Multi-variable control (MVC) has recently become the standard solution for realizing more stable process control. Yokogawa helps clients implement multi-variable control using Exasmoc software.
Multi-variable control (MVC) enables optimum process stabilization, resulting in increased productivity. Yokogawa MVC provides predictive control using process cross-correlation, which is proven to increase throughput, save energy, and reduce quality giveaway. As the MVC control strategies vary for each process unit, consultation by experienced APC engineers is essential for the successful implementation.
Yokogawa has the rich experience and know-how to provide outstanding consulting & engineering implementation services. Over the past 20+ years, Yokogawa has provided more than 500 APC licenses and consulting & engineering services for a variety of process units. Yokogawa, as a DCS supplier, understands that better integration with APC and DCS results in more profitable operations and that regulatory control stabilization is important as a baseline for a control hierarchy.
Yokogawa's Advanced Process Control / MVC service is based on standardized Six Sigma DMAIC methodology. This provides clear and effective steps to achieve a defined target while ensuring consistent and high levels of service quality.
|1. Define||Define target e.g.
- Giveaway loss reduction: 3%
- Reduction of reblending / correction: 5%
- Control strategy
- Controller configuration
- Variables (control, manipulated, disturbance, economic) i.e.
- Flow controller
- Controlled / monitored properties
- Sources / destinations with steering factor / cost
|2. Measure||Gather baseline data e.g.
- Frequency of re-blends
- Quality give away
Review blend ratio control
Conduct blender dynamics test and gather response data
Gather historical blend data
Interview blend equation and parameter (if any)
|3. Analyze||Detailed design
- Simulation and initial tuning
|4. Improve||Modify DCS*3
- Switch, sequence, graphics, interface ,etc
Implement blend property control
- Controllability check
- Fine tuning
|5. Control||Measure and analyze improved data
Issue improvement report e.g.
- Giveaway loss reduction: 3.5%
- Reduction of re-blending/correction: 5.3%
Assess and report the result of implementation
Identify next opportunities
*1: This consulting service is based on blend property control software.
*2: This service is executed on one cycle of the above DMAIC step.
*3: DCS engineering work such as interface development will be proposed as required.
In 1999, Yokogawa Electric Corporation formed an alliance with Shell Global Solutions International B.V. (SGSI) in Advanced Process Control (APC), and both companies have since jointly developed products. This alliance successfully combined SGSI's experience gained through more than 800 projects in more than 30 years and Yokogawa's great deal of experience with the process control market, and strengthened the scheme to provide the APC technology.
Almost 20 years have passed since MVC came into use commercially. At first, MVC was only used in large-scale petroleum and petrochemical plants, because at that time computers were expensive and incapable of the performance required to execute an MVC package.
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