Qatar Gas I LNG Plant, Ras Laffan, Qatar

Qatar Liquefied Gas Company Ltd (Qatar Gas) was established to build, own and operate a 7.2 million tonnes per annum (mtpa) liquefied natural gas (LNG) plant in Qatar, using the giant North Field reservoir gas as feedstock, and to market the resultant LNG product. Qatar Gas is a joint venture company with five shareholders: Qatar General Petroleum Corporation (QGPC 65%); Total SA (10%); Mobil Qatar Gas Inc (10%); Mitsui & Co Ltd (7.5%); and Marubeni Corporation (7.5%).

The Qatar Gas I project involved the construction of a new LNG plant from scratch with all attendant infrastructure, such as LNG storage tanks, loading jetties and three liquefaction process trains (designated Trains 1, 2 and 3). The engineering procurement and construction (EPC) contract for the three process trains and the inclusive infrastructure was estimated at $2.3 billion. The plant was completed in 1997 and has over sold its entire capacity every year since. The main buyer is Chubu Electric of Japan (requiring LNG for gas-fired power stations) but additional sales have been made to a number of other buyers including Gas Natural in Spain and British Gas for the US market.

The existing fleet for LNG transport is 16 vessels, but the fleet is growing all the time as demand is high. In existing markets in 2004 global demand is approximately 150mtpa. Market analysts expect that between 2000 and 2030, LNG demand is going to increase five-fold. Qatar Gas has long-term plans to increase its LNG exports above 70mtpa by 2010 (expansion is ongoing - Qatar Gas II, and proposals are being considered for a further expansion, Qatar Gas III).

PROJECT MANAGEMENT

Within Qatar Gas, a Plant Project Task Force Team (PTF) was established to manage and supervise the EPC contractor, Chiyoda Corporation (Japan). The PTF, which consisted of a Project Director and about 35 staff at the project peak, was located at Chiyoda's Yokohama office during the engineering and procurement phase, and subsequently relocated to Ras Laffan, Qatar, during the construction and pre-commissioning phase of the project to provide supervision continuity.

THE LNG PLANT

• Number of process trains: 3
• Feed gas per train: 420mmscfd
• LNG capacity of each train: 2.4mtpa or 300t/hr
• Sulphur recovery: 120t/day x 2 trains
• LNG tanks: 85,000m³ x 4

Engineering work started with the verification of the front-end engineering design (FEED) package provided by the owner, which required the complete re-design of the acid gas removal unit, sulphur recovery unit, associated utilities and plot plan. Procurement work covered the assignment to Chiyoda of purchase orders for long-lead delivery items ordered by the owner in advance of the EPC award. Construction of the project started with the site preparation and infrastructure development, such as a 35km access road and camp facilities. The construction phase of the LNG process trains, jetty loading areas and storage tanks for the project required:

• Overall labour man-hours spent: 66.5 million
• Concrete poured: 182,600m³
• Steel erected: 9,300t
• Piping installed (pipe weight base): 28,000t
• Weight of equipment installed: 32,000t

PROJECT TIMESCALE

Plant Hand-Over (PHO) of the first train was achieved in September 1996, 39 months from contract award and PHO of the second train occurred three months later - both ahead of the contractual schedule. The optioned third train was awarded in July 1995, and PHO was achieved in March 1998, 32 months from contract award, 8 months ahead of schedule. The first LNG carrier departed Ras Laffan port in December 1996, delivering the initial shipment to the Kawagoe Terminal in Japan to a Japanese buyer, Chubu Electric Power Inc, where the world's largest LNG-fed power plant (4,700MW) was waiting for the first delivery.

LNG TRAIN DEBOTTLENECKING

In December 2001 Qatar Liquefied Gas Company (Qatar Gas) awarded an EPC contract (€100 million) to a joint venture between Technip and Chiyoda to expand the LNG facility located at Ras Laffan. Technip / Chiyoda carried out detailed engineering, procurement and construction for the debottlenecking of the three LNG process trains.

The work involved replacing or upgrading some of the key process equipment, such as compressors and turbines, in order to expand the capacity of each of the three LNG trains from 2mtpa to 3mtpa. The engineering upgrades are being executed during four shutdowns, scheduled between 2002 and 2005, of about one month each. Two of the three trains, originally designed and built by Chiyoda, have already been successfully debottlenecked and the upgrade to the third train is scheduled for completion in spring 2005.

NEW SHIPPING

Mitsui Engineering & Shipbuilding Company Ltd (MES) has completed and delivered a 135,000m³ type LNG carrier 'DUKHAN' (Hull No.1561) which had been under construction at its Chiba Works. This is the latest addition to the LNG transport fleet operated by Qatar Gas.

The ship is designed to have ship-shore interfacing at all major LNG terminals in North America, Europe and Japan. To establish a low boil-off rate of less than 0.15%/day, the insulation of the spherical aluminium tanks is made of a polystyrene construction and the supporting material of the tank is made of stainless steel.

The ship is equipped with a vaporising system to forcibly vaporise LNG so as to utilise this 'boil off' gas as fuel to supply the engines. Two safety valves are installed to prevent any abnormal pressure increase in the LNG tanks caused by excessive evaporation of boil off gas due to untoward temperature changes. The ship, which has a low complement of crew members, is capable of one-man bridge operation. The gas pumping system (cargo pump) is equipped with a soft start system and an inverter; this prevents damage to the piping when the cargo pump starts.