阅读说明：本技术 一种带强化预热的超低热值燃气燃烧器 (Ultralow-heat-value gas burner with intensified preheating function ) 是由 王恩宇 陈苗苗 于 2021-08-21 设计创作，主要内容包括：本发明涉及一种带强化预热的超低热值燃气燃烧器,包括预热用燃气进口、均质多孔介质、燃烧段、点火针、异构多孔介质、烟气段、多孔辐射层、内壳、外壳、预热段、螺旋叶片、低热值燃气进口、烟气出口和保温层；燃烧段内填充异构多孔介质；异构多孔介质沿内壳的轴向方向分为若干组多孔介质,并按照孔隙密度从靠近预热用燃气进口位置沿轴向方向阶跃递减排布；每组多孔介质由中心多孔介质层和环形多孔介质层组成,在径向方向上,从中心多孔介质层到环形多孔介质层的孔隙密度呈阶跃性递增分布；螺旋叶片置于预热段内,固定在内壳外侧,由烟气段延伸至燃烧段的中上游；本发明可拓宽贫燃极限,实现超低热值燃气高效燃烧并降低污染物排放。(The invention relates to an ultralow-calorific-value gas burner with strengthened preheating, which comprises a gas inlet for preheating, a homogeneous porous medium, a combustion section, an ignition needle, a heterogeneous porous medium, a flue gas section, a porous radiation layer, an inner shell, an outer shell, a preheating section, a spiral blade, a low-calorific-value gas inlet, a flue gas outlet and a heat insulation layer, wherein the gas inlet is connected with the combustion section; heterogeneous porous media are filled in the combustion section; the heterogeneous porous media are divided into a plurality of groups of porous media along the axial direction of the inner shell and are distributed in a step-by-step decreasing manner along the axial direction from the position close to the preheating fuel gas inlet according to the pore density; each group of porous media consists of a central porous medium layer and an annular porous medium layer, and the pore density from the central porous medium layer to the annular porous medium layer is distributed in a step-like increasing manner in the radial direction; the spiral blade is arranged in the preheating section, fixed on the outer side of the inner shell and extended to the middle upstream of the combustion section from the flue gas section; the invention can widen the lean combustion limit, realize the high-efficiency combustion of the gas with ultralow heat value and reduce the pollutant emission.)

1. The ultra-low heat value gas burner with the strengthened preheating function is characterized by comprising a gas inlet for preheating, a homogeneous porous medium, a burning section, an ignition needle, an isomeric porous medium, a flue gas section, a porous radiation layer, an inner shell, an outer shell, a preheating section, a helical blade, a low heat value gas inlet, a flue gas outlet and a heat insulation layer; the shell is a cuboid or a cylinder made of metal materials, and the preheating fuel gas inlet is positioned in the center of the side face of the shell; the inner shell is a metal cylinder and is positioned inside the outer shell; a gap between the inner shell and the outer shell in the radial direction of the inner shell is the preheating section; the inner shell is coated outside the homogeneous porous medium, the combustion section and the flue gas section; the homogeneous porous medium is filled in the front section of the inner shell and is communicated with the preheating fuel gas inlet and the preheating section; the other side of the homogeneous porous medium is communicated with the combustion section, and the ignition needle is arranged in a gap between the homogeneous porous medium and the combustion section; the combustion section is filled with the heterogeneous porous medium; the heterogeneous porous media are divided into a plurality of groups of porous media along the axial direction of the inner shell and are distributed in a step-by-step decreasing manner along the axial direction from the position close to the preheating fuel gas inlet according to the pore density; each group of porous media consists of a central porous media layer and an annular porous media layer, the central porous media layer is a cylinder, the annular porous media layer is coated outside the central porous media layer, and the pore density from the central porous media layer to the annular porous media layer is in step-like incremental distribution in the radial direction; the smoke section is positioned at the tail section of the inner shell, and the porous radiation layer is arranged in the smoke section; the spiral blade is arranged in the preheating section, fixed on the outer side of the inner shell and extended to the middle upstream of the combustion section from the flue gas section; the outer wall of the shell, which is far away from the preheating fuel gas inlet, is provided with the low-calorific-value fuel gas inlet, and the low-calorific-value fuel gas inlet is communicated with the preheating section; the shell is wrapped with the heat-insulating layer.

2. The ultra low heating value gas burner with enhanced preheating of claim 1, wherein the helical vane height is no less than three-quarters of the gap between the inner and outer shells.

3. The ultra low heating value gas burner with enhanced preheating of claim 1, wherein the helical blade extends to a position in the combustion section no less than one quarter of the total length of the combustion section from the start of the combustion section.

4. The ultra-low heating value gas burner with enhanced preheating according to claim 1, wherein the heterogeneous porous medium has a pore density of 5-70 PPI, a porosity of not less than 80%, and a thickness of 30-300 mm.

5. The ultra-low heating value gas burner with enhanced preheating according to claim 1, wherein the porous radiant layer has a pore density of 30-50 PPI, a porosity of 80-90%, and a thickness of 25-40 mm.

6. The ultra-low heating value gas burner with enhanced preheating according to claim 1, wherein the homogeneous porous medium has a pore density of 40-65 PPI, a porosity of 80-90%, and a thickness of 20-30 mm.

Technical Field

The invention relates to a gas burner, in particular to an ultralow-heat-value gas burner with intensified preheating.

Background

In industrial production, a large amount of recyclable ultralow-heating-value gas exists, the gas is difficult to effectively utilize due to factors such as difficult ignition, poor stability and the like, and the porous medium combustion technology has the advantages of wide load regulation range, high combustion efficiency, small volume of a combustor and low pollutant emission and is considered to be one of effective ways for economically and technically efficiently treating the ultralow-heating-value gas. Patent CN201110183845.5 proposes a porous medium burner for burning low calorific value gas fuel, which adopts a sectional porous medium pore structure to improve the flame stability of the low calorific value gas fuel and reduce the pollutant emission; patent CN201610918177.9 proposes a porous medium burner for gaseous fuel, which effectively prevents backfire and reduces NOx emissions. The prior art has certain improvement space in the aspects of heat flow direction control and heat flow reasonable distribution, can realize effective heat transfer by optimizing a pore structure and strengthening boundary heat transfer, widens the lean combustion limit, and obtains more reasonable temperature distribution.

Disclosure of Invention

The invention aims to provide an ultralow-heat-value gas burner with enhanced preheating, and provides an ultralow-heat-value gas burner which can promote combustion of gas, transfer heat through an optimized pore structure and an enhanced boundary, reasonably distribute heat flow, improve flame stability, widen lean combustion limit, realize efficient combustion of ultralow-heat-value gas and reduce pollutant emission aiming at ultralow-heat-value gas with difficult combustion and poor stability.

In order to achieve the aim, the invention provides an ultralow-calorific-value gas burner with strengthened preheating, which comprises a gas inlet for preheating, a homogeneous porous medium, a combustion section, an ignition needle, an isomeric porous medium, a flue gas section, a porous radiation layer, an inner shell, an outer shell, a preheating section, a spiral blade, a low-calorific-value gas inlet, a flue gas outlet and a heat insulation layer, wherein the gas inlet is communicated with the combustion section; the shell is a cuboid or a cylinder made of metal materials, and the preheating fuel gas inlet is positioned in the center of the side face of the shell; the inner shell is a metal cylinder and is positioned inside the outer shell; a gap between the inner shell and the outer shell in the radial direction of the inner shell is the preheating section; the inner shell is coated outside the homogeneous porous medium, the combustion section and the flue gas section; the homogeneous porous medium is filled in the front section of the inner shell and is communicated with the preheating fuel gas inlet and the preheating section; the other side of the homogeneous porous medium is communicated with the combustion section, and the ignition needle is arranged in a gap between the homogeneous porous medium and the combustion section; the combustion section is filled with the heterogeneous porous medium; the heterogeneous porous media are divided into a plurality of groups of porous media along the axial direction of the inner shell and are distributed in a step-by-step decreasing manner along the axial direction from the position close to the preheating fuel gas inlet according to the pore density; each group of porous media consists of a central porous media layer and an annular porous media layer, the central porous media layer is a cylinder, the annular porous media layer is coated outside the central porous media layer, and the pore density from the central porous media layer to the annular porous media layer is in step-like incremental distribution in the radial direction; the smoke section is positioned at the tail section of the inner shell, and the porous radiation layer is arranged in the smoke section; the spiral blade is arranged in the preheating section, fixed on the outer side of the inner shell and extended to the middle upstream of the combustion section from the flue gas section; the outer wall of the shell, which is far away from the preheating fuel gas inlet, is provided with the low-calorific-value fuel gas inlet, and the low-calorific-value fuel gas inlet is communicated with the preheating section; the shell is wrapped with the heat-insulating layer. The preheating gas enters the inner shell from the preheating gas inlet, passes through the homogeneous porous medium firstly, has the functions of rectifying and preventing tempering, is ignited by the ignition needle, is combusted in the heterogeneous porous medium of the combustion section, and is discharged from the flue gas outlet. When the combustion section reaches a certain temperature, the supply of gas for preheating is stopped, the premixed gas with ultralow heat value enters from the gas inlet with the low heat value, the premixed gas flows spirally in the preheating section for heat exchange, and the helical blades play a role in enhancing the heat exchange, so that the heat is transferred to the premixed gas with ultralow heat value from the flue gas section and the combustion section; the preheated premixed gas with the ultralow heat value passes through the homogeneous porous medium and is combusted in the heterogeneous porous medium, and due to the pore structure of the heterogeneous porous medium, the nonuniform temperature distribution in the combustion process is avoided, the flame stability is improved, and the emission of CO and NOX is reduced; the porous radiation layer arranged on the smoke section can prevent fire from happening, and finally the smoke is discharged through the smoke outlet.

Optimally, the height of the helical blade is not less than three-fourths of the gap between the inner shell and the outer shell, so that the uneven distribution of the internal resistance of the preheating section is avoided, and the ultra-low heat value premixed gas cannot be subjected to effective heat exchange.

Optimally, the helical blade extends to a position in the combustion section, the length from the starting point of the combustion section is not less than one fourth of the total length of the combustion section, the homogeneous porous medium and the outer side of the upstream of the combustion section do not cover the helical blade, the heat flow loss of the position is reduced, and effective ignition and stable initial combustion are guaranteed.

Optimally, the heterogeneous porous medium has the pore density of 5-70 PPI, the porosity of not less than 80% and the thickness of 30-300 mm.

Optimally, the porous radiation layer has the pore density of 30-50 PPI, the porosity of 80-90% and the thickness of 25-40 mm.

Optimally, the homogeneous porous medium has the pore density of 40-65 PPI, the porosity of 80-90% and the thickness of 20-30 mm.

Drawings

FIG. 1 is a schematic cross-sectional view of one embodiment of an ultra low heating value gas burner with enhanced preheating provided by the present invention; in the figure: a preheating gas inlet 1; a homogeneous porous medium 2; a combustion section 3; an ignition needle 4; a heterogeneous porous media 5; a flue gas section 6; a porous radiation layer 7; an inner shell 8; a housing 9; a preheating section 10; a helical blade 11; a low heating value gas inlet 12; a flue gas outlet 13; and an insulating layer 14.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The core of the invention is to provide an ultralow heat value gas burner with enhanced preheating, and provide an ultralow heat value gas burner which can promote combustion of gas, transfer heat through optimizing a pore structure and an enhanced boundary, reasonably distribute heat flow, improve flame stability, widen lean combustion limit, realize efficient combustion of ultralow heat value gas and reduce pollutant emission aiming at ultralow heat value gas which is difficult to burn and has poor stability.

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail by the following embodiments with reference to the accompanying drawings.

Example 1, in a specific embodiment, the present invention provides an ultra-low calorific value gas burner with enhanced preheating, as shown in fig. 1, including a preheating gas inlet (1), a homogeneous porous medium (2), a combustion section (3), an ignition needle (4), a heterogeneous porous medium (5), a flue gas section (6), a porous radiation layer (7), an inner shell (8), an outer shell (9), a preheating section (10), a helical blade (11), a low calorific value gas inlet (12), a flue gas outlet (13), and an insulating layer (14); the shell is a cylinder made of metal materials, and the preheating fuel gas inlet (1) is positioned in the center of the side surface of the shell (9); the inner shell (8) is a metal cylinder and is positioned inside the outer shell (9); a gap between the inner shell (8) and the outer shell (9) in the radial direction of the inner shell (8) is a preheating section (10); the inner shell (8) is coated outside the homogeneous porous medium (2), the combustion section (3) and the flue gas section (6); the homogeneous porous medium (2) is filled in the front section of the inner shell (8) and is communicated with the preheating fuel gas inlet (1) and the preheating section (10); the other side of the homogeneous porous medium (2) is communicated with the combustion section (3), and the ignition needle (4) is arranged in a gap between the homogeneous porous medium (2) and the combustion section (3); the combustion section (3) is filled with heterogeneous porous media (5); the heterogeneous porous media (5) are divided into 4 groups of porous media along the axial direction of the inner shell (8) and are distributed in a step-by-step decreasing manner along the axial direction from the position close to the preheating fuel gas inlet (1) according to the pore density; each group of porous media consists of a central porous media layer and an annular porous media layer, the central porous media layer is a cylinder, the annular porous media layer coated outside the central porous media layer is 1 layer, and the pore density from the central porous media layer to the annular porous media layer is in step-like increasing distribution in the radial direction; in general, the pore density of the central porous medium layer is 25 PPI, 20 PPI, 15 PPI and 1 respectively from the position close to the preheating fuel gas inlet (1) along the axial direction0 PPI, wherein the pore density of the annular porous medium layer is respectively 30 PPI, 25 PPI, 20 PPI and 15 PPI; the flue gas section (6) is positioned at the tail section of the inner shell (8), and a porous radiation layer (7) is arranged inside the flue gas section; the helical blade (11) is arranged in the preheating section (10), fixed on the outer side of the inner shell (8) and extended to the middle upstream of the combustion section (3) from the flue gas section (6); the outer wall of the shell (9) far away from the preheating fuel gas inlet (1) is provided with a low-heat-value fuel gas inlet (12), and the low-heat-value fuel gas inlet (12) is communicated with the preheating section (10); the shell (9) is wrapped with a heat-insulating layer (14). Preheating gas enters the inner shell (8) from the preheating gas inlet (1), passes through the homogeneous porous medium (2) firstly, has the functions of rectifying and preventing tempering, is ignited by the ignition needle (4), is combusted in the heterogeneous porous medium (5) of the combustion section (3), and is discharged from the flue gas outlet (13). When the combustion section (3) reaches a certain temperature, the supply of gas for preheating is stopped, the ultra-low heat value premixed gas enters from the low heat value gas inlet (12), spirally flows in the preheating section (10) for heat exchange, and the helical blades (11) play a role in enhancing heat exchange, so that heat is transferred to the ultra-low heat value premixed gas from the flue gas section (6) and the combustion section (3); the preheated premixed gas with ultralow heat value passes through the homogeneous porous medium (2) and is combusted in the heterogeneous porous medium (5), and due to the pore structure of the heterogeneous porous medium (5), the nonuniform temperature distribution in the combustion process is avoided, the flame stability is improved, and CO and NO are reduced_XDischarging; the porous radiation layer (7) arranged on the smoke section (6) can prevent the fire from happening, and finally the smoke is discharged through the smoke outlet (13).

Specifically, the height of the helical blade (11) is three quarters of the gap between the inner shell (8) and the outer shell (9), so that the uneven distribution of the internal resistance of the preheating section (10) is avoided, and the ultra-low heat value premixed gas cannot be subjected to effective heat exchange.

Specifically, the helical blade (11) extends to a position in the combustion section (3), the length from the starting point of the combustion section (3) is one fourth of the total length of the combustion section (3), the homogeneous porous medium (2) and the outer side of the combustion section (3) upstream do not cover the helical blade (11), the heat flow loss at the position is reduced, and effective ignition and stable initial combustion are ensured.

Specifically, the heterogeneous porous medium (5) has a pore density of 10-30 PPI, a porosity of 85% and a thickness of 120 mm.

In particular, the porous radiation layer (7) has a pore density of 50 PPI, a porosity of 85% and a thickness of 25 mm.

Specifically, the homogeneous porous medium (2) has a pore density of 50 PPI, a porosity of 85% and a thickness of 30 mm.

Mainly comprises CO and N₂The calorific value is about 3.0 MJ/m³The fuel gas is fuel, when the equivalence ratio is 0.9, the flame stability limit range is 107.38-311.40 kW/m²，NO_XLess than 2 mg/m³CO emission lower than 77 mg/m³。

Example 2, the ultra-low heating value gas burner with the intensified preheating of the embodiment is the same as the example 1, except that: in general, the pore densities of the central porous medium layer are 45 PPI, 35 PPI, 25 PPI and 15 PPI respectively, and the pore densities of the annular porous medium layers are 50 PPI, 40 PPI, 30 PPI and 20 PPI respectively along the axial direction from the position close to the preheating fuel gas inlet (1). The heterogeneous porous medium (5) has a pore density of 15-50 PPI, a porosity of 90% and a thickness of 100 mm. The main component of the ultralow-heat-value fuel gas is CH₄And N₂The calorific value is about 1.2 MJ/m³When the equivalence ratio is 0.9, the flame stability limit range is 76.43-183.44 kW/m²，NO_XLess than 9 mg/m³CO emission lower than 150 mg/m³。

The description of the embodiments of the present invention is only for the purpose of assisting understanding of the core idea of the present invention, and is not intended to limit the embodiments of the present invention. It should be understood that any modification, equivalent replacement, and improvement made by those skilled in the art without departing from the principle of the present invention shall be included in the protection scope of the claims of the present invention.