Six questions that can help remove advanced process control roadblocks

Advanced process control (APC) helps process manufacturers unlock the full value of automation to reduce variability, improve throughput, and reach sustainability goals.

By Sean Sims September 9, 2022
Courtesy: Emerson

Learning Objectives

  • Advanced process control (APC) brings regulatory control elements together to create a more sophisticated structure, fully unlocking the power of automation.
  • APC uses statistical modeling, analytics, model predictive control (MPC), multiple loop control and more.
  • APC lets manufacturers leverage the capabilities they often already have in the existing control system.

Advanced Process Control Insights

  • Advanced process control (APC) is a way for process manufacturers to augment and enhance the technology that often already exists on plant floors.
  • APC also lets manufacturers integrate many different strategies into one cohesive plan that runs from beginning to end.
  • APC does require expertise that companies don’t always have, but consultants and other third parties can help fill the void and even offer useful advice; being outside a company’s process and can result inout-of-the-box thinking.

Process manufacturers often take advantage of advanced process control (APC) features residing in control software, beyond solving basic regulatory control challenges. As process manufacturers come under increasing pressure to do more with less, many are investigating ways to drive better quality, less variability and higher throughput by using advanced automation. APC optimizes control for the best performance possible.  

APC brings regulatory control elements together to create a more sophisticated structure, fully unlocking the power of automation. While regulatory control is structured around well-known algorithms and strategies that have not changed significantly in the past few decades, APC requires teams to customize automation to the specific processes they are managing and controlling.  

However, perceived complexity has convinced many operations teams APC is beyond their means and capabilities, especially as plants struggle to retain fewer experienced personnel due to ongoing retirements. Asking these six questions around APC can help process manufacturers understand APC is feasible and often the key strategy needed to stay competitive. 

1. What is advanced process control?

APC is the application of software logic to capitalize on the full value of modern process control. Using advanced tools such as statistical modeling, analytics, model predictive control (MPC), multiple loop control and others, process manufacturers can maximize automation system effectiveness for tighter control and lower variability. A tighter running control system leads to improved quality, increased throughput and greater energy efficiency. 

2. Does the site have a business need for advanced process control?

APC has been available for a long time and has been prevalent in some processing industries. In plants manufacturing products with tight margins, APC has been a key driver for success, tightening control strategies to eliminate waste, reduce energy consumption and significantly lowering production costs. 

While all process manufacturers want to maximize profit and quality, markets are changing. Today, the public is scrutinizing corporations more closely. Investors and corporate offices are noticing. In response, more process manufacturers are sharing details regarding emerging sustainability initiatives, and those initiatives must be supported by product manufacturing plants. 

Often, people imagine sustainability is driven by big plant changes such as installing solar arrays or planning rip-and-replace overhauls of plant equipment, or installing more efficient machines. But the first place any organization should look when trying to find ways to operate more sustainably is the efficiency of its plant operations. Efficiency and sustainability are inseparable.  

APC reduces variability in operations to help ensure more efficient energy use, which is a key metric for sustainable operations. This was the case for one process manufacturer that implemented APC on electric arc furnaces. By tightening the span of control around the amount of energy for the furnace, engineers reduced process energy consumption by 15 to 20% . Energy reduction quickly demonstrated return on investment and reduced the plant’s energy footprint to drive more sustainable manufacturing.  

3. Will implementing advanced process control increase operator workloads?

Today’s operations and maintenance teams are far smaller than 10 years ago, but they also are expected to perform more efficiently than ever. Operating under these challenges often leaves teams working around the clock on maintenance and operational challenges. Such teams may feel they do not have the bandwidth to focus on optimization. 

However, much of the day-to-day firefighting that keeps operations and maintenance (O&M) teams tied up results from process variability in operations. When plants have big swings in production or in the way staff manage processes, fixed equipment – such as pumps, motors, and other assets – is often working harder in response to process variability. This constant change can lead to increased reliability issues and create process upset conditions downstream. 

When teams used to constant “firefighting” implement APC, they begin operating within much narrower bands, making the process more predictable. Assets such as rotating equipment are no longer subject to the same swings from a less controlled environment. Tighter control leads to less wear and tear, along with more predictability. 

This concept also applies across multiple unit operations. If a plant has five control strategies running without an overarching APC strategy, operations and maintenance may optimize each process individually, resulting in five individual strategies performing at their best. Yet those well-performing loops also may be competing, reducing or eliminating the efficiency gained by careful process tuning. APC optimizes all loops together, taking the needs of each loop into account and harmonizing strategies holistically across the plant to optimize a specific outcome. 

However, while APC can help operations and maintenance teams make significant strides in reducing day-to-day firefighting, the need often is hard to recognize from the inside. In many cases, teams are too busy to “know what they don’t know.” In these cases, it can be helpful to enlist help from automation partners.  

External advisors come with a different perspective as they are not in the weeds of day-to-day operation and can identify operational challenges that may be harder for embedded plant personnel to notice. They also can help identify areas for change, plan and implement those changes, and build a roadmap to keep APC logic, models, and practices up to date across the lifecycle of the plant’s equipment – activities the on-site teams may be too busy to pursue on their own. 

For one food and beverage manufacturer experiencing reduced product quality and unexpected process variability and outages due to poor performance from plant equipment, APC provided a comprehensive solution. The operations and reliability teams implemented an MPC solution to better control temperature and air flow on dryer units and stabilize the feed on a centrifuge. The changes reduced trips and stabilized operations, maximizing product throughput while also increasing product quality (Figure 1). 

Figure 1: DeltaV™ PredictPro uses model predictive control strategies to drive greater throughput, reduced operating costs, and increased quality. Courtesy: Emerson

Figure 1: DeltaV™ PredictPro uses model predictive control strategies to drive greater throughput, reduced operating costs, and increased quality. Courtesy: Emerson

4. Isn’t advanced process control for much bigger organizations?

APC projects are only as expansive as a facility needs them to be. In fact, some of the most successful APC projects are small and target specific problems within a plant.  

The most successful teams who implement APC identify a specific economic variable they want to control, and optimize the process around that variable, which in turn optimizes the whole unit operation. The best projects are often the most granular, as having a specific problem to solve not only helps secure funding for execution, but it also makes it easier to show return on investment after the win, generating appetite for further projects. 

A North American chemical manufacturer needed to improve production target rates, but was not ready for a plant overhaul. The operations team implemented MPC on production units to adjust variables and tighten constraints in the existing process. The estimated return on investment for the APC project – including a 10% reduction in off-spec production, increased yield, and more than six million pounds of steam savings per year – occurred in under six months (Figure 2). 

Figure 2: Advanced process control in the DeltaV distributed control system helped one process manufacturer dramatically improve performance and sustainability. Courtesy: Emerson

Figure 2: Advanced process control in the DeltaV distributed control system helped one process manufacturer dramatically improve performance and sustainability. Courtesy: Emerson

The key is understanding that starting small is possible, with new technologies such as cloud computing making this easier and scalable during implementation. Forward-thinking organizations start planning for APC with simulation software. Before the optimization project begins, these project teams build a simulation of the APC to demonstrate the theoretical uplift in value. The value of the simulation does not stop when the project is complete. The same simulation can be used to test and validate any changes before implementation on site, and it can also serve as a comprehensive testing and training tool for operators and engineers during and after implementation. 

A few years ago, the technology for such a simulation would have been out of reach for all but the largest organizations. Today, however, cloud simulation platforms provide subscription models that dramatically lower the barrier for entry. These cloud simulation services are scalable, and they provide third-party management to deploy, update, and maintain the technology more easily.  

5. Do site personnel have the expertise to implement advanced process control?

One of the key concerns considering APC is a lack of experienced, veteran personnel on site to design, deploy and manage advanced control logic. APC design does require an engineer with deep process knowledge and understanding, extensive experience in process control, and understanding of the deep complexities of advanced algorithms. However, that engineer does not need to be an in-house asset. 

Process manufacturers will often work with a service provider to help identify, design and execute an APC strategy. This partnership provides the obvious benefit of enabling an organization without a deep bench of experts to take advantage of APC, but an unexpected benefit is also the likelihood of generating faster return on investment.  

Expert service providers will wrap project design in an outcome-based plan to help build the business case for the project, and to help the on-site team clearly demonstrate its wins and the value of the project, building momentum for future advancements (Figure 3). 

Figure 3: A strategic partnership with an automation provider can help operations teams close expertise gaps when implementing advanced process control. Courtesy: Emerson

Figure 3: A strategic partnership with an automation provider can help operations teams close expertise gaps when implementing advanced process control. Courtesy: Emerson

In one case, a global chemical manufacturer needed to make process improvements at a site but lacked the personnel with the skill and time required for implementation. The organization partnered with a company to implement a control performance program, which included monthly services from an experienced advanced control consultant. The consultant handled regulatory control improvements and MPC and provided assistance with control system management.  

Ultimately, the manufacturer estimated a result of more than $100,000 per year in energy savings, and over $200,000 per year in direct process improvement from enhanced control, and the return on the initial investment came in less than 60 days. 

6. Why is today a good time for organizations to pursue advanced process control?

Many factors have recently come together to make APC a more valuable strategy than ever before. Today’s plants are under increasing pressure from tight margins and supply chain disruptions. Executives also are scrutinizing plant performance more than ever before as they tighten their focus on sustainable operations to meet the expectations of shareholders, employees, and the global public. 

As new initiatives put pressure on process manufacturers to do more with less, the world of automation and APC is changing. While the technologies discussed above still exist and still provide significant performance benefits to the organizations embracing them, the process control technology stack is also rapidly evolving. 

This rapid technology advancement is connecting people and processes, making it the best time in automation history for organizations to start on an APC journey. The technology stack resulting from such mergers makes it far easier to adapt and optimize software capabilities to move beyond linear control. Users can apply APC to more use cases than ever before, with more tools in their automation toolboxes to customize solutions to their unique environments. Moreover, that customization is built on a deep foundation of models already created for specific industries. Combined with artificial intelligence capabilities to create algorithms for quickly seeding and customizing those models, automation teams can create value and demonstrate return on investment very quickly often in less than a year. 

Consider a process plant with a top-down initiative to identify and tackle sustainability issues. To accomplish this, the team needed to run its process as tightly as possible across multiple units. By applying the sophisticated algorithms, the team can not only track process conditions, but also respond in real-time to changes in process conditions across every unit in the facility. Instead of working with linear control’s limitations, that same team can use APC to maintain optimum operating conditions. 

Bringing advanced process control into the plant

What might at first appear to be barriers to APC often prove, upon closer inspection, to be opportunities. APC enables process manufacturers to fully leverage the capability in systems they already have, as many of the key technologies are built into the existing control system. Taking advantage of those capabilities not only improves performance, but also frees plant personnel from many of the low-value tasks taking up their valuable time. It also reduces process variability to increase throughput and efficiency, helping increase profit and sustainability for top-tier performance. 

Sean Sims is the vice president of Emerson’s DeltaV platform. Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology, 


Keywords: process manufacturing, advanced process control (APC) 


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Author Bio: Sean Sims is the vice president for Emerson’s DeltaV platform. Prior to his current role, Sean also served as vice president of both the Measurement & Analytical business for the Asia Pacific region, and for Lifecycle and Performance services. Sean has a BSc Engineering degree (Metallurgy and Materials Science) from the University of the Witwatersrand (Johannesburg, South Africa). Prior to Emerson, Sean worked for Alpret Control Specialists, the local business partner for Emerson in Southern Africa, for 10 years. He held various positions during this time, including system group technical manager, company engineering director and company systems director.

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