Hydrocarbon Processing - April 2022 - GP-13

SPECIAL FOCUS: GREEN TECHNOLOGIES
Lessons learned to optimize flare gas recovery
systems in gas plant operations
A. H. AL-TIJANI, M. ALDAJANI, A. AL-SANAD and M. AL-MAHMOOD,
Saudi Aramco, Dhahran, Saudi Arabia
There are more than 100 flares spread
across many operating facilities in the
upstream and downstream oil and gas
processing plants of Saudi Aramco. Flare
systems are designed to provide the safe
disposal of hydrocarbons that are either
automatically vented or manually vented
from process units. Flare systems gather
vented gases and combust them to prevent
release directly to the atmosphere.
Since Saudi Arabia started producing
oil, associated gas has been flared. In
the 1970s, the Kingdom recognized the
value of the associated gas produced with
crude oil. Major investments in building
a sizable master gas system resulted in
capturing and utilizing all the associated
gas instead of burning it in gas flares. As
a result, the Kingdom's annual flaring has
been considerably reduced to facilities'
routine and emergency flaring only. The
environmental regulations from Saudi
Arabia's Presidency of Meteorology and
Environment require controls for smokeless
flaring only from industrial activities,
and there are no penalties for carbon dioxide
(CO2
) emissions.
These standards apply just to routine
emissions, and not to emergency, startup
or shutdown events. Most Saudi Aramco
facilities meet the environmental standard
for smokeless flaring. The corporate roadmap
on flaring was initiated as a response
to the escalating cost of the new project
proposals to make flares smokeless for
routine operations in all of the company's
facilities. The key element of this roadmap
is to minimize flaring by implementing
site-specific flaring minimization plans
(FMPs) and installing a flare gas recovery
system (FGRS) wherever feasible.
An FMP was initiated to reduce flaring
from all Saudi Aramco facilities over a defined
period by minimizing the frequency
and magnitude of flaring. A comprehensive
engineering standard for real-time
measuring, monitoring, reporting and
minimizing flaring was developed. Part
of this minimization plan was to study
the leakage rate to the flare system and
to determine purge optimization. These
two analyses play major roles in reducing
facility emissions. Furthermore, the
company's Process and Control Systems
department issued design guidelines for
FGRSs to give clear direction for selecting
and applying new FGRS projects in
all Saudi Aramco operating facilities. This
guideline is in line with the Saudi Aramco
corporate decarbonization strategy to reduce
greenhouse gas (GHG) emissions.
The company has had several technologies
in operation for a few years.
Therefore, Saudi Aramco has updated
its best practices with lessons learned
from the startup and commissioning of
compressor and ejector technologies at
its facilities. This compilation of information
provides additional insights that will
enhance designs and proactively address
common issues that can arise during the
startup and operation of FGRSs at Saudi
Aramco facilities.
FGRSs. Corporate management has recognized
the need to approve a flaring
roadmap, which calls for considering an
FGRS if any facility is flaring more than
1 MMsft3
d of gas after implementing all
flaring reduction measures. An FGRS will
eliminate flaring as required for plant safety,
provide routine process reliefs and return
gases back to the process to prevent
any leakages. Although FGRS technology
is proven in industry, it was not adopted
by the authors' organization in the past
because, during that time, there were no
compliance requirements for CO2
emissions
and there was a very low price to pay
for sales gas. In recent years, however, the
situation has changed. In the current industry
environment, the primary drivers
favoring FGRS projects include:
* Stricter global environmental
regulations governing the emissions
of GHGs, such as CO2
* Environmental impacts and health
effects of harmful emissions,
such as nitric oxide (NOx
oxide (SOx
), sulfur
) and volatile organic
compounds (VOCs)
* Improved economic returns in
recovered flared gas to the value
chain, thus saving on plant fuel gas
and steam consumption
* World Bank carbon credits for
uneconomic FGRS projects,
specifically for the elimination of
CO2
* Increased raw gas production
costs, which makes FGRSs more
attractive, since these systems
recover flared gas and recycle it
back to the process
* Rising sales gas costs, making FGRS
recovery projects more viable
* Shortage of natural gas
in the country
* FGRSs improve the reliability
of main flare tips (important for
larger-diameter flares that are prone
to damage from operation at low
daily flaring rates), enabling the
main flare to stay in standby mode,
which improves its reliability and
life, and minimizes the recurring
cost of flare tip replacement.
Additionally, one of Saudi Aramco's
key values is citizenship, where the organization
has a positive influence in communities
and requires a demonstration
of social responsibility. An FRGS proGas
Processing & LNG | MARCH/APRIL 2022 13
emissions, which can be traded
for monetary gains-thus helping
to improve returns on investment
(ROIs) for projects
Hydrocarbon Processing - April 2022

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