Non-dissociative and dissociative adsorption of oxygen on carbon: A theoretical comparison with prediction of reaction order

Determination of the Apparent Carbon Oxidation Reaction Order by a Microfluidized Bed and Its Application to Kinetic Models

“…The apparent reaction order n determined by the MFB experiment at 1073 K is 0.178, and the result has good repeatability, which means that the test error of the MFB is acceptable. Moreover, the determined n value is close to 0, which is also close to the n value determined in the kinetic control region by other researchers; ,, thus the reliability and accuracy of the MFB in determining the apparent carbon oxidation reaction order are verified.…”

“…This value is a little higher than the intrinsic E of the char combustion reported by other researchers (approximately 180 kJ/mol), 7,21 but Smith 21 found that the intrinsic E values of highly purified carbons were higher than those of chars in his combustion experiment. Furthermore, the structural differences (such as the C−C distance) of different highly purified carbons are assumed to result in different intrinsic E values, 15 so we consider it a reasonable intrinsic E value in this work. 4 shows the relationship between the α−t curve and temperature in the MFB experiment.…”

“…4,9−14 It has the following advantages: 4 (i) simple operation (compared to DTF) and instantaneous impulse feeding at preset temperatures and atmospheres; (ii) strengthening of heat and mass transfer, which minimizes the temperature drift and guarantees a higher test temperature in the kinetic control region (compared to TGA); and (iii) continuous and accurate monitoring of gas products via a fast process mass spectrometer. Many researchers have found that the apparent reaction order is close to zero in the kinetic control region, 6,15,16 which can guide the verification of the accuracy of the method used to determine the value of n. (The combustion of chars can be divided into two steps: oxygen diffusing to the particle surface and the reaction between the char and oxygen. For n = 0, the rate of oxygen diffusion is far higher than that of the reaction; thus the combustion rate is insensitive to the change of P O,s .…”

Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

“…increasing from zero at low temperatures (below 500 °C) to unity at high temperatures (above 2000 °C) [58]. Table 11 shows the experimentally measured and CFD predicted oxygen concentrations at the outlet of the EFR, as well the deviations between them.…”

The measurement of the rate of burning of different coal chars in an electrically heated fluidised bed of sand

“…Table 2 shows that for Brodsworth char the order of reaction is ∼ 0.5-0.6 at 700-800 • C, but is lower at higher temperatures. This lowering of the order with temperature is the opposite trend to that found by Essenhigh et al (1965) and Klimesh and Essenhigh (1998). Values of n ∼ 0.5-0.8 have been reported before and reviewed by Hurt and Haynes (2005); no systematic variation of n with temperature was found.…”