Every hydrogen plant does the same thing - remove all gases but hydrogen from a fuel feed such as natural gas or naphtha - but no two such plants share exactly the same design. Typically, the size of a plant and its piping scheme are determined by the type of fuel feed to be used and the amount of hydrogen to be produced. Engineers start with a basic design, then create new piping layouts in line with these parameters. The process can be tedious and time- consuming, especially when unforeseen interferences arise as pipes are installed - thus the appeal of quick-and-easy modular plants.

"The modular method allows for fast installation," said Chuck Richards, lead designer at Glitsch Process Systems in Atlanta. The company is a wholly owned subsidiary of Foster-Wheeler Corp. in Livingston, N.J. "We build the foundation out of a number of steel skids, which are the right size for shipping. These can be set in place and filled with gravel and cement and then shipped to the customer." The plants that Glitsch builds in this way range in size from tiny (8 feet by 50 feet) to very large (200 feet by 300 feet). The key to unlocking the potential of modular designs is the use of CAD software. Such software not only automates the generation of piping schematics but also helps engineers

visualize how the plant components will fit together. By gaining such a system-level view of a virtual plant, engineers can identify design problems before components are manufactured, let alone assembled and shipped to the customer.

With the aid of this technology, mechanical engineers have brought about a revolution in the way hydrogen plants are designed and built - and, perhaps even more important, in the speed with which customers' orders can be turned around. The reason is that the software enables engineers to manage complex projects efficiently. The design methods that Glitsch uses, for example, help ensure that plant construction, shipping, and installation can be performed as efficiently as possible.

Glitsch has automated the design process by integrating AutoCAD software from Autodesk Inc. in San Rafael, Calif., and AutoPLANT Designer from Rebis in Walnut Creek, Calif. With these tools running under Windows on his stand-alone personal computer, Richards has been able to design five hydrogen plants almost single-handedly since Glitsch opened its Atlanta office three years ago.

The lion's share of his work involves doing the complex pipe layout for each plant using Designer, which automates three- dimensional piping layout and orthographic drawing production. Each hydrogen-plant design involves approximately 40 orthographic drawings and 115 isometric drawings, which illustrate the components and dimensions of individual pipelines. To increase efficiency, Richards outsources production of the isometrics to a fabricator/assembler in Alabama.

"Once I have a model done, we send it to them via modem," he said. "They pull out the isometric drawings while I finish doing plans and elevations. Then, on the basis of the isometrics, they prefabricate all the pipe. As a result, when the vessels and steel are in place, they can put up all the piping at once instead of fabricating lines as they go."

The design methods that are used at Glitsch influence not only the speed with which Richards can produce a variety of complex drawings for each plant but also the time it takes to assemble the hydrogen plant itself. For example, by enabling engineers to create a virtual model of a plant in 3-D, the Designer software helps engineers identify piping interferences during the design phase, rather than during construction. "The software makes a drastic difference in the ease of checking for interferences and in the amount of rework that the shop has to do," Richards said. "By creating a 3-D model, you can see where interferences occur before they have a chance to happen."

The software also automatically generates bill-of-materials (BOM) reports listing every pipe length, nut, bolt, elbow flange, and gasket represented in a drawing. Richards estimated that creating such lists by hand for all the plant drawings would take a week. It now takes just 4 hours to produce several versions of the BOM report, including a combined BOM that provides totals of each kind of part used in the plant design, and a by-line BOM that lists the components that make up individual pipelines.

For customers, these techniques have made putting a hydrogen plant on-line more painless than ever. They can place an order, wait a few months for the plant to be delivered, and, when the utility tie-ins are hooked up, the plant is ready to go.

home | features | weekly news | marketplace | departments | about ME | back issues | ASME | site search

© 1996 by The American Society of Mechanical Engineers