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March
2017
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HYDROCARBON
ENGINEERING
S
ince the 1980s, corrosion inhibitors have
been used to effectively control naphthenic
acid corrosion. Certain high temperature
corrosion inhibitors with a general phosphate
ester structure have demonstrated good mitigation of
naphthenic acid corrosion in numerous commercial
applications. The generic structures of mono-, di- and
tri-esters of phosporic acid are shown in Figure 1
(where 'R' = alkyl groups).
These products are postulated to interact with the
metal surface forming a passivation layer. This mechanism
Sam Lordo, Dr. Kailash Sawhney,
Dr. Satheesh Kumar Sambandam
and M. Rajganesh, Nalco Champion;
An Ecolab Company, USA,
provide
an overview of the use of phosphate
ester inhibitors for controlling high
temperature naphthenic
acid corrosion.