Hydrocarbon Processing - December 2021 - GP-24

SPECIAL FOCUS: PLANT DESIGN AND PROCESS CONTROL
online: www.worldbank.org/en/programs/zeroroutine-flaring-by-2030
5
Hajilary,
N., M. Rezakazemi and A. Shahi, " CO2
emission reduction by zero flaring startup in gas
refinery, " Materials Science for Energy Technologies,
Vol. 20, 2020.
6
Mohd Ismail, E., B. Rajah, A. Suppiah and S. Mat
Ghani, " Low pressure-Condensate recovery system
LP-CRS. Creating value through waste, " SPE Russian
Petroleum Technology Conference, Moscow, Russia,
2018.
7
Offshore Technology, " Tembikai non-associated gas
development, " 2020, online: www.offshore-technology.com/projects/tembikai-non-associated-gasdevelopment
8
NGL
Tech, " Enhanced recovery systems, " 2017,
online: https://www.ngltech.com/lp-crs
FIG. 4. Excel Solver for solving the LP model.
maximize P = (FCond
((FM1
× CCond
+ FM2) × CM
) -
) (4)
where P ($/d) represents the profit generated
per day; CM
($/t) and CCond
($/t)
represent the unit cost of methanol and
unit price of condensate, respectively. CM
was taken as $295/t and CCond
the value of $50/bbl.12,13
was given
Note that the
above model is a linear program (LP),
which may be solved easily with any commercial
solver, including Excel.
The objective in Eq. 4 was solved,
subjected to the constraints in Eqs. 1, 2
and 3, yielding the maximum profit of
$18,136/d (see snapshot in FIG. 4). The
model determined that the profit corresponded
to 366.8 bpd of condensate
recovery (FIG. 4). Verification with the
simulation model determines that the
condensate recovery is actually 367.8 bpd.
Note that for this case, the amount of condensate
recovered is the dominant factor
of the profit, since the price of condensate
is much higher than that of methanol-in
terms of flowrate, the flowrate of condensate
is again higher than that of methanol.
Therefore, the profit obtained is solely dependent
on the condensate flowrate.
However, even if the condensate flowrate
is ignored, FIG. 2 shows that a lower
cold separator inlet temperature lowers
the amount of methanol required. This
scenario is justifiable with the increased
amount of water and hydrocarbons (C3
C4) being condensed from the
,
cold
separator as the temperature decreases.
Therefore, the amount of methanol required
in the Exp. Out stream drops
significantly as the temperature of the
HE02-Out1 stream decreases.
Based on the results from the optimizaion
model, it was concluded that the
optimum operating temperature for the
cold separator should be -21.6°C because
this temperature recovers the highest
amount of condensate with the minimum
amount of methanol consumed. It
is also worth noting that the condensate
recovered by the LP-CRS corresponded
to a significant reduction of 39,000 tpy of
CO2
. This was determined by performing
a complete combustion of the recovered
condensate (367.8 bpd) using a conversion
reactor model in the commercial
softwarea
(assuming 365 d/yr).
Takeaway. The study provided an optimization
study for a condensate recovery
process with an LP-CRS. High risk points
and their respective methanol flowrates
required for inhibition were determined.
The report also provided the study of
methanol flowrate and condensate recovered
as the function of temperature. The
mathematical model allows the user to
maximize profits gained from condensate
recovery, while minimizing the methanol
flowrate. The optimized temperature of
-21.6°C was obtained with the aid of Excel
Solver. The maximum profit gained
was calculated as $18,136/d, and it was
determined that at least 39,000 tpy of CO2
can be prevented through this system. GP
NOTES
a
AspenTech's HYSYS V10
LITERATURE CITED
1 2B1stconsulting,
2
" Associated gas, " 2012, online:
https://2b1stconsulting.com/associated-gas/
Vorobev, A. and E. Shchesnyak, " Associated petroleum
gas flaring: The problem and possible solution, "
Springer Proceedings in Earth and Environmental
Sciences, pp. 227-230, 2019.
3
Smith, B., " How oil companies are helping to reduce
emissions, " AZOCleantech, 2018, online: www.azocleantech.com
4
World Bank, " Zero routine flaring by 2030, " 2015,
24 NOVEMBER/DECEMBER 2021 | GasProcessingNews.com
Complete literature cited available online at
GasProcessingNews.com.
ZHEN KANG LIEW is a chemical
engineering graduate of the
University of Nottingham, Malaysia
(Department of Chemical and
Environmental Engineering).
His research interests include
process synthesis, design,
optimization, and oil and gas processing. He
completed his research internship, which involved
the integration of electrical-conductive waste powder
into the nylon pellets for 3D printing filament
synthesis, at Kun Shan University, Taiwan in 2019.
He also had experience developing mathematical
models for horizontal jet release scenario during his
summer internship at SynergenOG
Sdn. Bhd. in 2018.
His final year project covered the extraction and
characterization of gelatin from tilapia fish scales. The
author can be reached at samliew1996@hotmail.com.
DOMINIC C. Y. FOO is a Professor
of Process Design and Integration
at the University of Nottingham,
Malaysia (Department of Chemical
and Environmental Engineering
and Center of Excellence for Green
Technologies). He is a Professional
Engineer (Board of Engineers, Malaysia) and a
Chartered Engineer (Engineering Council UK), a
Fellow of the Academy of Science Malaysia (ASM),
the Institution of Engineers Malaysia (IEM), and
Institution of Chemical Engineers (IChemE), as well
as the President for the Asia Pacific Confederation
of Chemical Engineering (APCChE). Prof. Foo is also
the winner of the Innovator of the Year Award 2009
of IChemE, Young Engineer Award 2010 of the
IEM, Outstanding Young Malaysian Award 2012,
Outstanding Asian Researcher of the Society
of Chemical Engineers, Japan (SCEJ) and Top
Research Scientist Malaysia 2016. He has more
than 160 published papers in chemical, energy and
environmental engineering journals, a Chief Editor
and Subject Editor for several international journals,
and an author and editor for eight books. The author
can be reached at dominic.foo@nottingham.edu.my.
MIKE BOON LEE OOI is a Lead
Process Engineer at NGLTech
Sdn Bhd in Kuala Lumpur, Malaysia.
He has 15 yr of working experience
in the oil and gas engineering
design firm. His works include the
development of new technology
of condensate recovery systems, low-pressure
production units, separator design, and slug
suppression systems. The author can be reached
at boonlee77@gmail.com.

http://www.worldbank.org/en/programs/zeroroutine-flaring-by-2030 http://www.worldbank.org/en/programs/zeroroutine-flaring-by-2030 http://www.offshore-technology.com/projects/tembikai-non-associated-gasdevelopment http://www.offshore-technology.com/projects/tembikai-non-associated-gasdevelopment http://www.offshore-technology.com/projects/tembikai-non-associated-gasdevelopment https://www.ngltech.com/lp-crs http://www.GasProcessingNews.com https://www.2b1stconsulting.com/associated-gas/ http://www.azocleantech.com http://www.azocleantech.com http://www.GasProcessingNews.com

Hydrocarbon Processing - December 2021

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