CO₂ gasification kinetics of two alberta coal chars

Abstract

10, gasification kinetics of chars from two Alberta coals (Obed Mountain, high volatile bituminous and Highvale, subbituminous) have been studied using a thermogravimetric analyzer (TGA) and a fixed bed reactor. Charification and gasification reactions were performed sequentially in both the TGA instrument and in the fixed bed reactor to simulate real gasifier operating conditions. TGA and fixed bed data were processed numerically to evaluate the kinetic rate of CO, gasification of the chars. Calculated gasification kinetics could be correlated using both the volume reaction and the grain models. Activation energies of the kinetic rate constants were near 200 Wlmol for both Highvale and Obed Mountain coal chars using the TGA data. The activation energies calculated for the Obed Mountain coal char using the fixed bed reactor were about 250 kllmol. For all the cases studied the calculated activation energies were nearly the same for both the volume and grain reaction models.

Pyrolysis and Gasification Characteristics of High Ash Indian and Turkish Coals

“…As expected, higher gasification rates are noticed with smaller particles, the main features like diffusion restrictions and heat transfer limitations cannot be ignored while considering the high ash coal, over the temperature and sizes of coals tested [35]. As noted earlier [48,[54][55][56][57], the reduction in coal particle size, the TG and the DTG curves move into lower temperature regions, and burning rate increment of coal is seen so time for burnout is reduced. Owing to the fact that the more specific area available with the smaller pulverized coal particles influences the gasification rate over the larger ones, also smaller particles are favorable to the development and ignition of the coal particles.…”

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

“…Some other researchers found a linear decrease of gasification rate as reaction advances [26,27]. However, some studies regarding coal reactivity during gasification do not consider gasification rate variation with conversion and only report rate of gasification at a specific value of conversion [28,29]. Fig.…”

“…Kovacik et al [28] found diffusion restrictions for sub-bituminous and bituminous coals at 900 C and different particle size ranges i.e. À105 þ 74 mm (À140 þ 200 mesh), À600 þ 350 mm (À30 þ 45 mesh), and À2.4 þ 1.7 mm (À7 þ 14 mesh).…”

The Boudouard–Bell reaction analysis under high pressure conditions

“…By using the Arrhenius equation, the following expression can be derived [10][11][12][13][14][15][16][17][18][19]:…”