Limitation of thermogravimetry for oxy-combustion analysis of coal chars

Oxy-coal Combustion Studies

Kinetic models for the oxy-fuel combustion of coal and coal/biomass blend chars obtained in N2 and CO2 atmospheres

The thermal reactivity and kinetics of five coal chars, a biomass char, and two coal/biomass char blends in an oxy-fuel combustion atmosphere (30%O2-70%CO2) were studied using the non-isothermal thermogravimetric method at three heating rates. Fuel chars were obtained by devolatilization in an entrained flow reactor at 1273 K under N2 and CO2 atmospheres.Three nth-order representative gas-solid...

Enthalpy Calculation for Pressurized Oxy-coal Combustion

Oxy-fuel combustion is recognized one of the most promising available technologies that zero emission accomplishment may be in the offing. With coal burned under the pressure of 6MPa and oxygenenriched conditions, the high temperature and high pressure gaseous combustion product is composed of 95% CO2 and water-vapor, with the rest of O2, N2 and so on. However, once lauded as classic approach o...

Combustion kinetics of coal chars in oxygen-enriched environments

Oxygen-enhanced and oxygen-fired pulverized coal combustion is actively being investigated to achieve emission reductions and reductions in flue gas cleanup costs, as well as for coal-bed methane and enhanced oil recovery applications. To fully understand the results of pilot scale tests and to accurately predict scale-up performance through CFD modeling, accurate rate expressions are needed to...

The Combustion Rates of Coal Chars: a Review

A brief description is given of devolatilization of raw coal and combustion of the residual char. Major achievements in the study of devolatilization and important areas for further experimentation are noted; however, attention is focussed on the rate processes involved in char combustion. Means of calculating reaction rates are shown which account for temperatures of particles, mass transfer a...