In June this year, production started at the giant Pearl GTL (Gas To Liquids) petrochemicals plant at Ras Laffan Industrial City in the State of Qatar. Rotork is a major source of electric and fluid power valve actuators for this project, construction of which began in 2006. Built under a development and production sharing agreement between Shell and the Government of the State of Qatar, Pearl GTL has been one of the largest industrial developments in the world, employing more than 50,000 workers on a building site the size of New York's Central Park.
Pearl GTL is a fully integrated project, spanning production from an offshore gas field to finished marketable commodities. Gas flows from two platforms on the newly developed North Field, 60km offshore, through two underwater 30in diameter pipelines to Ras Laffan, where a gas separation plant extracts ethane, LPG and condensates. The ethane is used locally to make ethylene, the LPG is generally used for heating and cooking, and the condensates are used as refinery feedstocks. Extracted sulphur is pelleted for the production of fertilizer and other valuable products.
What remains is a clean methane gas, which flows into the GTL plant. Designed with proprietary Shell technology, the plant produces clean burning diesel and kerosene, base oils for top-tier lubricants, naphtha for the manufacture of plastics and paraffin for the production of detergents.
When fully operational in 2012, the Pearl project is expected to produce 1.6 billion cubic feet of gas per day from the North Field. This will be processed to deliver an expected 120,000 barrels per day of condensate, LPG and ethane and 140,000 barrels per day of GTL products. In total, Pearl GTL will add almost 8% to Shell's worldwide production.
Many of the Rotork actuators on the project are Fieldbus Foundation network enabled and linked to the Pearl control room, the nerve centre of one of the largest and most sophisticated process control systems in the oil and gas industry. The control room comprises almost 1,000 control cabinets hosting 200 computer servers, programmed with 12 million lines of software code. The system is linked to every part of the plant by almost 6,000km of control cables.
The Pearl project has been developed in line with sustainable principles, using technologies that help to limit any environmental impact. For example, the site sits in the desert, where temperatures can exceed 40°C and rainfall is slight. Therefore Pearl is designed to be self-sufficient in terms of water use. The GTL process produces one barrel of water for every barrel of product when the hydrogen in the natural gas reacts with oxygen. This water can be treated at a rate of up to 300,000 barrels a day and recycled for use in the GTL plant and irrigation at the site.
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