Hydrocarbon Processing - April 2021 - 73

Water Management

Takeaways. The amine-neutralizing technology can be a very

cost-effective program compared with classical neutralizing
amine treatments. As this article has shown, this is due to the
complexities involved with the use of secondary and tertiary
amines, which show pH-dependent partitioning and recycle
behavior vs. traditional primary amines. The large economic
and reliability benefits imparted by using such amines typically justify the extra complexity and attention needed to control and optimize them.
The ability for the amines to partition strongly into hydrocarbons and concentrate in the overhead system helps to
reduce neutralizing injection and chemical needs, while also
reducing detrimental pH fluctuations and salt precipitation
tendencies. When corrosion is not optimally mitigated, it can
often result in loss of production and increased maintenance
cost, which greatly increases total cost of ownership. If used
properly and considering the total costs of overhead corrosion
over time, the neutralizers can represent an optimal choice.
In summary, the amines helped TOTAL to better control
pH, with minimal risk of salt deposition. Partitioning and recycle advantages illustrated in these two case studies allow these
amines, in these two cases, to:

100

Amine 2 injected in MF recycled in PF

80
60

Percent

* Hydrocarbon samples
° MF RN
° PF RN.
Two different neutralizer products were chosen for the two
injection points. These included:
* The neutralizer (Amine 2 in FIG. 7) for the MF
overhead system and chosen to avoid any salt
deposition there by chloride ranging between
5 ppm-20 ppm
* A MEA-based neutralizer in the PF overhead
(Amine 1 in FIG. 7) and chosen because chloride
levels were consistently below 1 ppm, so salt
precipitation was unlikely.
First, no amine was analyzed in the NR of both the PF and
the MF. This confirmed what was analyzed in Case 1: a BW
pH range of 5.5-6.5 prevents amines to be recycled with NR.
It was reinforced by a pH target in PF in the range of 5.5-6 as
acidity is more expected to be organic than chlorhydric. The
pH and the choice of a conventional primary amine, which has
more affinity with water, explains why there is no recycling of
Amine 1 injected in PF via the desalter. The second confirmation is that the Amine 2 injected in the MF overhead was recycled into the PF. The data showed that approximately 30%
of neutralizing amine injected into the MF was recycled into
the PF (FIG. 8), with the variation driven primarily by changes
in the desalter pH. This phenomenon helped to reduce the
Amine 1 injection rate to a minimum level, which greatly reduced the risk for salt deposition, while effectively protecting
against dewpoint acid attack.
This second case confirmed the ability of the amine-neutralizing solution to recycle in the system and to reinforce corrosion protection, while reducing salt precipitation risk. At
the end, there was no more risk of salt precipitation in the MF,
and neutralization needs were reduced in the PF. This situation enabled TOTAL to better mitigate corrosion in both columns without additional costs.

40
Average 30%
20
0
Days

FIG. 8. Amine 2 recycled in PF.

* Concentrate in overhead of the atmospheric column
with a typical recycle ratio of 1.4, used to calculate
a more representative salt point in the overhead system
with reduced global neutralizer demand
* Recycle 30% of amine injected in a MF to a PF overhead
to eliminate amine salt deposition in the MF overhead
system, while reducing injection needs in PF.
Both the corrosion control program and the study were very
successful towards maximizing corrosion mitigation, with minimal risk of salt deposition in both affected units. Thanks to the
detailed ongoing analytical plan that was adopted, TOTAL and
the service provider were able to document the improved corrosion control, salt deposition potential and chemicals costs.
This work also helped to develop a more structured approach
to implementing an overhead neutralizer program using the
amine-neutralizing technology that considers the variation in
crude unit design and its operations over time.
NOTES
SUEZ - Water Technologies & Solutions
b
Refers to SUEZ's LoSALT technology
a

LAURENT-ALAIN BRUN is a Process Engineer based in TOTAL Research and
Technology in Gonfreville, France. He oversees troubleshooting and process support
for crude units for TOTAL Refining and Chemicals. He has 25 yr of experience in
refining process support for projects and operation. He earned chemical engineer
degrees from Mines de Nancy and ENSPM in Rueil-Malmaison, France.
CÉLINE MAJOREL is a Process and Corrosion Engineer based in TOTAL Research
and Technology in Gonfreville, France. She leads the feedstock and crude support
for TOTAL Refining and Chemicals. She has 12 yr of experience, primarily in research
and development and plant support within TOTAL. She earned a chemical and
material engineer degree from Phelma school in Grenoble, France.
JEAN-PIERRE THORET-BAUCHET is a Process Chemist, Fouling and Process
Treatment Specialist based in TOTAL Research and Technology in Feluy, France.
He has 25 yr of experience in plant support and troubleshooting within TOTAL.
He earned a chemical engineer degree from ENSCL Lille and a PhD in polymer
and organic chemistry from the University of Lille.
ALAIN POTHUAUD is French Senior Product Application in the Refinery and
Petrochemical business for 18 yr. With more than 33 yr of experience within
SUEZ -Water Technologies & Solutions, he is a member of the Center of Excellence
in corrosion and high-acid crudes processing. He earned a chemical engineer
degree from INSCIR Rouen.
COLLIN CROSS is a Global Product Line Manager for SUEZ - Water Technologies
& Solutions and leads the Center of Excellence for refinery corrosion. He has been
supporting process chemistry applications for 24 yr. Dr. Cross earned a PhD in
physical chemistry from the University of Oklahoma, where he participated in
the Institute for Applied Surfactant Research.
Hydrocarbon Processing | APRIL 2021

Hydrocarbon Processing - April 2021

Table of Contents for the Digital Edition of Hydrocarbon Processing - April 2021