GAS ENGINE OXY FUEL COMBUSTION FOR COMBINED HEAT AND POWER APPLICATIONS
Oxy-combustion; oxy-fuel; internal combustion engines; Otto cycle; gas engine; CHP; feasibility analysis; waste pyrolysis gas; RDF.
Oxy-fuel (oxy-fuel combustion) refers to the combustion process in which the oxidizer is pure oxygen or a mixture of oxygen with H2O or CO2 obtained through the recirculation of engine exhaust gases. The main objectives of this study were to evaluate oxy-combustion with different concentrations of CO2 and O2 as an oxidizer in internal combustion engines and using pyrolysis gas from municipal solid waste. The plant concept operates in cogeneration mode (Combined Heat and Power – CHP) where the heat rejected from the engine is used in the pyrolysis process of the solid substrate. Economic feasibility and ecological footprint were also addressed for a carbon capture and storage regime. To this end, a mathematical and numerical model was developed to analyze the thermoeconomic performance of the cogeneration plant. Numerical predictions confirmed the feasibility of the cogeneration plant in the range of 2 MW, with 43% of thermal efficiency in the steady state. Increases of the order of 5% in the concentration of CO2 as a diluent imply a decrease of at least 150 °C in the exhaust temperature, and an increase in carbon capture of at least 25% among the simulated oxy-fuel scenarios. The simplified economic feasibility analysis indicates the possibility of implementing a CHP plant based on the burning of waste pyrolysis gas at the Brasilia Sanitary Landfill.