Gas to Liquids (GTL)
GTL is the term used to describe the chemical conversion of a gas into synthetic crude (Syncrude) by the Fischer-Tropsch (FT) synthesis process. The Syncrude is then refined by traditional methods to produce ultra-clean liquid transport fuels. As a feedstock, the process uses synthesis gas (Syngas) generated from the gasification of solid, liquid or gaseous carbon rich materials, such as coal or natural gas. Linc Energy is planning to use Syngas from Underground Coal Gasification (UCG) to produce liquids commercially using GTL.
The following three main steps comprise the GTL process:
- Gas treatment: Removes impurities from the UCG Syngas.
- Fischer-Tropsch synthesis: Produces Syncrude through catalytic reactions.
- Product work-up and refining: Separates liquids and waxes and refines into final products.
Coal derived Syngas (such as UCG Syngas) contains various impurities that must be removed to meet specifications to run an efficient GTL plant. Some impurities act as poisons to catalytic reactions in the GTL process, reducing the efficiency of the process. Such impurities include condensed oils, solid particles, arsenic, mercury, oxygen, sulphur compounds and carbon dioxide. These originate from the coal itself or its gasification. Impurities are removed from the gas and their absence enables high conversion to liquid fuels over a prolonged period. On the completion of gas treatment, the Syngas is free of impurities and is rich in hydrogen and carbon monoxide, which are the basic elements needed to manufacture Syncrude.
Did you know?
- UCG means coal is accessed underground, without the need for a surface mine.
- New technology, such as directional drilling, and demand for energy, are driving expansion in the Syngas industry.