Nalco Chemical Company

Deborah M Rogers

Douglas G Kelley

Frederick J Swiecinski

Christine M Stuart

Michael P Sowinski

James R Van Camp

A method for determining the adequacy of corrosion prevention treatments applied to metal surfaces is disclosed. The method provides a qualitative determination of corrosion detection using inexpensive equipment. Generally, the method encompasses wetting at least a first and a second absorbent patches capable of retaining a liquid corrosive to metal surfaces to be tested with the corrosive liquid to obtain wetted patches and then contacting a portion of a first metal surface to be tested with the first patch under corrosive conditions and contacting a portion of a second metal surface to be tested with the second patch, wherein the second metal surface having the same composition as the first metal surface has been treated with an effective amount of a corrosion prevention treatment and subjecting the second patch in contact with the second metal surface to the same corrosive conditions as the corrosive conditions applied to the first patch in contact with the first metal surface. The method includes removing the first and the second patches from the first and the second metal surfaces; respectively and, treating the first and the second patches with an effective amount of a tetrazolium compound; and, comparing the amount of stain present on the first patch with the amount of stain present on the second patch, wherein the efficacy of the corrosion prevention treatment can be qualitatively determined.

Field method for determining if adequate corrosion inhibition has been

A method of removing dissolved oxygen from boiler water having and alkaline pH is disclosed. The method uses at least one hydrazone compound of one of the following formulae: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from hydrogen, C.sub.1 -C.sub.16 alkyl, aryl, substituted alkyl or substituted aryl, and R.sup.5 and R.sup.6 are independently selected from hydrogen, C.sub.1 -C.sub.16 alkyl, aryl, substituted alkyl, or substituted aryl, ##STR2## Preferably, an oxidation-reduction catalyst such as Cu(II) is used as well. The hydrazones used in the present invention are highly shelf stable and do not suffer the toxicity of hydrazine.

Hydrazones as oxygen scavengers in boiler water systems

The invention is directed generally to controlling corrosion in boiler systems and more particularly to treating boiler water to remove dissolved oxygen and to passivate metal surfaces.

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Naperville, IL, United States of America

Deborah M Rogers