The power turbine system includes two power turbines communicating with an ion transport membrane (ITM) reactor. Heavy liquid fuel is atomized and burned within the reactor to drive the first turbine, with the first turbine producing useful power. Exhaust from the first turbine is recycled back into the reactor. The reactor includes a series of concentric cylindrical ion transport membranes that separate atmospheric and exhaust gases into suitable components for combustion therein, with at least some of the gases being “cracked” to alter their molecular structure for further combustion to power the second turbine. The second turbine drives a compressor to supply air to the reactor. At least one of the ITMs precludes atmospheric nitrogen from the combustion processes, with the resulting exhaust including pure water and carbon dioxide. The carbon dioxide is either recycled into the reactor to facilitate fuel atomization, or compressed for sequestration.