Low-calorific gasification of underground coal with a higher humidity

• Possibilities of increasing the UCG efficiency in coal with a higher humidity.
• Experimental gasification equipment.
• Laboratory trials of underground coal gasification.
• Syngas composition analysis in term gasification front propagation.
• Exploration of the gasification method with moving exhausting pipe.

The technology of underground coal gasification (UCG) belongs to the group of so called clean coal technologies. It can form a product called syngas, which can serve as a fuel for energy production or can be further processed in the chemical industry. This technology can gasify coal underground which cannot be mined by current methods from economic and technological reasons. Like any technology, UCG also has its limitations. One of them is the high humidity of coal (40%). Article, based on long lasting experimental research, analyzes the possibilities of increasing the UCG efficiency. Especially for lignite with a higher humidity content using only air as an oxidiser. It analyzes the creation of syngas components (CO, H2H2, CH4CH4), its calorific value during the process in a special laboratory equipment for UCG research. It was demonstrated that the calorific value and syngas quality also depends on the location of sampling point. Based on this knowledge, the principle of a new method, that for the above mentioned conditions (low-calorific coal with a higher humidity), improves the UCG technology from the point of syngas quality and is mentioned in the conclusion.