Coal Pulverizer Control Device for Rapid Load Response
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Solution Overview
Problem
Existing coal pulverizing apparatuses are insufficient in reducing coal output delay, which hinders rapid load changes in coal-fired power plants, despite previous control methods that have limitations in improving response delays and maintaining classifying accuracy.
Innovation Solution
A control device for the coal pulverizing apparatus that generates command values for the rotational speed of the table, pressing force of the roller, and air supply amount based on load information, and for the rotational speed of the rotary classifier, to precede changes in load, thereby reducing both upstream and downstream response delays and maintaining classifying accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the amount of coal supplied to the coal pulverizing apparatus is changed to rapidly change the load, then the load response speed is improved, but there is a time lag (coal output delay) until the coal output changes
Solution Approach 1:
The control device calculates a preliminary correction signal by subtracting the output demand signal from a first-order lag operator processed signal. This correction signal is processed through a limiter and integrator to generate a rotational speed command for the rotary separator that anticipates the required coal output change, thereby reducing the coal output delay and improving load response speed.
2Loss of time
If the rotational speed of the rotary separator is increased to cover coal discharge amount deficiency, then the coal output delay is reduced, but the classifying accuracy of the rotary separator deteriorates
Solution Approach 1:
The control device dynamically adjusts the rotational speed of the rotary separator based on real-time coal discharge amount feedback. The system calculates a correction signal that modulates the rotational speed command, allowing the rotary separator to temporarily increase speed to cover coal discharge deficiency while maintaining overall classifying accuracy through continuous feedback control.
3Loss of time
If multiple control parameters (table rotational speed, roller pressing force, air supply amount, classifier rotational speed) are adjusted simultaneously, then the coal output delay is reduced, but the device complexity increases
Solution Approach 1:
The control device segments the control parameters into two groups: upstream parameters (table rotational speed, roller pressing force, air supply amount) and downstream parameters (classifier rotational speed). Each group is controlled through dedicated control circuits that calculate correction signals based on coal discharge amount feedback, reducing overall system complexity while effectively reducing coal output delay.
Data Source
AI summary
A control device for the coal pulverizing apparatus includes a first command value generation part for generating a command value of a first parameter including at least one of rotational speed of the table, pressing force of the roller to the table, or air supply amount in the air supply part, and a second command value generation part for generating a command value of a second parameter including a rotational speed of the rotary classifier. The first command value generation part is configured to determine the command value of the first parameter, based on a first preceding signal determined in accordance with at least load information of a combustion device which burns the pulverized coal from the coal pulverizing apparatus. The second command value generation part determines the command value of the second parameter, based on a second preceding signal determined in accordance with at least the load information.