Production flow of the Japan-GTL process. Click to enlarge.

The Japan-GTL process differs from technologies advanced by Sasol in South Africa and Shell in that it utilizes carbon dioxide gas as raw material and does not require any oxygen supply for the syngas reaction.

The GTL process uses innovative catalyst technology in both the syngas reformer and in the Fischer-Tropsch (FT) reactor. Syngas is produced by steam (H₂O)/CO₂ reforming rather than autothermal reforming (ATR) or non-catalytic partial oxidation (POX) used in other processes. The Fischer-Tropsch synthesis uses a slurry reactor with noble metal or non-noble metal catalysts, as compared to the copper or iron-based catalysts used in conventional processes.

The new GTL process is particularly effective when applied to natural gas feedstock containing 20-40 mol% of CO₂. The most preferable CO₂ content in the feedstock is around 30 mol%. In case the CO₂ content is less than 30 mol%, additional CO₂ can be supplied from other sources, such as flare gas, associated gas, remaining CO₂ from Enhanced Oil Recovery operations or exhaust gas from oil refineries or LNG plants.

The process eliminates the need for three expensive components:

• An oxygen supply plant;
• A unit for CO₂ separation; and
• An H₂ separation unit to optimize gas composition.

This makes the Japan-GTL process an attractive option to monetize stranded gas reserves which are located far from an existing gas market and have been left untapped due to the high cost of purification and gas transportation methods. Many gas fields are rich in CO₂ and therefore difficult to develop commercially. As an example cited by one of the partners, JAPEX, the Natuna gas field in Indonesia has reserves of more than 200 TCF. Due to its high CO₂ content (70%), however, the separation cost would have a major negative impact on the feasibility of the development.

The demo plant is scheduled to run for two years, and will be followed by the planned opening of a 30,000-bpd commercial plant near a gas field.