September 2024
Digital Features
Effective inventory management during a turnaround
Nothing will impede a successful plant turnaround like improper planning. One aspect of this planning is effective inventory management, and the keys to achieving this are properly identifying and communicating maintenance needs.
K. KOHONEN, Valin Corporation, Kent, Washington
Nothing will impede a successful plant turnaround like improper planning. Shutting down a plant can cost operations a significant amount of money, and there is not anything worse than being forced to have a shutdown that is not regularly scheduled. Thus, ensuring that a plant makes effective use of the opportunity to address its maintenance needs during a planned shutdown is essential. The only way to do this is through meticulous planning.
One aspect of this planning is effective inventory management, and the keys to achieving this are properly identifying and communicating maintenance needs. By opening the lines of communication with vendors and suppliers, the turnaround is more likely to be successful. In fact, conversations regarding fittings and valves should begin 12 mos–18 mos ahead of a planned turnaround.
Instrumentation fittings. The first step in properly planning for instrumentation fitting maintenance/replacement is identifying what units are being worked on. The number of valves scheduled to be repaired or replaced has a direct correlation with the number of fittings needed. For example, if the plan is for 20 valves, the maintenance schedule should be fairly mild. However, if 50 valves are on the ticket, one can expect there to be a significant number of fittings being repaired or replaced. Needs vary depending on the process unit being worked on. For example, a crude unit can have more piping and components, so the plant will use many more fittings during that outage. Once there is a basic level of understanding of the volume of work, more questions need to be answered about the nature of the work.
Supportive vendors will uncover truths about the needs during these kinds of conversations. Specifically concerning the fittings, it is important to understand how the plant intends to support its maintenance personnel with that particular product. Will they pull it from one of their standard stocking areas in the facility (i.e. the warehouse, machine shop, valve maintenance shop)? Or are they going to utilize remote field units that workers can easily access?
Labor time and lost productivity are measurable data points that should always be candidates for improvement. An inventory supplier that provides added value can offer guidance beyond merely selecting parts. To illustrate, plants can be massive facilities. Effective inventory management also includes making the best decisions in terms of physical locations and organization. Plant management would prefer to avoid having their personnel walk from one end of the plant to the other for a fitting if there is a better way. If a facility is taking advantage of a stocking location in a remote field unit, it can often make sense to dedicate some shelf space to an inventory management partner for instrumentation fittings. By keeping these fittings in a unit that is being repaired, the lost productivity associated with retrieving them is minimized.
Some inventory management partners offer smaller job boxes placed directly in the field that they ultimately manage. In these cases, some may also take care of the tidiness and organization of the equipment. This value-added labor component can save plants a considerable amount of money.
Finally, having access to an inventory specialist gives operations peace of mind from a safety perspective; there are certain parts and equipment that do not mix well from one manufacturer to another. Not only are there catastrophic operational failures, but there can be safety concerns, as well.
The key to a successful fitting schedule during a turnaround is driven by having the proper inventory on-hand during that time. However, as stated earlier, planning is critical. There are certain metallurgies that may have extraordinarily long lead times. In some cases, if an order is not placed 30 wks in advance, on time product delivery cannot be guaranteed.
A good supplier will usually try to minimize the potential risk of “over-ordering” by assuring the plant owners that they will take back any unused fitting at the end of a turnaround.
Valves. When discussing planning for valve maintenance and/or repair, the cycle is similar to that of the fittings, except there are more technical details involved. First, if there are process improvement needs or if the valve has had excessive failures over the last run time, it must be tuned. Certain units have expected lifecycles. It is important to know how the valves have been performing. Do they need maintenance? Have they had failures? Most plants value longevity with their valve performance. To put together an effective maintenance schedule for valves, the “problem children” must be identified so proper strategies can be developed to better support the effort.
Perhaps the problems were caused by the initial sizing. Alternatively, there could have been an issue with the metallurgy or the packing’s design. There are several problems that may need to be addressed. Once that is understood, the goal is to identify a manufacturer that can solve that problem. For instance, the solution may be to use a valve that has a highly engineered packing arrangement. Determining what the root cause is and selecting a valve that perhaps utilizes more modern technology that fixes the issue is often how the exercise goes.
A big issue with valves addressed during turnarounds is cavitation and noise abatement. These are widely known challenges in the industry that are notorious for causing premature failure. Cavitation can ultimately cause erosion of the valve internals, body or piping downstream. Identifying the root cause of the cavitation is the only way to devise a strategy to eliminate it. For example, maybe it would work more effectively to utilize newer technology for noise abatement trim designs from the valve manufacturer.
There are a few other typical causes of valve issues. One cause is under sizing actuators. This can lead to premature actuator failures. Another is packing leaks on the valve. Finally, there are valves that are not suitable for the service. One must be mindful of the process conditions and the technology used for that condition.
Coming out of a turnaround. As previously established, the two biggest requirements for a successful turnaround are open communication and planning far in advance. However, what about coming out of a turnaround? What are some best practices in terms of inventory management with this part of the process?
First, there is some nuance as to how to bring the filtration equipment back online after a turnaround. One needs to know which units are going to be starting up, and what filtration vessels they are coming online for. It is often recommended to open the filtration efficiency. If certain processes utilize a 5-micron filtration during standard processes, they may want to consider using a gradual phase-in during the startup. It may be more efficient to specify 25 microns. There may be downstream ramifications in changing filtration efficiency. These risks should be clearly identified and evaluated with a filtration supplier.
Finally, coming out of a successful turnaround means making sure the plant has enough spare sets on-hand. When there is significant work being done upstream, issues like corrosion can rear its ugly head. Ensuring there are enough changeout sets to get back online quickly is essential. When a plant fires back up, operators often burn through a fair number of sets. They must keep in mind that standard runtime efficiency does not correlate to efficiency during startup. For instance, if the minimum/maximum in the warehouse is 3–6, it is recommended to make sure there are adequate spares on-hand for the startup.
The best way to ensure a successful, efficient turnaround is to start early. Form a relationship with a supplier or master inventory management organization with recommendations and experience.
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