You have a seventeen-year-old reactor vessel that’s getting more than a little worn. You don’t want to change the process, just switch out the vessel for a new one. This should be and could be a simple process. But there are some serious potholes along the way that a little knowledge and planning can help avoid.
The key to changing out any piece of equipment in your process with a ‘like and kind’ replacement is that the new one must be IDENTICAL to the old one. Same vessel, same construction materials, same nozzle size and connections, same everything. The moment you make changes to the specification, you’re into new territory that requires Management of Change (MOC) documentation.
Behind this seemingly harsh approach is the notion of Mechanical Integrity, which is driven by two sets of laws. The first is Process Safety Management, which is governed by OSHA. The second is a Risk Management Program directed by the EPA. Each has slightly different requirements that we’ll examine in a future article. But behind them both is the strict need to have full documentation that exactly matches what you’re installing.
Let’s say the vessel you want to replace the old one with is exactly the same but, because of process changes over the years, you want to use stronger flanges. This requires going through the MOC process. Any change to the process including valves, instrumentation, pipe specs, corrosion allowance, automation, etc. have to be reflected on your P&IDs.
The truth is, very few vessel changes are truly ‘like and kind.’ Any changes to flow rates, pressures, temperature and specific gravity may change the vessel relief sizing. Likewise, if nozzles have been added or sizes changed, these factors have to be considered in a vessel replacement.
The takeaway is that documentation, in the form of your P&IDs, equipment files and process documentation must be absolutely accurate and up to date including drawings, specifications and calculations. So before you begin any swap out with ‘like and kind’ equipment, check your documentation. If it’s sketchy, incomplete or missing altogether, that must be your first step in the replacement.
MAI Engineering can guide you through the complexities of ‘like and kind’ vessel replacement.
Call us to get your documentation in order or to look after the entire project for you.