A secondary air distribution device 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

CN105864754BInactive Publication Date: 2018-05-15QINGDAO JINTIAN THERMAL POWER CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-05-15
Estimated Expiration
Not applicable · inactive patent

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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 particularly relates to a secondary air distribution device for a circulating fluidized bed boiler. Background technique

[0002] In the nitrogen oxides produced in the combustion process of the boiler, NO accounts for more than 90%, and nitrogen dioxide accounts for 5%-10%. The production mechanisms are generally divided into the following three types: (1) Thermal type: During combustion, nitrogen in the air is exposed to high temperature. Oxidation occurs. With the increase of the reaction temperature T, the reaction rate follows an exponential law. When T<1500℃, the amount of NO generated is very small, and when T>1500℃, the reaction rate increases for every 100℃ increase in T. 6-7 times larger; (2) Instantaneous reaction type: CH radicals generated by high-temperature decomposition of hydrocarbons in fuel volatiles can react with nitrogen in the air to generate HCN and N, ...

Examples

Embodiment Construction

[0023] The present invention will be further described in detail below with reference to 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 arranged on four walls in the boiler 1 with letting pipes, and 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 secondary air branch pipes 3, a plurality of secondary air risers 3 placed on the outside of the boiler front wall 8 and the boiler rear wall 11, and the secondary air risers arranged on the water wall and the secondary air risers. 3 connected secondary air nozzles 2, the secondary air nozzles 2 include double nozzles and single nozzles, the secondary air nozzles 2 are arranged in layers in the dilute phase area of ​​the boiler 1, and the let pipes include double-hole let-down pipes and single-h...