Process Plant Control Hierarchy for Dynamic APC Limit Optimization
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Solution Overview
Problem
Existing process plants face challenges in optimizing operations due to unplanned downtime, equipment failures, incorrect temperature settings, and inadequate raw material usage, leading to suboptimal output, increased energy consumption, and lower product quality, with conventional methods struggling to effectively integrate real-time data and predictive models for optimal adjustments.
Innovation Solution
A method and system involving a primary controller connected to secondary controllers via conjoint variables, utilizing plant-wide optimizer (PWO) and advanced process control (APC) limits, to determine optimal targets and adjust APC limits based on current operating conditions, enabling real-time monitoring and corrective actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional control systems are used to monitor and regulate process parameters, then basic process control is maintained, but real-time optimization and predictive adjustments cannot be effectively implemented
Solution Approach 1:
The control system is segmented into multiple hierarchical levels: primary controllers at the plant level for overall optimization, secondary controllers at the unit level for specific process control, and tertiary controllers for individual equipment. This segmentation allows each level to handle appropriate optimization tasks independently while maintaining overall system coordination, enabling real-time optimization without requiring complete system reintegration.
Solution Approach 2:
An intermediary optimization layer is introduced between conventional control systems and process equipment. This intermediary layer includes optimization engines that receive data from multiple sources, perform predictive analytics, and generate optimized setpoints that are then passed to conventional controllers. This mediator enables advanced optimization capabilities while preserving existing control infrastructure.
2Productivity
If plant-wide optimizer and advanced process control are integrated to optimize operations, then productivity and efficiency improve, but tracking real-time benefits and lost opportunities becomes challenging
Solution Approach 1:
A comprehensive feedback mechanism is implemented that continuously monitors actual process performance, compares it with optimized targets, and quantifies the difference as real-time benefits or lost opportunities. The system calculates performance metrics such as energy savings, production increases, and quality improvements, providing actionable feedback to operators and automatically adjusting control parameters to maximize benefits.
Solution Approach 2:
The optimization system incorporates multi-functional tracking capabilities that simultaneously monitor multiple performance metrics including productivity, energy consumption, material usage, equipment utilization, and quality parameters. This universal tracking approach consolidates diverse performance data into a unified view, enabling comprehensive real-time assessment of optimization benefits across the entire plant.
3Reliability
If APC limits are used to control process units, then individual unit performance is maintained, but plant-wide optimization opportunities are constrained
Solution Approach 1:
APC limits are transformed from static constraints into dynamic, adaptable parameters. The system continuously adjusts APC limits based on real-time plant conditions, optimization targets, and changing operational requirements. This dynamic approach allows APC limits to evolve with process conditions, enabling plant-wide optimization while maintaining unit performance through adaptive rather than fixed constraints.
Solution Approach 2:
The system implements parameter changes by modifying APC limit values based on optimization calculations. When plant-wide optimization identifies opportunities for improved performance, the system adjusts APC limits to enable these improvements while ensuring unit constraints are still respected. This parameter adaptation allows the transition from conservative fixed limits to optimized variable limits that maximize overall plant productivity.
Data Source
AI summary
The present disclosure relates to a method of enhancing an operation of a process plant. The method comprises configuring a primary controller to be connected to one or more secondary controllers via conjoint variables and sending at least one optimization call to the one or more secondary controllers, where the conjoint variables in the primary controller has a PWO limit and conjoint variables in the one or more secondary controllers has an advanced process control (APC) limit. A proxy limit is received from the one or more secondary controllers in response to the at least one optimization call and the APC limit and received proxy limit is analysed to determine an optimal target. The optimal target is sent to the one or more secondary controllers, which are instructed to adjust the APC limit to the optimal target.