On why do different carbons show different gasification rates: A transient isotopic CO2 gasification study

摘要: Abstract A suite of nine different carbons have been investigated by step-response experiments (SRE) using 13CO2 at 10 and 100 kPa and, predominantly, 1200 1250 K. Although the gasification activities vary a factor twenty, all behave similarly in their CO desorption patterns upon step change from reactive to an inert gas phase. This can be described two-stage exponential decay, irrespective type structure carbon used. The amounts desorbable surface oxygen complexes differ between various increase with increasing CO2 pressure temperature. are restored reversed atmosphere. Clear indications found that distribution activation energies exists. variation rate as function temperature is mainly due complex concentration. transient best accounted for recent model Chen, et al., where two types contribute rate. largest contribution comes highly intermediates five times more than stable complexes, but which present 3–4 smaller amounts. associated constants fairly similar carbons, averaged 0.6 0.034 s−1, respectively exhibit only weak dependency heterogeneity. Correlation total incompatible decay curves. use demonstrated phase reactant inserted according activated process, evidence reversibility reaction. Three show sharp maximum decaying curve CO2, peculiar phenomenon not yet explained.