A work on soot emission control simulation in stoker-fired boiler by secondary air has been done. Some models such as k-e, combustion, radiation, and soot Khan-Greeves have been adopted. Soot production and emission h...A work on soot emission control simulation in stoker-fired boiler by secondary air has been done. Some models such as k-e, combustion, radiation, and soot Khan-Greeves have been adopted. Soot production and emission has been reduced by secondary air; the highest mass concentration is reduced from 7.46 × 10^-14 to 6.94 × 10^15; mass concentration of soot is decreased from 1.12 ×10^-15 to 9.25 ×10^-32 in the upper areas.展开更多
The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated...The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated the physical and chemical properties mainly in particulate matter. However, the characterizations have not extended diameters below to 1.0 μm. In this study, it described chemical composition and shape measurements of individual aerosol particles with 50% cut-off diameters less than 1.1 μm emitted at ceramic-tile manufacturing. Four emission sites of process were selected, and their samples were collected using a cascade-impactor, investigated using X-ray diffraction, energy dispersive X-ray spectroscopy, and digital image processing, where the data were analysed applying a combination of principal component and cluster analysis. Particles of tectosilicate （quartz, zeolite）, phyllosilicate （illite, montmorillonite）, and inosilicate （calcium silicate） were founded in all sampling sites; also, silicates mixed with transition metals oxides used as pigments （e.g., Fe, Ti, Co, Ni, Zn and Mo）. Silicates were granulated and flat crystals with a transparent, translucent appearance; otherwise, the mixture had flake shapes and opaque appearance. Analyses of multivariate data showed that the process stages emissions were related with specific composition and shape suggesting the use three measurements related （1） the internal axis, （2） roundness and （3） roughness to isolate particles shapes, and the presence of transition metals oxides as emissions tracer of the ceramic industry.展开更多
Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investig...Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investigated experimentally. The burner consists of two coaxial jets： methane flowing out of the inner, oxidizer from the outer. The flame behavior is studied according to the proportion of oxygen in the oxidizer jet, the oxidizer and the methane jets velocities. The flame is either anchored to the burner, lifted, stationary or not or blown-out. The addition of oxygen produces a decrease of the lift height, a reduction of the length of the reaction zone and an increase in the soot emission. These results have been reported into diagrams of stability where the flame configurations are connected to the competition between the dynamic effect of the injection velocity and the chemical effect of oxygen addition.展开更多
文摘A work on soot emission control simulation in stoker-fired boiler by secondary air has been done. Some models such as k-e, combustion, radiation, and soot Khan-Greeves have been adopted. Soot production and emission has been reduced by secondary air; the highest mass concentration is reduced from 7.46 × 10^-14 to 6.94 × 10^15; mass concentration of soot is decreased from 1.12 ×10^-15 to 9.25 ×10^-32 in the upper areas.
文摘The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated the physical and chemical properties mainly in particulate matter. However, the characterizations have not extended diameters below to 1.0 μm. In this study, it described chemical composition and shape measurements of individual aerosol particles with 50% cut-off diameters less than 1.1 μm emitted at ceramic-tile manufacturing. Four emission sites of process were selected, and their samples were collected using a cascade-impactor, investigated using X-ray diffraction, energy dispersive X-ray spectroscopy, and digital image processing, where the data were analysed applying a combination of principal component and cluster analysis. Particles of tectosilicate （quartz, zeolite）, phyllosilicate （illite, montmorillonite）, and inosilicate （calcium silicate） were founded in all sampling sites; also, silicates mixed with transition metals oxides used as pigments （e.g., Fe, Ti, Co, Ni, Zn and Mo）. Silicates were granulated and flat crystals with a transparent, translucent appearance; otherwise, the mixture had flake shapes and opaque appearance. Analyses of multivariate data showed that the process stages emissions were related with specific composition and shape suggesting the use three measurements related （1） the internal axis, （2） roundness and （3） roughness to isolate particles shapes, and the presence of transition metals oxides as emissions tracer of the ceramic industry.
文摘Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investigated experimentally. The burner consists of two coaxial jets： methane flowing out of the inner, oxidizer from the outer. The flame behavior is studied according to the proportion of oxygen in the oxidizer jet, the oxidizer and the methane jets velocities. The flame is either anchored to the burner, lifted, stationary or not or blown-out. The addition of oxygen produces a decrease of the lift height, a reduction of the length of the reaction zone and an increase in the soot emission. These results have been reported into diagrams of stability where the flame configurations are connected to the competition between the dynamic effect of the injection velocity and the chemical effect of oxygen addition.
