CN101158469A - A segmented porous ceramic medium gas fuel burner - Google Patents

Abstract

The invention relates to a multi-stage porous ceramic medium gas fuel burner, which consists of a burner shell, a dust removal metal net or metal brush, an air pipe, a pre-mixing chamber, and a gas pipe. The main points are: the burner shell is bounded by a porous plate It is divided into upper and lower parts. Inside the upper cavity of the burner shell, from top to bottom, there are ceramic porous media in the large hole area placed on the ceramic porous media in the small hole area, and the ceramic porous media in the small hole area is placed on the porous plate. Below the perforated plate, dust-removing metal mesh or metal brushes are installed inside the burner housing. The perforated plate is clamped on the burner shell, and the periphery of the lower middle perforated plate extends to the outside of the burner shell. The advantage of the invention is that the ceramic porous media burner has a large calorific value range of the fuel, and can not only burn low-calorific-value gas or low-quality gas fuel, but also can burn high-calorific-value gas. The perforated plate added in the burner plays a good role in heat dissipation and can prevent backfire or explosion more effectively.

Description

A segmented porous ceramic medium gas fuel burner

technical field

The invention relates to a burner, in particular to a segmented porous ceramic medium gas fuel burner.

Background technique

At present, the combustion of gaseous fuels in China's industrial production is mainly space combustion characterized by free flames. In this combustion mode, the temperature gradient near the flame surface is steep and unevenly distributed, and the existence of local high-temperature areas causes a large amount of NO _X generation. Incomplete combustion results in low thermal efficiency and poor combustion stability. Now, the technology of adding porous media in the burner has gradually been paid attention to. Premixed combustion in porous media has many advantages: smaller lean burn limit, higher combustion rate and stability, wide load adjustment range, high combustion intensity, small burner volume, etc., and the nitrogen and sulfur in the combustion products Therefore, premixed combustion in porous media has great potential in practical applications.

In the combustion of gaseous fuels, in terms of material properties, porous media must have the characteristics of high temperature resistance, oxidation resistance, and easy heat conduction. Stainless steel, alloys, glass, and ceramics have all been used as research objects by scholars at home and abroad. In terms of structure, when the aperture is relatively large, the radiation penetrates farther and the temperature rises faster; when the aperture is relatively small, the relative optical thickness of the porous medium is relatively large, which has a good thermal storage effect. In order to effectively utilize the influence of pore size on combustion, most people use porous media with non-single pore size and single material. For example, the burner disclosed in the patent application titled "a metal fiber-porous ceramic medium surface burner" (application number 200610135085.X, filing date 2006.12.27), its composition includes a burner casing, a burner pipe , air pipes, and casings, the metal fiber medium in the combustion zone and the ceramic medium in the preheating zone are set in sequence from top to bottom, and the dust removal metal medium is set in the cavity above the gas pipeline under the ceramic medium in the preheating zone. Mesh or metal brush. Although the burner with this structure is better than the metal fiber surface burner, it solves the problems that the burner is prone to backfire during use, and the adjustment range of fuel and air is small, and the thermal efficiency is low. However, the use of this porous media burner still has the following defects: the porous media has a small aperture and is very easy to block, so most of the current burners are only used for a single pure gas fuel, and most of the actual production needs to burn dust content High gas or mixed gas, which brings limitations to the practical application of porous media burners.

Contents of the invention

Aiming at the shortcomings of existing gas fuel porous media burners, the present invention provides a segmented porous ceramic media gas fuel burner, which can be used for combustion calorific values ranging from 1000 to 10000 kcal/m ³ (4180 ~41800kJ/m ³ ), or even higher gas fuel, and can prevent backfire and explosion more effectively.

The composition of the burner of the present invention includes a burner shell, a dust removal metal mesh or a metal brush, an air pipe, a premixing chamber, and a gas pipe. Ceramic porous media, porous plates, dedusting wire mesh or metal brushes.

The casing of the above-mentioned burner is divided into upper and lower parts by a perforated plate. Inside the cavity formed by the upper part of the burner shell, ceramic porous media in the large hole area are arranged in sequence from top to bottom. The ceramic porous media in the large hole area is placed on the ceramic porous media in the small hole area, and the ceramic porous media in the small hole area is placed on the porous plate. On the top, there is a cavity between the top of the ceramic porous medium in the large hole area and the top surface of the burner shell; the porous plate is sandwiched between the upper and lower parts of the burner shell, and the periphery of the porous plate extends to the space outside the burner shell. Dust-removing metal mesh or metal brushes are assembled in the pre-mixing chamber at the lower part of the burner casing.

The large hole area in the burner belongs to the combustion area, and the porous medium material used is ceramics, which is suitable for high calorific value gas fuel (combustion temperature can reach 1500°C or even above); the small hole area has a small pore size, which can prevent tempering At the same time, the small hole area is a preheating area, which can effectively store the heat generated in the combustion area. The temperature here generally does not exceed 1200 ° C, and the porous media material used is also ceramics. In order to ensure a good heat conduction effect between the two regions, it is designed to be in close contact with each other. The small hole area ceramic porous media is placed on the porous plate. The perforated plate has strong thermal conductivity and can quickly export heat, which can prevent the occurrence of tempering due to improper operation or other reasons during the combustion process.

The material of the ceramic porous medium in the above-mentioned large-pore area is selected from yttria-based zirconia, calcium oxide-based zirconia or silicon carbide, with an average pore diameter of 2.5-5mm, a porosity of 80-85%, and the arrangement of the pores is straight or disordered. ; The material of ceramic porous medium in the small hole area is corundum (Al ₂ O ₃ ), calcium oxide-based zirconia or silicon carbide, with an average pore diameter of 0.25-0.5 mm, a porosity of 75-83%, and the arrangement of the pores is straight through. Or disorder; the porous plate is made of metal or alloy material with good thermal conductivity and ability to withstand a certain temperature (<600°C). The hole diameter on the plate is 2-5mm, the porosity is 80-90%, and the arrangement of the holes is a straight-through type. The holes of the perforated plate are arranged in an orthogonal manner or arranged in a ring around the center. The material of the dust removal metal mesh or metal brush is stainless steel. The material of the burner shell is stainless steel, cast iron or high temperature resistant stainless steel.

The axial section of the burner housing is circular, square or polygonal.

Compared with the prior art, the present invention has the most outstanding features and remarkable effects: since the present invention adds a porous plate in the burner structure, it can be processed by metal or alloy with good thermal conductivity and high temperature resistance (<600°C). Formed, and after the perforated plate is assembled, its periphery is extended outside the burner casing. When the flame propagates to the upstream of the burner, the heat carried by the flame can be quickly transferred to the outside of the burner through the perforated plate with good thermal conductivity, and lost to the environment. The presence of small holes on the plate can prevent flashback or explosion more effectively, greatly improving the safety factor of burner applications.

In addition, the combustion zone and the preheating zone designed by the present invention use ceramic porous media, so that the burner fuel has a large calorific value range, and can burn low calorific value gas or low-quality gas fuel, as well as high calorific value gas, and the calorific value is average. Can be 1000～10000kcal/m ³ (4180～41800kJ/m ³ ), or even higher fuel gas, such as blast furnace gas, coke oven coal or high-coke mixed gas, natural gas and other fuels, the present invention can be widely used in metallurgy, Chemical, energy and other industries.

Description of drawings

Fig. 1 is the axial sectional view of burner of the present invention;

Fig. 2 is a form of the A-A sectional view of Fig. 1, and the arrangement form of the holes is an orthogonal arrangement;

Fig. 3 is another form of the A-A sectional view of Fig. 1, and the arrangement form of the holes is an annular arrangement;

In Figures 1, 2, and 3: 1 burner shell, 2 ceramic porous medium in the large hole area, 3 ceramic porous medium in the small hole area, 4 porous plate, 5 dust removal metal mesh or metal brush, 6 air duct, 7 premixing chamber, 8. Gas pipeline, 9. Flange, 10. Nut, 11. Bolt, 12. Screw hole.

Detailed ways

Example 1, as shown in Figure 1 and Figure 2, the burner is composed of a burner shell, ceramic porous media in the large hole area, ceramic porous media in the small hole area, porous plate, dust removal metal mesh, air pipe, premixing chamber, and gas pipe . The burner shell is divided into upper and lower parts by a porous plate. Inside the cavity formed by the upper part of the burner shell, ceramic porous media in the large-pore area are arranged in sequence from top to bottom, and the ceramic porous media in the large-pore area are placed below On the ceramic porous medium in the small hole area, the two are in close contact. The ceramic porous medium in the small hole area is placed on the porous plate and is in close contact. There is a cavity between the upper surface of the ceramic porous medium in the large hole area and the top surface of the burner casing. The perforated plate is sandwiched between the upper and lower parts of the burner shell, and connected by flanges and bolts on the upper and lower parts of the burner shell. The periphery of the perforated plate extends in the outer space of the burner shell, and the middle part of the periphery of the perforated plate is a plate surface with holes. The dust-removing metal mesh made of stainless steel is embedded in the groove of the inner wall of the lower part of the burner shell, and its position is below the perforated plate and above the air duct in the premixing chamber of the burner shell. The air pipe is welded on the side wall of the lower part of the burner, and the lower port of the burner casing is a gas inlet.

The ceramic material in the large-pore area is selected from yttria-based zirconia, with an average pore diameter of 5 mm, a porosity of 80%, and a disordered arrangement of pores; the ceramic material in the small-pore area is corundum (Al ₂ O ₃ ), with an average diameter of 0.5mm, the porosity is 76%, and the arrangement of pores is disordered. The material of the porous plate is copper, with an average pore diameter of 5mm and a porosity of 82%. The arrangement of the holes is a straight-through type and an orthogonal arrangement. The axial section of the burner shell is circular, and its material is stainless steel.

Applying the burner of the present invention, the air and gas are mixed in the pre-mixing chamber after entering the air pipe and the gas pipe respectively, and after being dedusted by the dust-removing metal mesh, they pass through the perforated plate and enter the small-hole medium in the preheating zone with a lower temperature. Then it enters the combustion zone and burns in the macroporous medium.

The combustion gas is blast furnace gas, the gas flow rate is 1500m ³ /h, and the air flow rate is 220m ³ /h. The combustion effect is: air and gas fuel do not need to be preheated before entering the burner; in the burned gas, the content of unburned hydrocarbons, nitrogen compounds and sulfides is less than 50ppm, and the content of carbon monoxide is less than 40ppm.

Example 2:

The structure of the burner is the same as Example 1. The difference is: the ceramic material in the large-pore area is calcium oxide-based zirconia, with an average pore diameter of 4 mm, a porosity of 85%, and the arrangement of the pores is disordered; the ceramic material in the small-pore area is calcium oxide-based zirconia, with an average pore diameter of 4 mm. The hole is 0.4mm, the porosity is 80%, and the arrangement of the holes is disordered; the material of the porous plate is low carbon steel alloy, the average pore size is 4mm, and the porosity is 83%. The arrangement of the holes is straight-through and arranged in a ring around the center. The axial section of the burner shell is square, and its material is cast iron. The premix chamber is fitted with stainless steel dust removal metal brushes.

Burner application: the combustion gas is coke oven gas, the gas flow rate is 800m ³ /h, and the air flow rate is 1500m ³ /h. The content of unburned hydrocarbons, nitrides and sulfides in the combustion gas is less than 50ppm, and the carbon monoxide is less than 40ppm.

Example 3: The burner structure is the same as Example 2. The difference is: silicon carbide is used as the ceramic material in the large-pore area, silicon carbide is used as the ceramic material in the small-pore area, and metal aluminum is selected as the porous plate material, with an average pore diameter of 3mm and a porosity of 84%. The axial section of the burner shell is hexagonal, and its material is high-temperature resistant stainless steel.

Burner application: The combustion gas is natural gas, the gas flow rate is 2000m ³ /h, and the air flow rate is 3000m ³ /h. Burning effect is the same as Example 2.

Example 4: The average pore diameter of the ceramic material in the large pore area of the burner is 3mm, and the porosity is 84%. The average pore diameter of the ceramic material in the small pore area is 0.3mm, and the porosity is 82%. The other structures of the burner, the material selection of components and the application results are the same as Example 1.

Example 5: The average pore diameter of the ceramic material in the large hole area of the burner is 2.5mm, and the porosity is 85%. The other structures of the burner and the selection of components are the same as in Example 1. The combustion gas used in the application is liquefied petroleum gas, and the others are the same as in Example 1.

Example 6: The average pore diameter of the ceramic material in the large-pore area of the burner is 2.5mm, and the porosity is 85%. The average pore diameter of the ceramic material in the small-pore area is 0.25mm, and the porosity is 83%. Other formations of the burner are the same as in Embodiment 1.

Claims (5)

1. multisection type porous ceramic dielectric gas fuel combusting device, constitute and comprise burner housing, dedusting wire netting or metallic brush, air duct, premixer, gas pipeline, it is characterized in that the cavity inside that burner housing constitutes, be provided with big bore region ceramic porous medium, the orifice region ceramic porous medium, porous plate, dedusting wire netting or metallic brush.

2. by the described sectional type porous ceramic dielectric gas burner of claim 1, it is characterized in that burner housing is that the boundary divides upper and lower two parts with the porous plate, the cavity inside that burner housing top constitutes, be disposed with big bore region ceramic porous medium from top to bottom, big bore region ceramic porous medium is placed on above the orifice region ceramic porous medium, the orifice region ceramic porous medium is placed on above the porous plate, above the big bore region ceramic porous medium and be cavity between the burner housing top end face; Porous plate is clipped in the middle of the burner housing upper and lower part, and the porous plate periphery extends to the burner housing outside; Dedusting wire netting or metallic brush are assemblied in the premixer, burner housing bottom.

3. by claim 1 or 2 described sectional type porous ceramic dielectric gas burners, the material that it is characterized in that big bore region ceramic porous medium, select yttria-base zirconia, calcium oxide-based zirconia or carborundum for use, average pore size is 2.5～5mm, porosity is 80～85%, and the arrangement mode in hole is for straight-through or unordered; The material of orifice region ceramic porous medium is selected corundum (Al for use ₂O ₃), calcium oxide-based zirconia or carborundum, average pore size is 0.25～0.5mm, porosity is 75～83%, the arrangement mode in hole is for straight-through or unordered; The material selection metal or alloy of porous plate (4), aperture are 2～5mm, and porosity is 80～90%, and the arrangement mode in hole is a through type.

4. by the described sectional type porous ceramic dielectric gas burner of claim 3, the hole that it is characterized in that porous plate is the orthogonal arrangement mode or circularizes arrangement around the center.

5. by claim 1 or 2 described sectional type porous ceramic dielectric gas burners, it is characterized in that described burner housing axial cross section is circle, square or polygon.

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