In one aspect, an embodiment of the present disclosure provides an Integrated Gasification Combined Cycle (IGCC) apparatus. The apparatus includes a saturator configured to saturate NPG with water vapor, and a heat recovery steam generator (HRSG), a low pressure steam loop through the saturator, wherein the HRSG is configured to heat the low pressure steam loop. The apparatus further includes a compressor and a heat exchanger configured to heat the NPG using waste process heat and extraction air from the compressor, wherein the heated NPG thereby becomes diluent nitrogen.