CN110425536A - A kind of angle-style porous media combustor - Google Patents

Abstract

An angular porous media burner, including a gas inlet, a combustion front chamber, a burner casing, a protection zone, a preheating zone, a buffer zone, a combustion zone, and a flue gas outlet. The preheating zone, buffer zone, and combustion zone are collectively referred to as porous The medium area is filled with porous media materials; the preheating zone and the combustion zone are respectively tapered inward and outward by a certain angle α, and a buffer zone is set in the preheating zone and the combustion zone to reduce the airflow velocity. Prevent the flame from tilting. It can obviously widen the limit range of flame stability speed, not only effectively prevent flame backfire and defire, but also improve outlet radiation efficiency, and reduce the occurrence of thermal shock damage of porous media at the same time.

Description

An angular porous media burner

technical field

The invention belongs to the technical field of burners, in particular to an angular porous media burner.

Background technique

In recent years, with the rapid development of China's economy, energy and environmental issues have increasingly become the focus of attention. Our country is currently facing the dilemma of the continuous reduction of fossil fuels and the increasing environmental pollution. Therefore, in order to establish a sustainable economic model, improve the energy structure, improve the energy consumption mode, and improve the effective utilization of energy, we must make full use of industrial production and energy. Various low calorific value gases in production realize efficient and clean utilization of conventional energy. The combustible components of low-calorific-value gas are thin, and it is difficult to effectively use conventional combustion technology. How to realize the effective combustion of this kind of gas and reduce the environmental problems caused by direct emissions has always been a difficult problem in the combustion industry.

In recent years, in order to solve the above problems, it is necessary to continuously search for more efficient and low-emission combustion technologies. Among many new technologies for enhancing combustion and controlling emissions, the porous media burner, as a new type of energy-saving and environment-friendly burner, has attracted more and more attention due to its unique advantages. Porous media itself has thermal energy accumulation and feedback effects. Due to the large specific surface area of the porous medium, sufficient heat exchange can be carried out between the gas and the solid; at the same time, because the specific heat capacity of the solid itself is much greater than that of the gas, the heat released by the combustible gas is stored in the solid through convective heat exchange. A part of it is fed back upstream in the form of thermal radiation to preheat the unburned combustible gas. Premixed combustion in porous media has the following advantages: it improves fuel combustion efficiency, reduces pollutant emissions, and can significantly expand the lean burn limit of combustion. It has strong advantages in terms of equipment volume and miniaturization of combustion equipment, and provides a new way for efficient and clean combustion of gas, liquid, solid and other fuels, especially low calorific value gas fuels.

Traditional porous media burners are basically cylindrical or cuboid burners with the same axial width. In the practical exploration, the phenomenon of tempering and defiring of the burner appeared, and even caused safety problems such as explosion. In addition, the temperature gradient near the flame surface is steep, the temperature distribution is uneven, the local temperature is too high, the combustion is incomplete, and the internal pressure is too high, which destroys the structure of the burner and shortens the service life of the burner. .

Therefore, there is an urgent need for a porous media burner that can effectively solve the unstable phenomenon of burner backfire and defire, ensure a large power adjustment range, more complete combustion, and higher combustion efficiency.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides an angular porous media burner, which can effectively solve the unstable problems of burner tempering and defiring, and has the advantages of large power adjustment range, more complete combustion and higher combustion efficiency. advantage.

An angular porous media burner, characterized in that it includes a gas inlet (1), a combustion front chamber (2), a burner casing (3), a protection zone (4), a preheating zone (5), a buffer zone ( 6), the combustion zone (7) and the flue gas outlet (8), the buffer zone (6) is set between the preheating zone (5) and the combustion zone (7), the preheating zone (5), the buffer zone (6) , The combustion zone (7) is collectively referred to as the porous medium zone, all of which are filled with porous medium materials. The preheating zone 5 and the burner zone 7 taper and expand outwards at a certain angle α respectively, and the angle range is 0°<α<40 °.

The shape of the burner body is two funnels symmetrical about the center.

The preheating zone (5), the buffer zone (6) and the combustion zone (7) are respectively filled with small-pore porous media, medium-pore porous media and large-pore porous media.

The porous medium material is selected from alumina foam ceramics or zirconia foam ceramics, wherein the small-pore porous medium adopts alumina foam ceramics or zirconia foam ceramics with a pore density of 50PPI-60PPI and a porosity of more than 80%; Alumina foam ceramics or zirconia foam ceramics with a pore density of 30PPI-40PPI and a porosity of more than 80% are used; for macroporous porous media, alumina foam ceramics or zirconia ceramics with a pore density of 10PPI-20PPI and a porosity of more than 80% are used. Zirconium foam ceramics.

The protected area (4) is a baffle brick, the thickness of the baffle brick is 10-40mm, the porosity is 80%-90%, and a plurality of through holes are provided on the baffle brick, and the average aperture of the through hole is 2mm. ~4mm.

The through holes of the baffle bricks are arranged parallel to the axial direction of the burner shell.

The burner shell 3 is made of thermal insulation material.

When the gas enters the burner from below, the gas inlet (1) and the combustion front chamber (2) are arranged at the bottom of the burner casing (3), and the flue gas outlet (8) is arranged at the burner casing (3) when the gas enters the burner from above, the gas inlet (1) and the combustion front chamber (2) are arranged on the upper part of the burner casing (3), and the flue gas outlet (8) is arranged on the burner casing (3) bottom; when the gas enters the burner from the left, the gas inlet (1) and the combustion front chamber (2) are arranged on the left side of the burner housing (3), and the flue gas outlet (8) It is arranged on the right side of the burner casing (3); when the gas enters the burner from the right, the gas inlet (1) and the combustion front chamber (2) are arranged on the right side of the burner casing (3), and the The flue gas outlet (8) is arranged on the left side of the burner casing (3).

The beneficial effects of the present invention are: the present invention provides an angular porous media burner. When the ultra-low calorific value gas enters the burner for combustion, since the preheating zone of the burner adopts an inwardly tapered structure, the velocity of the incoming gas Gradually increases, so that the gas is not easy to stay in the preheating area or return to the gas inlet; because the burner combustion area adopts a structure that expands outwards, the velocity of the incoming gas gradually decreases, making it easier for the flame to stay in the combustion zone. It may not be easy to move to the outlet or even break away from the burner. At the same time, because the combustion zone adopts a structure that expands outwards, the cross-sectional area of the outlet is enlarged, and the porous media burner is used as a radiation heating device, which will strengthen the external radiation exchange of the outlet. Heat, so that the outlet radiation efficiency is as high as about 30%; setting a buffer zone in the preheating zone and the combustion zone can make the velocity of the incoming gas get a buffer effect, so as to prevent the local velocity from being too large, resulting in the inclination or uneven distribution of the flame surface .

Compared with the prior art, the present invention can obviously widen the limit range of the flame stability speed, not only effectively prevent the flame from tempering and defiring, but also improve the outlet radiation efficiency, and reduce the thermal shock damage of the porous medium at the same time. occur.

Description of drawings

Fig. 1 is an axial sectional view of an angular porous media burner of the present invention;

Fig. 2 is a schematic diagram of the porous medium region in the present invention;

Fig. 3 is a top view of an angular porous media burner of the present invention;

in,

1 gas inlet, 2 combustion front chamber, 3 burner shell, 4 protection zone, 5 preheating zone, 6 buffer zone, 7 combustion zone, 8 flue gas outlet.

Detailed ways

In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention will be described in detail below through specific implementation manners in conjunction with the accompanying drawings.

As shown in Figure 1-3, the interior of an angular porous media burner is composed of gas inlet 1, combustion front chamber 2, protection zone 4, preheating zone 5, buffer zone 6, combustion zone 7 and flue gas outlet 8 , surrounded by the burner shell 3 closed, the burner shell 3 using insulation materials, the preheating zone 5, the buffer zone 6, the combustion zone 7 are collectively referred to as the porous medium zone, the preheating zone 5 and the combustion zone in the multi-media zone 7 are all funnel-shaped, respectively set at both ends of the buffer zone 6, the preheating zone 5 and the combustion zone 7 are symmetrical about the center of the buffer zone 6. The protection area 4 is a baffle brick, the thickness of the baffle brick is 10-40mm, the porosity is 80%-90%, and a plurality of through holes are opened on the baffle brick, and the average diameter of the through hole is 2-4mm , the through holes of the baffle bricks are arranged parallel to the axial direction of the burner housing 3, the thickness of the baffle bricks in this embodiment is 10mm, the porosity is 80%, and the average aperture of the through holes is 2mm.

As shown in Figure 2, the porous medium area is composed of a preheating zone 5, a buffer zone 6, and a combustion zone 7. The preheating zone 5 and the combustion zone 7 gradually expand inward and outward at a certain angle α, and the range is 0° <α<40°, the angle is set to α=10° in this embodiment. The porous media area is filled with porous media materials, and the porous media materials are alumina foam ceramics or zirconia foam ceramics, and the preheating zone 5 is filled with small-pore porous media, with a pore density of 50PPI-60PPI and a porosity of more than 80%. Alumina foam ceramics or zirconia foam ceramics; the buffer zone 6 is filled with mesoporous porous media, and alumina foam ceramics or zirconia foam ceramics with a pore density of 30PPI-40PPI and a porosity of more than 80% are used; the combustion zone 7 is filled with large pores The porous medium adopts alumina foam ceramics or zirconia foam ceramics with a pore density of 10PPI to 20PPI and a porosity of 80% or more; in this embodiment, the preheating zone 5 is filled with a pore density of 60PPI and a porosity of 83.5%. Alumina foam ceramics, the buffer zone 6 is filled with alumina foam ceramics with a pore density of 40PPI and a porosity of 85%, and the combustion zone 7 is filled with alumina foam ceramics with a pore density of 10PPI and a porosity of 87%.

An angular porous media burner provided by the present invention can have four usage forms. When the gas enters the burner from below, the gas inlet 1 and the combustion front chamber 2 are arranged at the bottom of the burner shell 3. The flue gas outlet 8 is arranged on the upper part of the burner casing 3, that is, the gas enters from the bottom and goes out from the top; The flue gas outlet 8 is set at the bottom of the burner shell 3, that is, it goes in and out from the top; when the gas enters the burner from the left, the gas inlet 1 and the pre-combustion chamber 2 are set on the left side of the burner shell 3. The flue gas outlet 8 is set on the right side of the burner shell 3, that is, it enters from the left and goes out from the right; when the gas enters the burner from the right, the gas inlet 1 and the combustion front chamber 2 are set on the right side of the burner shell 3, The flue gas outlet 8 is arranged on the left side of the burner casing 3, that is, it enters from the right and exits from the left;

The gas combustion process of an angular porous media burner is as follows:

As shown in Figure 1, first, the gas enters the pre-combustion chamber 2 from the gas inlet 1, and then goes upstream to the preheating zone 5 through the porous medium. Continuous supply, the burning flame gradually settles in the combustion zone 7, and finally the high-temperature flue gas formed by combustion is discharged out of the burner through the flue gas outlet 8.

In this example, since the preheating zone 5 of the angular porous media burner adopts an inwardly tapering structure, the velocity of the incoming gas gradually increases, making it difficult for the gas to stay in the preheating zone 5 or return to the gas inlet 1 The occurrence of tempering phenomenon is curbed; since the combustion zone 7 of the angular porous media burner adopts a structure that gradually expands outwards, the velocity of the incoming gas gradually decreases, making it easy for the flame to settle in the combustion zone 7 or not easily Move to the flue gas outlet 8 or even break away from the burner, which suppresses the occurrence of fire-off phenomenon. At the same time, because the combustion zone 7 adopts a structure that expands outwards, the cross-sectional area of the flue gas outlet 8 is enlarged, and the porous media burner acts as a A radiation heating device, which will strengthen the external radiation heat transfer of the outlet. In this embodiment, the outlet radiation efficiency is defined as the ratio of the outlet radiated heat to the heat released by combustion. Through fluent16.0 simulation simulation, the equivalent ratio φ = 4.0- 6.0. When the inlet velocity v=0.4-0.6m/s, the outlet radiation efficiency is as high as 30%. The buffer zone 6 between the preheating zone 5 and the combustion zone 7 is to allow the velocity of the incoming gas to obtain a buffer effect, so as to prevent the local velocity from being too large, resulting in the inclination or uneven distribution of the flame surface, and reducing the thermal shock of the burner structure sexual destruction.

Claims (8)

1. An angle-shaped porous media burner is characterized in that: it comprises a gas inlet (1), a combustion front chamber (2), a burner casing (3), a protection zone (4), a preheating zone (5), a buffer Zone (6), combustion zone (7) and flue gas outlet (8), buffer zone (6) is set between preheating zone (5) and combustion zone (7), preheating zone (5), buffer zone ( 6), the combustion zone (7) is collectively referred to as the porous medium zone, all of which are filled with porous medium materials, the preheating zone 5 and the burner zone 7 taper and expand outwards at a certain angle α, and the angle range is 0°<α <40°. 2. An angular porous media burner according to claim 1, characterized in that: the preheating zone (5) and the combustion zone (7) in the multi-media zone are both funnel-shaped, respectively arranged in the buffer zone (6) Both ends, the preheating zone (5) and the combustion zone (7) are symmetrical about the center of the buffer zone (6). 3. A kind of angular porous media burner according to claim 1, characterized in that: the preheating zone (5), the buffer zone (6) and the combustion zone (7) are respectively filled with small hole porous media, medium Porous porous media and macroporous porous media. 4. An angular porous media burner according to claim 3, characterized in that: the porous media material is made of alumina foam ceramics or zirconia foam ceramics, wherein the small-pore porous media adopts a pore density of 50PPI-60PPI Alumina foam ceramics or zirconia foam ceramics with a porosity of more than 80%; mesoporous porous media adopts alumina foam ceramics or zirconia foam ceramics with a pore density of 30PPI-40PPI and a porosity of more than 80%; macroporous porous media The medium adopts alumina foam ceramics or zirconia foam ceramics with a pore density of 10PPI-20PPI and a porosity of more than 80%. 5. An angular porous media burner according to claim 1, characterized in that: the protected area (4) is a baffle brick, the thickness of the baffle brick is 10-40mm, and the porosity is 80% -90%, there are multiple through holes on the baffle brick, and the average diameter of the through holes is 2-4mm. 6 . The angular porous media burner according to claim 5 , wherein the through holes of the baffle bricks are arranged parallel to the axial direction of the burner shell. 7 . 7. An angular porous media burner according to claim 1, characterized in that: the burner casing 3 is made of heat insulating material. 8. An angular porous media burner according to claim 1, characterized in that: when the gas enters the burner from below, the gas inlet (1) and the combustion front chamber (2) are arranged in the burner shell (3), the flue gas outlet (8) is arranged on the top of the burner housing (3); when the gas enters the burner from above, the gas inlet (1) and the combustion front chamber (2) are arranged on The upper part of the burner casing (3), the flue gas outlet (8) is arranged at the bottom of the burner casing (3); when the gas enters the burner from the left, the gas inlet (1), the combustion front chamber ( 2) It is arranged on the left side of the burner casing (3), and the flue gas outlet (8) is arranged on the right side of the burner casing (3); when the gas enters the burner from the right, the gas inlet (1 ), the combustion front chamber (2) is arranged on the right side of the burner casing (3), and the flue gas outlet (8) is arranged on the left side of the burner casing (3).