New technology based on an intermediate closed propane loop that uses seawater as the heating medium for vaporising LNG has been accepted by the market, after the delivery of the first vessels to feature regasification.
The first ship to complete its official regasification test was Golar LNG’s 138,000m3 LNG floating storage and regasification unit (FSRU) Golar Winter.
“Golar Winter’s acceptance followed testing of two skids to be operated in parallel at full regasification capacity of 14 million Sm3/day at 120 bar, equivalent to 460 tonnes/hr. This is a major achievement in bringing new technology to the market,” said Reidar Strande, director of LNG Marine, Hamworthy Gas Systems, which supplied the onboard vaporiser system comprising three LNG regasification skids.
“The intermediate propane circuit between seawater and LNG is applied to avoid freezing. As it is based on seawater heating the equipment has a high level of efficiency and therefore requires less fuel and operating cost to regasify the LNG than steam-based systems. This is a milestone in the introduction of another new technology to the offshore market.”
Hamworthy signed a contract with Golar LNG in July 2007 and delivered the three propane re-gasification skids. Capacity per skid is 7 million Sm3/day; outlet pressure is 103 bar and outlet temperature up to 6°C. Two skids will be used during nominal send-out, with a third on standby.
Each 70-tonne skid is 10.5m long, 6.1m wide, 8m high, and contains the required pumps, motors, heat exchangers, instrumentation and control systems to provide the required capacity. The equipment is designed for marine installations and cryogenic working conditions and can handle large variations in send-out capacity. Only proven equipment with extensive references was included in the delivery.
Chartered by Petrobas, Golar Winter is part of an LNG import project in Guanabara Bay, Brazil. LNG carriers will tranship their cargoes to the FSRU, which will then send gas to an onshore gas grid through a subsea pipeline. Golar Winter was built as an LNG carrier in 2004, and converted into an FSRU by Keppel Shipyard in Singapore. After leaving the Keppel yard at the end of May, Golar Winter collected a cargo of LNG in Trinidad en-route to Petrobras's Pecem Terminal, Brazil. Initial commissioning and testing began in Pecem before the vessel departed for Petrobras's Rio terminal for a further period of testing.
Hamworthy’s next onboard vaporiser system to be commissioned is on the 145,000m3 LNG shuttle regasification vessel (SRV) Suez Neptune, delivered in December 2009 by Samsung Heavy Industries. The vessel went on to pick up an LNG cargo in Trinidad and is undergoing regasification tests off Boston, Massachusetts, which are due completion in mid-February. Suez Neptune is to be followed by a second Neptune SRV, Suez Cape Ann, to be delivered in the second quarter of 2010. Both SRVs are for Höegh LNG.
SRVs are designed to transport and store LNG, then vaporise it into natural gas that can be sent ashore by subsea pipeline. Hamworthy is supplying three regasification skids per ship. Each ship set will have regasification capacity of 210 tonnes/hr of LNG with send-out pressure of 115 bar.
Hamworthy’s third regasification project was for the 126,000m3 FSRU Golar Freeze for Dubai Supply Authority (DUSUP) and Shell in Dubai; Hamworthy delivered the regasification skids for this vessel in September 2009. The system was installed on the 1977-built LNG carrier that is being converted into an FSRU before being time chartered by DUSUP for 10 years, with options to extend for up to another five years.
After its delivery to DUSUP in the second quarter of 2010, Golar Freeze will be permanently moored alongside a purpose-built jetty within the existing Jebel Ali port. The FSRU will be capable of storing 125,000m3 of LNG and delivering up to 14 million m3/day (about 3 MTA) of regasified LNG to DUSUP, for further delivery into the Dubai gas network. As DUSUP's adviser, Shell has worked closely with Golar LNG in the development of this project.
“Onboard LNG regasification is a good example of Hamworthy’s offshore oil and gas innovations,” Mr Strande said. Hamworthy’s offshore business is expanding, complementing its marine and onshore activities. Hamworthy specialists have extensive experience and know-how in supporting the offshore exploration and production sector with environmentally friendly, innovative and integrated equipment solutions. These benefit vessels engaged in every stage of oil field development, from exploration and construction through to production and maintenance.