Boiler pipeline secondary air on-line monitoring system

Abstract

The invention belongs to the technical field of boiler air duct secondary air monitoring and relates to a boiler pipeline secondary air on-line monitoring system. According to the system, a cross section array of a secondary air duct straight pipe section is equally divided into a plurality of sampling areas; the sampling areas in the section of a secondary air duct are correspondingly provided with sampling points, and the sampling points are provided with sampling probes; a sampling mechanism performs weighted averaging on the high and low voltage signals of the corresponding sampling areas obtained by the sampling probes to obtain differential pressure signals; and analysis signals obtained after the differential pressure signals pass through a signal processor are outputted and are fed back to an upper control system. According to the online monitoring system provided by the invention, the sampling point probes are arranged in each sampling areas by adopting a gridding sampling design, and the flow velocity signal of each sampling area in the air duct is subjected to weighted average, so that the real-time average flow velocity in the air duct can be obtained; measurement distortion under the conditions of serious turbulent flow and turbulent flow field is effectively solved, and the air volume and the flow field in the air duct can be rapidly and accurately monitored.

Description

technical field [0001] The present invention relates to the technical field of boiler air duct secondary air monitoring, and more specifically, relates to an online monitoring system for secondary air of boiler pipes Background technique [0002] Due to the short length of the straight pipe section used for measurement, the layout of the secondary air duct adopted by the existing boiler cannot meet the requirements for the position of the measurement section in the "Performance Test Regulations for Power Plant Boilers" (GB10184-88), and cannot obtain Accurate parameter data, coupled with the existence of vortex and backflow in the flow field in the secondary air duct of the boiler, and the change of unit load during operation, the pressure at the outlet of the secondary fan will also be adjusted accordingly, resulting in The flow velocity is redistributed, and the situation in the flow field changes quickly and the change gap is large. [0003] At different positions of the...

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Problems solved by technology

[0002] Due to the short length of the straight pipe section used for measurement, the layout of the secondary air duct adopted by the existing boiler cannot meet the requirements for the position of the measurement section in the "Performance Test Regulations for Power Plant Boilers" (GB10184-88), and cannot obtain Accurate parameter data, coupled with the existence of vortex and backflow in the flow field in the secondary air duct of the boiler, and the change of unit load during operation, the pressure at the outlet of the secondary fan will also be adjusted accordingly, resulting in The flow velocity is redistributed, the situation in the flow field changes quickly, and the change gap is large

[0003] At different positions of the secondary air duct cross-section, there are great differences in the flow velocity distribution of the flow field inside the air duct. At present, the secondary wind measurement of the power plant adopts the wing-type measurement system, and the pressure-taking holes are extremely easy to be blocked, and the flow resistance is large. Severe wear and tear, unable to respond to changes in boiler working conditions in real time, bringing huge risks to boiler AGC regulation

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