GTL as a Potential Source of Future Clean Transportation Fuels

Abstract There are several technologies that could be useful in substituting natural gas-based liquid fuels for oil-derived fuels. They include gas to liquids (GTL), methanol, DME, LPG, and gas hydrates. Natural gas can be used as the raw material for manufacturing GTL fuel, producing a final petroleum product (middle distillates, gasoline, or jet fuel) that has extremely clean properties, basically free of sulfur and nitrogen. Perhaps the biggest challenge for the petroleum industry over the next decade is to develop the technology for economical conversion of natural gas to liquid (GTL) to obtain such products as methanol, benzene, gasoline, and diesel. Consequently, there are great research activities in both industry and academia to develop such strategies for GTL. In the last few years, there has been a steady improvement in GTL technology, most notably involving air separation, membrane technology, improved selectivity/activity catalysts for syngas conversion, and the Fischer-tropsch process. It should be noted that all GTL projects are also very sensitive to both the base cost of gas and the tax regime for capital costs. Many prospective host countries for GTL projects-such as Qatar-have been willing to ask a moderate price on gas feedstock for either LNG or GTL projects. Increasingly, in order to encourage GTL as an alternative to LNG exports, many natural gas producers-and their state oil companies-are willing to give substantial tax break to get GTL projects up and running. Around the world there are substantial volumes of gas often associated with production of oil from offshore fields, that are either flared, re-injected or remain unused because of the lack of ways to bring the gas to market. Up to 30 per cent of the world's discovered gas can be considered stranded according to GTL. This gas can be bought cheaply and then converted into liquids, essentially, at the moment, methanol. Methanol, also known as methyl alcohol or "wood alcohol" can provide the building blocks for a number of other chemical products. They are predominantly formaldehyde, methyl tertiary butyl ether (MTBE) and acetic acid. A number of other products are possible. World demand for methanol is put at 29 million tones a year by GTL. Since 1997 average annual growth in demand has been approximately 3.5 per cent a year, with a particularly strong demand in Asia. Natural gas is expected to play an expanding role in meeting rising Asian energy demand. The use of natural gas as an energy source in Asia in 1999 was 10 percent of total primary energy use, which was substantially lower than the world average of 23 percent, suggesting tremendous room for grow natural gas is mainly used in Asia for electricity generation and petrochemical feedstock. Petroleum fuels such as gasoline and light oil have dominated as the primary transportation fuels because of the convenience of handling, storage, and transportation for such fuel that can be kept at ordinary temperatures. If natural gas can be imported after converting it into ordinary-temperature liquid fuels, the use of gas in the transport sector could substantially increase.