logic after the failure of the flue gas oxygen content detector is as follows:

[0016] Kd = g(Vgas, Py, Ty, φO2set);

[0017] Wherein, φO2set is the set target oxygen content of the flue gas; Kd is the opening degree of the baffle valve; Py is the flue gas pressure monitored online; Ty is the flue gas temperature monitored online; Vgas is the gas volume of the fuel gas monitored online, which comes from the data of the burner system.

[0018] The beneficial effects of the present invention are as follows: An energy-saving, efficiency-increasing and safety-guaranteeing device for a combustion system of a negative-pressure heating furnace and its control method according to the present invention can realize the online maintenance and replacement of the chimney baffle valve without moving the chimney, with small disassembly and assembly workload, simple and fast, and does not affect the normal production of the heating furnace; the baffle valve of the present invention adopts an electric adjustment design, which can adjust the valve opening degree in real time according to the exhaust parameters to optimize and match the operating conditions of the heating furnace, and ensure that the heating furnace can operate for a long time, safely, stably and efficiently; the present invention adds a water collecting tank on the inner wall of the cylinder body to effectively discharge the flue gas condensate and avoid the corrosion damage of the baffle valve and the heating furnace body caused by acidic condensate; through the edge computing function of the control system and relying on a large amount of actual operation data, the present invention realizes the purpose of regulating the baffle valve with the oxygen content as the target, and solves the problem of the adverse impact on the efficient operation of the whole system caused by the high failure rate of the flue gas oxygen content detector.

[0019] Illustration: 1 - cylinder body; 2 - flue gas outlet; 3 - upper maintenance hole sealing plate; 4 - electric actuator; 5 - front bearing plate; 6 - lower maintenance hole sealing plate; 7 - flue gas inlet; 8 - flue gas oxygen content detector; 9 - condensate drain pipe; 10 - reducer pipe; 11 - condensate collecting pipe; 12 - lifting lug; 13 - flue gas temperature detector; 14 - flue gas pressure detector; 15 - rear bearing; 16 - baffle; 17 - valve shaft; 18 - bearing cover; 19 - water collecting tank; 20 - retaining pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The front view of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention;

[0021] Figure 2 The right view of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention;

[0022] Figure 3 The left view of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention;

[0023] Figure 4 is Figure 3 the sectional view taken along the A-A direction of

[0024] Figure 5 The top view of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention;

[0025] Figure 6 is Figure 1 the sectional view taken along the B-B direction of

[0026] Figure 7 The three-dimensional schematic diagram of one perspective of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention;

[0027] Figure 8 The three-dimensional schematic diagram of another perspective of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention; Figure 9 The on-site installation schematic diagram of the energy-saving, efficiency-enhancing and safety installation device for the combustion system of the negative-pressure heating furnace of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following non-limiting embodiments can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. It is necessary to point out that the following embodiments cannot be understood as limiting the protection scope of the present invention. If those skilled in the art make some non-essential improvements and adjustments to the present invention based on the above content of the present invention, it still falls within the protection scope of the present invention.

[0029] Please refer to Figures 1 to 9, the present invention provides an energy-saving, efficiency-enhancing and safety-protecting device for a combustion system of a negative-pressure heating furnace, comprising: a cylinder body 1, with connecting flanges installed at both the upper and lower ends of the cylinder body 1. The lower end is the flue gas inlet 7, and the upper end is the flue gas outlet 2; a long and narrow rectangular hole is opened on the middle cylinder wall of the cylinder body 1, and a method flange structure composed of four steel plates is welded around the rectangular hole of the cylinder wall. The method flange and the front bearing plate 5 are connected by a flange. A front bearing is fixedly provided in the middle of the front bearing plate 5. There is a bearing cover 18 in front of the front bearing. Pin holes are opened on the upper side walls of the bearing cover 18 and the front bearing. The bearing cover 18 and the front bearing are fixed by a pin 20; a circular hole is opened on the cylinder wall opposite to the rectangular hole. A rear bearing 15 is welded outside the circular hole. The valve shaft 17 and the baffle 16 of the electric damper valve are fixedly connected by welding or a pin. The rear end of the valve shaft 17 penetrates into the rear bearing 15. The front section of the valve shaft 17 and the electric actuator 4 are fixed by threads or a pin. The valve shaft 17 is provided with a pin hole in the area between the front bearing and the bearing cover 18, and the displacement of the valve shaft 17 in the horizontal direction is restricted by installing a pin 20; an upper maintenance manhole is welded on the upper cylinder wall of the cylinder body 1, and the end of the upper maintenance manhole is connected to the upper maintenance hole sealing plate 3 by a flange; a water collecting trough 19 inclined backward and downward is arranged along the inner side of the cylinder wall above the upper maintenance manhole. A drain hole is opened at the lowest point of the water collecting trough 19. A condensate collecting pipe 11 is welded on the cylinder wall around the drain hole. A reducing pipe 10 is welded behind the condensate collecting pipe 11, and a condensate drain pipe 9 with a smaller pipe diameter is welded below the reducing pipe 10; a lower maintenance manhole is welded on the lower cylinder wall of the cylinder body 1, and the end of the lower maintenance manhole is connected to the lower maintenance hole sealing plate 6 by a flange; lifting lugs 12 are arranged on both sides of the upper maintenance manhole on the cylinder wall, and a flue gas temperature detector 13 is arranged below the lifting lugs 12 on the cylinder wall; a flue gas oxygen content detector 8 and a flue gas pressure detector 14 are respectively installed on both sides of the lower maintenance manhole on the cylinder wall.

[0030] This product is installed between the flue gas outlet of the heating furnace and the chimney. The flue gas discharged from the heating furnace enters the cylinder body 1 through the flue gas inlet 7. First, it contacts the flue gas oxygen content detector 8 and the flue gas pressure detector 14 at the lower part of the cylinder body 1 to obtain the oxygen content and the flue gas discharge pressure data of the flue gas. Then it passes upward through the baffle 16, and then contacts the flue gas temperature detector 13 to obtain the flue gas discharge temperature data. Finally, it passes outside the water collecting trough 19 and is discharged to the chimney through the flue gas outlet 2, and finally is discharged to the atmosphere through the chimney. During the flue gas discharge process, heat will be dissipated to the atmospheric environment through the inner wall of the chimney. When the flue gas temperature drops below the water dew point, some condensate water will precipitate from the flue gas. This part of the condensate water will flow downward along the inner wall of the chimney and finally gather at the water collecting trough. Under the guiding action of the water collecting trough, it is discharged along the condensate drainage system, thus significantly reducing the corrosion of the acidic flue gas condensate water on the flue gas damper valve and reducing the risk of the baffle rusting and jamming.

[0031] Control method for energy-saving, efficiency-enhancing and safety-installing device of combustion system for negative-pressure heating furnace of the present invention, including: the opening degree of the electric baffle valve is jointly controlled by the oxygen content in the flue gas, the gas volume, the flue gas pressure and the flue gas temperature. This strategy is mainly formulated based on the actual situation that the failure rate of the oxygen content detector 8 in the flue gas is relatively high; when the oxygen content detector in the flue gas is in normal working condition, the opening degree of the electric baffle valve is controlled by the oxygen content, and at the same time the control system records the data of the flue gas pressure, the flue gas temperature and the gas volume in the same period, and through the edge computing function of the control system, sorts out the internal logical relationship between the oxygen content in the flue gas and the flue gas pressure, the flue gas temperature, the gas volume and the baffle opening degree, so that when there are large deviations in the failure data of the oxygen content detector in the flue gas, relying on the internal logical relationship between the above several parameters, sets the desired oxygen content in the flue gas, and accurately controls the opening degree of the electric baffle valve, and finally achieves the goal of matching and optimizing the operating conditions of the heating furnace.

[0032] The control logic in the normal state of the oxygen content detector in the flue gas is as follows:

[0033] Kd = f1(Vgas, φO2jc);

[0034] 0 = f2(Py, Vgas, Kd);

[0035] 0 = f3(Ty, Vgas, Kd);

[0036] Among them, φO2jc is the oxygen content in the flue gas monitored online; Kd is the opening degree of the baffle valve; Py is the flue gas pressure monitored online; Ty is the flue gas temperature monitored online; Vgas is the gas volume monitored online, coming from the data of the burner system.

[0037] When the oxygen content detector in the flue gas is in the normal stage, the opening degree Kd of the baffle valve is controlled by the oxygen content, and at the same time through edge computing, the internal logical relationship function among the above five parameters is obtained: that is, the above functional relationship.

[0038] The control logic after the oxygen content detector in the flue gas fails is as follows:

[0039] Kd = g(Vgas, Py, Ty, φO2set);

[0040] Among them, φO2set is the set target oxygen content in the flue gas; Kd is the opening degree of the baffle valve; Py is the flue gas pressure monitored online; Ty is the flue gas temperature monitored online; Vgas is the gas volume monitored online, coming from the data of the burner system.

[0041] When the oxygen content detector in the flue gas fails, using the relationship function Kd = g(Vgas, Py, Ty, φO2set), φO2set is specified as a relatively optimal target oxygen content value, and through edge computing, the opening degree Kd0 of the baffle valve is obtained, and the opening degree Kd of the baffle valve is adjusted to the valve position of Kd0.

[0042] When the baffle valve fails, first shut down the combustion system, then open the upper and lower maintenance manhole seals. After the temperature of the cylinder body drops to normal temperature, the front bearing plate can be removed, and the baffle valve can be disassembled for repair or replacement. After repair, it can be reinstalled; the whole process takes a short time and has no impact on the normal production of the heating furnace; in addition, the flue gas parameter detector can be regularly cleaned through the maintenance manhole, effectively improving the measurement accuracy and service life of the flue gas detector.

[0043] In summary, the energy-saving, efficiency-enhancing and safety-guaranteeing device and control method for the combustion system of a negative-pressure heating furnace of the present invention realize the flange connection mode between the baffle valve and the chimney, ensuring that the baffle valve can be conveniently disassembled, maintained and replaced, and effectively improving the use efficiency of the baffle valve; for the energy-saving, efficiency-enhancing and safety-guaranteeing device and control method for the combustion system of a negative-pressure heating furnace of the present invention, the baffle valve adopts an electric adjustment form, which can automatically adjust the opening according to the oxygen content in the flue gas to adapt to the operating conditions of the heating furnace, intelligently ensuring the safe, stable and efficient operation of the combustion system and improving the operating safety of the heating furnace; for the energy-saving, efficiency-enhancing and safety-guaranteeing device and control method for the combustion system of a negative-pressure heating furnace of the present invention, it integrates the oxygen content, temperature and pressure detectors of the flue gas, and combines with the edge computing function of the control system to realize the joint precise control of the oxygen content, flue gas temperature, flue gas pressure and gas volume on the baffle valve; for the energy-saving, efficiency-enhancing and safety-guaranteeing device and control method for the combustion system of a negative-pressure heating furnace of the present invention, by adding a water collecting tank and a supporting drainage system on the inner wall of the cylinder body, the flue gas condensate generated during the flue gas emission process is effectively intercepted and discharged, avoiding the corrosion damage of the baffle valve by the condensate and extending the service life of the baffle valve; for the energy-saving, efficiency-enhancing and safety-guaranteeing device and control method for the combustion system of a negative-pressure heating furnace of the present invention, the overall structure is simple, with an integrated skid-mounted design, and all external interfaces adopt flange connection methods, which are convenient for transportation and installation. In addition, this structure or a similar structure can also be integrated onto the heating furnace body or the chimney body as a new heating furnace or a new chimney to achieve the same effect.

[0044] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A combustion system energy-saving and efficiency-enhancing safety device for a negative pressure heating furnace, characterized in that: include: The cylinder (1) is provided with connecting flanges at both upper and lower ends of the cylinder (1), the lower end being a smoke inlet (7) and the upper end being a smoke outlet (2); a long narrow square hole is provided on the cylinder wall in the middle of the cylinder (1), a square flange structure consisting of four steel plates is provided around the square hole of the cylinder wall, the square flange and the front bearing plate (5) are connected by flanges, a front bearing is fixedly provided in the middle of the front bearing plate (5), a bearing cover (18) is provided in front of the front bearing, and the bearing cover (18) and the upper side wall of the front bearing are connected to each other. A bayonet hole is provided, and the bearing cover (18) and the front bearing are fixed by a bayonet (20); a round hole is provided on the cylinder wall opposite to the square hole, and a rear bearing (15) is welded outside the round hole; a valve shaft (17) of the electric baffle valve is fixedly connected to the baffle (16); the rear end of the valve shaft (17) penetrates into the rear bearing (15), the front section of the valve shaft (17) is fixed to the electric actuator (4), and a bayonet hole is provided in the area of ​​the valve shaft (17) between the front bearing and the bearing cover (18); by installing the bayonet, the valve shaft (17) is fixedly connected to the baffle (16); and the rear end of the valve shaft (17) is inserted into the rear bearing (15). The front section of the valve shaft (17) is fixed to the electric actuator (4). A pin (20) is used to limit the displacement of the valve shaft (17) in the horizontal direction; an upper inspection manhole is welded on the cylinder wall at the upper part of the cylinder body (1), and the end of the upper inspection manhole is connected to the upper inspection hole sealing plate (3) through a flange; a water collecting trough (19) inclined backward and downward is provided above the upper inspection manhole along the inner side of the cylinder wall, a drainage hole is provided at the lowest point of the water collecting trough (19), a condensate collection pipe (11) is welded on the cylinder wall around the drainage hole, and a reducer is welded behind the condensate collection pipe (11) (10), a condensate drain pipe (9) of a smaller diameter is welded below the reducer (10); a lower inspection manhole is welded on the cylinder wall at the lower part of the cylinder body, and the end of the lower inspection manhole is connected to the lower inspection hole sealing plate (6) through a flange; lifting ears (12) are provided on the cylinder wall at both sides of the upper inspection manhole, and a smoke temperature detector (13) is provided below the lifting ears (12) on the cylinder wall; a smoke oxygen content detector (8) and a smoke pressure detector (14) are respectively installed on the cylinder wall at both sides of the lower inspection manhole.

2. The energy-saving and efficiency-enhancing safety device for combustion system of negative pressure heating furnace according to claim 1, characterized in that: A square flange structure consisting of four steel plates is welded around the square hole of the cylinder wall.

3. The energy-saving and efficiency-enhancing safety device for combustion system of negative pressure heating furnace according to claim 1, characterized in that: The valve shaft (17) and the baffle (16) of the electric baffle valve are fixedly connected by welding or bayonet pins.

4. The energy-saving and efficiency-enhancing safety device for combustion system of negative pressure heating furnace according to claim 1, characterized in that: The front section of the valve shaft (17) and the electric actuator (4) are fixed by means of threads or bayonet pins.

5. A control method for the energy-saving and efficiency-enhancing safety device for the combustion system of a negative pressure heating furnace as claimed in claim 1, characterized in that: include: The opening of the electric damper valve is controlled by the oxygen content of the flue gas; When the flue gas oxygen content detector is operating normally, the opening of the electric damper valve is controlled by the oxygen content. At the same time, the control system records the flue gas pressure, flue gas temperature and gas volume data of the same period, and uses the edge computing function of the control system to sort out the internal logical relationship between the flue gas oxygen content and the flue gas pressure, flue gas temperature, gas volume and damper opening. When the fault data of the flue gas oxygen content detector shows a large deviation, the desired flue gas oxygen content can be set based on the internal logical relationship between the above parameters to accurately control the opening of the electric damper valve, thereby ultimately achieving the goal of matching and optimizing the operating conditions of the heating furnace.

6. The control method of the energy-saving and efficiency-enhancing safety device for the combustion system of a negative pressure heating furnace according to claim 5, characterized in that: The normal state control logic of the flue gas oxygen content detector is as follows: Kd=f1(Vgas,φO2jc); 0 = f2(Py, Vgas, Kd); 0 = f3 (Ty, Vgas, Kd); Among them, φO2jc is the flue gas oxygen content monitored online; Kd is the damper valve opening; Py is the flue gas pressure monitored online; Ty is the flue gas temperature monitored online; Vgas is the gas volume monitored online, which comes from the burner system data.

7. A control method for a combustion system energy-saving and efficiency-enhancing safety device for a negative pressure heating furnace as claimed in claim 6, characterized in that: The control logic after the flue gas oxygen content detector fails is as follows: Kd=g(Vgas,Py,Ty,φO2set); Among them, φO2set is the set target flue gas oxygen content; Kd is the damper valve opening; Py is the online monitored flue gas pressure; Ty is the online monitored flue gas temperature; Vgas is the online monitored gas volume, which comes from the burner system data.

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