Hydrocarbon Processing - April 2021 - 69

Water Management
L. A. BRUN and C. MAJOREL, TOTAL, Gonfreville,
France; J. P. THORET-BAUCHET, TOTAL, Feluy,
France, A. POTHUAUD, SUEZ - Water Technologies
& Solutions, Paris, France; and C. CROSS, SUEZ -
Water Technologie & Solutions, Tomball, Texas

TOTAL refineries improve overhead systems corrosion
and salting with amine-neutralizing technology
Weak organic amines are commonly used in crude unit overhead systems to prevent acidic corrosion from chlorides and
other acidic contaminants via a neutralization reaction. While
using commodity amines, some refineries experience salt-induced fouling and corrosion issues, which may prompt them to
move to non-salting, lower strength amines. TOTAL decided
to test this approach to improve reliability for its overhead systems in crude units. This was done through partnership with
an industry-leading water technology and process providera
to use their proprietary amine-neutralizing technologyb. This
technology is based on a set of principles surrounding the
blending of a variety of targeted amines to achieve a balanced
neutralization profile, which minimizes salting potential for a
given operating envelope. This article describes the route used
by TOTAL and the service provider to develop individualized
selection and implementation programs for two of their crude
units. Each program was based on comprehensive analysis used
to choose the best product, define the specific application strategy and define the subsequent benefits of the program changes,
according to unit characteristics.
Purpose. The neutralizers are designed to improve both pH

control and chloride salt precipitation potential in overhead systems vs. classical amine neutralizer programs. The unique properties of the amine strength and favorable water/hydrocarbon
partitioning reinforces these abilities.
The following studies were driven by TOTAL and the service
provider to validate amine speciation results between water and
hydrocarbon flows over time in two of TOTAL's European refineries. Results from the studies reveal the complex partitioning
and recycle behaviors by which these products work and show
how detailed water analysis helps to achieve optimization of both
neutralizer consumption and corrosion mitigation. The benefits
of the analytical campaigns and the overall knowledge of amine
behaviors were not possible without a wide collaboration and
involvement of all TOTAL teams in developing a systematic and
exhaustive monitoring program around the overhead system.
Part of a modern overhead corrosion control program calls
for the speciation of amines in a wider variety of flows and computation of detailed salt point calculations on a more frequent

basis than are traditionally performed. The advantage is that a
refinery can know in a much more granular fashion the precise
amount of amine in the overhead circuit and surrounding flows
and how they change over time. This allows better control and
understanding of the prevailing salt point, which changes over
time and is influenced by many complex, dynamic factors that
are linked with operations and crude diet. In such a program,
amine salt point calculations should not be based on the rate
of amine injected into the overhead vapor line, but should be
based on the measured amount of amine present in the overhead system receiver at a given time.
Such a program can be important for optimal results because
the concentration of amines in the system-and the prevailing
salt points that depend on them-is key to ensuring that the
transition to a neutralizer will benefit the refinery in terms of its
overall corrosion treatment cost.
For both the initiation and ongoing control of the new programs, it was decided that both TOTAL and the service provider would work together to optimize the balance between ongoing neutralization needs and salt point deposition constraints
and to then quantitatively validate the specific benefits gained
by crude units adopting the new programs.
Amine properties. Commodity amines have been used for
decades to protect overhead condensing systems in both atmospheric and vacuum fractionation units. One of the foremost
challenges toward the control of corrosion rates in overhead
systems is avoiding deposition due to amine hydrochloride neutralization salts.
Traditional primary amines, like monoethanolamine (MEA)
and methoxypropylamine (MOPA), have a high polarity and
relatively large base strengths (pKa), causing them to react readily with acidic species at relatively low injection rates. However,
these same properties also make it difficult to control pH in the
typical target range of 5.5-6.5 (blue line in FIG. 1). In addition,
the neutralization salts formed have higher than desired salt
point temperatures that increase the potential for salt-induced
corrosion and fouling.
Conversely, the neutralizers used in this study are generally
composed of blends of both secondary and tertiary amines. As
Hydrocarbon Processing | APRIL 2021 69

Hydrocarbon Processing - April 2021

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