Flue gas circulation system and method for circulating fluidized bed boiler

Abstract

The invention discloses a flue gas circulation system for a circulating fluidized bed boiler. The flue gas circulation system comprises a leading-out flue gas circulating pipeline, a flue gas circulating branch pipe and a first electric door opening and closing door; a leading-out flue gas circulating pipeline connector is arranged at an outlet of an induced draft fan, and the first electric dooropening and closing door is arranged at the inlet of the leading-out flue gas circulating pipeline; the flue gas circulating branch pipe comprises a first branch pipe communicated with an inlet flue of an absorption tower of a desulfurization system, a second branch pipe communicated with a boiler secondary air hot air main pipe and a third branch pipe communicated with the boiler primary air hotair main pipe; the first branch pipe, the second branch pipe and the third branch pipe are correspondingly provided with electric adjusting doors; and meanwhile, the invention further discloses an operating method for the circulating fluidized bed boiler, the flue gas circulation system can be independently used for adjusting the flue gas quantity at an inlet of a circulating fluidized bed semi-dry desulfurization absorption tower, so that the stable operation of the absorption tower can be stabilized, the control of the NOx generation amount can be realized by independently adjusting the temperatures and oxygen quantities of different areas of the boiler hearth, and under the same energy consumption condition, compared with a conventional flue gas circulation system, the flue gas circulation system has higher environmental protection characteristics.

Description

technical field [0001] The invention belongs to the technical field of energy saving and environmental protection of coal-fired circulating fluidized bed boilers, and in particular relates to a flue gas circulation system and method for circulating fluidized bed boilers. Background technique [0002] With the improvement of our country's economy and living standards, people will pay more and more attention to the environment. In order to strengthen environmental protection and achieve energy conservation and emission reduction goals, relevant state ministries and commissions have put forward stricter environmental protection standards and energy conservation transformation goals for the coal power industry. By 2020, qualified units across the country will achieve ultra-low emissions, and the average coal consumption of active units for power supply will be less than 310 grams of standard coal / kWh. [0003] The combustion technology of circulating fluidized bed boiler techno...

AI Technical Summary

Problems solved by technology

When the desulfurization system is operating at a load lower than 70%, the output of the induced draft fan needs to be maintained above 70%. The lower the load of the boiler, the greater the proportion of the power consumption of the induced draft fan to the factory power consumption, and this part of the power consumption cannot bring any benefit, but cause a greater waste

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