Cooling flame low nitrogen combustion device and combustion method thereof

Abstract

The invention relates to a cooling flame low nitrogen combustion device. The device comprises a premixed gas inlet and a combustion chamber, wherein a first heat exchange tube assembly and an igniterin the flow direction of premixed gas are successively arranged in the combustion chamber; the first heat exchange tube assembly is composed of a plurality of outer hexagonal tubes arranged in parallel, and gaps are formed between the adjacent outer hexagonal tubes to allow the premixed gas to pass through; and the position of the igniter opposite to the first heat exchange tube assembly is set insuch a way that the igniter can directly ignite the premixed gas passing through the gaps. Cooling fluid circulates in the outer hexagonal tubes, and the temperature of a flame is reduced duo to thecold wall effect of the cooling fluid, so that the formation of nitrogen oxides is inhibited; and at the same time, when the flame propagation speed is greater than the air flow speed, and the flame returns into the gaps between the outer hexagonal tubes, the energy of the flame becomes smaller and smaller under the cooling effect of the cooling fluid until the flame goes out in the gaps, so thatthe explosion caused by the tempering phenomenon is avoided.

Description

technical field [0001] The invention relates to the field of combustion devices, in particular to a cooling flame low-nitrogen combustion device and a combustion method thereof. Background technique [0002] In order to strengthen environmental governance, my country once again tightened the emission standards of nitrogen oxides, requiring existing boilers to undergo low-nitrogen transformation and new boilers to adopt low-nitrogen combustion technology to ensure that nitrogen oxide emissions are below 30mg / m 3 the following. [0003] Pre-mixing technology is to mix gas and air in a certain ratio before combustion, and increase the heat-absorbing working medium in the flame area by increasing the excess air coefficient to reduce the temperature of the flame, thereby reducing the formation of nitrogen oxides. The heat exchange condensation technology is to transfer the heat generated by the flame to the water in the heat exchange tube through the heat exchange tube with high...

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Problems solved by technology

At present, my country's fully premixed condensing technology is not yet mature, such as the water-cooled surface combustion low-nitrogen burner disclosed in the patent CN108443876A, the boiler with it and its applicable method, the combustion-supporting air and natural gas are completely mixed and then evenly overflow through the gap of the spiral cooling pipe and The ignition gun cooperates with the combustion, because the fully premixed flame spreads quickly, and it is easy to produce backfire phenomenon. Although the cold water pipe in this way can reduce the flame temperature, it cannot prevent backfire. Mixed gas, prone to deflagration

In addition, the premixed gas overflows unevenly in the spiral cooling tube, which is easy to generate a local flame high temperature area, resulting in a large amount of nitrogen oxides

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