Proven world natural gas reserves, which currently exceedrn5,000 trillion cubic feet (TCF), have been growing at a fasterrnrate than proven oil reserves. These gas reserves currentlyrnrepresent over 83% of the energy equivalence of proven oilrnreserves, of which about 75% is considered to be the lessrndesirable heavy crude. In some remote locations, wellheadrncosts of natural gas have been estimated to be belowrn$0.25/MMBtu, while the cost of reinjecting “associated” gasrnfrom crude oil production as an alternative to flaring mayrngreatly exceed its value. About 3,000 TCF of such gasrnreserves is considered to be “stranded”; I.e., accessible byrndrilling but located too far from potential markets forrneconomical transportation to those markets.rnThe chemical conversion of methane to liquid fuels andrnother higher value products or derivatives which may be morerncost effective to transport long distances from remote gasrnsources has therefore attracted renewed interest. Even thoughrnFischer-Tropsch (FT) synthesis is a technically proven gas-toliquidsrn(GTL) technology, the conversion of natural gas tornliquid fuels such as diesel and gasoline as opposed to higherrnvalue chemical products such as chemical grade methanol hasrnonly relatively recently been perceived to be a potentiallyrnviable commercial proposition. Recent advances in FTrnsynthesis technologies, particularly with regard to natural gasrnreforming and catalytic partial oxidation, coupled withrnanticipated increased demand for “clean” diesel fuel appear tornbe enhancing the economic viability of this route to GTL.rnThe focus of this paper is the prospective economics ofrnpromising technologies for FT based GTL diesel production.rnThe scope of this paper includes a brief discussion ofrnpotentially important new developments which could have arnsignificant impact on GTL process economics.
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