|Marine Solutions to the Oil, Gas & Power Industries
|Waller Marine, Inc. 14410 W. Sylvanfield Dr. Houston, TX 77014 PH: 281.444.9650 FX: 281.444.8055 email@example.com
|Floating Gas to Liquids Plant
Waller Marine has supported its offshore oil & gas industry
clients in many ways since the Company's inception. The
different facets of the industry require different expertise in
the design and construction of vessels and facilities that
serve them; offshore drilling, production, construction, sub
sea systems and pipelines, gas-to-liquids and transportation;
Waller Marine has served them all in the past and continues
to provide design, technical assistance and construction
services to it's clients worldwide.
The integration of a new methanol process technology with
a marine vessel permits the conversion of large quantities of
remote or stranded gas to a liquid for transport to markets
for use as fuel for power generation or feedstock for the
petrochemical industry in the conversion of methanol to
The facility is based upon the Starchem methanol process that utilizes enriched air extracted from the compressor side of a gas turbine
to produce synthesis gas in an auto thermal reformer. This technology eliminates the need for an oxygen plant and permits much larger
methanol production capacities than prior world scale plants, thus reducing overall capital cost and methanol product competitive with
other forms of energy.
The methanol plantship comprises a double hull structure of 1,000 ft in length by 200 ft beam, with storage capacity of 250,000 tons of
methanol product. The process plant is supported on the process deck, similarly to a traditional FPSO. Moored by an extended turret,
gas is supplied through a riser and swivel at rates up to 400 mmscf/d.
The barge is designed with high motion suppression features, constant draft and has the ability to change it's vertical center of gravity
by moving ballast in order to moadify it's natural frequency for motion reduction. Designed for worldwide operations, the facility can
accept wellhead and dry gas, producing either fuel or AA grade methanol for shipment. Product is stored in sufficient quantities to load
out 200,000 dwt tankers for transport to either the power generation or MTO chemical markets.
The floating offshore power generation facility was initially conceived as a means of monetizing stranded offshore natural gas, while
simultaneously permitting offshore oil production in the deep waters of the Gulf of Mexico. Interest is now being shown by Independent
Power Producers (IPPs) to generate electrical power offshore in order to reduce the need for lengthy permitting applications needed for
land based power plants.
The facility comprises a combined cycle generating plant using eight GE LM 6000 gas turbines producing a total of 380 MW, each with
a heat recovery steam generator (HRSG) to raise steam to power a 120 MW steam turbine generator, providing a total capacity of the
plant at 500 MW. Gas is supplied either directly from the wellhead or from an FPSO and delivered to the semi-submersible facility for
treatment and compression prior to entering the turbines.
Electrical power is generated at 13,800 volts, 60 hz, 3 phase and raised to 230 Kv by step-up transformers. To reduce line losses and
cost of transmission the AC power is converted to DC power through a high voltage direct current ABB, (HVDC) rectifier. Two 250
MW capacity DC transmission lines carry the power ashore to a land based HVDC inverter, where it is converted back to AC for
connection with the grid.
A permanently moored semi-submersible platform with dimensions
of 300 ft. by 200 ft. supports the power plant and its associated
equipment. Design considers hurricane storm conditions and
temporary loss of gas supply with diesel storage to maintain
generation availability. Consideration is given to reducing pollution
by installing selective catalytic reduction (SCR) units to reduce
NOX on the HRSGs. The power plant may be operated similarly to
any land based combined cycle generating facility, with onboard
operators performing similar functions. The multiple turbines, gas
compressors and transformers built into the design provide a high
degree of redundancy.