• Energy Research

Combustion of torrefied biomass for power generation has many advantages over combustion of raw biomass, one of which is lower emissions of chlorine-bearing gases. This is because partial evolution of these gases takes place during the torrefaction process; hence, the resulting torrefied biomass has a lower chlorine mass fraction than its raw biomass precursor. Research showed that, during torrefaction of corn straw, the predominant chlorinated species in the evolving gas (“torgas”) are CH3Cl and HCl. The former is more prevalent when torrefaction takes place at temperatures under 350 °C, whereas the latter is more abundant at higher temperatures. In this work, corn straw was torrefied at a furnace temperature of 300 °C for 20 min under atmospheric pressure in an inert nitrogen flow. Under this condition, corn straw lost nearly 40% of its original mass, along with 73% of its chlorine mass to the gas phase. To control the emissions of the chlorinated species, the torrefaction gas was heterogeneously reacte...

Combustion of torrefied biomass for power generation has many advantages over combustion of raw biomass, one of which is lower emissions of chlorine-bearing gases. This is because partial evolution of these gases takes place during the torrefaction process; hence, the resulting torrefied biomass has a lower chlorine mass fraction than its raw biomass precursor. Research showed that, during torrefaction of corn straw, the predominant chlorinated species in the evolving gas (“torgas”) are CH3Cl and HCl. The former is more prevalent when torrefaction takes place at temperatures under 350 °C, whereas the latter is more abundant at higher temperatures. In this work, corn straw was torrefied at a furnace temperature of 300 °C for 20 min under atmospheric pressure in an inert nitrogen flow. Under this condition, corn straw lost nearly 40% of its original mass, along with 73% of its chlorine mass to the gas phase. To control the emissions of the chlorinated species, the torrefaction gas was heterogeneously reacte...

Abstract Propane (C3H8) is being considered as an alternative refrigerant, besides being used as an alternative fuel, because of its low Global Warming Potential and zero Ozone Depletion Potential. Using blends of C3H8 with CO2 as refrigerants, diminishes the fire safety concerns in case of accidental leak of this flammable substance in refrigeration applications. This paper reports on the effects of CO2 on laminar burning speed and flame instability of C3H8/air blends at elevated temperatures and pressures. The flame structures were investigated in a Schlieren system. The laminar burning speeds of C3H8/CO2/air mixtures were measured in a spherical chamber and were fitted by a power-law mathematical correlation. The one-dimensional flame code from Cantera with kinetic model was also used to predict laminar burning speed. The high-speed photography showed that CO2 inhibits the flame instability because of its hydrodynamic and diffusional-thermal effects. Results showed that the laminar burning speed decreased with increasing CO2 mole fraction in the mixtures and that CO2 promotes the flame stability. The high temperature C3H8 oxidation was governed by the reaction of H + O 2 = O + OH . The effects of CO2 on laminar burning speed were mainly determined by the reaction of CO 2 + H = CO + OH and the high energy capacity (specific heat) of CO2.

Abstract Propane (C3H8) is being considered as an alternative refrigerant, besides being used as an alternative fuel, because of its low Global Warming Potential and zero Ozone Depletion Potential. Using blends of C3H8 with CO2 as refrigerants, diminishes the fire safety concerns in case of accidental leak of this flammable substance in refrigeration applications. This paper reports on the effects of CO2 on laminar burning speed and flame instability of C3H8/air blends at elevated temperatures and pressures. The flame structures were investigated in a Schlieren system. The laminar burning speeds of C3H8/CO2/air mixtures were measured in a spherical chamber and were fitted by a power-law mathematical correlation. The one-dimensional flame code from Cantera with kinetic model was also used to predict laminar burning speed. The high-speed photography showed that CO2 inhibits the flame instability because of its hydrodynamic and diffusional-thermal effects. Results showed that the laminar burning speed decreased with increasing CO2 mole fraction in the mixtures and that CO2 promotes the flame stability. The high temperature C3H8 oxidation was governed by the reaction of H + O 2 = O + OH . The effects of CO2 on laminar burning speed were mainly determined by the reaction of CO 2 + H = CO + OH and the high energy capacity (specific heat) of CO2.

This article presents a method for real-time simultaneous measurements of the temperature and soot volume fraction distribution of volatile matter flames, forming during combustion of biomass pelle...

This article presents a method for real-time simultaneous measurements of the temperature and soot volume fraction distribution of volatile matter flames, forming during combustion of biomass pelle...