 |
|
GPA Research Data help save time, money in BG plant design
GPA Research Data help save time, money in BG plant design
Published in the Oil & Gas Journal, January 17, 2000
Authors: Megan Evans, J. J. (Roger) Chen, IPSI LLC, Houston, and Steve Jones, Sarah Lee, British Gas Tunisia Ltd., Sfax, Tunisia
Data from a GPA research program saved time and money in designing British Gas’ Hannibal gas plant, Sfax, Tunisia.
The plant, wholly owned and operated by British Gas Tunisia Ltd., was designed and constructed by IPSI LLC/Bechtel Corporation, Houston, and has been operating at full capacity since June 1996. The plant supplies more than 80% of the gas used in Tunisia.
Feed gas originates in the Miskar field, about 113 km offshore in the Mediterranean Sea. The plant is designed to produce 4.9 million cubic meters/day (MMcmd) of sales gas with less than 6.5 mole % nitrogen, a hydrocarbon dew point lower than –5oC., water content less than 80 ppmw, and a pressure of 75 barg.
The Process
The feed gas from Miskar contains more than 16% nitrogen and 13% carbon dioxide. The nitrogen must be removed down to 6.5% to meet the sales-gas specification. Water, BTEX (benzene, toluene, ethylbenzene, and xylene), and carbon dioxide must be reduced to low enough levels to allow cryogenic operation without solid precipitation. The design feed gas composition is shown in Table 1. An inlet feed gas rate of 7.13 MMcmd is required to produce the 4.9 MMcmd of sales gas specified. Fig. 1 shows all the major process units in the Hannibal gas plant.