ABSTRACT
The Fischer–Tropsch synthesis, in which low molecular hydrocarbons are catalytically converted to liquid hydrocarbons, is the most fundamental reaction in the gas-to-liquid (GTL) process. GTL technology has gone through significant changes in the nearly 200 years since the discovery of Fischer–Tropsch synthesis. Prior to the year 2000, most of the commercial GTL facilities were medium-scale plants, while between 2000 and 2010, large-scale GTL plants were commissioned. The last decade, however, has seen the emergence of newer GTL plants, the so-called mini GTLs and modular GTLs, with significantly reduced production capacity. There are several driving forces behind these changes, including gas-to-oil price ratio, volatility in the gas market, the large capital expenditure of GTL facilities and the development of shale-gas in the U.S. In addition to the large economic benefits stemming from the valorization of stranded and associate gases, GTL is widely acknowledged as clean-burning fuel, due to its zero sulfur and aromatic contents. Due the very fundamental nature of the Fischer–Tropsch synthesis in the GTL reactors, large quantities of water are produced along with liquid hydrocarbons. This chapter provides an overview of GTL process water generation, current technologies to process water separation and treatment, and the fundamental aspects of TiO2 mediated photocatalytic removal of non-acid oxygenated (NAO) hydrocarbons, such as aldehydes, ketones, and alcohols.
