Energy-saving heating furnace

Abstract

This invention relates to the field of heating furnaces, and particularly to an energy-saving heating furnace. The energy-saving heating furnace includes a furnace body, a burner, a flame sleeve, a heating tube, and a fuel control system. The furnace body has a flue gas outlet. The burner is located at the bottom of the furnace body, with a gas nozzle located inside the furnace body at its top. The burner also has a gas inlet and a combustion air inlet located outside the furnace body. A gas pipe is located inside the burner, and the gas inlet is connected to the gas nozzle via the gas pipe. The flame sleeve is located at the top of the burner and surrounds the flame area of ​​the gas nozzle. The flame sleeve is made of metal oxide or has its inner wall coated with a metal oxide material. The heating tube is located above the flame sleeve and has a working fluid inlet and a working fluid outlet. This invention enhances the combustion reaction through the metal oxide material of the flame sleeve, improves the effective heat absorption in the high-temperature zone of the working fluid in the heating furnace, and reduces the unit energy consumption of the product through fuel flow control, thus achieving energy-saving goals.

Description

Technical Field

[0001] The present invention relates to the field of heating furnaces, and in particular to an energy-saving heating furnace. Background Technology

[0002] In the field of heating furnaces, the most mature energy-saving technology is flue gas waste heat recovery technology. Flue gas waste heat recovery is a low-grade heat energy recovery technology. The heat energy utilization is mainly in the form of low-temperature and low-pressure steam, hot water, hot air, etc. After adopting waste heat recovery technology, the thermal efficiency of the heating furnace can reach more than 90%. However, the reduction in energy consumption per unit of working fluid is limited, and it cannot significantly save energy or reduce carbon dioxide emissions.

[0003] The unit production energy consumption of the working fluid mainly depends on its effective utilization rate of the heat generated by fuel combustion. The effective heat absorption range of the working fluid during heating is primarily located in the high-temperature combustion zone. The high-temperature heat generated by fuel combustion is a high-grade thermal energy. Only by improving the utilization efficiency of this high-grade thermal energy can the unit production energy consumption of the working fluid be effectively reduced, that is, the fuel consumption per unit of product produced, thereby achieving the goal of energy conservation in combustion. Summary of the Invention

[0004] To address the technical problem that existing energy-saving and emission-reduction technologies in the field of heating furnaces cannot effectively improve the utilization efficiency of high-grade thermal energy of fuel, this invention utilizes the enhancing and promoting effect of oxide functional materials on the flame and initial combustion reaction to shift the peak value of the fuel exothermic curve forward, increase the temperature gradient in the initial flame combustion zone, and increase the thermal energy utilization efficiency in the high-temperature zone by improving radiative heat transfer efficiency. This achieves the transformation from low-grade thermal energy utilization to high-grade thermal energy utilization, as well as the energy-saving goal of saving fuel under the same heat absorption load conditions.

[0005] The present invention aims to provide an energy-saving heating furnace to reduce the unit production energy consumption of the heating furnace.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An energy-saving heating furnace is provided, comprising a furnace body, a burner, a flame sleeve, and a heating tube. The furnace body has a flue gas outlet; the burner is located at the bottom of the furnace body, and a gas nozzle is located inside the furnace body at the top of the burner. The burner also has a gas inlet and a combustion air inlet located outside the furnace body. A gas pipe is located inside the burner, and the gas inlet is connected to the gas nozzle through the gas pipe. The flame sleeve is located at the top of the burner and surrounds the flame area of ​​the gas nozzle. The flame sleeve is made of metal oxide or has its inner wall coated with metal oxide material. The heating tube is located above the flame sleeve, one end of which is connected to the furnace body or extends outside the furnace body and has a working fluid inlet, and the other end is connected to the furnace body or extends outside the furnace body and has a working fluid outlet.

[0007] Optionally, the burner further includes a guide plate, which is installed between the gas nozzle and the combustion air inlet. The guide plate is provided with a through swirl channel and a direct current air hole, which are connected to the combustion air inlet below the guide plate and the combustion space cavity at the top of the flame sleeve burner above the guide plate.

[0008] Optionally, the heating tube is provided with a U-shaped heating tube for heating the working fluid inside, and the portion of the U-shaped heating tube located above the flame sleeve is bent into a U-shape into the vertical space between the two burners.

[0009] Optionally, the burners are arranged vertically and symmetrically on both sides of the heating tube, and the number is two.

[0010] Optionally, the energy-saving heating furnace further includes a temperature sensor, a flow sensor, a fuel control valve, and a fuel controller. The temperature sensor is used to detect the working fluid temperature at the working fluid inlet and the working fluid outlet, and feeds it back to the fuel controller for fuel flow control. The flow sensor is used to detect the working fluid flow rate at the working fluid inlet. The fuel control valve is installed at the gas inlet. The fuel controller is connected to the flow sensor, the temperature sensor, and the fuel control valve, and the fuel controller is used to control the fuel control valve according to the electrical signals from the temperature sensor and the flow sensor.

[0011] Optionally, the energy-saving heating furnace further includes a support base located at the bottom of the furnace body to support the furnace body.

[0012] Compared with the prior art, the energy-saving heating furnace of this invention has the following advantages:

[0013] During normal operation of the heating furnace, the fuel gas is ejected from the gas nozzle through control valves and pipelines, and mixes with the combustion air passing through the swirl channel to form a stable swirling flame. Under the action of centrifugal force, the swirling flame comes into close contact with the functional material sleeve. After a certain period of combustion, the functional material sleeve is fully heated. Under high-temperature conditions, the oxide functional material sleeve enhances the initial flame, making the initial combustion reaction after ignition more intense, shifting the peak value of the fuel exothermic range forward, and significantly increasing the flame temperature in the initial stage of combustion.

[0014] The heat absorbed by the heating surface of the working fluid in the furnace mainly comes from high-temperature flame radiation heat transfer and flue gas convection heat transfer, with high-temperature flame radiation heat transfer being dominant. According to the Stefan-Boltzmann law of radiation heat transfer, as the flame temperature increases, the radiation heat transfer increases according to the fourth power law, and the flame radiation intensity increases significantly. The heating surface near the high-temperature zone of the flame absorbs more heat, causing the temperature of the heated working fluid to rise accordingly. When the furnace's fuel control system is operating normally, it receives the inlet flow signal of the cold working fluid and the outlet temperature signal of the hot working fluid in real time. After comparing and judging with the process setpoint, it outputs a fuel flow adjustment signal. The fuel flow control valve receives the signal and executes the corresponding action to complete the fuel flow control. When the flame temperature and flame radiation heat transfer intensity increase, causing the heating surface temperature to rise, in order to ensure that the heating temperature of the working fluid remains within the set range, the receiving control system actively reduces the fuel input to the furnace, thereby achieving the goal of saving fuel and energy for the same heating process. In other words, the present invention uses high-temperature functional materials to enhance combustion technology, which can improve the utilization efficiency of high-grade heat energy in the main combustion zone of the heating furnace, thereby achieving the goal of higher efficiency and energy saving, with good energy-saving effect. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the specific embodiments will be briefly described below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0016] Figure 1 This is a schematic diagram of the energy-saving heating furnace provided in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram from another perspective of the energy-saving heating furnace.

[0018] Figure 3 yes Figure 1 A magnified view of part A in the image.

[0019] In the diagram: 100, furnace body; 110, flue gas outlet;

[0020] 200. Burner; 210. Gas nozzle; 220. Gas inlet; 230. Combustion air inlet; 240. Gas pipe; 250. Flow guide plate; 251. Swirl channel;

[0021] 300. Flame sleeve; 310. Metal oxide material layer;

[0022] 400. Heating element; 410. Working fluid inlet; 420. Working fluid outlet;

[0023] 500. Support base;

[0024] 600. Feedback adjustment system; 610. Temperature sensor; 620. Flow sensor; 630. Fuel control valve; 640. Fuel controller. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and similar expressions used in this specification are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0027] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Please refer to this as well. Figure 1 , Figure 2 and Figure 3 The diagrams provided are schematic diagrams of the energy-saving heating furnace according to an embodiment of the present invention, and schematic diagrams of the energy-saving heating furnace from another perspective. Figure 1 The enlarged view of section A shows that this energy-saving heating furnace includes a furnace body 100, a burner 200, a flame sleeve 300, and a heating tube 400. The furnace body 100 has a flue gas outlet 110. The burner 200 is located at the bottom of the furnace body 100, and a gas nozzle 210 located inside the furnace body 100 is located at the top of the burner 200. The burner 200 also has a gas inlet 220 and a combustion air inlet 230 located outside the furnace body 100. A gas pipe 240 is located inside the burner 200, and the gas inlet 220 is connected to the gas nozzle 210 via the gas pipe 240. The flame sleeve 300 is located at the top of the burner 200 and surrounds the flame area of ​​the gas nozzle 210. The inner wall of the flame sleeve 300 is covered with a metal oxide material layer 310. The heating tube 400 is located above the flame sleeve 300. One end of the heating tube 400 is connected to the furnace body 100 or extends to the outside of the furnace body 100 and is provided with a working fluid inlet 410. The other end is connected to the furnace body 100 or extends to the outside of the furnace body 100 and is provided with a working fluid outlet 420.

[0029] Gas is supplied from gas inlet 220 and gas pipe 240 to gas nozzle 210, while combustion-supporting gas flows in from combustion air inlet 230. The gas burns at gas nozzle 210, and the combustion reaction intensifies when the flame comes into contact with the metal oxide material layer 310 of flame sleeve 300. The metal oxide material layer 310 enhances the combustion reaction because it increases the oxygen ion concentration during combustion. Flame sleeve 300, also known as an oxide functional material sleeve, enhances the initial flame, making the initial combustion reaction after ignition more intense, shifting the peak value of the fuel exothermic zone forward, and significantly increasing the flame temperature in the initial combustion stage.

[0030] The heat absorbed by the working fluid inside the heating tube 400 mainly comes from the thermal radiation of the high-temperature flame and the thermal conduction of the heating tube 400, with the thermal radiation from the high-temperature flame being the primary source. According to the Stefan-Boltzmann law of radiative heat transfer, the radiative capacity of a heating furnace is directly proportional to the fourth power of its temperature. Increasing the flame temperature even slightly will significantly increase the radiative capacity of the heating furnace. Furthermore, rapidly reaching the peak temperature and reducing the initial combustion zone length helps to efficiently utilize fuel, thereby reducing fuel consumption for the same production energy expenditure.

[0031] Specifically, regarding the furnace body 100, please refer to... Figure 1 and Figure 2 As the combustion reaction site, the furnace body 100 requires a good exhaust gas outlet. Therefore, an exhaust port 110 is provided at the top of the furnace body 100 to discharge combustion exhaust gases. Furthermore, a support base 500 is placed at the bottom of the furnace body 100 to support the furnace body 100 and facilitate the lifting and transportation of the furnace body 100.

[0032] Please refer to the information regarding burner 200 as well. Figure 1 , Figure 2 and Figure 3A burner is a general term for a device that sprays fuel and air in a certain manner for combustion. The function of a burner is to atomize the fuel gas through flame combustion. When fuel gas enters the burner, under the influence of flame temperature and atmosphere, the combustion chemical reaction produces a large number of ground-state atoms, as well as some excited-state atoms, ions, and molecules. A well-designed burner should have high atomization efficiency, low noise, and stable flame performance. In this embodiment of the invention, the energy-saving heating furnace is equipped with a pair of burners 200, which are vertically arranged. To enhance the flow rate of the combustion-supporting gas, the energy-saving heating furnace has a blower at the combustion air inlet 230 of the burner 200. Simultaneously, the burner 200 is equipped with a guide plate 250. A guide plate 250 is installed between the gas nozzle 210 and the combustion air inlet 230. The guide plate 250 has a through swirling channel 251 and a direct-flow air hole (not shown). The swirling channel 251 and the direct-flow air hole connect the combustion air inlet 230 below the guide plate 250 and the cavity of the flame sleeve 300 above the guide plate 250. The swirling channel 251 is used to form a combustion air vortex, which can drive the combustion flame to rotate. The centrifugal effect produced by the flame is obvious, and it makes the flame contact the metal oxide material layer 310 more fully. As a result, the more oxygen ions participate in the combustion reaction, the more intense the combustion reaction. It can be understood that the gas flows through the gas pipe 240, the combustion air flows through the burner 200 cavity, and the gas and combustion air meet at the gas nozzle 210 to produce a combustion reaction.

[0033] For information on the 300 flame sleeve, please refer to [link / reference]. Figure 2 The flame sleeve 300 is fitted onto the top of the burner 200 and is the main area where the gas nozzle 210 generates flame. As mentioned earlier, the flame sleeve 300 is fully heated. Under high-temperature conditions, the oxide functional material sleeve enhances the initial flame, making the initial combustion reaction after ignition more intense, shifting the peak value of the fuel exothermic zone forward, and significantly increasing the flame temperature in the initial combustion stage, thereby promoting the combustion reaction and increasing the flame intensity. It is worth mentioning that the metal oxide material layer 310 of the flame sleeve 300 is sintered from one or more of the following components: zirconium oxide, cerium oxide, yttrium oxide, dysprosium oxide, samarium oxide, barium oxide, copper oxide, magnesium oxide, and aluminum oxide, or coated onto the surface of the sleeve.

[0034] For information about the 400 heating element, please refer to [link / reference]. Figure 1 and Figure 2 In this embodiment, the portion of the heating tube 400 located directly above the flame sleeve 300 is bent downwards into a U-shape. It is understood that the closer the heating tube is to the burner 200, the better the heat exchange effect. To utilize the furnace heat energy more efficiently, multiple heating tubes 400 can be arranged side-by-side.

[0035] This embodiment of the invention also includes a feedback adjustment system 600, please refer to... Figure 2 The feedback control system 600 includes a temperature sensor 610, a flow sensor 620, a fuel control valve 630, and a fuel controller 640. The temperature sensor 610 detects the working fluid temperature at the working fluid outlet 420, the flow sensor 620 detects the working fluid flow rate at the working fluid inlet 410, the fuel control valve 630 is installed at the gas inlet 220, and the fuel controller 640 is connected to the temperature sensor 610, the flow sensor 620, and the fuel control valve 630. The fuel controller 640 controls the fuel control valve 630 based on the electrical signals from the temperature sensor 610 and the flow sensor 620. If the outlet working fluid temperature is too low, the fuel controller 640 appropriately opens the fuel control valve 630 to increase the fuel intake; conversely, if the outlet working fluid temperature is too high, the fuel controller 640 appropriately closes the fuel control valve 630 to reduce the fuel intake.

[0036] As the combustion reaction intensifies through the flame sleeve 300, the initial flame temperature rises accordingly. This significantly increases the flame radiation intensity, causing the U-shaped heating tube 400, located near the high-temperature zone of the flame, to absorb more heat. Consequently, the temperature at the working fluid outlet 420 rises, and the temperature sensor 610 outputs a temperature increase signal. At this time, the furnace fuel controller 640 receives the cold working fluid inlet flow signal and the working fluid outlet temperature increase signal in real time. It compares these signals with the process setpoints. To ensure the heating temperature of the working fluid remains within the set range, the control system receiving the temperature increase signal outputs a signal to reduce the fuel flow rate. Upon receiving this signal, the fuel control valve 630 executes a corresponding action, reducing the fuel input to the furnace, thereby achieving fuel savings and energy efficiency for the same heating process.

[0037] More specifically, another embodiment of the present invention provides specific functional features and parameters of the energy-saving heating furnace: the metal oxide material layer 310 of the flame sleeve 300 is composed of zirconium oxide, aluminum oxide, yttrium oxide, and cerium oxide, with a mass ratio of 80%:10%:5%:5%. The power of a single burner in the energy-saving heating furnace is set to 5KW, the excess air coefficient is set to 1.1, and the flame temperature is measured after stable combustion. At the center position 40cm above the burner outlet, the measured flame temperatures with and without the flame sleeve 300 are 870℃ and 820℃, respectively. The flame temperature with the flame sleeve 300 installed increases by an average of approximately 50℃. Under the same heating surface operating conditions, the radiative heat transfer efficiency of the heating medium is increased by approximately 12%, resulting in a fuel saving rate of approximately 5%, thus achieving the goal of energy saving in the heating furnace combustion.

[0038] Compared with the prior art, the energy-saving heating furnace of this invention has the following advantages:

[0039] Gas is supplied from the gas inlet and gas pipe to the gas nozzle, while combustion air flows in from the combustion air inlet. The fuel burns at the gas nozzle, and the combustion reaction intensifies when the flame comes into contact with the metal oxide material of the flame sleeve. Consequently, the temperature in the combustion front reaches its peak within a relatively short time, which is higher than the peak temperature in existing technologies, achieving rapid and efficient heat exchange between the high-temperature section of the furnace and the working fluid inside the heating tube. In other words, this embodiment of the invention enhances the combustion reaction through the flame sleeve and its metal oxide material layer, improving the effective heat absorption efficiency of the working fluid in the energy-saving heating furnace and achieving energy-saving goals.

[0040] It should be noted that while the preferred embodiments of the present invention are given in the specification and accompanying drawings, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of the present invention; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of the present invention specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An energy-saving heating furnace, characterized in that, include: The furnace body is equipped with a flue gas outlet; The burner is located at the bottom of the furnace body. The top of the burner is provided with a gas nozzle located inside the furnace body. The burner is also provided with a gas inlet and a combustion air inlet located outside the furnace body. A gas pipe is provided inside the burner. The gas inlet is connected to the gas nozzle through the gas pipe. A flame sleeve is disposed at the top of the burner and surrounds the flame area of ​​the gas nozzle. The flame sleeve is made of metal oxide or has its inner wall coated with metal oxide material. A heating tube is located above the flame sleeve. One end of the heating tube is connected to the furnace body or extends to the outside of the furnace body and is provided with a working fluid inlet. The other end of the heating tube is connected to the furnace body or extends to the outside of the furnace body and is provided with a working fluid outlet. The burner also includes a guide plate, which is installed between the gas nozzle and the combustion air inlet. The guide plate is provided with a through swirl channel and a direct flow air hole, which connect the combustion air inlet and the combustion space cavity at the top of the burner. The energy-saving heating furnace also includes a temperature sensor, a flow sensor, a fuel control valve, and a fuel controller. The temperature sensor is used to detect the working fluid temperature at the working fluid inlet and the working fluid outlet, and feeds it back to the fuel controller for fuel flow control. The flow sensor is used to detect the flow rate of the working fluid at the inlet of the working fluid; The fuel control valve is installed at the gas inlet; The fuel controller is connected to the flow sensor, the temperature sensor, and the fuel control valve. The fuel controller is used to control the fuel control valve based on the electrical signals from the temperature sensor and the flow sensor. When the intensity of the combustion reaction increases through the flame sleeve, the temperature sensor outputs a temperature increase signal. The fuel controller receives the cold working fluid inlet flow signal and the temperature increase signal in real time, compares them with the process set value, and outputs a fuel flow reduction signal. The fuel control valve receives the fuel flow reduction signal and reduces the fuel input to the heating furnace.

2. The energy-saving heating furnace according to claim 1, characterized in that, The burners are arranged symmetrically and vertically, and there are two of them.

3. The energy-saving heating furnace according to claim 2, characterized in that, The heating tube is bent into a U-shape towards the center of the burner.

4. The energy-saving heating furnace according to any one of claims 1-2, characterized in that, It also includes a support base, which is located at the bottom of the furnace body to support the furnace body.

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