A systematic framework is developed for the thermo-environomic modeling, analysis and optimization of fuel decarbonization processes using precombustion routes to decarbonize the fuel by CO2 removal before burning the purified H2-rich gas in a gas turbine for power generation. For each process step, the different technological options are summarized in a process block flow diagram. For the syngas synthesis coal and biomass gasification, steam and methane reforming, partial oxidation with pure oxygen or air, and autothermal reforming are considered. For the CO2 capture chemical absorption, adsorption and membrane processes are investigated. The different process options are analyzed and optimized with regard to energy efficiency, economic and environmental performances by applying a systematic methodology based on energy-flow models, process integration techniques, and a multi-objective optimization procedure. The conceptual process design allows assessing the energetic, economic and environmental cost of carbon capture. The influence of process integration on the performance is highlighted based on the optimization of the polygeneration of heat, power and fuel.