Methods for Cleaning OTEC Heat Exchangers

摘要

The objectives for the two tasks of this program were: (1) To provide a critical compilation and evaluation of the mechanical and chemical procedures currently in use for cleaning heat exchangers. (2) To provide an in-depth conceptual study of those mechanical and chemical methods as being potentially suitable for use in cleaning heat exchangers for OTEC power plants. The experience available from the power industry is mostly limited to conventional tube and shell type heat exchangers. The tubes considered for OTEC, however, may have either smooth or enhanced surfaces; they could be circular or otherwise shaped and seawater may be flowing on the inside or outside. The problem of difficult-to-clean heat exchanger configurations is addressed as well, and evaluations and suggestions of methods that may be suitable for biofouling control in these various designs are provided. The methods that have been reviewed are broadly classified within three categories: (1) surface treatment methods that are applied to the seawater/heat exchanger interface to prevent the adhesion of biofouling organisms; (2) water treatment methods that are either chemical, mechanical, or optical in nature, and render microorganisms incapable of active fouling; and (3) chemical or mechanical cleaning methods that are purged through the heat exchanger to kill and/or remove fouling. The discussion of each method addresses the following topics: equipment and expendables, process effectiveness, negative technical aspects, adverse environmental effects, available data describing effects on heat transfer, sources of data used in the review, and the potential of the method for application to OTEC. (ERA citation 04:022173)