System for online monitoring of gathered dust on convection heating surface of boiler

Abstract

The invention discloses a system for online monitoring of gathered dust on a convection heating surface of a boiler. The system comprises a data acquisition device, a dust blowing monitoring control device and a dust blowing device. The system is used for directly monitoring and calculating the thickness of the gathered dust on the convection heating surface in real time and comparing the thickness of the gathered dust with a critical thickness of the gathered dust, and if the thickness of the gathered dust is more than or equal to the critical thickness of the gathered dust, the system outputs a dust blowing control signal to realize intelligent monitoring and control of the gathered dust on the convection heating surface. The system for online monitoring of the gathered dust can calculate the thickness of the gathered dust in real time no matter how the running state of the boiler changes; the data acquisition device is simple in structure, and the current data acquisition device of a power station boiler can be fully used; dust blowing can be performed on the convection heating surface of the boiler accurately in real time; the thickness data of the gathered data, which is calculated in real time, can be uploaded to a DCS (distributed control system) of a power station to provide technical data for optimization of the running of the boiler.

Description

technical field [0001] The invention belongs to the technical field of on-line monitoring of fuel combustion ash accumulation, in particular to an on-line ash monitoring system for the convective heating area of ​​a boiler tail flue. Background technique [0002] The safety and economy of power plant boiler operation are affected by many factors, among which the dust accumulation on the heating surface of the boiler is a major factor affecting the safe and economical operation of the boiler. The ash accumulation on the heating surface of the coal-fired power plant boiler increases the heat transfer resistance and reduces the heat transfer, which directly leads to an increase in the exhaust gas temperature of the boiler and a decrease in the thermal efficiency of the boiler. In order to ensure the load, the fuel volume can only be increased, but the increase in fuel volume will intensify The degree of ash accumulation on the heating surface forms a vicious cycle. At the same ...

AI Technical Summary

Problems solved by technology

However, the current soot blowing operation has a certain degree of blindness and uneconomical

First, the current soot blowing operation cannot directly judge when and which heating surface needs to be soot blown according to the degree of soot on the heated area, but according to the soot blowing regulations given by the boiler manufacturer or according to the experience of the operating personnel, all Comprehensive timing soot blowing on the heating surface

The type of coal used by power plant boilers often changes, so the soot blowing regulations formulated according to the designed coal type are not applicable, so the result of regular soot blowing is sometimes: too frequent or insufficient soot blowing, too frequent soot blowing will lead to boiler The heating surface is damaged due to abrasion and thermal stress, which shortens the service life and increases the maintenance cost of the soot blowing device. Insufficient soot blowing will make the heating area serious, resulting in reduced operating economy and safety

Second, whether it is air or steam soot blowing, it consumes a lot of energy. The current domestic soot blowing device is mainly based on steam soot blowing, and the steam imported from the superheater after the boiler is in operation is used as the soot blowing device after decompression. The main steam source, the steam consumption generally accounts for 1% of the total steam output, which reduces the power generation efficiency by about 0.7%, and the soot blowing steam cannot be recovered

However, for the economizer, its own heat transfer rate is relatively high, and the change of heat transfer before and after soot blowing is only 3% to 5% of the total heat transfer. The heat fluctuation range caused by instability is relatively close, and the degree of dust accumulation cannot be accurately judged

[0008] It can be seen that the above three monitoring technologies are all indirect monitoring of the degree of dust accumulation on the heating surface of the boiler

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