摘要 |
An improved method for cleaning heat exchangers, wherein a first liquid containing a cleaning agent is used to remove substantially all of the accumulated sludge and deposits from the surfaces of the heat exchanger, and a second liquid containing a cleaning agent is used to remove deposits from the crevice regions of the heat exchanger. The concentration of cleaning agent in the second liquid and/or the duration of exposure for the second liquid are preferably greater than those of the first liquid, because the risk of corrosion is reduced as a result of a lower concentration of ferric ions in the second liquid. Furthermore, improved crevice region cleaning is obtained with the second liquid because the available cleaning agent is not depleted by the large volume of sludge and deposits removed by the first liquid. Mechanical cleaning techniques such as pressure pulse cleaning may be utilized with either or both of the cleaning liquids. Additional liquids may be introduced into the heat exchanger to provide further cleaning action or to facilitate flushing of the previous cleaning liquids.
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