Small Pulverized Coal Silo Feeding Control for Fast Boiler Load Response
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Solution Overview
Problem
Existing direct-blow pulverized coal systems in power plant boilers face significant delays in fuel control, unable to quickly adapt to load changes, leading to safety and environmental issues during rapid load adjustments.
Innovation Solution
A control method and system for small pulverized coal silos that accurately control coal delivery to the furnace, quickly changing combustion rates by determining and implementing coal feeding signals based on load increase signals, using a piecewise function to calculate coal mill output and adjusting feeder and air supply to match boiler demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional direct-blow pulverized coal system is used, then system structure is simple, but fuel control delay is significant (several minutes)
Solution Approach 1:
The pulverized coal system is segmented into multiple independent storage silos (at least two silos) with separate coal feeding pathways to the boiler. This allows one silo to be filled while another supplies coal, enabling parallel operation that reduces the overall fuel control delay from several minutes to under one minute.
Solution Approach 2:
Coal is pre-ground and stored in the pulverized coal silos before being needed for combustion. The silos maintain a ready supply of pulverized coal, so when load increase is required, the coal is already prepared and can be delivered to the boiler immediately through the rapid feeding mechanism, eliminating the need for on-demand grinding.
2Productivity
If small pulverized coal silo is added, then load regulation speed improves, but system complexity increases
Solution Approach 1:
The pulverized coal silos serve as intermediary storage between the coal mill and the boiler. They buffer the coal supply, allowing the coal mill to operate independently while the silos manage the timing and rate of coal delivery to the boiler, thus enabling rapid load regulation without directly coupling the mill and boiler operations.
Solution Approach 2:
The system replaces traditional mechanical coal handling mechanisms with a control system that uses sensors, processors, and automated feeding mechanisms. The control system calculates the required coal feeding rate based on load demands and automatically adjusts the feeding process, substituting complex mechanical coordination with intelligent control algorithms.
3Speed
If rapid load increase is achieved, then response time to load changes improves, but combustion stability deteriorates
Solution Approach 1:
The coal feeding rate is dynamically adjusted based on real-time boiler load demands. The control system continuously monitors load changes and modifies the feeding rate from the silo accordingly, allowing rapid response to load increases while maintaining combustion stability through proportional adjustments rather than abrupt changes.
Solution Approach 2:
The system implements feedback control where the actual coal feeding rate and boiler combustion parameters are continuously monitored and compared with target values. The control processor adjusts the feeding rate based on this feedback, ensuring that rapid load changes are achieved while maintaining combustion stability by correcting deviations in real-time.
Data Source
AI summary
The present invention provides a coal feeding control method and system for a small pulverized coal silo, the method includes: acquiring a boiler load increase signal, and determining the target function F(t) for boiler load control obtaining the current coal mill output signal B(t), where B(t) is the fuel quantity signal at the outlet of the coal mill that changes over time from the start time; comparing B(t) with F(t): if B(t) cannot meet the fuel quantity requirements of F(t), activate the small pulverized coal silo connected to the boiler; otherwise, the small pulverized coal silo remains inactive; determining the coal feeding signal f(t) for the small pulverized coal silo, and further determining the coal feeding control signal f(t) for the small pulverized coal silo; controlling the small pulverized coal silo to feed coal to the boiler, quickly changing the combustion rate in the furnace, and increasing the boiler load.