Control method for restraining influence of coal mill start/stop to main vapour pressure of boiler

Abstract

The invention relates to a control method for inhibiting the influence on main steam pressure of a boiler caused by that a coal pulverizer is started or stopped, and a rapid control layer of average rotating speed of a coal feeder is added on the basis of three-layer control mode of the original boiler fuel, so that the influence on the main steam pressure of the boiler caused by various operation of the operators is effectively inhibited when in the process that the coal pulverizer is started or stopped. A dynamic feed-forward technique based on the actual differential coefficient is applied to the feed-forward design of a boiler main control system by the method, so that the command of automatically modifying the coal quantity in the boiler can be realized in the process that the coal pulverizer is started or stopped, and the excessive part of coal dust quantity which enters the boiler to be burnt is counteracted due to start grinding, warm grinding or stop grinding in the process of powder extraction, thus ensuring the combustion conditions of the boiler to be stabler and effectively inhibiting the influence on main steam pressure caused by that the coal pulverizer is started or stopped.

Description

technical field [0001] The invention relates to a control method for suppressing the influence of starting and stopping coal mills on boiler main steam pressure, especially a dynamic feed-forward technology using actual differential links and a rapid control layer by increasing the average speed of coal feeders, effectively suppressing In the process of starting and stopping the coal mill, various interferences that affect the combustion conditions of the boiler and an advanced control method for effectively reducing the fluctuation of the main steam pressure of the boiler belong to the field of thermal power engineering and automatic control. Background technique [0002] The combustion control system of the boiler is one of the most critical control systems in thermal power plants. The fuel control of the boiler basically adopts the three-layer control mode of the boiler main control layer, the fuel control layer and the coal feeder speed control layer. The main problems I...

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Problems solved by technology

[0002] The combustion control system of the boiler is one of the most critical control systems in thermal power plants. The fuel control of the boiler basically adopts the three-layer control mode of the boiler main control layer, the fuel control layer and the coal feeder speed control layer. The main problems In the process of raising and lowering the load of the unit, it is necessary to start and stop the coal mill frequently, but the current three-layer control mode is difficult to restrain the influence of starting and stopping the coal mill on the combustion conditions of the boiler, resulting in the main The steam pressure fluctuates greatly, and the maximum dynamic deviation often reaches more than 1.0MPa, which further causes other important parameters of the boiler such as main steam temperature, drum water level, furnace negative pressure and oxygen content to fluctuate greatly

These two types of disturbances are the main reasons for large fluctuations in the main steam pressure.

At present, there is no report on improving the boiler combustion control system for these two types of disturbances

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