Gasification Process

Step-by-step

Gasifying coal involves dismantling its molecular structure (by combustion) and reassembling the resulting hydrogen and carbon as methane gas (methanation), which is then sent to a pipeline. The heart of the Synfuels Plant is its 14 gasifiers. These gasifiers are cylindrical pressure vessels, 40 feet high with an inside diameter of 13 feet.

Each day 18,000 tons of lignite are fed into the top of the gasifiers.
Steam and oxygen are injected into the bottom of the coal beds causing intense combustion: 2,200 degrees F.
The hot gases break down the molecular bonds of coal and steam, releasing compounds of carbon, hydrogen, sulfur, nitrogen and other substances to form a raw gas that exits the gasifiers.
The raw gas is cooled.
Tar, oils, phenols, ammonia and water coproducts are condensed from the gas stream and purified and sent on.
The gas moves to a cleaning area where further impurities are removed.
Methanation occurs when the cleaned gas passes over a nickel catalyst causing carbon monoxide and the remaining carbon dioxide to react with free hydrogen to form methane.
Carbon dioxide is removed.
The gas is then cooled, dried, and compressed, and enters the pipeline with a heating value of 975 Btu per cubic foot.