Low nitrogen combustion device with free diffusion premixed combustion layer and its combustion head

Abstract

The invention discloses a low-nitrogen combustion device with a free diffusion premixed combustion layer and a combustion head thereof. The combustion head includes a combustion head body, and the combustion head body is provided with a central pipe, a plurality of first annular layer pipes, a plurality of second annular layer pipes, a free diffusion premixed combustion layer; the first annular layer, the second annular layer They are arranged on the outer side of the central pipe in sequence; in the present invention, by arranging the first ring-layer pipe and the second ring-layer pipe on the periphery of the central pipe, the combustion head body can form a plurality of mutually independent premixes along the radial direction on the periphery of the central pipe. If one of the premixed areas fails to work properly during the combustion process, it will not affect the normal operation of other areas. The fuel gas and air of the present invention can be fully premixed through the free diffusion premixed combustion layer, so there is almost no local high temperature point during combustion, which can effectively and significantly reduce the generation of nitrogen oxides.

Description

technical field [0001] The invention relates to a combustion device, in particular to a low-nitrogen combustion device capable of fully premixing air and gas through free diffusion. Background technique [0002] According to statistics from China Energy News, by the end of 2017, there were about 400,000 industrial boilers in use in my country, and the number of small civil boilers was even larger (no statistical data available). With the country's strict requirements on environmental protection, local environmental protection departments have successively issued documents requiring that old boilers need to be retrofitted to meet the emission standards. A large part of the boiler renovation is to replace the low-nitrogen burner to meet the low-nitrogen emission requirements, and the old boilers are directly replaced to meet the emission requirements. [0003] At present, the well-known gas boiler burner is a relatively mature combustion technology. European and American low-...

AI Technical Summary

Problems solved by technology

[0013] 1. The requirements for gas pressure are high, and the pressure cannot be boosted in some renovation areas, making renovation difficult

[0014] 2. The size of the furnace is required to be larger when the boiler is renovated, and the old boiler cannot enlarge the furnace at all.

Many boilers that have just been used for two or three years are forced to be replaced, which increases the burden on enterprises

[0015] 3. Newly built boilers require larger furnaces, which increases boiler manufacturing costs

[0016] 4. To achieve NOX≤30mg / m3 requires the assistance of FGR (flue gas reflux), which will produce acidic condensed water into the furnace, reduce the thermal efficiency of the boiler, and corrode the burner and furnace, reducing the service life of the boiler

[0018] 6. In extremely cold regions, the condensed water produced by FGR will quickly condense into ice cubes, which will block the inlet of the fan and cause the shutdown of the furnace.

Or some ice cubes are sucked into the fan, damaging the fan impeller, resulting in unstable performance of the equipment, increasing the maintenance rate and reducing the service life of the equipment

[0019] 7. Insufficient and uneven mixing of air and gas, incomplete combustion and high oxygen content

[0023] 1. This technology has an extra part of the gas premixing device in advance, which needs to increase the size of the burner body (bulky), which also increases the manufacturing cost

[0024] 2. Due to the pre-mixing device for some gases in advance, tempering occurs when the gas pressure is unstable

[0025] 3. The size of the furnace is required to be large when the boiler is renovated, and the old boiler cannot enlarge the furnace at all.

Many boilers that have just been used for two or three years are forced to be replaced, which increases the burden on enterprises

[0026] 4. Newly built boilers require larger furnaces, increasing boiler manufacturing costs

[0027] 5. To achieve NOX≤30mg / m3 requires the assistance of FGR (flue gas return), which will produce acidic condensed water into the furnace, reduce the thermal efficiency of the boiler, and corrode the burner and furnace, reducing the service life of the boiler;

[0029] 7. In extremely cold regions, the condensed water produced by FGR will quickly condense into ice cubes, which will block the inlet of the fan and cause the shutdown of the furnace

Or some ice cubes are sucked into the fan, damaging the fan impeller, resulting in unstable performance of the equipment, increasing the maintenance rate and reducing the service life of the equipment

[0030] Based on the above two combustion methods, there are still many defects, mainly to achieve the purpose of low nitrogen at the expense of energy consumption

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