QATAR - Gas Processing.

QP processes associated gas at its four NGL plants in Mesaieed (formerly known as Umm Said), which produce propane, butane and NGL for export and as feedstock to industries and fuel for water desalination and power plants. The plants have the capacity to produce 96,000 b/d of butane, propane, natural gasoline (NGL), naphtha, condensate (NGL), ethane-rich gas and methane.

NGL-1 came on stream in late 1980 to process associated gas produced from onshore Dukhan. Capacity: 1,350 tons/day of ethane-rich gas; 1,284 t/d of propane; 851 t/d of butane; and 588 t/d of NGL.

NGL-2 came on stream in late 1980 to process associated gas produced from the offshore fields. Capacity: 127 MCF/d of methane-rich gas; 1,145 t/d of ethane-rich gas; 1,079 t/d of propane; 899 t/d of butane; and 903 t/d of NGL.

NGL-3, or North Field Gas Plant (NFGP), came on stream several years later to fill the gap in Qatar's need of ethane as feedstock for the ethylene complex at Mesaieed and methane as feedstock for the fertiliser complex at the same industrial zone, as well as to produce LPG and NGL for export. Its capacity: 1,030 MCF/d of lean gas; 3,000 t/d of raw NGL; 3240 t/d of stabilised condensates; and 280 t/d of sulphur.

NGL-4, on stream in late 2002, has this capacity: 1.1m t/y of ethane; 1m t/y of propane; 700,000 t/y of butane; and 400,000 t/y of NGL. This plant processes gas and condensates from the second phase of Dukhan's Arab D gas recycling system and from the Arab C gas recycling system at the offshore field of Bul Hanine. Its ethane output is dedicated as feedstock to an ethylene complex at Mesaieed built for Q-Chem, a JV between QGPC and ConocoPhillips (see Qatar's petrochemical sector in DT 11). NGL-4 was built by a Snamprogetti/Hyundai partnership under a $400m EPC contract awarded in August 1999.

Fractionators at Mesaieed are inter-connected, so each one can process liquids either from the onshore or from offshore systems. They share export and storage facilities. The NGL-2 streams are combined, stripped and fractionated to produce additional liquids for export.

Onshore associated gas coming with crude oil is separated at degassing stations in Dukhan. The gas is collected from separators and, after compression at field stations, flows to Fahaheel's stripping plant. After the heavy ends are liquefied and removed, lean gas is routed to the domestic distribution system. Offshore associated gas is separated from oil at three GOSPs at ISND, Maydan Mahzam and Bul Hanine fields. The gas is compressed at each of the platforms. Mixed liquids are brought ashore through an 85 km marine pipeline and carried to NGL-2 at Mesaieed.

QP has had the control systems at NGL-1 and NGL-2 upgraded. It has a rich associated gas (RAG) utilisation system, which has covered modifications to the four NGL plants. This has enabled QP to handle 340 MCF/d of RAG from Dukhan, about 205 MCF/d of offshore RAG, 200 MCF/d of al-Shaheen gas and about 800 MCF/d of North Field gas. The system has reduced gas flaring, secured ethane to petrochemical producers and maximised product recovery.

LPG Output/Exports: Together with the above-mentioned plants, the big number of LNG export trains will raise Qatar's production of LPG to 14m t/y by 2012, from 4m t/y in 2005. With Saudi Aramco to divert most of its LPG output for local ventures producing petrochemicals, this will make Qatar the largest exporter of the butane-propane mix in the world.

Having begun to build up the biggest fleet of LNG tankers in the world (see Gas Market Trends No. 11), QP intends to acquire up to 30 LPG tankers of 80,000 m3 each.