06/02094 Production of hydrogen by thermal decomposition of methane in a fluidized-bed reactor - effects of catalyst, temperature, and residence time: Dunker, A. M. et al. International Journal of Hydrogen Energy, 2006, 31,(4),473–484.

Abstract

High temperature gasification has been considered as one of the most promising routes for the clean and efficient utilization of high-sulfur petroleum coke (petcoke). However, petcoke usually contains high content of vanadium (V). It has been proven that V element in petcoke can lead to fouling or corrosion problems in the process of combustion, which captures the attention to the fate of V during petcoke gasification. In this paper, thermodynamic equilibrium calculations based on the FactSage were used to investigate the reaction mechanism of V with the main associated mineral elements (Si, Ca, Al, Fe, Ni and Na) during petcoke gasification. The influence of gasification temperature and atmospheres on the V species equilibrium composition was also evaluated. The results indicate that V reacts with the mineral elements of Ca, Fe and Na to form V-containing species (CaO)3V2O5(s), FeV2O4(s), (Na2O)3V2O5(s) and (Na2O)2V2O5(l), respectively. The presence of H2S(g) suppresses the reactions of V with Ca and Fe due to the formation of sulfides (CaS and FeS). In addition, it is verified that V does not participate in the reactions with Si, Al and Ni. However, the associated mineral elements may have remarkable co-effects on V species equilibrium composition. Ca reacts with Si or Al easily to form the Ca-containing minerals (CaSiO3(s), Ca3Si2O7(s), Ca2SiO4(s), CaAl4O7(s), CaAl2O4(s)), impeding the formation of (CaO)3V2O5(s). Na combines with Al to generate Na-containing minerals (NaAlO2(s), Na2Al12O19(s)), inhibiting the formation of (Na2O)3V2O5(s) and (Na2O)2V2O5(l). When all of the main associated mineral elements are present, the V-containing species formed in the whole process of gasification are V2O3(s), FeV2O4(s) and a small amount of VO2(g).