Cascade Burner Controller for Uniform Temperature Distribution
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Solution Overview
Problem
In large-scale industrial plants, such as pelletizing plants with traveling grate firing machines, the existing control methods for burner groups result in non-uniform temperature distribution across the burners due to uniform fuel supply, leading to inefficiencies and increased fuel consumption.
Innovation Solution
A temperature-to-flow cascade control system is implemented, using a temperature master controller to set a mean fuel supply for all burners and fuel supply slave controllers to adjust fuel supply based on individual burner conditions, incorporating disturbance variables to correct for temperature deviations and optimize heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform fuel supply is used for all burners in the burner group, then the control system is simple, but the temperature distribution across the burners becomes non-uniform
Solution Approach 1:
The burner group is divided into multiple burner subgroups, with each subgroup having an independent fuel supply slave controller. This segmentation allows individualized fuel supply control for each subgroup while maintaining overall system simplicity through hierarchical control structure.
Solution Approach 2:
Each burner subgroup is assigned a specific fuel supply rate that is optimized for its local temperature characteristics. The fuel supply slave controllers adjust fuel supply individually for each subgroup based on local temperature measurements, achieving uniform temperature distribution across the entire burner group.
2Temperature
If individual fuel supply control is implemented for each burner, then temperature distribution uniformity is improved, but the control system complexity increases
Solution Approach 1:
The control system is segmented into a temperature master controller that oversees the entire burner group and multiple fuel supply slave controllers that manage individual burner subgroups. This hierarchical segmentation reduces overall complexity by distributing control functions across multiple manageable components.
Solution Approach 2:
Adjacent burners are grouped into burner subgroups that share common fuel supply control. This merging approach reduces the number of independent controllers needed compared to controlling each burner individually, while still achieving sufficient temperature uniformity across the burner group.
3Use of energy by stationary object
If mean fuel supply is used for all burners, then fuel consumption is high, but temperature distribution becomes non-uniform
Solution Approach 1:
Each burner subgroup receives a fuel supply rate tailored to its specific thermal requirements and local conditions. This localized optimization ensures that each subgroup operates at its most efficient fuel consumption level, reducing overall fuel consumption while maintaining uniform temperature distribution across the entire burner group.
Solution Approach 2:
The fuel supply rate parameter is dynamically adjusted for each burner subgroup based on temperature measurements and process conditions. The fuel supply slave controllers continuously optimize the fuel supply parameter for each subgroup, achieving both uniform temperature distribution and reduced fuel consumption compared to fixed mean fuel supply approaches.
Data Source
AI summary
A method for controlling the fuel supply to several burners (2) of a burner group (1) and a corresponding burner controller are described. In the method, the temperature (TY) in the burner group (1) is determined as control variable and in dependence on the control deviation of the temperature (TY) determined for the burner group (1) to a specified setpoint temperature (TSP) the fuel supply to the several burners (2) of the burner group (1) is specified as correcting variable. It is provided that the controller is formed as temperature-to-flow cascade controller with a temperature master controller (8) for all burners (2) of the burner group (1) and a plurality of fuel supply slave controllers (10) for one burner (2) each or one burner subgroup each, wherein the temperature master controller (8) specifies a common mean fuel supply (XAVG) for each of the burners (2) of the burner group (1) and each fuel supply slave controller (10) uses at least one disturbance variable (TT, TYL/R) associated to the burner (2) and/or the burner subgroup, in order to take account of a correction of the fuel supply (X) to the burner or the burner subgroup.