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Abstract

The process of Underground Coal Gasification (UCG) bears the potential to produce medium to high calorific syngas for several industrial applications, e.g. electricity generation in the frame of the Integrated Gasification Combined Cycle (IGCC) concept; or Coal-To-Liquid (CTL) technologies as the Fischer-Tropsch synthesis. In view of preferred environmentally sound operations and stable gas qualities for these applications previous global UCG research led to considerable process experience. Despite this knowledge background however UCG still remains a challenging technology as many physical and chemical sub processes are not sufficiently traceable by aboveground instrumentation, in turn hampering enhancement of overall process efficiency and engineering performance. In this context equilibrium modeling becomes a useful strategy to gain a better process understanding of coal gasification at different depths and its related engineering geological boundary conditions (i.e. coal type, p/T conditions and overburden water influx). The recent CO2SINUS project thus investigated sensitivities of various boundary conditions on establishing optimized gas qualities at simultaneous minimum tar production rates during active operation by using a new selfdeveloped thermodynamic model. The main potential of this model approach is seen in the pre-assessment of individual field boundary condition effects, amongst other criteria indicating coal type related gas qualities as well as tar related long-term groundwater pollution risks. © Springer International Publishing Switzerland 2015.