TABLE OF CONTENTS Dennis J. O'Rear and Fred Goede
ChevronTexaco Corporation, 100 Chevron Way, P.O. Box 1627, Richmond, CA 94952 Sasol Limited, Baker Square West, 33 Baker Street, Rosebank 2196, South Africa
Life Cycle Assessments (LCA) of Gas-To-Liquids (GTL) processes and conventional petroleum refining have found comparable Green House Gas (GHG) emissions1 ,2. In the GTL system, higher GHG emissions are associated with the production phase are offset by lower GHG emissions in the use phase. While about 1/3 rd of the carbon in the natural gas ends up as CO 2 during the GTL process step, portions of this CO 2 are concentrated in various streams in the process. LCA studies have indicated that conventional amine scrubbing coupled with sequestration can be used to capture most of this CO 2 thus giving GTL an advantage over conventional refinery based systems. However, the conventional amine scrubbing/sequestration approach suffers a high capital cost - approximately 30% of the costs to make the syngas3 -- primarily associated with compressing the captured CO 2. This paper explores improvements over the conventional amine scrubbing/sequestration system. The two general approaches are improved absorption systems and reaction systems.
As noted, a significant cost for CO 2 sequestration in a GTL facility is associated with the compression of the captured CO 2. In the conventional amine scrubbing system, the CO 2 is freed from the amine by reducing its pressure and raising the temperature. The CO
