Intelligent control method applied to central discharge type cement raw mill system

Abstract

The invention relates to an intelligent control method applied to a central discharge type cement raw mill system. Aiming at various working conditions encountered in the process of cement raw material milling, a load optimization set value is given by an operator according to experience of the operator, mill sound and fine powder inlet pressure are respectively adopted by a coarse powder bin and a fine powder bin to serve as main manipulated variables, sectional type proportion integration differentiation (PID) control with feedforward compensation is carried out, and decoupling control is achieved through a method that sampling points of a main control step length and sampling points of a monitoring step length of a control circuit of the coarse powder bin are spaced; dead zone amplitude limiting of controller inputting is adjusted in real time through the adoption of an expert system; a sampling period of a control algorithm adopts a mode combining the main control step length with the monitoring step length; and an effective intelligent control method is provided for the cement raw mill system that disturbance is large, accurate measurement cannot be carried out on load, feeding is delayed, coupling among various variables is severe, and therefore the automatic degree of cement raw mill operating is improved, and intelligent control for the cement raw mill system is achieved.

Description

technical field [0001] The invention relates to an intelligent control method suitable for a mid-unloading cement raw meal mill system, which uses an expert system structure based on a blackboard model to handle various working conditions encountered in the raw meal grinding process, and at the same time coordinates the coarse powder bin and An intelligent control method for the reasonable distribution of the material level of the fine powder bin. Background technique [0002] Cement raw meal grinding is a complex industrial process involving mass transfer, (heat exchange,) mechanical grinding and two-phase flow. The control difficulties of the grinding system mainly lie in the process delay, internal coupling and the inherent nonlinearity of the crushing and grinding process. Process delays are mainly due to delays in particle size analysis of finished products as well as delays in material transfer. The coupling lies in: 1) The speed of the powder classifier not only aff...

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Problems solved by technology

[0003] At the same time, the filling rate inside the mill cannot be accurately measured. The electric ear and the vibration signal of the mill spindle are more susceptible to external interference. At the same time, the signal-to-noise ratio is relatively small, so the application is not ideal. Now it is only used as a reference for the operator. signal, but it is an important parameter to reflect whether the mill has abnormal working conditions such as jamming

The status quo of industrial production is that the mill usually works in an area far away from the optimal working point to ensure that there is no grinding blockage, so the output of the mill is always below the maximum

At the same time, the particle size of cement raw meal cannot be detected online, and it can only be tested by screening every 1 to 2 hours in the laboratory, so the quality of cement raw meal fluctuates greatly

[0004] The control difficulties of the mid-unloading cement raw meal mill system mainly focus on the following aspects: 1) The signal-to-noise ratio of the data collected on site is small, and the data of the operating variables and controlled variables cannot be used normally, and filtering, etc. are required technical processing

2) Due to the large delay in the control of the feed to the mill material level, it is difficult to adjust the mill material level in time, and it is necessary to control the feed in advance by means of prediction and compensation

It took 1 hour and 32 minutes in this process. Since the feeding mechanism of the mill itself cannot be operated frequently, it needs to be adjusted at least once every 2 minutes. In addition, the raw material mill system itself is nonlinear and has a large delay, which eventually leads to It will take a long time for the mill to return to a stable running state. During this period, the continuous adjustment of the feeding will make the material level of the system fluctuate greatly, and the current of the main motor of the mill will also fluctuate greatly, which will eventually cause grinding The increase in power consumption of the mill will waste a lot of power, which will also affect the service life of the mill and eventually affect the pass rate of the finished product

Therefore, sometimes in order to make the grinding sound close to the set value, changing the feeding amount will destroy the existing stable operation state of the grinding system and consume more power

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