Qatargas' onshore operations occupy a site within Ras Laffan Industrial City on a plot of land 7.8 square kilometres in area. The original plant consisted of only three trains to process the natural gas from offshore into the export product known as Liquefied Natural Gas (LNG). The capacity of these first three trains is 10 million tonnes per annum (mtpa) of LNG.
Through step out technologies a new era of mega-trains began. In 2009, Qatargas' Trains 4 and 5 began operating, each with a capacity of 7.8 mtpa. In late 2010 Qatargas' Train 6 began producing LNG followed by Qatargas' Train 7 in early 2011. Qatargas' Trains 6 and 7 each have a capacity of 7.8 mtpa.
Qatargas' onshore facilities include 14 LNG trains, of which 6 are 'mega-trains' (each with a capacity of 7.8 mtpa). For pipeline sales gas to the domestic market, Qatargas operates the Al Khaleej Gas (AKG) trains, AKG-1 and AKG-2, supplying approximately two bscfd.
We also produce condensate feedstock for downstream industries as well as other associated products such as liquefied petroleum gas (LPG), ethane, sulphur and natural gas liquids (NGL). Qatargas also manages and operates Ras Laffan Helium Plants 1 and 2, with a combined liquid helium production capacity of 2.1 bscf per year.
The first step on the onshore facilities is the separation of condensate from gas. The separated condensate is stabilised and sent to storage to await export. The natural gas then flows to the liquefaction trains for processing into LNG. During the first phase of this process, sulphur compounds, carbon dioxide, and water are removed in stages. The gas is then chilled using propane and mixed refrigeration processes.
The heavy hydrocarbons are separated out and fractionated into liquefied petroleum gas (LPG) and plant condensate. The cryogenic main heat exchanger in each train then cools the gas to approximately - 150 °C, liquefying it in the process. Finally, as the pressure is reduced to almost zero, the temperature decreases to - 162 °C, nitrogen is removed and LNG is transferred to one of the storage tanks prior to being loaded into a LNG vessel.