Adjustable air-coal step-by-step mixing low-NOx combustion device

Abstract

Provided is an adjustable air-coal step-by-step mixed combustion device. The device comprises a central air pipe, a primary air pipe, a rotational flow inner secondary air pipe, and a direct flow outer secondary air pipe which are sequentially arranged from inside to outside. Pre-combustion chambers are arranged at the tails of the air pipes in the airflow direction, and tertiary air pipes are arranged outside the pre-combustion chambers. An annular air flow channel between the primary air pipe and the rotational flow inner secondary air pipe is provided with an air-coal mixing first-stage regulator, and the primary air pipe is sleeved by the air-coal mixing first-stage regulator. An annular air flow channel between the rotational flow inner secondary air pipe and the direct flow outer secondary air pipe is provided with an air-coal mixing second-stage regulator of the same structure as the air-coal mixing first-stage regulator. By controlling the mixing time and the mixing position ofprimary air carrying pulverized coal, rotational flow inner secondary air, and direct flow outer secondary air, stable combustion of the pulverized coal is guaranteed, the production of NOx is remarkably reduced, and the coal type adaptive capacity of the combustion device is improved.

Description

technical field [0001] The invention relates to the technical field of pulverized coal combustion and environmental protection, in particular to an adjustable air-coal stepwise mixed low NOx combustion device. Background technique [0002] The basic characteristics of my country's energy structure, that is, "rich in coal, poor in oil, and low in gas", means that coal resources will be the main source of energy in our country. According to the "China Statistical Yearbook" statistics, my country's total energy consumption in 2017 was 4.4 billion tons of standard coal, of which coal accounted for 60.4% of the total energy consumption. However, as an energy source with serious environmental pollution, coal will produce a large amount of nitrogen oxides, sulfur oxides, and particulate matter during the combustion process, which will seriously damage the environment and even cause acid rain and photochemical pollution, which is extremely harmful to the human body. Therefore, redu...

AI Technical Summary

Problems solved by technology

However, during the operation of this kind of burner, it will be difficult to control the mixing timing of primary air, secondary air and overburning air. Premature mixing will lead to insufficient pyrolysis of coal powder, less reducing gas, and the combustion process Only a small amount of NOx is reduced to N 2 , NOx emissions are high at this time; too late mixing will lead to insufficient oxygen and heat required by pulverized coal in the ignition stage, unstable combustion and even flameout

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