Effect of refractory agent on ash fusibility temperatures of briquettet

To solve the problem of the low ash fusion point of briquette, this paper reported that the ash fusibility temperatures can be elevated by changing ash ingredients through blending refractory agents in briquette ash, which will create favorable conditions for moving bed continuous gasification of briquette with oxygen-rich air. The effects of A1203, SiO2, kaolin, dry powder and bentonite on ash fusibility temperatures were studied, based upon the relationship between briquette ash components and ash fusibility. The results show that the increasing of ash fusibility temperatures by adding the same amount （11%, w） of refractory agents follows the sequence of SiO2, bentonite, dry powder, kaolin, A1203, with the softening temperatures being elevated by 37.2, 57.6, 60.4, 82.6 and 104.4℃. With the same ratio of SIO2/A1203 in briquette, adding the A1203 component is more effective than SiO2 for raising ash fusibility temperatures. In this paper, inexpensive kaolin and bentonite rich in A1203 are found to be better refractory agents, and the suitable adding quantities are 9% and 11%, respectively.

Laminar Diffusion Flames of Methane in a Co-annular Jet of Oxygen-Enriched Air

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.

Thermal Analysis and Kinetics of Coal during Oxy-Fuel Combustion

The pyrolysis and oxy-fuel combustion characteristics of Polish bituminous coal were studied us/ng non- isothermal thermogravimetric analysis. Pyrolysis tests showed that the mass loss profiles were almost similar up to 870℃ ha both N2 and CO2 atmospheres, while further mass loss occurred ha CO2 atmosphere at higher temper- atures due to char-CO2 gasification. Replacement of N2 ha the combustion environment by CO2 delayed the com- bustion of bituminous coal. At elevated oxygen levels, TG/DTG profiles shifted through lower temperature zone, ignition and burnout temperatures decreased and mass loss rate significantly increased and complete combustion was achieved at lower temperatures and shorter times. Kinetic analysis for the tested coal was performed using Kissinger-Akahira-Sunose （KAS） method. The activation energies of bituminous coal combustion at the similar oxygen content in oxy-fuel with that of air were higher than that in air atmosphere. The results indicated that, with O2 concentration increasing, the activation energies decreased.