Circulating Fluidized Bed Boiler Effectively Reducing Carbon Oxide Emissions

Abstract

The invention discloses a circulating fluidized bed boiler for effectively reducing oxycarbide emission. The circulating fluidized bed boiler for effectively reducing oxycarbide emission comprises a combustion furnace, a cyclone separator connected with the combustion furnace, and a secondary air system for arranging secondary air. An outlet of the combustion furnace is connected with an inlet of the cyclone separator, a burn-out chamber is arranged at an outlet of the cyclone separator, and overfire air is introduced into the burn-out chamber. The secondary air system comprises a secondary air pipe, a plurality of secondary air vertical pipes arranged on the outer sides of a front wall and a back wall of the combustion furnace, and secondary air nozzles arranged on a water-cooled wall and connected with the secondary air vertical pipes. According to the circulating fluidized bed boiler for effectively reducing oxycarbide emission, part of flue gas is mixed with primary air and secondary air, so that NOx emission is reduced; secondary air classification in the height direction and the horizontal direction is achieved through a secondary air arrangement mode; the burn-out chamber is arranged at the outlet of the separator, carbon in fine flying ash at the outlet of the separator is burned again in the burn-out chamber, the carbon content of the flying ash is reduced, and thus the contradiction caused by reduction of the oxygen content of the combustion furnace between NOx emission reduction and the high carbon content of the flying ash can be overcome effectively.

Description

technical field

[0001] The invention belongs to the technical field of boiler combustion, in particular to a circulating fluidized bed boiler that can effectively reduce carbon oxide emissions. 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 for...

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