Integrated DCS Control Block for Steam Temperature
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Solution Overview
Problem
Traditional steam temperature control systems in utility boilers face delays and reduced effectiveness during rapid load changes, requiring additional communication links and ad hoc circuits to address the issue, which complicates the control strategy.
Innovation Solution
Implementing a single integrated DCS control block that includes upstream and downstream PID control routines, along with other necessary control routines within a common storage area, allowing for rapid response to load changes without additional communication links, facilitating a more aggressive control strategy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional cascaded function blocks are used for steam temperature control, then the control system is modular and easier to implement, but the response to rapid load changes is delayed and reduced effectiveness occurs
Solution Approach 1:
The patent combines multiple discrete function blocks (upstream PID, downstream PID, and communication routines) into a single integrated control block. This integration eliminates inter-block communication delays and allows all control routines to access shared memory directly, thereby reducing response time to rapid load changes while maintaining the modular control strategy within the integrated block.
2Speed
If additional communication links are added to address rapid load changes, then the responsiveness improves, but the device complexity increases
Solution Approach 1:
The patent merges all control routines and communication functions into a single integrated control block, eliminating the need for additional communication links between separate function blocks. The integrated block contains all necessary PID control routines and can access process variables and control outputs directly through shared memory, achieving rapid responsiveness without increasing device complexity.
3Productivity
If a single integrated control block is used, then the response to rapid load changes is quicker, but the integration complexity increases
Solution Approach 1:
While integrating multiple control routines into a single block, the patent maintains internal segmentation by implementing distinct upstream PID and downstream PID control routines within the integrated block. Each routine operates independently with its own control logic, allowing the system to achieve quick response times while managing integration complexity through structured internal organization of control functions.
4Ease of manufacture
If traditional cascaded control is used, then the control strategy is simpler to implement, but the effectiveness during rapid load changes is reduced
Solution Approach 1:
The patent integrates upstream PID control, downstream PID control, and all necessary communication routines into a single control block. This integration ensures that all control routines have direct access to the same process variables and control outputs through shared memory, eliminating communication delays and ensuring coordinated action between upstream and downstream control, thereby maintaining control simplicity while improving effectiveness during rapid load changes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The integrated DCS control block enables quicker response to rapid load changes by providing necessary indications within the control block, enhancing the control strategy's responsiveness and reducing delays in steam temperature adjustments.
Implementation Method 1
control of the steam temperature is often achieved by spraying saturated water into the steam at a point before the final heat exchanger section
Implementation Method 2
spraying saturated water into the steam... where such a heat exchanger section is located immediately upstream of the turbine
Data Source
AI summary
The disclosure is directed to a saturated water spraying system configured to rapidly respond to rapid load changes by implementing a single integrated DCS control block. The integrate DCS control block may include a plurality of process control routines that are necessary to control the operation of the spraying system. For example, upstream and downstream PID control routines may determine and output control variables, and other control routines may be provided as necessary to handle disturbances within a boiler affecting the outlet and spray steam temperatures, and to ensure that the steam temperatures do not fall into the saturation region during operation of the boiler. Because the routines are part of the same control block, the common storage for the control block may be accessed by each of the routines without the necessity of establishing additional communication links for transferring the information as is required when using cascaded function blocks.