Nalco Chemical Company

Paul R Kraus

Barbara E Moriarty

Donald A Johnson

Dmitri L Kouznetsov

Linda R Robertson

Louis DiSanto

Jeffrey P Chamberlain

A method measuring a rate of fouling caused by a heat flux through the surface subjected to electrochemical polarization. The method includes the steps of: providing a piezoelectric microbalance comprising a piezoelectric material with electrodes disposed thereon; exposing the working electrode of the microbalance to a flowing liquid, the liquid containing at least one fouling forming species; maintaining the liquid at a constant first temperature; maintaining the liquid at required hydrodynamic conditions; applying either a constant heat flux through the microbalance resulting in its working electrode having a variable second temperature or applying a variable heat flux through the microbalance resulting in its working electrode having a constant second temperature; and measuring a rate of fouling on the microbalance surface. The method also comprises measuring the surface density and heat transfer resistance of the deposit independently, thereby the corresponding ratio can be determined contributing to the deposit identification. The working electrode of the microbalance can be subjected to an electrochemical polarization in a wide range to systematically simulate the conditions of heat exchange surface produced by corrosion or other electrochemical processes. The possibility to apply electrochemical polarization, cooling or heating flux in the direction opposite to that causing fouling can be used to clean the immersed microbalance surface in-situ.

Method for measuring the rate of a fouling reaction induced by heat transfer using a piezoelectric microbalance

A system and a method are provided for detecting and monitoring changes in frequency in a process stream. At least one probe is placed in the process stream that is capable of detecting a change in frequency due to a build-up of mass on the probe from scale, corrosion, biofilm or the like in the process stream. A processor receives the signal produced by the probe to produce an output signal indicative of the change in frequency which is proportional to mass detected by the probe. A feeder is capable of feeding a product into the process stream as a result of the detected change in frequency of the probe to combat the mass build-up from scale, corrosion, biofilm or the like in the process stream. The system and method are further capable of measuring anti-scalant, corrosion inhibitor, biocide efficacy and controlling product feed into the process stream based on the determined efficacy.

System and method for determining a deposition rate in a process stream

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Batavia, IL, United States of America

Paul R Kraus