TABLE OF CONTENTS The oxygen supply to a gasifier is one of the most expensive parts of any gasification project. Cost estimates for various different IGCC projects put the ASU with its associated compressors at between 10 and 15% of the total plant cost. It also makes a xssignificant contribution to overall operating costs, the power requirement for compression being of the order of magnitude of 5-7% of gross generator output. The arrangement for oxygen supply is one of the most important early decisions in any gasification project.
This decision on oxygen supply is not only technical, but also to a high degree commercial. This is because the industrial gas market is dominated by a small number of highly competitive companies who are not only able to build oxygen plants for third parties, but are also willing to build and operate their own plants close to or even on a client's site and supply oxygen and other gases "over the fence". In some parts of the world these companies have their own extended pipeline networks, which can also be integrated into the oxygen supply strategy for a gasification project.
Since the commercialization of the Linde-Fr nkle process in the 1920s, oxygen supply has been dominated by cryogenic technology.
The principle features of cryogenic air separation are shown in Figure 8.1. Air is compressed, dried in a pre-purification unit, and cooled to its liquefaction temperature. The liquid air is then distilled into its two main constituents, oxygen and...
