Hydrocarbon Processing - August 2022 - 69

Plant Design,
Engineering,
Construction and
Commissioning
A. AL-QAHTANI, Saudi Aramco, Dhahran,
Saudi Arabia; and A. AL-WARTHAN and
M. AL-SUBAIE, Saudi Aramco, Jubail, Saudi Arabia
Soft startup of best practices
for the commissioning of amine plants
The startup and commissioning of
hydrocarbon plants can present unique
challenges that, if not anticipated and
addressed in the pre-commissioning
and commissioning periods, will inhibit
plant startup and increase the difficulty
of achieving product specifications in
a timely manner. This article provides
details on potential multiple challenges
during commissioning, as well as a method
to avoid these challenges by applying
a soft startup concept on a massive scale.
The acceptance criteria and successful
results of the soft startup concept are detailed
here.
Plant A sought to avoid or reduce
the common commissioning challenges
of a new amine system (e.g., gas treatment
facility), including foaming, the
presence of unwanted debris or materials
in piping and vessels, etc. To ensure
the short- and long-term reliability of an
amine system facility, Plant A elected to
implement a soft startup concept on a
massive scale, where the amine circuits
are filled completely with pure demineralized
water (rather than amine), then
pressurized by nitrogen (rather than fuel
gas) up to the operating pressure. This
was completed for multiple safety and
reliability reasons to:
* Test system tightness with a
safer medium (nitrogen,
as compared to fuel gas)
* Debug the associated process
control and emergency shutdown
(ESD) systems
* Test the functionality and
reliability of all rotating equipment
* Clean the system of any remaining
debris and suspended solids prior
to charging with expensive solvent
into the unit
* Limit the potential for future
foaming incidents.
During the soft startup, circulation is
started in both cold and hot modes to ensure
that all debris and suspended solids
are removed from the pipe walls, fittings,
valves and other equipment and vessels,
and the debris and suspended solids are
caught by the strainers and filters. This
approach was successfully utilized in the
other amine units.
Sweet wet gas
Filters
Wash water
pump
Circulation
pump
Contactor
Off-gas
Lean/Rich
exchanger
Reboiler
Sour feed
gas
Feed filter
separator
Lean cooler
Regenerator
Reflux pump
Amine system process description-
acid gas removal unit. The gas enters
the treating train through the inlet filter
separator. The separator is provided to
remove any particulate matter or traces
of liquids that may be received with the
incoming gas. Without a spare separator,
a bypass valve (sized for full flow) is installed
to allow maintenance servicing of
the separator.
The gas coming from the inlet filter
is fed to the amine contactor for carbon
dioxide (CO2
) removal. The contactor
is a tray column divided in two sections.
The bottom amine absorber section consists
of trays. The lean amine is fed to the
top tray and the rich amine is withdrawn
Condenser
Acid gas to SRU
Lean amine
Flash drum
FIG. 1. Typical PFD for an acid gas removal unit.
Hydrocarbon Processing | AUGUST 2022 69
booster pump
Reclaimer
for DGA
Hydrocarbon Processing - August 2022

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