Double-heat-reflux partially-premixed low-nitrogen combustor and combustion method

Abstract

The invention discloses a double-heat-reflux partially-premixed low-nitrogen combustor and combustion method. The double-heat-reflux partially-premixed low-nitrogen combustor comprises a guide cylinder, a main fuel pipe and an on-duty fuel pipe; and an injection control baffle is arranged on the front portion of the main fuel pipe and arranged on the periphery of the main fuel pipe in a surrounding mode to form an injection area, an injection pipe is arranged at the front end of an outlet of the main fuel pipe, an outlet of the injection pipe extends out of the injection area, an on-duty fuelpremixing cavity is arranged on the front portion of the guide cylinder, a main air channel is formed between the premixing cavity and the guide cylinder, the front portion of the on-duty fuel pipe isprovided with a plurality of on-duty fuel nozzles and extends into the on-duty fuel premixing cavity, a swirl disc, a first porous medium unit and a second porous medium unit are arranged in the on-duty fuel premixing cavity from back to front, and the porosity of the first porous medium unit is smaller than that of the second porous medium unit. The combustor has the advantages of being good inadaptability and stable in combustion, the contradiction between great reduction of the oxygen content during low-NOx combustion and combustion stability is overcome, and low NOx emission can be achieved.

Description

technical field [0001] The invention relates to a dual-heat reflux partially premixed low-nitrogen burner and a combustion method thereof, belonging to the technical field of combustion. Background technique [0002] With the increasing environmental protection standards, it is necessary to further reduce NOx emissions to 15mg / Nm 3 even near zero emissions. The NOx produced by the combustion of natural gas and other gases is mainly thermal and rapid, of which thermal NOx accounts for up to 95%. Suppressing the formation of thermal NOx is the main way to reduce NOx. [0003] At present, in various low-nitrogen combustion technologies, the main measures are to reduce the flame combustion temperature, disperse the high-temperature zone and reduce the residence time of the high-temperature zone. Natural gas low-nitrogen combustion technologies include flue gas recirculation, flue gas internal circulation, and premixed lean combustion technologies. In the flue gas recirculatio...

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Problems solved by technology

Chinese patent document CN2078153 proposes to use the Venturi principle to obtain fuel jet entrainment. This method is easily affected by the large flow field in the furnace. The entrainment back pressure at the root of the burner fluctuates with the fluctuation of the recirculation area, resulting in a sharp increase in the entrainment amount. Changes, causing violent pulsation of combustion, and even causing flameout

In order to solve the above problems, the Chinese patent document CN 108738333 discloses that the jet ejection area is buried in the furnace wall, but it will lead to problems such as overheating of the outer wall of the furnace wall and difficulty in layout.

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