Secondary air distribution device used for circulating fluidized bed boiler

A circulating fluidized bed and secondary air technology, applied in the field of boiler combustion, can solve the problems of poor flue gas disturbance, inability to achieve grading in the horizontal direction, and unfavorable full combustion of fuel, so as to prolong the residence time, facilitate reburning, improve The effect of flow

CN105864754AActive Publication Date: 2016-08-17QINGDAO JINTIAN THERMAL POWER CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2016-08-17

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Abstract

The invention discloses a secondary air distribution device used for a circulating fluidized bed boiler. The secondary air distribution device comprises the boiler, water walls arranged on the four walls of the interior of the boiler and provided with receding pipes and a secondary air system. The lower portion of the boiler is a dense-phase zone, and the upper portion of the boiler is a lean-phase zone. The secondary air system comprises a secondary air branch pipe, a plurality of secondary air stand pipes arranged on the outer side of the front wall of the boiler and the outer side of the rear wall of the boiler, and secondary air nozzles arranged on the water walls and connected with the secondary air stand pipes. The secondary air nozzles comprise the double nozzles and the single nozzles and are arranged in the lean-phase zone of the boiler in a layered mode. The receding pipes comprise the double-hole receding pipes and the single hole receding pipes. The disturbing effect of smoke in a boiler hearth is added through the secondary air distribution modes, fuel can be completely burnt, generation of NOx is reduced, grading of secondary air in the height direction is achieved, and grading of the secondary air in the horizontal direction is achieved.
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Description

technical field

[0001] The invention belongs to the technical field of boiler combustion, and in particular relates to a secondary air distribution device for a circulating fluidized bed boiler. Background technique

[0002] In the nitrogen oxides produced during boiler combustion, NO accounts for more than 90%, and nitrogen dioxide accounts for 5%-10%. The production mechanism is generally divided into the following three types: (1) Thermal type: During combustion, nitrogen in the air is Oxidation, with the increase of the reaction temperature T, the reaction rate follows an exponential law. When T<1500°C, the amount of NO produced is very small, and when T>1500°C, the reaction rate increases for every 100°C increase in T. 6-7 times larger; (2) Instantaneous reaction type: CH free radicals generated by pyrolysis of hydrocarbons in fuel volatiles can react with nitrogen in the air to form HCN and N, and then react with oxygen to form at an extremely fast speed. Its fo...

Examples

Embodiment Construction

[0023] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0024] A secondary air distribution device for a circulating fluidized bed boiler, comprising a boiler 1, a water-cooled wall and a secondary air system provided on four walls inside the boiler 1, and a secondary air system. The lower part of the boiler 1 is a dense-phase area, The upper part is the dilute phase area, and the secondary air system includes the secondary air branch pipe 3, multiple secondary air risers 3 placed outside the boiler front wall 8 and the boiler rear wall 11, and the secondary air riser arranged on the water wall and connected to the secondary air riser. 3 connected secondary air nozzle 2, the secondary air nozzle 2 includes double nozzles and single nozzles, the secondary air nozzle 2 is arranged in layers in the dilute phase area of ​​the boiler 1, and the let-off pipe includes a double-hole let-off pipe an...