Underground Coal Gasification (UCG) is the process of reacting subsurface coal with an oxidant (air, enriched air or oxygen) and steam via an injection well to produce a mixture of gases known as synthesis gas (syngas) which is extracted from a linked production well. The process avoids mining related costs, hazards and emissions and eliminates surface handling of coal and post-combustion ash.
CGE's UCG CRIP method (Controlled Retractable Injection Point) creates dedicated in-seam boreholes, using drilling and completion technology adapted from oil and gas production. The key feature of the process is a moveable / retractable injection point. The method is combined with directional inseam drilling, and generally uses oxygen or enriched air for gasification. This process produces a uniform syngas composition due to better control of gasification chamber growth and movement and keeping the position of the ignition point relatively close to the fresh coal seam.
The UCG technology has been developed over the last 20 years by CGE’s Technical Director, Dr Michael Green and proven in the successful European UCG trial conducted in Spain between 1992 and 1999. Dr Green has continued to further develop the process used in this trial from the trial’s conclusion to the present day.
