Improving Pilot Plants.

Any effort to extend a pilot plant's life can help put off costly expenditures and boost performance

Increased global competition continues to place heavier demands on all research activities, resulting in a sustained drive to perform research more quickly and with fewer resources than were available a decade ago. In many cases, the development and use of pilot plants -- both laboratory-scale and larger -- offer great potential for improvement.

A new pilot plant may be required to support a developing program or research need, especially one that requires increasingly demanding conditions, such as higher accuracy, corrosive conditions, or higher operating temperatures or pressures. Alternately, an older pilot plant may be performing inadequately and require replacement or modification.

In either case, one way to reduce pilot plant costs is to defer construction of a new unit, by using or reusing an existing pilot plant. Any extension of an existing pilot plant's life has the effect of putting off -- perhaps indefinitely -- costly expenditures and leadtime associated with the conventional pilot plant cycle, shown in Figure 1.

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The conventional cycle progresses through the stages of design, construction, startup and use, and ultimately concludes with decommissioning of the plant. While most pilot plants progress through these stages in a sequential fashion, researchers can prolong plant life by repairing, upgrading, modernizing, relocating or rebuilding a previous pilot plant configuration. Varying degrees of investment are required, and resultant savings depend on a number of factors. Research facilities must evaluate their available resources and decide on a strategy for continued use.

This article looks at the major options for extending a pilot plants' life and discusses the advantages, disadvantages and pitfalls of each alternative. An overall comparison of the costs and relative benefits associated with various pilot plant improvement strategies is included in the table on p. 90. For examples from ExxonMobil's operating experience, see the box on p. 90.

 A COMPARISON OF THE TYPICAL COSTS AND RELATIVE BENEFITS ASSOCIATED WITH VARIOUS PILOT PLANT IMPROVEMENT STRATEGIES  Area                      Repair      Upgrade     Modernize  Cost, % of complete unit replacement          < 10        5-25        30-70 Schedule, weeks(*)              <$100,000    <6          5-10        6-15       $100,000-500,000    5-10(**)    5-15        8-20     $500,000-1,000,000    5-15(**)    5-20        10-30            >$1,000,000    10-20(**)   10-30       15-40 Designer experience       Low         Medium      High level required                        to high Downtime                  Low         Medium      Medium Lead time                 Low         Medium      Medium                                       to high Average life extension    Very low    Low         Medium Start up, weeks(*)              <$100,000    <2          4-8         4-8       $100,000-500,000    2-4         6-8         6-10     $500,000-1,000,000    2-6         8-10        8-12            >$1,000,000    4-10        10-15       12-20 Effect on maintenance     25-75       30-120      90-125 costs, % of existing Effect on operational     Medium      Medium      High efficiency                to high     to high  Area                      Relocate    Rebuild  Cost, % of complete unit replacement          30-70       100 Schedule, weeks(*)              <$100,000    6-10        10-15       $100,000-500,000    10-20       25-40     $500,000-1,000,000    15-30       30-50            >$1,000,000    20-40       40-60 Designer experience       High        Medium level required                        to high Downtime                  High        Low to                                       none Lead time                 High        High Average life extension    Medium      High Start up, …