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Process Control – Everything You Need To Know

If you’re considering working in the process manufacturing industry, and you’d like to learn more about the basics of process control and how it’s used, you’re in the right place. In this article, we’ll discuss everything that you need to know about process control – with a special emphasis on process control in manufacturing, and understanding different process control systems. Ready to get started? Let’s jump in, and start by discussing the basic definitions of process control, and how it’s used.

process control

What Is Process Control?

Process control is used in continuous production – in manufacturing and in other fields and industries where some kind of material is produced without any kind of interruption – as well as in “batch processing.” It’s used to automatically control the conditions in which a product is made – ensuring better quality and efficiency.

​Wastewater management, for example, involves the continuous and unceasing treatment of greywater and sewage, without any interruptions – so this is a field in which process control is used.

The diagram below is a typical example of some of the process control systems in place: 

Wastewater management process control

Image courtesy of Fab-Tech Inc

Another example would be oil and gas refining, and even oil and gas transportation through pipelines, where uninterrupted, even flow of the material is required. The diagram below has various system requirements, such as:

  • Remote monitoring, control, and management of oil pipelines from the control centre
  • Use fibre optics for long-distance transmission of data across the country of installation
  • Gigabit redundant ring for high data availability
  • Rugged design capable of operating under harsh environmental
Oli Pipeline Process Control

Basically, process control combines the disciplines of control engineering and chemical engineering – and uses specialised, often custom-built industrial control systems. These systems control the flow, output, mixture, and other such aspects of a continuous production process, based on feedback from sensors, data monitoring systems and more.

​In turn, this allows the company to produce a safer, more economically-viable, and consistent product for public use. Process control systems operate on a much more refined, powerful level than a system that is purely controlled by humans.

For example, consider what would offer better results when pasteurising milk – a single individual taking a temperature reading manually, then shutting off the heat when the milk reaches the right temperature – or a sensor in a pasteurisation tank that automatically senses when the milk has been pasteurised properly, and then automatically empties the machine, and moves the product onto the next step.

Essentially then, process control is all about eliminating human feedback – and allowing the advanced, automated systems of an industrial plant to handle minor adjustments automatically, without intervention beyond human monitoring of each system.

This video from CrashCourse, explains in detail more about the key elements of process control together with examples of where process control is used, and problems that may arise without it:

What Disciplines Can Process Control Be Used In?

There are a number of different disciplines and workplace specialties in which process control can be used such as:

  • Engineering – Engineers are typically responsible for designing process control systems and machinery. Using specifications laid out by a manufacturer or other company, it is the responsibility of an engineer to design the proper system, and ensure that it’s reliable, functional, and operationally bulletproof. Engineers are also usually responsible for developing process control instrumentation for operations personnel, allowing them to monitor each individual process on a granular basis, and ensure that it is operating properly.
  • ​Software and systems development – Software and systems designers and developers are typically responsible for software-based systems that interface with the physical machinery used for process control. Engineers and software engineers usually work closely with one another when developing process control systems.
  • Operations – Operations personnel, such as supervisors and their workers, are responsible for monitoring process control equipment to ensure that it is functioning properly, and without errors. Despite advances in automation, human oversight is a necessity to ensure that process control systems are functioning properly – and to ensure that manual intervention is possible, if needed. 
  • Quality assurance – QA is still required in plants that use process control – to catch errors and mistakes, adjust process control systems, and take other such necessary actions that are required to ensure perfect product quality, safety, and efficiency.

What Is The Importance Of Process Control? What Are Its Benefits?

Now that you understand the basics about process control systems and how they are used, as well as the professions and disciplines which most commonly make use of process control, let’s discuss the benefits of process control.

Why is it important – and why should industrial companies make efforts to improve their process control systems, or add new process controls? Here are just a few reasons. 

  • Increase system throughput without additional expenditures – When systems and processes are automated, and can be performed automatically without human intervention, you can get more from your existing equipment and manufacturing processes. The need for human intervention is reduced, and you can ensure maximum efficiency – and quality – of every machine used in your plant. This allows you to increase the maximum throughput of your plant or facility, without additional expenditures in costly equipment.
  • Increase automation, decrease human intervention – Automation is a key element to any manufacturing process. While human intervention and oversight are always going to be necessary, automation allows you to eliminate redundancies and unnecessary manual checks – thereby reducing human error and inefficiency, and time-consuming, unnecessary steps that can reduce the throughput of your plant.
  • Eliminate rework, scrap, and inefficiencies – Automation and process control helps keep every system in your plant operating at maximum efficiency, eliminating inefficiencies, as well as the need for reworks and scrapping of products, where applicable.
  • Enhance your capabilities to take on more work – Not only does process control help you increase system throughput, it also allows your plant or company to take on more work – as you continue to automate process control, more employees and systems will be freed up to work on other projects and products, enhancing profitability.
  • Boost energy efficiency – Using your existing equipment and machinery to their fullest capacity will help you increase the energy efficiency of your plant, as there will be no wasted work or products, thanks to process control. Energy consumption is a major expense for industrial and manufacturing plants, so maximising energy efficiency helps minimise costs and boost profits – in addition to helping to preserve the environment.

​For these reasons – and dozens of others – process control is an absolutely essential part of manufacturing and industrial processing in many different industries. Enhanced automation helps you make the most of your existing systems, minimise waste, streamline efficiency, take on more work, and boost your profitability – and that’s just the beginning of the benefits you’ll enjoy with process control systems.

Software And Products Used To Help With Process Control

Each process control system is different, and this is especially true when it comes to process control in manufacturing. From custom-built process control instrumentation to cloud-based software suites, there are quite a few different pieces of software, as well as numerous different products used to help with process control, so let’s discuss some of them now. 

Screenshot of MPC in a typical application

Screenshot of MPC in a typical application courtesy of Siemens

  • Process control software – Process control software is at the heart of any process control system. While it is usually custom-made, based on your plant, industrial processes, and specific needs, there are some companies out there who offer basic, pre-built process control platforms. This includes Automation Direct, Sartorius, PQ Systems and many more.

    These platforms can usually be customised and built to fit the needs of most large-scale industrial plants and manufacturers. While large companies usually prefer hiring software engineers to build custom process control software, a pre-built platform can be useful if you are on a more limited budget, or must use the same system across multiple plants or facilities.
  • ​Process control instrumentation – At its most basic, process control instrumentation is simply one – or several – computer monitors, providing readings, outputs, information about each system and process, and other such information in real-time, based on your process control systems. This type of process control instrumentation may be used in a small-scale manufacturing plant.

    More complex plants and facilities – such as a nuclear power plant, for example – use a variety of different types of process control instrumentation, including large, complex screens, physical readouts and buttons, computers, and numerous other pieces of instrumentation, including dials, meters, digital readouts, and other such tools.

    Regardless of its complexity, all types of process control instrumentation are intended to do the same thing – to provide human operators with an at-a-glance overview of the feedback loops and functions that are occurring within a given facility at any given time. 
  • Sensors and monitoring systems – At the heart of every process control system is a series of sensors and monitoring systems, which are used to gather real-time data about a particular process, or “feedback loop.” In a food factory, for example, thermometers and temperature sensors can be used to check the temperature of a product, to ensure that it’s within safe levels, and that the temperature can easily be adjusted to the proper level, ensuring maximum product quality.
  • QA programs and software – QA software is a critical part of process control, as quality assurance must be used to confirm the overall quality of a product, and ensure that it meets all required standards. QA also allows individual processes to be adjusted – if a batch of a product does not quite meet the required standards, for example, each individual process and machine involved in its manufacturing can be examined for faults, or the process itself can be revised, based on the data collected by the process control system.
  • Analytics and data warehousing systems – Long-term data warehousing and analytics ensure that all data collected by a process control system can be stored for long-term archival. If a product ends up being faulty, for example, data from the production batch can be examined to determine the cause, and to ensure the issue does not recur. Long-term data analytics can also be used to enhance efficiency of process control systems.

Depending on the company, industry, application, and type of process control system, the products and systems used to implement process control can vary wildly. This is why most large companies turn to specialised process engineering companies to develop their own custom process control tools and systems. The complexity of developing a process control system means most companies cannot handle the entire process “in-house.”

Key Industries For Process Control

As mentioned above, process control is typically used in any industry where continuous production occurs – where some kind of product or material is constantly being manufactured, with little-to-no downtime. So, with that in mind, let’s take a quick look at a few of the key industries for process control systems – and how they’re used. 

  • Pharmaceuticals – Extreme precision is required when creating pharmaceutical medications. Even minor errors can render a batch of medication or other such products completely unusable – so pharmaceutical companies must minimise human intervention and error as much as they possibly can. This means that most pharmaceutical companies make use of advanced process control systems – allowing for granular control of the manufacturing process, minimising product waste, and guaranteeing the safety of all medications manufactured at the plant.
  • OEM and manufacturing – Manufacturing companies of all types can make use of process control. A company manufacturing structural steel, for example, will likely make use of process controls for tasks such as ensuring the proper temperature of blast furnaces, controlling the viscosity of molten metal, and for other such tasks that help ensure the right overall quality for the products.
  • Pulp and paper – Process control is extremely important in the pulp and paper industry. This is partially because the raw material (wood) used for pulp and paper can vary in quality wildly, and regular, constant adjustments to manufacturing processes are required to take this into account – ensuring that a varied input (wood) always creates a consistent output (pulp and paper products).
  • Semiconductor companies – Manufacturers of semiconductors (microchips), such as Intel, AMD, Nvidia, and others, make extensive use of process control. The environments in which microchips are created must be controlled to an incredibly precise degree – otherwise entire batches of semiconductors could be completely ruined, and rendered unusable.
  • Petrochemicals – Consistency is absolutely key in the petrochemical industry, particularly when creating products such as high-quality rubber and petroleum-derived plastics. Process control can be used to closely monitor products during the refining and production process, ensuring consistent quality, and uninterrupted, continuous production of a given petrochemical product.
  • Power generation – Power plants do not generate a physical product, but rather generate electricity and power to be used elsewhere – and they must do so constantly, so they always make use of a number of process control systems. These systems are used to control power production, ensuring that excess power is not generated – and that the plant does not under-produce power. Fuel, the temperature of the plant, delivery of coolant, and other factors must be constantly adjusted to ensure proper power generation.
  • Food and dairy – Earlier, we gave an example of the use of process control in the pasteurisation of milk. Using process control to automate the production of food and dairy products is a great way to ensure that the food is safe and is of a consistent quality – and to maximise total output from a food factory or food processing plant.
  • Water – Water treatment is an ideal application for process control, as the input (wastewater, seawater, etc.) never stops – and can vary quite a bit in composition. Not only that, but the output (potable water) must also be released in a constant stream, and be of a high enough quality to be consumable. Process controls help automatically adjust the treatment processes to handle varied inputs, and ensure healthy, safe, and potable drinking water is the result of the treatment process.
  • Oil & gas – Oil and gas pipelines must deliver a constant, steady stream of oil or gas, and be maintained at the proper pressure. Process controls can help automatically adjust pipelines and product throughput – keeping the pipeline reliable, safe, and ensuring a steady flow of oil or gas. Refineries also make use of process controls to ensure safety, product quality, and uninterrupted production. 

These are some of the industries in which process control is the most heavily-used – but every industrial company makes use of process control in some way.

3 Examples Of Applications For Process Control

To simplify things, process control uses automated sensors, programs, and computers to adjust any given “feedback loop.” For example, to control the temperature of a rubber compound during manufacturing, to keep it from “setting,” and ensure that it’s malleable. 

Process control could involve just one of these feedback loops – or be used across an entire plant, consisting of thousands of individual, yet linked, feedback loops, which must be interoperable with each other to ensure maximum safety and efficiency. 

Interested in learning more about process control with concrete examples? Here are a few examples of process control applications, how they’re used, and why they’re so important. 

  • Nuclear power plant control rods – Control rods are a very easy-to-understand example of process control, and a feedback loop. The power output of a nuclear reactor is, in part, controlled by control rods. Control rods are built of a material, like boron, which readily absorbs the energy released by nuclear fission.

    When the power output of a reactor climbs, automated sensors are used to lower these control rods into the reactor. In turn, they absorb energy and reduce power output to the proper level. Then, if the level begins to drop too quickly, the control rods are automatically adjusted once again.

    This feedback loop occurs continuously – and usually without the intervention of a human. By making minor adjustments to the control rods, the process control system keeps power output within the specified level. However, operators do use a process control monitoring system to ensure that the reactor is functioning properly – and to ensure the control rods do not fail.
  • Desalination – Desalination is used to convert seawater or saltwater into potable drinking water, through the process of removing salt and other impurities.

    Reverse-osmosis desalination is the most common type of desalination, consisting of a specialised membrane through which water is “pushed.” The water is able to push through the membrane, while salts and contaminants are left behind.

    A simple example of process control in reverse-osmosis desalination would be the cleaning process. As time goes on, the membrane used to filter out contaminants must be cleaned. A process control system can monitor the performance of the membrane, then automatically detect when it must be cleaned – and shut off the system in order to flush it with clean, fresh water, removing these contaminants and restoring the membrane automatically.
  • Cooking of a meat product – As mentioned, process control is commonly used in the food industry. Take a meat product like a hot dog as an example. The meat must be cooked to the proper temperature to make sure it’s edible and free of any food-borne contaminants – but it must not be overcooked, or the product may be ruined.

A process control system could be used to analyse the volume of food products in a particular oven or cooking area, and the temperature of the oven – and calculate the optimal time for the food to remain in the cooking area. Then, the product is placed in the oven, cooked, and removed automatically. This ensures fast batch processing without human intervention, and perfectly consistent results every time the system is used. 

Understand Process Control – And Why It’s Important For Your Company!

​Hopefully, this article has been helpful, and has been useful in furthering your understanding of process control, its benefits, the disciplines in which it’s used, and in the industries in which it’s the most important.

​By implementing better process controls, companies of all types, sizes, and specialties – in any industry – can benefit from a more efficient production process, better product quality, higher output, and a number of other advantages. So start thinking about how you can improve your own process controls today – and get a competitive edge!

Process Industry Informer

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