CH4_Comb_PPwithCO is methane combustion property package containing CH4, O2, CO2, CO, H2O, N2 ch4_comb_reactionWithoutKinetics is methane combustion reaction package. Only expresses stoichiometry and heat of reaction without kinetic parameters. methane_boiler_heater models heat duty of reactor directly transferred to water stream by Heater unit. methane_boiler_flue_heatexchanger models reactor exit flue gas exchanging heat to water by a HeatExchanger unit. Solves for HX area and water flow rate with fixed deltaTemp.