Gas biofuels: study of fundamental properties of combustion using the divergent channel technique and oxy-combustion at high temperatures and pressures

Abstract

The development and validation of chemical kinetics combustion mechanisms require the knowledge of fundamental properties of fuel mixtures in the different operating conditions of piston engines and gas turbines. Among these properties, the laminar flame speed, Su. In this research project we intend to study the Su of real and synthetic mixtures of biogas (CH4/CO2/N2) and synthesis gas (CO/H2/CH4/CO2/N2) burning in air and in an oxy-combustion atmosphere, investigating how the variation of composition, equivalence ratio, initial temperature and pressure affect the laminar burning velocity. Understanding the chemistry of the gas phase under an oxy-combustion atmosphere and developing the appropriate kinetic reaction models are essential to establish the design and operation of advanced biomass combustion systems under oxy-combustion conditions. The determination of Su under oxy-combustion conditions is, therefore, essential to prove the reliability of the chemical kinetics of combustion mechanisms under these conditions. To carry out the experimental measurements, the innovative technique of flat flame, produced in an externally heated divergent channel burner will be used. A test bench will be assembled and validated throughout the project. The bench uses a set of mass flow controllers that feed a quartz micro burner that allows viewing the position of the flame in the divergent section of the channel and extracting the Su values. The combined effect of pressure and temperature will be studied by inserting the micro burner in a properly instrumented pressure vessel. The bench will be designed to work with starting pressures up to 10 bar and starting temperatures up to 650 K. (AU)