The question of plant layout goes hand-in-hand with the sequencing and is pivotal in the "do-ability" of a revamp project. The revamp project provides the opportunity to either bring order out of chaos or to make a bad situation worse! Older plants, the ones most in need of revamping, have likely grown over the years in a topsy-turvy fashion. They are often already over crowded, yet must now accommodate yet more equipment. So, proper plant layout should take advantage of the opportunity to reclaim space as well as provide a strategy for further future expansion. The layout personnel must also keep in mind that portions of the plant must be kept running while construction is occurring.
Plant layout designers of revamp projects have to keep in mind that such projects are far more restrictive than green-field sites. A green-field site can accommodate practically any design but in a revamp project space or clearances may be restricted. For example: Will the 50-foot tower go under the pipe rack; will the new equipment fit where the worn-out equipment was?
Another area of concern is with the supporting infrastructure of pipe racks, buildings, electrical switchgear etc. and having an eye to the future. Such infrastructure must be carefully evaluated to determine whether or not some or all of it should be replaced or rebuilt in another location. Establishing a viable path forward is a key ingredient in the long-term vitality of the plant.
If the decision is to go through with the revamp, the chances are the intent is to extend the life of the
plant for at least another 20 years. So the proposed layout must make sense not just for the present but for the next 20 years as well and the entire real estate area of the plant should be reviewed and not wasted.
Some practical plant issues include:
- Are there plans for modifying those parts of the plant that are not included in the current project?
- Is their room for future expansion?
- What do we want the layout of this plant to look like when we're finished?
- Is there a potential to expand the plant later?
- Is there adequate maintenance access?
- Is there good access for pipe and people into and out of the plant?
- Are there existing pile foundations that could be reused?
- When rebuilding a pipe rack, for example, are the levels spaced so that they make sense and with a view to the future?
Most of these issues are normal design questions. However, with a revamp project there may be some sacrifice required in the short-term, especially during construction, so that in the long-term the plant will perform adequately throughout its entire life expectancy. Plant layout must also factor in provision for plant outages, or eliminate the need for plant outages altogether, and hence the need for this task to be aligned with the sequence.