Chemical Cleaning of Fossil Steam Generators with Organic Solvents:North American Experience

摘要

Use of organic-based solvents as an alternative to inorganic solvents has been practiced in North America since the 1960s.Solvents in use include hydroxyacetic-formic acid,citric acid,and ethylenedi-aminetetraacetic acid.Initial applications were in the cleaning of waterwalls of conventional fossil fueled boilers,including drum-type boilers and once-through subcritical and supercritical steam generators,and subsequently in the cleaning of superheaters and reheaters.Most recently,organic solvents have been used in the preoperational cleaning of heat recovery steam generators of combined cycle units.The organic solvents offer certain advantages as well as some limitations and these aspects must be considered during the selection process.Various characteristics and features of these organic solvents are considered and comparisons to commonly used inorganic solvents are made.Case studies based on field application of the organic solvents for specific purposes are presented to demonstrate the possible uses of these solvents and the required process conditions.