Guidelines for Mothballing Process Plants

Corrosion in an idle process plant may be reduced by the judicious selection and application of preservatives so that the plant may be recommissioned. This manual provides information on which to base a mothballing program for a selected shutdown period at the lowest cost, and with the fewest problems when a plant is returned to service.

Various protective systems and their methods of application are outlined as they have been used in major facilities of the chemical, petrochemical, refining, power generation and oil exploration industries. The advantages and disadvantages of each system are given. Guidelines are presented for the preparation of detailed field instructions to personnel performing protection work on different types of equipment.

Three other important stages are outlined as well: the inspection and the maintenance of the mothballed facility and the recommissioning of such a plant. The protection periods of plant equipment may be classified according to the life expectancy of the preservatives: short-term (1-18 months), medium-term (19-60 months) and long-term (over 60 months). Section 6, Selection of Preservatives, is the basis for each of the protection sections (7, 8 and 9 for process plants, 10, 11 and 12 for power houses).