Alternate Fuels for Use in Commercial Aircraft

The engine and commercial aircraft research and development communities have been investigating the practicality of using alternative fuels in near, mid, and far-term aircraft. Presently, it appears that an approach of using a “drop in” jet fuel replacement, which may consist of a kerosene and synthetic fuel blend, will be possible for use in existing and near term aircraft. Future mid-term aircraft may use a bio-jet and synthetic fuel blend in ultra-efficient airplane designs. Future, long-term engines and aircraft in the 50-plus year horizon, may be specifically designed to use a low or zero-carbon fuel. Synthetic jet fuels are manufactured, using a Fischer-Tropsch process, from coal, natural gas or other hydrocarbon feedstocks. These fuels are very similar in performance to conventional jet fuel, but have almost zero sulfur and aromatics. This may result in lower particulate exhaust emissions. In addition, synthetic fuels exhibit excellent low-temperature properties, maintaining a low viscosity at lower ambient temperatures. Thermal stability properties are also improved, resulting in less fuel system deposits. As synthetic fuels have very good performance, and have already been in use for many years in Johannesburg airport (Sasol fuel) it will be easy to supplement current jet fuel supplies with synthetic derived fuel. If the additional CO2 that is produced during the manufacturing process can be captured and permanently sequestered, synthetic fuel could be a good near-term supplement.