Procedures are everywhere; and nowhere is this more obvious than in the process industries. Many like to refer to the process industries as being largely “continuous,” but this – in fact – is a misrepresentation. The state of process facilities constantly changes. Whether starting up, shutting down, changing grades or in the middle of a turnaround, a plant operates by procedures and transitional states. These can either run smoothly to pro-vide superior plant performance and a safe and orderly start-up/shutdown/transition, or result in costly unplanned shutdowns, incidents, lost product and lost opportunities.
Procedures are a predetermined group of tasks that must be completed in a set order and in a consistent manner to achieve a desired goal or result. Startups, shutdowns, and grade changes are probably the most common. Of course, procedures vary in terms of complexity and duration and requirements for plant procedures vary for each industry, but the common denominator is that plants cannot operate without them.
Manual, Prompted and Automated
Today, operational procedures fall into three primary categories: manual, prompted and automated. Some procedures consist of all three.
With manual procedures, operators perform the necessary actions either guided by their own years of experience or by a standard operating procedure (SOP) manual. As one might expect, the consistency with which manual procedures are performed can vary greatly depending upon the amount of experience and attention paid by the individuals carrying out the procedures. In some cases, the written procedures haven’t been kept current, forcing workers to rely more on personal experience than intended. Manual record keeping, which often accompanies manual procedures, can also vary in its effectiveness and quality. However, even when electronic records are created for manual procedures, their quality can also vary de-pending upon how well they were entered into the system and only reflect the procedures purported to be carried out. Often, there is no way to verify that the manual procedures followed were, in fact, consistent with printed SOPs.
Prompted operational procedures go one step further. Prompted procedures are implemented in the process automation system. The system asks the operator to acknowledge that each manual step has been completed successfully to be able to continue. Prompted procedures make it easier to keep electronic records, verify that procedures were followed correctly, and can help decrease transition times and procedural variability.
Like prompted operational procedures, automated procedures are implemented in the process automation system. The difference here is that automated procedures will go through an entire operational sequence before stopping, unless either the operator or system intervene on an exception basis. Automated procedures can provide even greater reductions in variability and transition time. Automated procedures are the equivalent of having the best operator on the board all the time.
Many industries have been using prompted or automated procedures for some time. The batch industries, such as life sciences and food & beverage, have been using the ISA88 standard for years. This defines a modular approach to batch automation and batch procedures. In the continuous process industries, however, prompted and automated procedures are not yet well-established. With the increasing awareness of the ISA106 standard, however, which is the process industry equivalent of ISA88, this should gradually change. Traditionally, many process industry end users have considered operations such as starting up and shutting down a coker unit or cat cracker in a refinery (or the refinery as a whole) to be a craft or an art form that relies heavily on experience and knowledge of the particular plant and its quirks. But times and technology have changed.
This is not to say that automated procedures are unknown in the continuous process industries. Many companies have implemented sequence logic that allows procedures to be automated. However, these have been done largely in an ad hoc manner, often using poorly documented, custom programming methodologies that are difficult to troubleshoot and can become cumbersome when it is time to upgrade the automation infrastructure. This ad hoc approach also carries a high cost of ownership, since the end user must maintain the procedure. Changes made to the code over time can create a tangled mass of “spaghetti code” that can be difficult, if not impossible to translate.
Many end user companies in the process industries today are also the result of mergers and acquisitions. This often means that many system platforms and unstructured code implementations have accumulated over the years. Clearly, this is not a sustainable way to do business. As a result, more and more end users are now standardizing their approaches.
Real-World Operations Call For Modular Procedural Automation
Overcoming the issues associated with custom approaches based on proprietary code requires a standard, modular approach to automated procedures. Modular applications help make functions more manageable and standardized across plants, sites, and the entire business enterprise. A standardized approach reduces engineering costs, labor costs, and total cost of ownership.