Ultra-low NOX combustion system and method of tangential combustion boiler

Abstract

The invention relates to an ultra-low NOX combustion system and method of a tangential combustion boiler. The ultra-low NOX combustion system comprises a hearth, primary air combustors, over-fire air nozzles and secondary air nozzles. The primary air combustors are arranged at the four corners of the lower portion of the hearth in a four-corner tangential mode. Each primary air combustor comprises a plurality of layers of pulverized coal pipelines and a primary air nozzle, and the pulverized coal pipelines are each provided with a pulverized coal dense-thin separation device, a dense-phase pulverized coal pipeline and a thin-phase pulverized coal pipeline. The pulverized coal dense-thin separation devices are used for separating air pulverized coal in the pulverized coal pipelines into dense-phase airflow and thin-phase airflow. The over-fire air nozzles are arranged at the upper portion of the hearth, each over-fire air nozzle comprise an over-fire air exhaust nozzle and an over-fire air secondary air nozzle, and the over-fire air exhaust nozzles are connected with the thin-phase pulverized coal pipelines. The secondary air nozzles are arranged between the adjacent primary air nozzles, are arranged above the primary air nozzle at the top and are arranged below the primary air nozzle at the bottom. According to the ultra-low NOX combustion system and method of the tangential combustion boiler, the problem that the ratio of secondary air to primary air in a main combustion area is unbalanced is thoroughly solved.

Description

technical field [0001] The invention relates to the technical field of boiler combustion, in particular to an ultra-low NO X Combustion systems and methods. Background technique [0002] For boilers burning lignite, on the one hand, due to the high moisture content of lignite (received base moisture is 30-40%) and low calorific value (received base low calorific value is 10-15MJ / kg), when using medium-speed grinding When grinding lignite in the direct blowing system, in order to meet the requirements of drying output, higher hot primary air temperature (360-390°C) and higher primary air rate (primary air rate 33-40%) are often required. [0003] On the other hand, as the country's environmental protection requirements become more and more stringent, thermal power plants are facing more and more pressure on emissions. Existing units are retrofitted with low-nitrogen combustion to meet the ultra-low emission requirements of NOx, and new units require advanced combustion techn...

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Problems solved by technology

[0004] The purpose of the present invention is to provide an ultra-low NO X Combustion system and method to solve the problem of imbalance between the secondary air and primary air in the main combustion area after the SOFA nozzle is installed in the lignite tangential combustion boiler, and control the mass ratio of the secondary air to the primary air in the main combustion area within a reasonable range , so as to organize a good and efficient combustion

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