How APC 2.0 enables on-site teams to rapidly identify, implement and sustain multivariable control applications without complex projects or specialized resources.
APC agility insights
- Modern APC can be implemented in a far more agile, on-the-fly manner, shifting it from a complex, project-based effort to a routine operational tool.
- Frequent operator and loop interventions are often clear indicators of missing multivariable control opportunities that can now be systematically identified and automated.
- APC delivers the greatest value when it is affordable, timely and easily owned and maintained by on-site operations and control engineers without reliance on specialized resources.
Control engineers are usually busy people. Most have little trouble listing five accomplishments at the end of a week. They tune loops, reconfigure controllers, add advanced regulatory control (ARC) schemes, implement online calculations, update graphics, rationalize alarms, investigate performance and more. Industry-wide, onsite control engineers are generally trusted to carry out these activities on live processes. Industry enjoys this highly beneficial combination of competency, agility and technology.
Agility means these things can be done in a timely, reliable and affordable manner. When an operational problem arises or someone has a good idea, operating teams — which include process engineers, operators and control engineers — want to fix it as quickly as possible. They do not want to wait on a budgeting cycle or lengthy engineering study to solve a problem that’s solution is, quite often, rather obvious to a team of local onsite experts.
After 50 years of APC experience, it is now possible to move many APC applications from a complex project modus operandi to a more fluid and agile technology. Many multivariable control applications today can be identified and implemented on the fly to capture benefits and solve problems in real-time without special budgets, lengthy schedules or specialized resources. This adds an essential tool and a whole new dimension to continuous operational improvement and real-time optimization that should not be overlooked in pursuit of these objectives.
Spotting APC opportunities
Thanks to decades of APC experience, industry now has a much better overall understanding of the nature of multivariable control and optimization. For example, nearly all process operations can now be seen as essentially exercises in multivariable control and optimization. Most console operator actions can be seen as effectively manual multivariable control. From this perspective, when console operators are overly busy with frequent loop interventions (setpoint, mode and output changes), it is now often possible to see clearly that the root cause is a missing multivariable control application that, if it were in place, could be making these adjustments routinely in a more timely, automated, safe and optimal manner. This is one aspect of APC agility and expertise — the ability to readily spot missing or potential multivariable control applications behind mild or severe console chaos or frequent sub-optimal operation.
A more systematic method of identifying missing multivariable control applications is loop intervention analysis, which involves analyzing the console log to quantify the number of interventions for individual loops and for total loops overall. This is like alarm management, which quantifies the overall number of alarms as well as individual “bad actor” alarms. Loop intervention analysis reveals the overall size of the problem, as well as individual “bad actor” loops. It also reveals which loops are related (i.e., which loops will likely be grouped together to form a multivariable control APC application) to automate and optimize these interventions.
The ability to spot missing applications or to extract missing applications from a console log analysis is another aspect of APC agility.
Realizing APC benefits
Having the eye and tools to readily spot APC opportunities is one step. Turning that insight into automation and optimization results and benefits is another. This requires an affordable and agile approach to APC projects and implementation.
Affordable means APC costs are low and fall within normal operating budgets, so projects don’t break existing budgets or must wait for new future budgets. Agility means implementation time frames that allow new opportunities to be captured and problems to be solved as they arise within reasonable operational time frames. This effectively happens in “real time,” not “future time;” typically in weeks or months, not months or years. This translates into APC applications that can be accomplished on the fly without interrupting normal operation, or that can be included within projects, not as separate follow-on projects, without becoming critical path items. Finally, APC agility means tools and technology that do not require continuous or specialized support — or fall apart without it. It means technology that can be effectively owned and operated by on-site control and operations personnel without dependence on specialized off-site resources.
AUTHOR BIO
Allan Kern, P.E., is principal APC consultant with Lin & Associates, Inc., Phoenix, Arizona, USA. He is the inventor of patented rate-predictive control (RPC) and model-less multivariable control (XMC).
LEARNING OBJECTIVES
- Learn the elements of APC agility: cost, timeliness and owner-friendliness.
- Learn why APC agility is essential to top-tier operating success.
- Structure process control capabilities to achieve APC agility.
CONSIDER THIS
Is your current APC approach agile enough to let on-site teams identify and implement multivariable control solutions quickly — using normal operating budgets and timelines — rather than treating APC as a slow, specialized, project-based effort?
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