E-mail: bvernyi@penton.com

The construction of a major petrochemical complex represents one of the most difficult jobs in engineering.

These complexes often are measured in terms of the acreage that the cover, and they contain a seemingly endless maze of pipes and pressure vessels that encompass the processes that transform raw materials, whether they are crude oils or another chemical feedstock, into the products that make our modern lifestyles possible.

The number of pipelines and conduits that are required to provide energy to run the processes within a petrochemical plant is multiply the intricacy of the entire complex. Electrical power and, often, steam are used to crack hydrocarbons from oils or to distill and to purify the chemical that the plant is built to supply or, simply, to provide power for the pumps that keep the feedstock stream flowing through the system.

Whether it's pipeline or pressure vessel, steam line or conduit, a great amount of engineering detail goes into the design and execution of these facilities. And, despite their huge size, these petrochemical facilities are fine instruments that must be both robust and precise.

In this issue of Welding Senior Editor Richard Mandel looks how that engineering work has been taken to the next level, as the designs for these facilities are being broken into smaller parts and distributed among fabrication shops that, in turn, build the plant in modules.

The production modules are being built away from the petrochemical complex site, they are transported to the site and they are joined together to complete the petrochemical plant or the portion of the plant for which they are designed.

There are numerous reasons for the modular construction of petrochemical plants. By building modules in an indoor facility a higher degree of quality can be achieved. Production conditions indoors can be controlled much better than building the entire facility all at once on-site. Standard practices can be more easily put into use, and provisions for welding safely can be made. And, building indoors provides a solid base for cutting costs and keeping to schedule.

That the various modules come together — and fit together as they are designed to — is a tribute to the level of manufacturing that the job shops that are producing them have achieved.

Working only from — and exactly to — the design prints, the shops that are doing this work are working at the top of their games, producing components for some of the most delicate and complicated processing machinery ever made.

These shops primarily work with stainless steel and high-nickel content pipe and pressure vessels. Their welds have to be high quality, and their finished product has to be exact, so that it will match the other modules on the final assembly site.

There are plenty of other welding jobs that are intricate and require a high degree of skills to complete, but I can't think of many that involve the complexity of design and the necessary welding skills called for by these modules.