Hydrocarbon Processing - July 2022 - 56

Process Optimization
TABLE 7. Finished product results
Property
Cetane number
Cetane index
Density at 15°C,
kg/m3
CFPP, °C
CP, °C
53.7
53.4
842
-29
-15
Additive A Additive B
55.1
55
834
-29
-12
refinery evaluated WAFI additives from
multiple suppliers to meet the target cold
flow properties limit.
Preliminary studies conducted by two
different suppliers concluded that ULSD
produced from the MAA refinery's DHT
unit has an ultra-narrow distillation range,
which is less than 80°C. ASTM Test
Method D86 determines the distillation
temperature considered for the diesel fuel
product. The target endpoint for the feed
stream is between 350°C-355°C, with
an initial point target of less than 197°C.
Based on the narrow distillation range
and wax content profiles, both suppliers
offered a specific type of WAFI additive
for a field trial (i.e., Additive A and Additive
B). Upon completion of the lab-scale
analysis and chemical procurement process,
the WAFI field trial was scheduled
to establish the MAA refinery's capabilities
in actual refinery operation.
Preparation stage. A multidisciplinary
team composed of operational
planning (coordinator), process engineering,
operations and the laboratory
was formed to implement the field trial.
The field trial was conducted in two
phases with Additive A and with Additive
B at different periods. The selection
of finished tanks was significantly important
to ensure that there was no interruption
to the supply of committed diesel
product for local and export customers.
In terms of diesel-producing units
(i.e., gasoil desulfurization and DHT
units) and the preparation of upstream
units, the distillation initial point and
endpoint for the feed streams were controlled
to achieve a ∆ (T90%-T20%)
above 80°C. The operations and process
engineering divisions monitored unit
conditions closely prior to the target
date of the field trial by adjusting the
unit parameters, such as the column
separation temperature and severity of
the units. Subsequently, the dewaxing
bed of the DHT unit was activated to
56 JULY 2022 | HydrocarbonProcessing.com
achieve a preliminary CFPP of approximately
-15°C to -17°C. These actions
are to ensure a better additive response
to the diesel product.
During the field trial. The additive
was injected through the unit's injection
facilities to achieve the desired CFPP
temperature of less than -22°C. The
injection dosage rate was closely monitored
and controlled as per the recommended
rate by each supplier. Samples
were collected during every shift to test
the key parameters and to ensure additive
effectiveness and product qualities.
Other important parameters that were
monitored were the density at 15°C,
which must be less than 845 kg/m3
, as
well as a CP of less than -7°C. Furthermore,
other additives injected to meet
lubricity and electrical conductivity parameters
were controlled as per existing
practice to meet the final specification.
Once the tank filling was completed, the
existing sampling and analysis procedure
was undertaken against the winter-grade
specification agreed upon with KPC.
The final finished tank results for each
field trial are shown in TABLE 7.
Various blends were
both trials to ensure diversity in future
conditions and to establish the additives
response and behavior during these conditions.
Blends consisted of gasoil desulfurization,
and DHT and HCR products,
while other blends considered only dewaxed
DHT products and gasoil desulfurization
and HCR products separately.
Post field trial. The challenges faced
during the field trial were consolidated
and then discussed by the team members.
Some of the key challenges were
resolved during the first phase of the
field trial, such as injection pump failure
and off-specification in one of the parameters
during tank filling. Other challenges
(e.g., a wild kerosene stream that
was routed to slop, which was observed
during the first phase, and which affected
crude unit operations) were resolved
prior to Phase 2 by routing the same to a
kerosene desulfurizer unit. Furthermore,
an economic assessment was carried out
of the additional cost that was incurred
during the field trial to evaluate the MAA
refinery's competitiveness in selling winter-grade
ULSD product.
Takeaways. To adhere to Europe's most
stringent diesel specifications, KNPC
performed two field trials with two different
WAFI additives to achieve a CFPP
limit of less than -22°C. This was accomplished
by adjusting the upstream
units' stream qualities to meet the required
distillation range, the operation
of the DHT unit's dewaxing bed and the
controlled additives' dosing rate. Still,
overall optimization is critical to ensure
economic viability.
The CFPP limit can be achieved by
controlling the feed stream's condition
to achieve a ∆ (T90%-T20%) of more
than 80°C for better WAFI additive response
toward the final diesel product.
Further dosing rate controls of other additives
are equally important to achieve
the desired product specifications.
With this accomplishment, the MAA
refinery is in the position to diversify its
target market, strengthen KNPC's position
in the export market and produce
clean diesel products that conform to the
latest European standards.
ACKNOWLEDGMENTS
The authors would like to acknowledge Nik
used during
Mohn Ridhwan, Operational Planning, KNPC, and
Raghu Kutikuppala, Section Head of Operations,
KNPC, for their help in authoring this article.
LITERATURE CITED
1
U.S. EPA, " Final rule for control of air pollution
from new motor vehicles: Heavy-duty engine and
vehicle standards and highway diesel fuel sulfur
control requirements, " January 18, 2001, online:
https://www.govinfo.gov/content/pkg/FR-200101-18/pdf/01-2.pdf
2
EU,
" Directive 2003/17/EC of the European
Parliament and of the Council of 3 March 2003
amending Directive 98/70/EC relating to the quality
of petrol and diesel fuels, " March 2003, online:
https://eur-lex.europa.eu/legal-content/EN/TXT
/?qid=1435618704689&uri=CELEX:32003L0017
3
European Committee for Standardization, " EN590:
Automotive fuels and diesel requirements and test
methods, " October 2021.
4
Rand, S. J. and A. W. Verstuyft, Significance of Tests
for Petroleum Products, 9th Ed., ASTM International,
West Conshohocken, Pennsylvania, January 2018.
MOHAMMAD B. MATAR is a chemical engineer and
the Team Leader for Operational Planning at KNPC.
He has experience in refinery operations, planning
and process engineering.
ALI AL-MANE is a chemical engineer with more
than 15 yr of experience. He works in operational
planning and has played a significant part in the
commissioning of the MAA CFP.
ABDUL AZIZ Y. LAYRI is the Operations Section Head
for Hydrotreaters at KNPC's MAA refinery. He has
more than 17 yr of experience in the refining industry
and earned a BS degree in chemical engineering from
the University of Dayton in Ohio.
https://www.govinfo.gov/content/pkg/FR-2001-01-18/pdf/01-2.pdf https://www.govinfo.gov/content/pkg/FR-2001-01-18/pdf/01-2.pdf https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1435618704689&uri=CELEX:32003L0017 https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1435618704689&uri=CELEX:32003L0017 http://www.HydrocarbonProcessing.com
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