1. The heat-accumulating oxidation low-nitrogen combustion method is characterized in that: the medium fuel and the oxidant are mixed in advance, the generated low-concentration mixed gas (1) flows through the oxidation section (2) to be subjected to primary oxidation, the heat storage material (4) is arranged in the oxidation bed (2), and the flue gas generated after the primary oxidation is medium-temperature flue gas and enters the combustion head (6) through the medium-temperature flue gas channel (7) to further mix and combust the main fuel and the medium-temperature flue gas.

2. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the heat storage material (4) is a small ball or a honeycomb body.

3. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the low-concentration mixed gas passes through the heat accumulator (4) to heat the mixed gas (1), the mixed gas (1) is ignited and combusted in the heat accumulator (4), the generated ignition heat keeps balance with the heat taken away by the mixed gas, and the temperature of the heat storage material (4) of the oxidation section (2) is stable and is kept above the ignition point of combustible gas.

4. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the oxidation material of the oxidation section (2) is movable and replaceable, and two ends of the heat storage material (4) are fixed on the inner wall of the oxidation section (2) through the grating (3).

5. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the oxygen content in the medium-temperature flue gas channel (7) is between 8 and 19 percent.

6. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the medium-temperature flue gas in the medium-temperature flue gas channel (7) and the rest fuel are subjected to secondary mixed combustion.

7. The regenerative thermal oxidative low-nitrogen combustion method of claim 6, wherein: the medium-temperature flue gas flow channel (7) and the combustion head (10) are of an integrated burner structure and are used for producing low-nitrogen combustor products; or the mixed gas is matched with a gas nozzle and sprayed into the furnace to carry out secondary mixed combustion with the medium-temperature flue gas in the low-oxygen medium-temperature flue gas channel (7).

8. The regenerative thermal oxidative low-nitrogen combustion method of claim 6, wherein: the combustion method can combine the oxidation section (2) with a furnace body or a furnace wall and is used for discharging in a furnace kiln.

9. The regenerative thermal oxidative low-nitrogen combustion method of claim 1, wherein: the primary oxidation section (2) is used for an independent hot blast stove, an independent small air duct burner or surface combustion oxygen.

Background

The low-nitrogen combustion method commonly adopted in the fields of the prior art furnace kiln, the boiler and the like comprises the following steps: 1. the method for increasing the distribution quantity of the fuel nozzles at the head part of the combustion head and the method for different nozzle distribution positions realize the effects of combining the sprayed fuel and the oxidant with one of gradation and combination time difference, and finally realize the distribution control of the temperature field of the combustion flame. 2. The low-nitrogen combustion is realized by controlling the oxygen content of a combustion improver in the combustion process by adopting a method of flue gas recirculation inside and outside the furnace.

At present, nitrogen oxide control is generally carried out by adopting a mode that the first burner head structure and the second flue gas recirculation low-nitrogen method are coupled.

The above two low-nitrogen combustion structures or methods have fundamental problems: 1) the method cannot be suitable for various hearth temperatures (particularly high-temperature hearths); 2) the combustion method cannot be applied to various process furnaces: such as flameless combustion environments, flat flame combustion environments, and the like; 3) near "0" emissions of nitrogen oxides cannot be achieved.

The existing method of the 1 st low-nitrogen combustor is generally and purely unstable in the combustion process of the combustor, and the combustion has pulse vibration and is relatively dangerous; the main purpose of fuel and oxidant distribution in combustion is temperature control, rather than intensified combustion, so that the problems of unstable ignition, poor low-load combustion stabilizing effect and the like are solved, and corresponding potential safety hazards are also accompanied; the above 2 nd flue gas circulation low-nitrogen method is at the cost of sacrificing boiler efficiency, or adding external energy supply, which brings essential changes to the flow field in the furnace, resulting in the phenomena of increased flue gas temperature, accelerated flue gas flow rate, unreliable condensate water and fire detection, and unsafe and unstable conditions.

Summary of the invention

In order to solve the problems of applicability, emission and safety and stability of the low-nitrogen combustion control method, the invention provides a heat storage oxidation low-nitrogen combustion method which is used for organizing various combustion processes and achieving the results of near 0-emission, high-efficiency combustion and universal application of nitrogen oxides.

In order to achieve the technical purpose, the invention adopts the following method:

the heat-accumulating oxidation low-nitrogen combustion method is characterized in that a medium fuel and an oxidant are mixed in advance to generate a low-concentration mixed gas, the mixed gas flows through an oxidation section to be subjected to primary oxidation, a heat-accumulating material is filled in an oxidation bed, and the flue gas generated after the primary oxidation is medium-temperature flue gas and enters a combustion head through a medium-temperature flue gas channel to further mix and combust a main fuel and the medium-temperature flue gas.

The heat storage material is a small ball or a honeycomb body.

The low-concentration mixed gas passes through the heat accumulator to heat the mixed gas, the mixed gas is ignited and combusted in the heat accumulator, the generated ignition heat is balanced with the heat taken away by the mixed gas, and the temperature of the heat storage material of the oxidation section is stable and is kept above the ignition point of the combustible gas.

The oxidation material of the oxidation section is movable and replaceable, and two ends of the heat storage material are fixed on the inner wall of the oxidation section through grids.

The oxygen content in the medium temperature flue gas channel is between 8 and 19 percent.

And the medium-temperature flue gas in the medium-temperature flue gas channel and the rest fuel are subjected to secondary mixed combustion.

The medium-temperature flue gas flow channel and the combustion head are of an integrated burner structure and are used for producing low-nitrogen combustor products; or the mixed gas is matched with a gas nozzle and sprayed into the furnace to carry out secondary mixed combustion with the medium-temperature flue gas in the low-oxygen medium-temperature flue gas channel.

The combustion method can combine the oxidation section with the furnace body or the furnace wall and is used for discharging in the furnace.

The primary oxidation section is used for an independent hot blast stove, an independent small air duct burner or surface combustion oxidation. The main fuel and the medium-temperature flue gas are further mixed and combusted, and the generated tail flue gas has NO content of 3.5 percent_XThe emission is 0-5 PPM. The method solves the problem of the limit emission of the nitrogen oxides in the combustion process, so that the thermal nitrogen oxides of various fuels can be infinitely close to '0' emission; provide aA general approach to low-nitrogen combustion design of different fuels; the method is suitable for various boiler combustors, industrial furnace combustors and the like. The device has the advantages of environmental protection, safety, stability, high flexibility, convenient maintenance and the like.

The invention has the technical effects that:

1. according to the difference of various fuels, different ignition temperatures of different fuels are analyzed, mixed gas is oxidized into medium-temperature flue gas in a first stage, and the oxygen content is 8-19%; after the part of the medium-temperature flue gas is mixed with the secondary fuel or is mixed at the combustion head, the mixing speed of the secondary fuel and the medium-temperature flue gas is very violent due to the volume expansion of the medium-temperature flue gas, and the mixing is very uniform.

2. Near "0" emissions for low nitrogen combustion are achieved, for example: NO at 3.5% of final flue gas oxygen content_XDischarging at 0-5 PPM;

3. the combustion process can be combined with a burner alone to produce a single low-nitrogen burner product.

4. The combustion method can be independently combined with a furnace body (furnace wall) to generate a novel low-nitrogen-emission furnace.

5. The combustion method can independently separate out the primary oxidation section and realize the functions of the oxidation section in an independent process unit, such as: independent hot blast stoves, independent small duct burners, etc., or without the use of heat storage.

6. The combustion method is suitable for various process furnaces.

7. Suitable for various combustion flame patterns, for example: flat flame combustion, flameless combustion, high speed combustion, and the like.

8. Is suitable for conventional burners and regenerative burners.

9. The fuel is suitable for the stability of combustion of all fuels, particularly low-heating-value fuels.

Drawings

FIG. 1 is a side sectional view of the inventive regenerative oxidative staged combustion low nitrogen process.

FIG. 2 is a rear view of the inventive regenerative oxidative staged combustion low nitrogen process.

FIG. 3 is a schematic diagram of the inventive regenerative oxidation staged combustion low-nitrogen method.

In the figure: 1. the device comprises a channel of low-concentration fuel mixed gas, 2, an oxidation section of low-concentration fuel gas, 3, a support isolation structure of a heat storage oxidation material, 4, a heat storage material, 5, a connection of the oxidation section and a medium-temperature flue gas outlet, 6, a combustion head, 7, a medium-temperature flue gas flow channel, 8 and a spray gun nozzle of secondary main fuel.

Detailed Description

The invention will be further described with reference to fig. 1, 2 and 3.

The low-nitrogen combustion method of heat accumulation oxidation, the medium fuel and oxidizing agent are mixed in advance, the low-concentration mixed gas 1 produced, this mixed gas 1 flows through the oxidation section 2 and carries on the primary oxidation, the oxidation bed 2 is equipped with the heat accumulation material 4 inside, the flue gas produced after the primary oxidation is the medium temperature flue gas, enter the burner 6 through the medium temperature flue gas runner 7, make main fuel and medium temperature flue gas further mix and burn.

The heat storage material 4 is a pellet or a honeycomb body.

The low-concentration mixed gas passes through the heat accumulator 4 to heat the mixed gas 1, the mixed gas 1 is ignited and combusted in the heat accumulator 4, the generated ignition heat keeps balance with the heat taken away by the mixed gas, and the temperature of the heat storage material 4 of the oxidation section 2 is stable and is kept above the ignition point of the combustible gas.

The oxidation material of the oxidation section 2 is movable and replaceable, and two ends of the heat storage material 4 are fixed on the inner wall of the oxidation section 2 through the grids 3.

The oxygen content in the medium temperature flue gas channel 7 is between 8 and 19 percent.

And the medium-temperature flue gas in the medium-temperature flue gas channel 7 and the rest fuel are subjected to secondary mixed combustion.

The medium-temperature flue gas flow passage 7 and the combustion head 6 are of an integrated burner structure and are used for producing low-nitrogen combustor products; or the mixed gas is matched with a gas nozzle and sprayed into the furnace to carry out secondary mixed combustion with the medium-temperature flue gas in the low-oxygen medium-temperature flue gas flow passage 7.

The combustion method can combine the oxidation section 2 with a furnace body or a furnace wall and is used for discharging in a furnace kiln. Will be provided withThe fuel participating in combustion is distributed, part of the fuel is mixed with oxidant namely air, the mixed fuel passes through the step (1), low-heat-value mixed gas enters the oxidation section 2, the heat storage bed 4 of the oxidation section performs primary pre-combustion on the low-concentration mixed gas, the heat storage bed 4 is fixed by the support grid 3, the medium-temperature flue gas which comes out from the oxidation section is 8% -19%, the medium-temperature flue gas is mixed with secondary fuel or is mixed at a combustion head, the mixing speed of the secondary fuel and the medium-temperature flue gas is very violent due to the volume expansion of the medium-temperature flue gas, the mixing is very uniform, the combustion head (10) sprays outwards to be the mixture of the medium-temperature flue gas and the secondary fuel, further mixing and combustion are carried out, tail flue gas is generated, and NO (NO) of the tail flue gas is 3.5% of oxygen content_XThe emission is 0-5 PPM.