(5a) Improving Design and Start-up Using a Virtual Plant

Bechtel is constructing a grass-roots liquefied natural gas (LNG) plant at Bioko Island in Equatorial Guinea, West Africa based upon the ConocoPhillips Optimized CascadeSM LNG Process. Work on the project began in March 2004 and is expected to be completed by last quarter of 2007. As part of the technology initiative, ConocoPhillips Company (COP) and Bechtel Corporation (Bechtel) have jointly developed Virtual Plant Technology for troubleshooting design problems, improving operator training and de-bottlenecking studies.

Quantifying the impact of Virtual Plant Technology on the design and training is the main thrust of this paper. Operations of the compressor control strategy were evaluated and insight obtained under upset conditions. Improvements in the inlet control strategy were identified in the Virtual Plant. Potential improvements within the DCS complex loop design and SIS logic were also identified with the Virtual Plant. Many set-points and SIS logic functions were modified based upon the Virtual Plant recommendations.

The Virtual Plant was installed at the site 5 months prior to first gas to conduct training of the operators. An extensive training program was conducted by the Bechtel/EGLNG operations team to train operators by simulating warm start-up, cool down/start-up of the Liquefaction section, recovery from compressor trips, recovering from SDP and ESDP situations and a host of other operating scenarios. The Bechtel/EGLNG operations team learned valuable lessons about the LNG Plant Operations. Many practice sessions were conducted to focus on key areas of the Plant.