The process
Figure 4 shows a schematic representation of the liquefaction
process technology.
Pretreatment
Feed gas routes from the gas gate station to each LNG train and
initially passes through an inlet filter coalescer to separate any
liquids/solids to prevent foaming in the acid gas removal unit
(AGRU). Removal of acid gases (CO
2
and H
2
S) using a proprietary
amine solution occurs in an absorber column. Removal of CO
2
to approximately 50 ppm avoids freezing in the downstream
liquefaction unit. An ammonia refrigeration systemprecools the
water-saturated sweet gas exiting the absorber column, which
passes through a knockout separator to remove bulk water from the
gas. The condensed water and trace amounts of amine are recycled
to the amine system as make-up water.
Depending upon the design of the dehydration unit, the gas
recycled back to the process will beminimised, or even eliminated.
The dry gas stream also accommodates any shortfall in fuel gas.
Amercury removal unit, provided after themolecular sieve dust
filters (typical position), removes any tracemercury in the gas prior to
entering the liquefaction unit. A treated gas filter downstreamof the
mercury removal unit is also in place to capture any loose dust
particles from themercury removal system.
Heavy hydrocarbon removal plant
The final pretreatment unit involves removal of heavy hydrocarbons,
such as pentanes and benzene. Benzenemust be removed to avoid
freezing in the liquefaction plant. The heavy hydrocarbon removal
Figure 4.
Schematic of OSMR liquefaction process
technology.
Proven LNG
Capabilities
Our 20,000-strong Oil & Gas professionals deliver end-to-end
services to our clients in the global LNG sector.
We offer capabilities in:
›
Liquefaction plant build
›
Completions and commissioning
›
Non-process infrastructure
›
Marine infrastructure
›
Operations and maintenance
›
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›
Re-gasification and receiving terminals
›
Off-sites and utilities
›
Gas processing and handling
›
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