CN206973561U - Continuous disperse formula burner - Google Patents

Abstract

The utility model discloses a continuous dispersion type combustion device, comprising a combustion chamber, the combustion chamber is provided with a fuel inlet, a combustion air inlet and a smoke exhaust port, and also includes a preheating body, and the preheating body has a series of flame radiation absorbing A combustion-supporting air passage is formed between the heat-receiving surfaces, and the preheater transfers heat energy obtained by converting flame radiation energy to the combustion-supporting air flowing through and directly contacting the heat-receiving surfaces. The continuous dispersive combustion device of the utility model uses the flame radiation energy to heat the combustion-supporting air to reach the temperature of the combustion-supporting air required for the dispersive combustion, and can achieve a continuous and stable dispersive combustion state, which overcomes the need for storage in the existing high-temperature and low-oxygen combustion technology. The problem of unsteady and intermittent combustion operation caused by the flue gas and air switching of thermal heat exchangers.

Description

Continuous Dispersion Combustion Device

technical field

The utility model relates to the technical field of combustion, in particular to a continuous dispersion combustion device.

Background technique

Diffusion combustion (also known as high-temperature low-oxygen combustion or high-temperature air combustion) is a combustion method different from traditional diffusion and premixed flames, and has a series of advantages such as high thermal efficiency and low pollutant emissions. It is generally believed that one of the necessary conditions for the occurrence of diffuse combustion is to preheat the combustion air to a very high temperature (about 800 to 1000 ° C). The existing diffusion combustion technology relies on the regenerative heat exchanger to preheat the combustion-supporting air to reach a high temperature. Then stop feeding the hot flue gas, and switch to passing air into the regenerative heat exchanger so that the internal heat storage material releases heat to provide the air to heat the air to a high temperature. See: Jiang Shaojian et al., "High Temperature and Low Oxygen Combustion Technology and Application", Central South University Press, December 2010; Luo Guomin, "Regenerative High Temperature Air Combustion Technology", Metallurgical Industry Press, July 2011; CN201610528356" A continuous regenerative combustion device", CN201510900684 "reduction smelting regenerative combustion system and method for smelting using the system", CN201510685654 "multi-stream, high temperature, low oxygen, low NOx left and right combined single regenerative burner", CN201520872026 "regenerative combustion device and trolley furnace with it", CN201520485201 "a radiant tube regenerative combustion system", CN201410810830 "regenerative combustion furnace and working method", CN201410490919 "a kind of heat storage system for radiant tubes" Thermal burner", CN201420437951 "continuous regenerative diffuse flame combustion equipment", CN201310705395 "heat storage component structure for regenerative burner", CN201310119635 "combustion device and combustion control method of combustion device", CN201210367670 "a metal Magnesium and metal calcium reduction furnace regenerative combustion system and its control method", CN201210100728 "Double regenerative burner", CN201220591469 "An integral regenerative burner", CN201110052562 "A regenerative flameless combustion technology" .

In my country, regenerative high-temperature air combustion devices have been initially used in metallurgy, chemical industry, machinery manufacturing and other industrial sectors, and have achieved a certain degree of energy-saving and emission-reduction results. However, when the existing high-temperature air combustion technology uses a regenerative heat exchanger to preheat the combustion air, it needs to configure an even number of burners and regenerative heat exchangers, as well as the corresponding high-temperature flue gas and air pipelines and switching. During operation, flue gas and combustion-supporting air need to flow into the regenerative heat exchanger through frequent switching of pipelines and valve systems. At the same time, the burner is ignited and extinguished in turn, which is an unsteady intermittent combustion operation. Sometimes there are abnormal phenomena such as pressure fluctuation, deflagration, misfire, tempering, ignition failure, etc., and its switching mechanism and control system are quite complicated and expensive. These problems limit the practical application of the existing high-temperature air combustion technology. Therefore, in recent years, researchers have been actively seeking new combustion devices capable of diffuse combustion (for example, CN201510128053 "A direct-flow diffuse combustion tubular heating furnace system and burner").

Utility model content

The purpose of this utility model is to provide a steady-state and high-efficiency continuous dispersion combustion device that does not need to switch between flue gas and air. state of diffuse combustion. The utility model also provides a method for forming continuous dispersed combustion.

For this reason, the utility model provides:

The continuous dispersion combustion device includes a combustion chamber, the combustion chamber is provided with a fuel inlet, a combustion air inlet and a smoke exhaust port, and is characterized in that it also includes a preheater, and the preheater has a series of flame radiation absorbing A combustion-supporting air passage is formed between the heat-receiving surfaces, and the preheater transfers heat energy obtained by converting flame radiation energy to the combustion-supporting air flowing through and directly contacting the heat-receiving surfaces.

Further, the structural form of the preheating body is set such that the preheating body exhibits a black body effect for the flame radiation directed at the preheating body.

Further, the preheating body is composed of several metal sheets, the surface of the metal sheets is the heat transfer surface, and the metal sheets are arranged to form between every two adjacent heat transfer surfaces, which can be used as combustion-supporting air. The slit gap of the channel, and the opening position and direction of the slit gap between every two adjacent heat transfer surfaces are all facing the flame so that the flame radiation can be injected into the slit gap to generate a black body effect.

The above-mentioned preheater that uses flame radiation to preheat combustion-supporting air includes, but is not limited to, the following specific forms: porous and breathable preheater, vortex-fin preheater, and heat-exchanging tube-and-tube preheater.

The continuous dispersion combustion device with porous air-permeable preheating body is characterized in that it includes a burner, a drum and a porous air-permeable preheater located inside the drum and adapted to the shape of the drum. The porous air-permeable preheating body is a porous metal body, a metal fiber body, a foamed ceramic body or a honeycomb ceramic body, and a hollow interlayer is formed between the cylindrical drum and the porous air-permeable preheating body. A burner is installed at the bottom, and there is an annular smoke outlet around the burner, and an air inlet is opened tangentially on the wall of the drum.

Further, the above-mentioned continuous dispersion combustion device with a porous gas-permeable preheating body also includes a fan and a heat exchanger, the annular smoke outlet is connected to the shell-side gas inlet of the heat exchanger, and the gas outlet of the fan is connected to The tube-side gas inlet of the heat exchanger, and the tube-side gas outlet of the heat exchanger are connected to the air inlet on the wall surface of the cylindrical drum.

The continuous dispersion type combustion device with vortex finned preheating body is characterized in that it includes a vortex finned preheating body, an inner cylinder, an outer cylinder, a dome plate, a circular bottom plate, a blower fan and a heat exchanger, and the vortex The finned preheater is composed of a series of axisymmetrically distributed vortex-shaped fins made of metal sheets, and the vortex-shaped fins are arranged on the inner cylinder with the central axis of the inner cylinder as the center. In the lower half of the cylinder, the narrow gap between the vortex-shaped fins is the combustion air passage, a hollow interlayer is formed between the inner cylinder and the outer cylinder, and the top and bottom of the outer cylinder are respectively formed by the The dome plate and the round bottom plate are closed, the inner cylinder is fixedly installed on the dome plate, there is a gap between the lower end of the inner cylinder and the round bottom plate, and the wall surface of the outer cylinder is opened along the tangential direction. The air inlet, the wall of the inner cylinder is provided with a fuel inlet along the tangential direction, and the dome plate is provided with a smoke exhaust port and an opening for accommodating heated objects, and the smoke exhaust port on the dome plate is connected to the heat exchange The shell-side gas inlet of the device, the gas outlet of the fan is connected to the tube-side gas inlet of the heat exchanger, and the tube-side gas outlet of the heat exchanger is connected to the air inlet on the wall surface of the outer cylinder.

The continuous dispersion combustion device with heat exchange tubular preheater is characterized in that it includes heat exchange tubular preheater, first cylinder, second cylinder, third cylinder, fourth cylinder, cylinder The top plate, the round bottom plate and the fan, the heat exchange tubular preheating body is composed of a series of heat exchange tubes, the top and bottom of the third cylinder and the fourth cylinder are respectively closed by the dome plate and the round bottom plate, A hollow interlayer is formed between the third cylinder and the fourth cylinder, the first cylinder is fixedly installed on the lower surface of the dome plate, there is a gap between the lower end of the first cylinder and the circular bottom plate, and the second cylinder is fixedly installed on the circular bottom plate On the upper surface, there is a gap between the upper end of the second cylinder and the dome plate, the heat exchange tubes pass through the first cylinder and the second cylinder, and the heat exchange tubes communicate with the combustion zone and the third cylinder and The hollow interlayer between the fourth cylinders, and the heat exchange tubes are uniformly arranged in the third cylinder around the circumferential direction, the wall of the fourth cylinder is provided with an air inlet along the tangential direction, the The air outlet of the fan is connected to the air inlet on the wall surface of the fourth cylinder.

Further, the continuous diffused combustion device with heat exchange tube-type preheating body also includes a number of Venturi ejectors corresponding to the number of heat exchange tubes, and each heat exchange tube injects combustion-supporting air into A Venturi ejector is installed at the nozzles of the combustion zone, which is used to introduce the flue gas in the combustion zone so that the flue gas and the combustion-supporting air are mixed with each other.

The continuous dispersive combustion device of the utility model uses the flame radiation energy to heat the combustion-supporting air to achieve the temperature of the combustion-supporting air required for the dispersive combustion, and can achieve a continuous and stable dispersive combustion state, which overcomes the need for storage in the existing high-temperature and low-oxygen combustion technology. The problem of unsteady and intermittent combustion operation caused by the flue gas and air switching of thermal heat exchangers.

Description of drawings

Fig. 1 is a schematic structural view of a continuous dispersion combustion device with a porous air-permeable preheater according to Embodiment 1 of the present invention.

Fig. 2 is a schematic structural view of a continuous dispersion combustion device with a vortex-fin preheater according to Embodiment 2 of the utility model.

Fig. 3 is a schematic structural view of a continuous dispersion combustion device with a heat exchange tube-and-tube preheater according to Embodiment 3 of the present utility model.

Fig. 4 is a schematic diagram of installing a Venturi ejector at the heat exchange tube nozzle of Embodiment 4 of the present invention.

Detailed ways

The utility model will be further described below in conjunction with specific embodiments. Wherein, the accompanying drawings are for illustrative purposes only, and represent only schematic diagrams, rather than actual drawings, and should not be construed as limitations on this patent; in order to better illustrate the embodiments of the present utility model, some parts of the accompanying drawings will be omitted , enlargement or reduction, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some known structures and their descriptions in the drawings may be omitted.

The data enumerated in the following examples are only exemplary data provided in order to better illustrate the content of the present utility model, and unless otherwise specified, do not constitute any limitation to the claims of the present utility model.

In this specification, "flame radiation" refers to all radiation caused by flame combustion, including all radiation emitted by the luminous area of the flame (including visible, ultraviolet and infrared parts), all radiation emitted by combustion products in the non-luminous area, and the above-mentioned The portion of radiation that is reflected and scattered by other surfaces, and the infrared radiation emitted by a heated object or other surface after the heated object or other surface has reached a high temperature. "Heat transfer surface" refers to those surfaces that can absorb flame radiation and transfer the heat energy converted from flame radiation energy to the combustion-supporting air that is in direct contact with the heat transfer surface. "Diffuse combustion preheating temperature" refers to the combustion air preheating temperature required for diffuse combustion to occur.

Example 1

As shown in FIG. 1 , it is a structural schematic diagram of a continuous dispersion combustion device with a porous air-permeable preheater of the present invention. Referring to Fig. 1, the combustion device includes a burner 60, a cylindrical drum 62 and a porous air-permeable preheater 61 located inside the cylindrical drum 62, which is adapted to the shape of the cylindrical drum 62, as well as a blower 68 and a heat exchanger 69 . A hollow interlayer A is formed between the cylindrical drum 62 and the porous air-permeable preheater 61 . A burner 60 is installed at the bottom of the cylindrical drum 62, and there is an annular smoke outlet 64 around the burner 60, and the exhausted smoke is passed into the shell side of the heat exchanger 69 for preheating the combustion-supporting air. The wall surface of the drum 62 is provided with an air inlet along the tangential direction. The combustion-supporting air from the outside is pressurized by the fan 68 and passed into the tube side of the heat exchanger 69 to be heated by the waste heat of the flue gas to a temperature of about 500 to 700°C, and then flows into the hollow interlayer A through the air inlet on the wall of the cylinder 62, Then the combustion-supporting air flows through the porous air-permeable preheater 61 and is further heated to a temperature of about 800 to 1000° C. before entering the combustion zone. The fuel provided by the burner 60 and the high-temperature combustion-supporting air entering from the porous air-permeable preheating body 61 undergo diffuse combustion in the combustion zone. The drum 62 can be made of heat-resistant metal material or non-metal refractory material, and its outer surface is provided with an insulating layer. The air intake of the blower fan 68 for extracting outside air is equipped with a high-efficiency dust filter. In this embodiment, the internal space of the porous air-permeable preheater 61 constitutes a combustion chamber.

The function of the porous air-permeable preheater 61 is to absorb the flame radiant energy and transfer the heat energy converted from the flame radiant energy to the combustion-supporting air passing through the porous air-permeable preheater and entering the combustion zone. In this embodiment, the porous air-permeable preheater 61 should meet the following conditions at the same time: first, it has a larger area in contact with the combustion-supporting air, and its inner surface area is much larger than the outer surface area, so that the combustion-supporting air flows through the porous air-permeable preheater The internal surface area of 61 is significantly heated; second, it has a high flame radiation absorption rate; third, it has good heat resistance; fourth, it has good thermal conductivity; fifth, it has proper air flow Resistance, so that the combustion-supporting air introduced by the fan 68 first fills the hollow interlayer A between the cylindrical drum 62 and the porous air-permeable preheater 61, and then flows evenly through all the air holes of the porous air-permeable preheater 61 to enter burning zone. As an example, four methods for making the porous air-permeable preheating body 61 are given below. According to specific conditions, one of these four methods or other appropriate methods can be used to make the porous air-permeable preheater 61:

(1) Porous metal body: select the metal material and use the casting method to obtain the required metal thick wall in the shape of a drum (when used for small equipment, the wall thickness of the metal thick wall is 20 to 30mm; when used for large and medium-sized equipment , the wall thickness of the metal thick wall is 100 to 150mm), and then densely and uniformly drill holes in the direction perpendicular to the surface of the metal thick wall to penetrate the metal thick wall, and the depth of the formed air hole is equal to the wall thickness of the metal thick wall Thick, the depth/aperture ratio of the air holes reaches 20 to 30, the surface porosity is 70%, and the volume porosity of the porous metal body is 70%. Since the above-mentioned porous metal body has a relatively high surface porosity, and the depth/aperture ratio of the vent holes reaches 20 to 30, the flame radiation from the combustion zone is reflected/absorbed multiple times on the inner surface of the vent holes after being injected into these vent holes As a result, the black body effect occurs, so the above-mentioned porous metal body has a high flame radiation absorption rate. The inner surface of the air holes in the porous metal body is a heat-receiving and heat-transfer surface that absorbs flame radiation energy and transfers the heat energy converted from the flame radiation energy to the combustion-supporting air that flows through these air holes and enters the combustion zone.

(2) Metal fiber body: select a commercially available metal fiber blanket product (the average aperture of the micropores is 0.1 mm, and the volume porosity is 85%), and a metal guard in the shape of a drum is installed on the inside and outside of it. The metal fiber blanket is made of metal fiber filaments, with a three-dimensional space grid microstructure, its micropores have a high absorption rate for flame radiation, and have a large internal surface area, better heat resistance and thermal conductivity and appropriate flow resistance. The inner surface area of the metal fiber body can be used as a heat receiving and heat transfer surface for absorbing flame radiation and transferring the heat energy converted from the flame radiation energy to the combustion-supporting air flowing through the micropores and entering the combustion zone.

(3) Foamed ceramic body: select commercially available foamed ceramic plate products (micropore size distribution range is 10 to 100 nm, and volume porosity is 90%). A plurality of ceramic foam plates are used to splice into a porous air-permeable preheater 61 of the shape shown in FIG. 1 . The micropores of the foam ceramic plate have a higher absorption rate for flame radiation, and have a larger inner surface area, better heat resistance and appropriate flow resistance. The inner surface area of the foam ceramic plate can be used as a heat-receiving and heat-transfer surface for absorbing flame radiation and transferring heat energy converted from flame radiation energy to combustion-supporting air flowing through micropores into the combustion zone.

(4) Honeycomb ceramic body: when used in medium and large combustion equipment, the porous air-permeable preheater 61 can be formed by stacking many honeycomb ceramic bodies. The common specifications of the commercially available honeycomb ceramic body are as follows: the overall size of a single honeycomb ceramic body is 50x50x200mm, the honeycomb channel is straight, the honeycomb wall thickness is 0.2 to 0.5mm, the cell spacing is 1 to 3mm, and the depth/aperture ratio of the honeycomb channel is 70 to 70mm. 200. The flame radiation from the combustion zone is injected into these honeycomb channels and is reflected/absorbed multiple times on its inner surface, thereby causing a blackbody effect, so the above-mentioned honeycomb ceramic body has a high flame radiation absorption rate. The inner surface of the honeycomb channels in the honeycomb ceramic body is a heat-receiving and heat-transfer surface that absorbs flame radiant energy and transfers the heat energy converted from the flame radiant energy to the combustion-supporting air flowing through these honeycomb channels into the combustion zone.

The ignition process of this continuous dispersion type combustion device is described as follows: when the device was in a cold state, start the fan 68, a small amount of combustion-supporting air was passed into the combustion zone, and simultaneously use the burner 60 to spray a small amount of fuel into the combustion zone, and use the igniter (Fig. 1), a conventional diffusion flame is generated above the burner 60. The porous air-permeable preheater 61 absorbs flame radiation and is heated up, and the combustion-supporting air entering the combustion zone through the porous air-permeable preheater 61 is heated up accordingly. The diffusion flame of the burner 60 is maintained to allow the entire plant to heat up. When the temperature of the combustion-supporting air entering the combustion zone from the porous air-permeable preheater 61 reaches the diffuse combustion preheating temperature, diffuse combustion begins to occur in the combustion zone.

In the state of diffuse combustion, the burner 60 is used to inject fuel at a high speed, driven by the kinetic energy of the jet, the smoke around the burner 60 is entrained into the jet, resulting in a petal shape as shown by the curved arrow line in Figure 1 Circulating flow, the velocity distribution of the circulating flow is an axisymmetric distribution centered on the central axis of the burner 60 . During the above-mentioned circulating flow process, various components in the combustion zone are fully mixed, so that the fuel injected by the burner 60 is diluted to a fuel concentration of about 1%, while the combustion-supporting air entered by the porous air-permeable preheater 61 Diluted to an oxygen concentration of about 5%. The fuel that enters from the burner 60 will not meet the air with an oxygen concentration of 21%, and a chain reaction will not occur, and the traditional flame that strongly glows and emits heat in a narrow area and in a short time will not appear. When the preheating temperature of the combustion-supporting air is higher than the ignition temperature of the fuel, the temperature conditions required for the oxidation reaction of the fuel can be reached everywhere in the combustion zone, but only 1% concentration of fuel and 5% concentration of oxygen can meet in each place Therefore, only mild, uniformly luminescent, large-volume oxidation reactions depending on the collision probability of fuel molecules and pyrolysis product molecules with oxygen molecules can occur everywhere to form continuous and steady-state diffuse combustion .

Dispersed combustion can emit light radiation (including visible, ultraviolet and infrared parts), and the combustion products carbon dioxide and water vapor contained in the flue gas also emit strong infrared radiation. The above-mentioned four types of porous air-permeable preheater 61 all have a relatively high flame radiation absorption rate and good thermal conductivity, and the flame radiation from the diffuse combustion zone is mainly on the inner surface of the porous air-permeable preheater 61 It is absorbed and converted into heat energy, so that the inside of the porous air-permeable preheater 61 is heated by the flame radiation energy. When the combustion-supporting air flows through the porous air-permeable preheater 61 , it contacts with its inner surface and is heated to become high-temperature air, and then flows into the diffuse combustion zone.

In this specification, the combustion-supporting air preheating temperature required for the diffuse combustion to occur is referred to as "diffuse combustion preheating temperature". If the combustion-supporting air can be heated by the porous air-permeable preheater 61 to reach the ignition temperature of the fuel, the moment the combustion-supporting air is sprayed into the combustion zone from the air holes of the porous air-permeable preheater 61, it can oxidize with the fuel to form diffuse combustion; If the temperature reached by the combustion-supporting air heated by the porous air-permeable preheater 61 is about several hundred degrees lower than the ignition temperature of the fuel, the combustion-supporting air injected into the combustion zone from the air holes of the porous air-permeable preheater 61 will mix with the burned smoke Oxidation reaction may also occur after reaching a high temperature to form diffuse combustion; but if the temperature reached by the combustion-supporting air heated by the porous air-permeable preheater 61 is too low, it may cause incomplete combustion. The "diffusion combustion preheating temperature" is related to the specific structure and characteristic parameters of the combustion device, and is estimated to be a temperature several hundred degrees below the ignition temperature of the fuel used (for example, the fuel ignition temperature is 800 °C, and the "diffusion combustion preheating temperature" is about 400°C).

This embodiment does not need to use a regenerative heat exchanger to preheat the combustion-supporting air as in the prior art, nor does it need to configure a switching mechanism for flue gas and air. This embodiment can achieve uninterrupted diffuse combustion state. As mentioned above, the preheating of the combustion air in the continuous dispersion combustion device shown in Figure 1 is to first use the waste heat of the flue gas to heat, and then use the flame radiation to reach the temperature of the combustion air required for the diffusion combustion. This embodiment has all the known advantages of diffuse combustion. In addition, the cylindrical drum 62 and the porous air-permeable preheater 61 of this embodiment jointly constitute the combustion chamber wall (or furnace wall, stove wall) of the combustion equipment, thus also having the following advantages:

(1) The wall of the combustion chamber does not need to use refractory materials, especially suitable for occasions where the heat load changes rapidly.

The combustion chamber walls (or hearth walls, hearth walls) of existing combustion equipment (such as industrial furnaces and commercial gas stoves) are usually made of refractory materials. In the case of rapid changes in thermal load, the refractory wall is subject to large thermal stress, making it prone to cracks. After a period of use, the refractory material cracks, peels off, and often needs to be repaired or replaced. A typical example is a commercial Chinese cooking stove with a burner power of up to 60kW. Due to the strong firepower, when the commercial Chinese cooking stove is ignited and cooking, the stove heats up sharply, and after the cooking is finished, the stove cools down. Such repeated heating and cooling will result in a short service life of the refractory wall of the commercial Chinese cooking stove, which generally takes one to two years. replace. Similarly, many types of industrial furnaces have large operating temperature changes, which are easy to damage the refractory furnace wall, and often need to stop the furnace for manual maintenance of refractory materials, which is labor-intensive and time-consuming.

In this embodiment, the combustion chamber wall formed by the cylindrical drum 62 and the porous air-permeable preheater 61 can replace the combustion chamber wall made of refractory material. First of all, the surface opening rate of the porous air-permeable preheater 61 in this embodiment is as high as 70% or more, and the air holes have a relatively large depth. The flame radiation in the zone can be injected into the interior of the porous air-permeable preheater 61 through the vent holes to generate a black body effect so that the entire interior of the porous air-permeable preheater 61 is uniformly heated, not just the surface facing the combustion zone is heated. Secondly, the porous air-permeable preheater 61 of this embodiment is far away from the burner 60, and its curved shape provides considerable room for thermal expansion and contraction, which can reduce thermal stress caused by drastic temperature changes from normal temperature to flame temperature. Again, the metal, metal fiber, foam ceramics or honeycomb ceramic material used in the porous air-permeable preheater 61 of this embodiment can withstand the large thermal stress generated by repeated heating and cooling without breaking easily. Finally, the combustion-supporting air fed by the fan 68 has a good cooling effect on the porous air-permeable preheater 61 . The above-mentioned factors make the porous air-permeable preheater 61 of this embodiment have a long service life when used on the combustion chamber wall; and the volume void ratio of the porous air-permeable preheater 61 reaches more than 70%, which is relatively light, and is especially suitable for use in Combustion heating equipment with large changes in heat load during periodic or intermittent operation, such as heat treatment furnaces, melting furnaces, roasting furnaces, drying furnaces and various stoves.

(2) The heat storage loss of the combustion chamber wall can be reduced.

The thickness of the refractory wall of a typical industrial furnace in the prior art is generally several hundred millimeters, and the thickness of the insulation layer is also several hundred millimeters. These refractory walls absorb flame radiation and are heated and cause a relatively large heat storage loss. In this embodiment, the volume porosity of the porous air-permeable preheater 61 is more than 70%, light in weight, and the combustion-supporting air flows through it inside, the temperature of the porous air-permeable preheater 61 is low, and the heat absorption is small, so Heat storage loss can be reduced.

In some applications, the hot flue gas discharged from the annular exhaust port 64 needs to be used for other purposes (such as passing through industrial radiant heaters or dryers), so it cannot pass through the heat exchanger 69 in FIG. 1 . In this case, the heat exchanger 69 can be omitted. The cold air from the outside is pressurized by the fan 68 and flows into the hollow interlayer A through the air inlet on the wall of the cylinder 62, and then the cold air flows through the porous air-permeable preheater 61 and is heated to a temperature of about 800 to 1000°C before entering Dispersive combustion occurs in the combustion zone and the fuel. This situation requires the porous air-permeable preheater 61 to have a large enough internal surface area, which can absorb and convert the flame radiation emitted by the diffuse combustion zone into heat energy to preheat the combustion air to reach a high temperature.

Under the above circumstances, since the inner surface area of the porous air-permeable preheater 61 is far greater than the outer surface area, the temperature rise is not large when the cold air introduced by the fan 68 contacts the side of the porous air-permeable preheater 61 facing the hollow interlayer A. Hollow interlayer A is full of cool air that is passed in by blower fan 68, so the convective heat transfer accepted by the side of cylindrical drum 62 facing hollow interlayer A is not large. Moreover, the side temperature of the porous air-permeable preheater 61 facing the hollow interlayer A is relatively low and the flame and smoke radiation that can pass through the porous air-permeable preheater 61 are limited, only a small amount of flame and smoke radiation can pass through the porous air-permeable The air hole of the type preheater 61 (without touching the side wall of the air hole) finally reaches the side of the drum 62 facing the hollow interlayer A, so the radiation heat transfer received by the side of the drum 62 facing the hollow interlayer A is not large. . The temperature of the outer surface of the cylindrical drum 62 as the outer wall surface of the combustion chamber is only slightly higher than normal temperature, even if no heat insulating material is used, the heat dissipation loss of the outer surface is very low. Therefore, under the above circumstances, the additional advantage of this embodiment is that the outer wall surface of the combustion chamber is close to normal temperature, and the heat dissipation loss is extremely low.

In this specification, "flame radiation" refers to all radiation caused by flame combustion, including all radiation emitted by the luminous area of the flame (including visible light, ultraviolet and infrared parts), all radiation emitted by combustion products in the non-luminous area, and the above-mentioned The portion of radiation that is reflected and scattered by other surfaces, and the infrared radiation emitted by a heated object or other surface after the heated object or other surface has reached a high temperature. This is because most of the radiation caused by flame combustion can be absorbed by the preheater of the utility model and used for preheating the combustion-supporting air. For example, the porous gas-permeable preheater 61 in the continuous dispersion combustion device shown in FIG. 1 can receive most of the radiation emitted by the combustion zone. The carbon dioxide and water vapor contained in the flue gas have a strong ability to emit infrared radiation. When the flue gas temperature is higher than 1200°C, the infrared radiation emitted is quite strong; when the temperature is 900°C, the infrared radiation is still strong; when the temperature is lower than 600°C, the infrared radiation is relatively weak. The carbon particles in the flue gas also have a strong radiation ability (including visible light and infrared part). The petal-shaped circulating flow of the flue gas in Fig. 1 makes the flue gas have a longer residence time inside the device. As long as the flue gas temperature is kept higher than about 900°C, the flue gas radiation energy can be transferred to the porous air-permeable preheater 61 . In addition, the bottom of the object to be heated in FIG. 1 will also reflect part of the flame and smoke radiation to the porous air-permeable preheating body 61 . When the heated object reaches a high temperature, its bottom will also emit infrared radiation. The above radiations will all be received by the porous air-permeable preheater 61 . In the absence of a yellow flame, the above radiant energy accounts for about 10% to 20% of the total heat release of fuel combustion. In the case of diffuse combustion, complete combustion can be achieved only by supplying combustion-supporting air that meets the equivalence ratio, so the amount of combustion-supporting air required is relatively low. The physical sensible heat needed to preheat the combustion-supporting air required for fuel combustion to the combustion temperature accounts for about 10% of the total heat release (chemical energy) of fuel combustion. It can be seen from the above that the flame radiation energy is sufficient to heat the combustion air to the combustion temperature. The key is that the porous air-permeable preheater 61 must have a higher flame radiation absorption rate and a larger area in contact with the combustion-supporting air, so that the flame radiation energy can be converted into heat energy and transferred to the combustion-supporting air.

It should be understood that, in a traditional diffusion or premixed flame, after the cold air supplied to the combustion zone enters the combustion zone, it also needs to consume the heat of the flame to heat the cold air to the combustion temperature, and then fuel and oxygen may occur. the combustion reaction between them. The continuous dispersive combustion device of the utility model just uses the flame radiation energy to preheat the combustion-supporting air that has not yet entered the combustion zone to the combustion temperature in advance. After the combustion-supporting air that has reached the combustion temperature enters the combustion zone, it does not need to consume Flame heat to heat up. The overall energy balance of the continuous dispersion combustion device of the present utility model still follows the known laws of fuel combustion thermodynamics. However, since the combustion-supporting air has reached a relatively high temperature when it enters the combustion zone, and the interior of the combustion zone is fully mixed, the changes in these boundary conditions, airflow movement and heat and mass transfer conditions have caused a huge change in its combustion form: the traditional The intensely luminous and exothermic conical flame in a narrow space spreads out to become a large-volume, uniformly luminous and mildly exothermic diffuse flame. When the combustion-supporting air that has been preheated to the combustion temperature enters the combustion zone from the porous air-permeable preheater 61, it will start to oxidize the fuel, and the oxidation reaction between low-concentration fuel and low-concentration oxygen will occur everywhere in the combustion zone. The mild oxidation reaction, thus reaching the state of diffuse combustion.

Some other improvements of this embodiment are: the air holes of the porous air-permeable preheater 61 are arranged in a certain direction, which can generate gas swirl and backflow in the combustion zone or enhance the effect of the petal-shaped circulation flow shown in FIG. 1 . The hollow interlayer A between the cylindrical drum 62 and the porous air-permeable preheater 61 is divided into several parts, each part is provided with a separate air inlet, so that the combustion-supporting air can flow into the combustion zone more evenly through the porous air-permeable preheater 61 . The cylindrical drum 62 can also adopt other shapes such as waist drum shape, cylinder shape, cuboid shape etc. instead.

Figure 1 only schematically draws the shape and position of the object to be heated. Depending on the purpose of the continuous dispersion combustion device, the object to be heated can be a crucible, pan, round bottom pan, material, food, product, part, workpiece, instrument, heat exchanger tube or coil, etc. Many times the object to be heated is located inside or on the wall of the combustion chamber. The structure and arrangement of the continuous dispersion combustion device in this embodiment can be changed according to different purposes.

In this embodiment, the inner surface of the porous air-permeable preheater 61 is a heat-receiving and heat-transfer surface that absorbs flame radiation and transfers the heat energy converted from the flame radiation energy to the combustion-supporting air that directly contacts it. The vent holes (combustion-supporting air channels) inside the porous air-permeable preheater 61 are surrounded by these heat-receiving and heat-transfer surfaces.

In this embodiment, the combustion air is firstly heated by the waste heat of the flue gas in the heat exchanger 69, and then heated by the flame radiation energy in the porous air-permeable preheater 61, so there is a two-stage combustion air preheating of partition heating-radiation heating Way. In the case that the hot flue gas needs to be used for other purposes and the heat exchanger 69 is canceled, the combustion air is heated by the flame radiation energy in the porous air-permeable preheater 61, which is a one-stage combustion air preheating method of radiation heating .

Example 2

As shown in FIG. 2 , it is a structural schematic diagram of a continuous dispersion combustion device with a vortex-fin preheater of the present invention. Referring to FIG. 2 , the combustion device includes a vortex-fin preheater 7 , an inner cylinder 721 and an outer cylinder 722 , a dome plate 751 and a round bottom plate 752 , as well as a fan 78 and a heat exchanger 79 . A hollow interlayer B is formed between the inner cylinder 721 and the outer cylinder 722 . The top and bottom of the outer cylinder 722 are closed by a dome plate 751 and a round bottom plate 752, respectively. The inner cylinder 721 is fixedly installed on the lower surface of the dome plate 751 , and there is a gap between the lower end of the inner cylinder 721 and the round bottom plate 752 . The lower half of the inner cylinder 721 is provided with a vortex-finned preheater 7, and the vortex-finned preheater 7 is composed of a series of axially symmetrical distribution centered on the central axis of the inner cylinder 721, with a thickness of It is composed of spiral fins 71 made of thin metal sheets with a thickness of 0.5 mm or more. The upper wall of the outer cylinder 722 is provided with an air inlet along the tangential direction, and the wall of the inner cylinder 721 is provided with a fuel inlet along the tangential direction at about three quarters of the height, and the dome plate 751 is provided with a smoke outlet. The object to be heated is located in the middle of the dome plate 751 . The inner cylinder 721 and the spiral fins 71 are made of heat-resistant metal material. The outer cylinder 722, the dome plate 751 and the round bottom plate 752 can be made of heat-resistant metal materials or non-metal refractory materials. The outer wall surfaces of the outer cylinder 722, the dome plate 751 and the round bottom plate 752 have thermal insulation materials. In this embodiment, the upper half of the inner space of the inner cylinder 721 constitutes a combustion chamber.

When in use, under the stable combustion state after ignition, the outside air is passed into the heat exchanger 79 by the blower 78 to recover the waste heat of the flue gas and reaches an air temperature of about 700°C. The air at a temperature of 700°C is then injected into the air inlet at the wall of the outer cylinder 722 along a tangential direction at a high speed, forming a swirling flow in the hollow interlayer B between the inner cylinder 721 and the outer cylinder 722, which is connected to the outer surface of the inner cylinder 721. The wall generates strong convective heat transfer and is heated by the relatively high temperature inner cylinder 721 wall to reach an air temperature of about 850°C. The air at a temperature of 850°C enters the gap between the vortex-shaped fins 71 of the vortex-finned preheater 7 through the gap between the lower end of the inner cylinder 721 and the circular bottom plate 752, and then is guided by the vortex-shaped fins 71. The bottom enters the combustion zone above the vortex-finned preheater 7 in the form of swirling flow. The gap between every two adjacent vortex-shaped fins 71 presents a black-body effect for the flame radiation injected into the gap, so that the vortex-fin preheater 7 can efficiently absorb the heat radiation emitted by the combustion zone above it, thus achieving fairly high temperature. The aforementioned air that has been heated by the wall surface of the inner cylinder 721 to a temperature of about 850° C. is further heated to a temperature of about 1000° C. when flowing through the vortex finned preheater 7 .

The fuel is sprayed into the inner cylinder 721 at a high speed along the tangential direction from the fuel inlet on the wall surface of the inner cylinder 721 , forming a swirl flow inside the inner cylinder 721 . The above-mentioned air swirl flow at the hollow interlayer B between the inner cylinder 721 and the outer cylinder 722, the air swirl flow generated at the vortex-fin type preheater 7, and the fuel swirl flow in the inner cylinder 721 (or its combustion The direction of rotation of the swirl of the reaction mixture) is the same (the swirl at the above three places is clockwise or counterclockwise at the same time). The combustion-supporting air at a temperature of 1000°C enters the combustion zone in the form of swirling flow through the gap between the vortex-shaped fins 71, and the fuel jet also enters the combustion zone in the form of a high-speed swirling flow, and the supply of fuel and combustion-supporting air roughly corresponds to the equivalent ratio. Under certain conditions, diffuse combustion occurs in the combustion zone inside the inner cylinder 721 . In the state of diffuse combustion, the combustion zone inside the inner cylinder 721 is filled with the fuel (and its pyrolysis products) undergoing oxidation reaction and the mixture of air and combustion products, and the temperature and composition of each place are relatively uniform (the temperature is about 1200 ℃ ℃, the fuel concentration is about 1%, the oxygen concentration is about 5%, and the rest are combustion products), and the temperature conditions required for the oxidation reaction of fuel can be reached everywhere, but only 1% concentration of fuel and 5% concentration of Oxygen encounters reactant concentration conditions such that only mild diffuse combustion that occupies most of the volume in the inner cylinder 721 is possible. There will be no violent oxidation reaction (that is, a traditional flame) that occurs between the fuel and the air with an oxygen concentration of 21% in a very short time and in a very small space.

Dispersion combustion differs from traditional diffusion, premixed or atmospheric flames further explained below. In the diffusion flame, the fuel ejected from the burner meets the surrounding air with an oxygen concentration of 21%, and a chain reaction occurs, which instantly produces intense light and heat, forming a conical flame. The situation is similar for premixed flames and atmospheric flames. In FIG. 2 , the fuel swirl and the air swirl allow the fuel, air and combustion products inside the inner cylinder 721 to be thoroughly mixed. It is impossible for the fuel injected from the fuel inlet to meet the air with an oxygen concentration of 21%, a chain reaction will not occur, and a traditional conical flame will not appear. The combustion-supporting air at a temperature of 1000°C injected from the gap between the vortex-shaped fins 71 meets the mixture in the inner cylinder 721 (which only contains 1% fuel concentration) so that its original 21% oxygen concentration is fully exhausted. Diluted to an oxygen concentration of about 5% (when the combustion-supporting air with an oxygen concentration of 21% at a temperature of 1000° C. is injected into the combustion zone from the gap between the swirl-shaped fins 71 and meets a mixture containing 1% fuel concentration, it has reached Oxidation occurs under conditions such that these 1% fuels are quickly oxidized and consumed without a sharp temperature rise). At this time, mild oxidation reactions occur simultaneously in various places inside the inner cylinder 721 , depending on the collision probability of fuel molecules and their pyrolysis product molecules with oxygen molecules, thereby forming diffuse combustion.

Compared with the traditional combustion method, the main advantages of the utility model continuous dispersion combustion device are:

(1) Complete combustion can be achieved only by supplying combustion-supporting air that meets the equivalence ratio, and the exhaust smoke basically does not contain residual oxygen, thus reducing the amount of flue gas and avoiding the residual oxygen in the exhaust smoke and the corresponding nitrogen carrying away the heat. exhaust heat loss. In comparison, the traditional combustion method requires a large amount of combustion-supporting air (the excess air coefficient is often above 1.5) to achieve complete combustion. The residual oxygen concentration in the exhaust smoke is as high as 15%, and the flue gas volume and exhaust heat loss are quite large.

(2) The heating effect is good, because there is a strong swirling flow around the heated object, the convective heat transfer coefficient is large, and the interior of the inner cylinder 721 is a uniformly luminous diffuse combustion zone above the vortex-shaped fins 71. Radiant heating intensity is high.

(3) The adjustable range is large, there are no restrictive factors such as tempering and defiring of traditional flames, and it can run stably under both low-power and high-power conditions, and low calorific value fuels can also burn stably.

(4) The content of carbon monoxide in the exhaust smoke is low, because the interior of the inner cylinder 721 above the vortex-fin type preheater 7 is all a combustion zone, and the mixture of fuel (and its pyrolysis products) and air and combustion products is in the combustion zone. The residence time is very long, and the reaction time is long enough to achieve complete oxidation in a high enough temperature region.

(5) The content of nitrogen oxides in exhaust smoke is low, because there is no local high-temperature zone in diffuse combustion, and the highest temperature is only 1200 ° C, which does not meet the conditions for stimulating nitrogen molecules in the combustion-supporting air to participate in the reaction.

(6) There is no yellow flame. The yellow flame of the traditional flame is due to the severe chain oxidation reaction forming a local high-temperature anoxic zone, which leads to the cracking of part of the fuel to produce carbon particles (PM2.5). The maximum temperature during diffuse combustion does not exceed 1200°C, which does not meet the conditions for fuel cracking to produce carbon particles.

(7) It can reduce the heat resistance requirements of the production materials, because the internal temperature of the inner cylinder 721 is uniform, there is no local high temperature, and the lower part of the inner cylinder 721 is connected with the vortex-shaped fins 71 so that the heat can be conducted to the vortex-shaped fins 71. The outer wall of the inner cylinder 721 has air swirling flow, which has better heat dissipation conditions, so the heat resistance requirements of the manufacturing materials can be reduced. In comparison, traditional combustion heating equipment produces intensely luminous and exothermic flames in the narrow space of the combustion chamber, resulting in local high temperatures. The wall of the combustion chamber is continuously heated by the flame radiation and it is difficult to dissipate heat. The requirements for the heat resistance of the materials used for the equipment are relatively high. high.

The ignition procedure of the diffused combustion heating equipment in this embodiment is described as follows: under the condition of cold start, a small amount of fuel is injected continuously and at a low speed from the fuel inlet, and the combustion-supporting air is passed into the air inlet with the blower 78, and the igniter is used to Ignite near the fuel inlet to form a traditional diffuse flame; gradually increase the fuel and combustion air supply, and the flame volume will increase accordingly. Keep it for a period of time, and use the diffusion flame to gradually heat up the whole set of equipment; when the temperature of the combustion-supporting air sprayed from the gap between the vortex fins 71 reaches the preheating temperature of the diffuse combustion of the fuel, it enters the diffuse combustion state, and the high-speed injection The fuel and combustion air form a swirl flow, and the supply of combustion air is controlled (the excess air coefficient is about 1).

One of the key points of the diffuse combustion heating equipment in this embodiment is that the combustion-supporting air injected into the combustion zone from the gap between the vortex fins 71 must have a sufficiently high temperature (generally need to reach 800 to 1000 ° C, depending on the type of fuel) ). When the temperature of the combustion-supporting air sprayed into the combustion zone from the gap between the vortex fins 71 is too low, the ignition condition cannot be reached, resulting in incomplete combustion. The innovation of the diffuse combustion heating equipment in this embodiment is mainly that the preheating method of the combustion-supporting air includes three stages:

(1) Partition wall heating stage: use the heat exchanger 79 to recover the waste heat of the flue gas to heat the combustion-supporting air to about 700°C. The heat exchanger 79 can be a conventional partitioned wall heat exchanger (shown in FIG. 2 is a partitioned wall heat exchanger with a radiation heat transfer section and a convective heat transfer section). The temperature of the flue gas discharged from the exhaust port on the dome plate 751 is about 1200°C. The heat transfer temperature difference between the flue gas side and the air side of the heat exchanger 79 is 500 to 200°C. The heat transfer temperature difference is quite large, so that the heat exchanger 79 only needs to be provided with a small heat transfer area.

(2) High-speed swirl stage: the air is injected into the air inlet of the outer cylinder 722 wall along the tangential direction at a high speed, and then forms a swirl flow in the hollow interlayer B, which produces strong convective heat exchange with the outer wall of the inner cylinder 721 . On the inner wall of the inner cylinder 721, the swirling flow of the combustion reaction mixture also undergoes strong convective heat exchange with the inner wall of the inner cylinder 721, and the inner wall of the inner cylinder 721 is also heated by radiation from the large-volume diffuse combustion zone. Therefore, the heat transfer conditions in the high-speed swirl stage are quite good. Although the heat exchange area is not large (it can only be used for high-speed swirl heat exchange is limited to the outer wall area of the inner cylinder 721), and the heat exchange time is short, at this stage, the combustion air with an inlet temperature of 700°C can be heated to an outlet of about 850°C temperature.

(3) Radiation heating stage: the gap between the vortex-shaped fins 71 presents a blackbody effect on the thermal radiation from the combustion zone injected into the gap, so the vortex-fin preheater 7 can efficiently absorb the heat emitted by the diffuse combustion zone Thermal radiation thus reaches a relatively high temperature. Moreover, the structural form of the preheating body arranges a relatively large heat-receiving and heat-transfer area in direct contact with the combustion-supporting air in a limited volume. Therefore, at this stage, the radiant energy in the diffuse combustion zone can be used to heat the combustion-supporting air with an inlet temperature of 850°C to an outlet temperature above 1000°C.

The above-mentioned three-stage combustion air preheating method of partition heating-high-speed swirling flow-radiation heating can preheat the combustion air to a very high temperature, and achieve a diffuse combustion state in the combustion equipment, and it is continuous operation, steady state, Efficient, simple and cheap. In comparison, it is difficult to preheat the combustion-supporting air to a temperature above 800°C using only a conventional partition wall heat exchanger in the prior art, because the heat transfer temperature difference between the high-temperature combustion-supporting air and the flue gas is too small, and the heat transfer between the partition walls The heat exchange efficiency of the heat exchanger is not high, and only using a conventional partition wall heat exchanger requires a very large heat exchanger area to preheat the combustion air to a temperature above 1000 °C. The high-temperature low-oxygen combustion equipment in the prior art relies on the regenerative heat exchanger to preheat the combustion-supporting air to a high temperature above 1000°C. It needs to be equipped with an even number of burners and regenerative heat The hot flue gas and combustion-supporting air are fed into the thermal heat exchanger in turn, and at the same time, the burner is ignited and extinguished in turn (the switching period of the burner and the regenerative heat exchanger is within one minute), which is an unsteady state. Intermittent combustion operation is prone to safety hazards such as pressure fluctuations, deflagration, misfire, backfire, and ignition failure, and its switching mechanism and control system are quite complicated and expensive. This embodiment uses the three-stage diffusion combustion equipment of partition heating-high-speed swirling flow-radiation heating to preheat the combustion-supporting air for continuous combustion operation, which has great advantages compared with the existing regenerative high-temperature low-oxygen combustion technology. The continuous dispersion combustion device of the utility model can burn continuously after being ignited, and the pressure fluctuation in the combustion chamber is small; the inlets of the fuel and the combustion-supporting air are in different positions, so tempering will not occur; the possibility of deflagration and deflagration is also greatly reduced.

The specific shape of the vortex-shaped fins 71 in this embodiment can adopt any form that can make the air flow generate swirl. In the prior art, guide vanes with a certain angle with the airflow direction are commonly used to make the airflow swirl (the number of guide vanes generally does not need to be too large). The difference between the vortex-shaped fins 71 of this embodiment and the guide vanes of the prior art is that the vortex-shaped fins 71 of this embodiment should be arranged very closely so that a narrow gap is formed between adjacent vortex-shaped fins 71, and the vortex Shaped fins 71 should have a larger depth so that the depth/opening width ratio of the narrow slit gap reaches 20 to 30, and the number of vortex-shaped fins 71 should be relatively large to obtain a large enough total area of heat transfer surface, so as to achieve The purpose of absorbing flame radiation and preheating the combustion air.

Parts not mentioned in this embodiment are similar to those in Embodiment 1, and will not be repeated here.

Example 3

The current industrial furnace design specification mainly includes three parts: burner, furnace body and waste heat recovery heat exchanger. Burners mainly include premixed and diffused burners, etc., which are used to send fuel and air into the combustion zone and achieve stable combustion. Some problems to be overcome include: more excess air is required to achieve complete combustion, flame The temperature in the area is very high, and the amount of nitrogen oxides is generated in a large amount. The furnace body is used to form the combustion chamber. Some problems to be overcome include: the heat storage loss of the refractory furnace wall and the insulation layer and the heat dissipation loss of the outer surface are relatively large. In some cases, the refractory material often needs to be repaired. Waste heat recovery heat exchanger is used to recover flue gas waste heat. Some problems to be overcome include: limited heat exchange area, low flue gas waste heat recovery rate, and often limited by the site conditions of industrial furnaces. The installation position of waste heat recovery heat exchanger Far away from the industrial furnace, the high-temperature flue gas pipeline and high-temperature air pipeline are too long, and the heat dissipation loss is large.

In order to help overcome the above problems, this embodiment combines the burner, furnace body and waste heat recovery heat exchanger of the industrial furnace into a whole. As shown in FIG. 3 , it is a structural schematic diagram of a continuous dispersion combustion device with a heat exchange tubular preheater of the present invention. Referring to FIG. 3 , the combustion device includes a heat exchange tubular preheater 8 , a first cylinder 821 , a second cylinder 822 , a third cylinder 823 , a fourth cylinder 824 , a dome plate 851 and a round bottom plate 852 . The top and bottom of the third cylinder 823 and the fourth cylinder 824 are closed by a dome plate 851 and a round bottom plate 852, respectively. A hollow interlayer C is formed between the third cylinder 823 and the fourth cylinder 824 . The first cylinder 821 is fixedly installed on the lower surface of the dome plate 851 , and there is a gap between the lower end of the first cylinder 821 and the circular bottom plate 852 . The second cylinder 822 is fixedly installed on the upper surface of the round bottom plate 852 , and there is a gap between the upper end of the second cylinder 822 and the dome plate 851 . The heat exchange tube-type preheater 8 is composed of a series of heat exchange tubes 81 . These heat exchange tubes 81 pass through the first cylinder 821 and the second cylinder 822, the heat exchange tubes 81 communicate with the combustion zone and the hollow interlayer C, and the heat exchange tubes 81 are evenly arranged around the circumferential direction It is inside the third cylinder 823 and forms a certain angle with the third cylinder 823 radially. The combustion-supporting air from the outside is pressurized by the fan 88 and passed into the hollow interlayer C, and then sprayed into the combustion zone through the heat exchange tube 81 and generates swirl in the combustion zone. The fuel inlet opened in the middle of the circular bottom plate 852 is used to inject fuel into the combustion zone in the form of high-speed swirling flow. The burnt smoke flows into the gap between the first cylinder 821 and the second cylinder 822 through the gap between the lower end of the first cylinder 821 and the round bottom plate 852, then flows upward, and then passes through the upper end of the second cylinder 822 and the dome plate 851 The gap between them flows into the gap between the second cylinder 822 and the third cylinder 823 , and then flows downwards, and the cooled smoke is discharged from the exhaust port opened on the round bottom plate 852 . In this embodiment, the inner space of the first cylinder 821 constitutes a combustion chamber.

The preheating of combustion air includes partition heating stage and radiation heating stage. The partition heating stage is: the combustion air in the heat exchange tubes 81 flows from the hollow interlayer C to the first cylinder 821, and the combustion air in the heat exchange tubes 81 is heated by the hot flue gas outside the tubes. The radiation heating stage is: the combustion-supporting air in the heat-exchanging tubes 81 flows from the first cylinder 821 to the nozzle part where it is sprayed into the combustion zone. During the process, the combustion-supporting air in the heat-exchanging tubes 81 is heated by flame and smoke radiation heat up. Since the nozzle of the heat exchange tube 81 faces the combustion area, the flame and flue gas radiation can be injected into the heat exchange tube 81 through the nozzle and then reflected/absorbed multiple times on the inner surface of the heat exchange tube 81, resulting in a blackbody effect Therefore, the inner surface of the heat exchange tube 81 is a heat receiving and heat transfer surface that absorbs the flame radiation and transfers the heat energy converted from the flame radiation energy to the combustion air in the heat exchange tube 81 . In addition, part of the flame and flue gas radiation will be directed between the outer surfaces of the heat exchange tubes 81 . The black body effect can also occur between the outer surfaces of all the tube sections of the heat exchange tubes 81 located inside the first cylinder 821 for the flame and smoke radiation injected into the outer surfaces of all the tube sections of the heat exchange tubes 81, so these heat exchange columns The outer surface of the pipe section of the pipe 81 also absorbs the flame and smoke radiation energy, and the outer surface of these heat exchange tube sections 81 is also heated by the convection of the hot flue gas, and then the radiation and convection heating heat received by the outer surface of the heat exchange tube section 81 is reduced by The heat transfer mode of the partition wall is transferred to the combustion air in the tube.

As mentioned above, the combustion-supporting air in the heat exchange tubes 81 is heated by the convection of the flue gas during the heating stage of the partition wall, and is heated by the radiation of the flame and the flue gas injected into the tube at the same time during the radiation heating stage, and the flame and the flue gas injected into the outer surface of the tube are simultaneously heated. Radiant heating as well as flue gas convective heating of the outer surface of the tube. The temperature of the combustion-supporting air sprayed into the combustion zone by the nozzle of the heat exchange column tube 81 can easily reach the ignition point temperature of the fuel, and diffuse combustion occurs in the combustion zone. When the temperature of the combustion-supporting air ejected from the nozzle of the heat exchange column tube 81 is much lower than the ignition temperature of the fuel, a traditional diffused or partially premixed flame is generated in the combustion zone.

This embodiment can achieve the beneficial effects listed in Embodiments 1 and 2. Other advantages of this embodiment are:

(1) Integrate the burner, furnace body and waste heat recovery heat exchanger into one device. The heat exchange tubular preheater 8 provides combustion air that has been preheated to a high temperature to the combustion zone, and makes the combustion air fully mixed with the fuel to burn stably, and partially plays the role of the burner; the heat exchange tubular preheater The heating body 8, the first cylinder 821 and other components together constitute the combustion chamber, which plays the role of the furnace body; at the same time, the heat exchange tubular preheating body 8 uses the waste heat of the flue gas to heat the combustion-supporting air, and acts as a waste heat recovery heat exchanger. role. This embodiment achieves the functions of burner, furnace body and waste heat recovery heat exchanger in the same equipment, and has a compact structure, greatly reducing the heat dissipation area of the outer surface of the equipment, especially omitting the prior art furnace body and waste heat recovery heat exchanger The high-temperature flue gas pipe and high-temperature air pipe between them further reduce heat loss.

(2) The flowing air in the heat exchange tubes 81 has a cooling effect on the heat exchange tubes 81 . The heat of the first cylinder 821 can also be conducted to the heat exchange tubes 81 . Therefore, the requirements for the heat resistance of the materials for the heat exchange tubes 81 and the first cylinder 821 are not high.

(3) The infrared radiation on the inner surface of the first cylinder 821 and the outer surface of the heat exchange tubes 81 inside the first cylinder 821 can enhance the heating effect on the object.

The heat exchange tubes between the first cylinder 851 and the third cylinder 853, together with the first cylinder 851, the third cylinder 853, the dome plate 851 and the round bottom plate 852 constitute the partition heat exchange in the prior art. device. Therefore, in order to enhance the convective heat transfer effect of the hot flue gas to the combustion air, various technical means of the partition wall heat exchanger in the prior art can be used. For example: heat transfer fins can be added on the outer surface of the heat exchange tubes 81; more cylinders or spiral partitions can be added between the first cylinder 821 and the third cylinder 823 to separate more hot smoke gas channel. Due to the particularity of this embodiment that the heat exchange tubes are arranged radially in the cylindrical space, several branch tubes of the heat exchange tubes 81 can also be arranged between the first cylinder 821 and the third cylinder 823. The branch pipes are merged and lead to the combustion zone; the heat exchange tubes between the first cylinder 851 and the third cylinder 853 are arranged in the form of coiled tubes. In addition, the tube sections of the heat exchange tubes 81 within the first cylinder 821 can be turned, bent or coiled according to certain rules to change the injection direction of the combustion air, which is beneficial to produce various airflow effects in the combustion zone, and can extend the The length of the tube sections of the heat exchange tubes 81 inside the first cylinder 821 helps to increase the preheating temperature of the combustion air. On the other hand, adding more fuel inlets on the circular bottom plate 852 to inject fuel at a high speed can enhance the gas swirl in the combustion zone, which is beneficial to the backflow of the burned smoke and the formation of a large-volume diffuse combustion zone.

Parts not mentioned in this embodiment are similar to the above embodiments, and will not be repeated here.

Example 4

This embodiment is similar to Embodiment 3, the difference is that a Venturi ejector is installed at the nozzle of the heat exchange tubes 81 of this embodiment where the combustion-supporting air is injected into the combustion zone. As shown in FIG. 4 , the Venturi ejector 86 is composed of a shrinking pipe section 861 , an expanding pipe section 862 and a straight pipe section 863 . The nozzles of the heat exchange tubes 81 for injecting combustion air into the combustion zone are located at the throat of the Venturi ejector 86 . When the combustion-supporting air is ejected from the nozzle of the heat exchange column tube 81, the flue gas flowing in from the gap between the shrinking tube section 861 and the first cylinder 821 is introduced into the expanding tube section 862, and the combustion-supporting air and the smoke are fully mixed in the straight tube section 863 , and then sprayed into the combustion zone from the outlet of the straight pipe section 863. In this embodiment, a Venturi ejector 86 is installed at the nozzle of each heat exchange tube 81 . These Venturi ejectors 86 are supported by supports (not shown in FIG. 4 ).

The difference between this embodiment and Embodiment 3 is that in Embodiment 3, the combustion-supporting air is injected into the combustion zone from the nozzle of the heat exchange column tube 81 before being mixed with the flue gas to achieve a hypoxic state, and the mixing effect is affected by the gas in the combustion zone. The swirl intensity has a great influence, so it is required to have a high velocity when the fuel is injected into the combustion zone to achieve a better mixing effect. In this embodiment, the venturi ejector 86 is used to fully mix the combustion-supporting air and the flue gas to achieve a high-temperature and low-oxygen state, so it is less affected by the gas swirl intensity in the combustion zone.

In this embodiment, the combustion-supporting air is heated by the flame and smoke radiation injected into the straight pipe section 863 of the Venturi ejector 86, and is heated by the flame and smoke radiation injected into the outer surface of the Venturi ejector 86 during the radiation heating stage. , and the flue gas on the outer surface of the Venturi ejector 86 is heated by convection, and the combustion air is also heated due to mixing with the high-temperature flue gas introduced by the Venturi ejector 86 . Therefore, in this embodiment, the combustion-supporting air is more likely to reach the diffuse combustion state of high temperature and low oxygen.

Parts not mentioned in this embodiment are similar to the above embodiments, and will not be repeated here.

The core invention of the above content is to use the flame radiation energy to preheat the combustion air to reach the temperature of the combustion air required for continuous diffuse combustion. The difference between the utility model and the existing high-temperature low-oxygen combustion technology is that the prior art uses a regenerative heat exchanger to heat the combustion-supporting air, while the utility model mainly uses flame radiation energy to heat the combustion-supporting air. In Fig. 1, in the case where the hot flue gas needs to be used for other purposes and thus cancels the heat exchanger 69, Embodiment 1 is a one-stage combustion air preheating method of radiation heating; in the case of using the heat exchanger 69, Example 1 is a two-stage combustion air preheating method of partition heating-radiation heating. The continuous diffuse combustion device with vortex-fin preheater in Example 2 adopts a three-stage combustion-supporting air preheating method of partition heating-high-speed swirling flow-radiation heating. The continuous diffused combustion device with heat exchange tubular preheater in Example 3 adopts a two-stage combustion air preheating method of partition heating-radiation heating. Therefore, the method for forming continuous diffuse combustion of the present utility model can be summarized as follows: preheating the combustion-supporting air to make its temperature reach the diffuse combustion preheating temperature, providing fuel and the combustion-supporting air that has been preheated to the diffuse combustion preheating temperature to the combustion air zone, and the fuel and/or the combustion air that has been preheated to the preheating temperature of the diffuse combustion are mixed with the combusted flue gas to achieve a high temperature and low oxygen state, thereby forming continuous diffuse combustion. Among them, preheating the combustion-supporting air is to use the heat of the flue gas to heat first, and then use the heating of the flame radiation to make the combustion-supporting air reach the preheating temperature of the diffuse combustion, or the preheating combustion-supporting air only uses the heating of the flame radiation to make the combustion-supporting air reach the preheating temperature of the diffuse combustion heat temperature. Further, the method for forming continuous diffuse combustion includes a three-stage combustion air preheating method including partition heating, high-speed swirling flow, and radiation heating, or a two-stage combustion air preheating method including partition heating and radiation heating, or, including One-stage combustion air preheating method of radiant heating.

Air itself cannot absorb flame radiation. This is because both oxygen and nitrogen in the air have a diatomic symmetrical molecular structure, and the air is transparent to flame radiation, solar radiation or other artificial light source radiation. Therefore, the continuous dispersion combustion device of the present invention includes a preheating body, the preheating body has a series of heat-receiving and heat-transfer surfaces that absorb flame radiation, a combustion-supporting air passage is formed between the heat-receiving and heat-transfer surfaces, and the preheating body The heat body transfers the heat energy converted from the flame radiation energy to the combustion-supporting air that flows through and directly contacts the heat transfer surface. The surface of the vent hole inside the porous air-permeable preheater in Example 1 is a heat-receiving heat transfer surface, and a combustion-supporting air passage is formed between these heat-receiving heat transfer surfaces; a series of vortex-fin preheater in Example 2 The surface of the vortex-shaped fins is a heat transfer surface, and a combustion-supporting air passage is formed between these heat transfer surfaces; the inner surface of each tube of the heat exchange tubular preheater in embodiment 3 is a heat transfer surface, Combustion air passages are formed between these heat receiving and heat transfer surfaces. Therefore, these embodiments have the same core technical features, and these embodiments are different specific forms of the same general inventive concept.

The preheating body of the utility model must have a relatively high flame radiation absorption rate, a relatively large contact area with the combustion-supporting air, and good heat resistance and thermal conductivity, so as to achieve the purpose of the utility model. In order to efficiently absorb flame radiation, the structural form of the preheating body of the present invention is set such that the preheating body exhibits a black body effect on the flame radiation directed at the preheating body. The porous air-permeable preheater in Example 1, the vortex-fin preheater in Example 2, and the heat-exchanging tube-and-tube preheater in Example 3 all exhibit blackbody effects on flame radiation.

In Example 1, porous metal bodies, metal fiber bodies, foamed ceramic bodies, and honeycomb ceramic bodies are listed as examples of porous air-permeable preheating bodies. In fact, any porous body with a higher porosity or microporous body with a higher porosity has a higher flame radiation absorption rate, and also has many pores or micropores that can be used as combustion-supporting air channels. And its larger inner surface area can be used as a heat transfer surface for absorbing flame radiation and transferring the heat energy converted from flame radiation energy to the combustion-supporting air flowing through these pores or micropores into the combustion zone. Any porous body with relatively high porosity or microporous body with relatively high porosity can be used in the porous air-permeable preheating body of Example 1. It can be seen that, in addition to the porous metal body, metal fiber body, foamed ceramic body, and honeycomb ceramic body listed in Example 1, the porous air-permeable preheater in Example 1 has many other equivalent replacement forms.

Embodiment 2 uses a vortex-fin preheater. In fact, as long as a certain number of metal sheets are densely arranged in a certain way, the narrow gaps between every two adjacent metal sheets are used as combustion air passages, and the depth/opening width ratio of these narrow gaps is about 20 to 20. 30, and make the opening positions and directions of these narrow gaps towards the flame so that the flame radiation can be injected into the narrow gaps to generate blackbody effect, then these metal sheets can constitute the preheating body of the present invention. When the combustion-supporting air is required to generate swirling flow, it is the best implementation mode to arrange these metal sheets in a vortex shape; when the combustion-supporting air is not required to generate a swirling flow, these metal sheets can be arranged in a radial shape, grid shape, louver shape, etc. It can be seen that there are many other equivalent replacement forms for the vortex-fin preheater in Embodiment 2.

Embodiment 3 adopts heat exchange tube and tube type preheating body. In fact, the nozzle of a long tube is a good black body (looking in from the nozzle, the depth of the long tube is always dark. But because natural light is scattered light, not direct light, the inner surface of the tube near the nozzle is still visible). In Example 3, each nozzle of the heat exchange tubes can exhibit a black body effect on the flame radiation, and the outer walls of the heat exchange tubes can also exhibit a black body effect on the flame radiation. Therefore, when the heat exchange tubes are used as combustion air passages, they can efficiently absorb flame radiation energy to preheat the combustion air. These tubes can be round or square, straight or bent, single or sleeved. In addition, the wall of the combustion chamber can be entirely composed of a series of radial passages, some of which are combustion air passages, and others are smoke exhaust passages, the smoke in the smoke exhaust passages and the combustion air in the combustion air passages The air passes through the walls of these radial passages for heat exchange, and the same effect as that of Embodiment 3 can be obtained by using the flame radiation and waste heat of the flue gas to preheat the combustion-supporting air. It can be seen that there are many other equivalent replacement forms for the heat exchange tube and tube preheater in Embodiment 3.

The preheater in the continuous dispersion combustion device of each of the above embodiments can be changed to adopt the preheater form of other embodiments.

Apparently, the above examples are just examples for clearly illustrating the utility model, rather than limiting the implementation of the utility model. For those skilled in the art, on the basis of the above-mentioned embodiments, other changes or changes in different forms can be made according to specific situations. These changes or modifications that can be made according to specific situations will be obvious to those of ordinary skill in the art. Any modifications, simplifications, substitutions, additions, combinations, modifications, equivalent replacements and improvements made within the spirit and principles of the utility model shall be included within the protection scope of the claims of the utility model.

Claims (8)

1. continuous disperse formula burner, including combustion chamber, the combustion chamber is provided with fuel inlet, combustion air inlet and smoke evacuation Mouthful, it is characterised in that：Also include preheating body, the preheating body has a series of heated heat-transfer area for absorbing Fire Radiation, institute State and combustion air passage is formed between heated heat-transfer area, the heat energy that the preheating body can change Fire Radiation gained passes to stream Through and directly contact the combustion air of the heated heat-transfer area.

2. continuous disperse formula burner according to claim 1, it is characterised in that：The structure type of the preheating body is set It is set to Fire Radiation of the preheating body for preheating body described in directive and black body effect is presented.

3. continuous disperse formula burner according to claim 1, it is characterised in that：The preheating body is by some metal foils Piece is formed, and the surface of the sheet metal is heated heat-transfer area, and the sheet metal is arranged as the adjacent heated heat transfer of each two Being formed between face can be as the narrow slit space of combustion air passage, and narrow slit space between the adjacent heated heat-transfer area of each two Aperture position and direction towards flame Fire Radiation is injected black body effect occurs inside narrow slit space.

4. continuous disperse formula burner according to claim 1, it is characterised in that：Including burner, circle drum barrel and position Porous breathable formula preheating body on the inside of the round drum barrel, adaptable with the shape of the round drum barrel, the porous breathable formula Preheating body is porous metal bodies, metallic fiber body, foamed ceramic body or honeycomb ceramic body, the round drum barrel and porous breathable formula Hollow sandwich is formed between preheating body, the round drum barrel bottom installs burner, has annular exhaust opening around the burner.

5. continuous disperse formula burner according to claim 4, it is characterised in that：Also include blower fan and heat exchanger, institute The shell side gas access that annular exhaust opening connects the heat exchanger is stated, the gas outlet of the blower fan connects the tube side of the heat exchanger Gas access, the tube side gas vent of the heat exchanger connect the air intlet on the round drum barrel wall.

6. continuous disperse formula burner according to claim 3, it is characterised in that：Including vortex it is finned preheating body, Inner cylinder, outer cylinder, dome plate, round bottom plate, blower fan and heat exchanger, the finned preheating body of vortex is by a series of axial symmetry Distribution, by sheet metal make swirl shape fin formed, the swirl shape fin using the axis of the inner cylinder as Center is arranged in the lower half inside the inner cylinder, and narrow slit space is combustion air passage between the swirl shape fin, institute State and hollow sandwich is formed between inner cylinder and outer cylinder, the top and bottom of the outer cylinder are respectively by the dome plate and round bottom Plate is closed, and the inner cylinder is fixedly mounted on the dome plate, between having between the lower end of the inner cylinder and the round bottom plate Gap, the outer cylinder wall tangentially offer air intlet, and the inner cylinder wall tangentially offers fuel inlet, described Dome plate is provided with exhaust opening and accommodates the perforate of heating object, and the exhaust opening on the dome plate connects the heat exchanger Shell side gas access, the gas outlet of the blower fan connect the tube side gas access of the heat exchanger, the tube side gas of the heat exchanger Body outlet connects the air intlet on the outer cylinder wall.

7. continuous disperse formula burner according to claim 1, it is characterised in that：Including heat exchanging pipe formula preheating body, First cylinder, the second cylinder, the 3rd cylinder, the 4th cylinder, dome plate, round bottom plate and blower fan, the heat exchanging pipe formula preheat body It is made up of a series of heat exchanging pipe, the top and bottom of the 3rd cylinder and the 4th cylinder are sealed by dome plate and round bottom plate respectively Close, hollow sandwich is formed between the 3rd cylinder and the 4th cylinder, the first cylinder is fixedly mounted on dome plate lower surface, the first cylinder Lower end and round bottom plate between have gap, the second cylinder is fixedly mounted on round bottom plate upper surface, the upper end of the second cylinder and dome There is gap between plate, the heat exchanging pipe passes through the first cylinder and the second cylinder, and the heat exchanging pipe connects combustion zone and the 3rd Hollow sandwich between cylinder and the 4th cylinder, and the heat exchanging pipe is that circumferentially direction is uniformly distributed in the 3rd cylinder Within, the wall of the 4th cylinder tangentially offers air intlet, gas outlet connection the 4th circle of the blower fan Air intlet on the wall of cylinder.

8. continuous disperse formula burner according to claim 7, it is characterised in that：Also include the number with heat exchanging pipe Several corresponding Venturi transmission ejectors, the spout that combustion air is sprayed into combustion zone of each heat exchanging pipe are respectively mounted one Venturi transmission ejector, for introducing the flue gas of combustion zone so that the flue gas is mutually mixed with combustion air.