Abstract:The sulfur related thermochemical water-splitting cycles are an important class of chemical processes considered for hydrogen production. Recently, the magnesium sulfate thermal decomposition has been reported as a potential unit operation in one of these cycles. Therefore, some interest has been observed in the use of catalysts to lower the activation energy of such reactions. In this context, the present manuscript reports the thermodynamics and kinetics modeling results associated with this reaction system … Show more
“…For each analysis, the modeling quality was determined by the value of the correlation coefficient (R 2 ) calculated for each dataset. This methodology was recently successfully applied for the thermal decomposition modeling of MgSO 4 [40] and potassium alum [46] reaction systems.…”
Section: Thermogravimetric Analysis and Kinetic Modelingmentioning
confidence: 99%
“…In the work of Mello et al [40], who also used the Pd/Al 2 O 3 catalyst, it was observed that palladium tended to oxidize and initiate the formation of PdO up to approximately 900 • C in the reaction system and then dissociate, returning to the metallic form at higher temperatures. According to O'Keefe et al [54] and Barbarossa et al [17], the oxide's catalytic activity forms in the decomposition of sulfur trioxide.…”
Section: Samplementioning
confidence: 99%
“…However, there is a paucity of information on the effects of incorporating catalytic materials on the kinetic parameters of these thermal decomposition processes. Consequently, there is a lack of information about the behavior of the reaction system through a more quantitative approach, with one reported work so far for MgSO 4 .7H 2 O thermal decomposition [40]. Nevertheless, this sulfate tends to decompose directly into its oxide in a manner that is novel to systems in which an intermediate is formed (e.g., ZnO•2ZnSO 4 from ZnSO 4 and FeSO 4 from Fe 2 (SO 4 ) 3 ).…”
The sulfur–iodine thermochemical water-splitting cycle is a promising route proposed for hydrogen production. The decomposition temperature remains a challenge in the process. Catalysts, such as Pd supported on Al2O3, are being considered to decrease reaction temperatures. However, little is known regarding the kinetic behavior of such systems. In this work, zinc sulfate thermal decomposition was studied through non-isothermal thermogravimetric analysis to understand the effect of a catalyst within the sulfur–iodine reaction system context. The findings of this analysis were also related to a thermodynamic assessment. It was observed that the presence of Pd/Al2O3 modified the reaction mechanism, possibly with some intermediate reactions that were suppressed or remarkably accelerated. The proposed model suggests that zinc sulfate transformation occurred in two sequential stages without the Pd-based material. Activation energy values of 238 and 368 kJ.mol−1 were calculated. In the presence of Pd/Al2O3, an activation energy value of 204 kJ.mol−1 was calculated, which is lower than observed previously.
“…For each analysis, the modeling quality was determined by the value of the correlation coefficient (R 2 ) calculated for each dataset. This methodology was recently successfully applied for the thermal decomposition modeling of MgSO 4 [40] and potassium alum [46] reaction systems.…”
Section: Thermogravimetric Analysis and Kinetic Modelingmentioning
confidence: 99%
“…In the work of Mello et al [40], who also used the Pd/Al 2 O 3 catalyst, it was observed that palladium tended to oxidize and initiate the formation of PdO up to approximately 900 • C in the reaction system and then dissociate, returning to the metallic form at higher temperatures. According to O'Keefe et al [54] and Barbarossa et al [17], the oxide's catalytic activity forms in the decomposition of sulfur trioxide.…”
Section: Samplementioning
confidence: 99%
“…However, there is a paucity of information on the effects of incorporating catalytic materials on the kinetic parameters of these thermal decomposition processes. Consequently, there is a lack of information about the behavior of the reaction system through a more quantitative approach, with one reported work so far for MgSO 4 .7H 2 O thermal decomposition [40]. Nevertheless, this sulfate tends to decompose directly into its oxide in a manner that is novel to systems in which an intermediate is formed (e.g., ZnO•2ZnSO 4 from ZnSO 4 and FeSO 4 from Fe 2 (SO 4 ) 3 ).…”
The sulfur–iodine thermochemical water-splitting cycle is a promising route proposed for hydrogen production. The decomposition temperature remains a challenge in the process. Catalysts, such as Pd supported on Al2O3, are being considered to decrease reaction temperatures. However, little is known regarding the kinetic behavior of such systems. In this work, zinc sulfate thermal decomposition was studied through non-isothermal thermogravimetric analysis to understand the effect of a catalyst within the sulfur–iodine reaction system context. The findings of this analysis were also related to a thermodynamic assessment. It was observed that the presence of Pd/Al2O3 modified the reaction mechanism, possibly with some intermediate reactions that were suppressed or remarkably accelerated. The proposed model suggests that zinc sulfate transformation occurred in two sequential stages without the Pd-based material. Activation energy values of 238 and 368 kJ.mol−1 were calculated. In the presence of Pd/Al2O3, an activation energy value of 204 kJ.mol−1 was calculated, which is lower than observed previously.
“…All the calculations were made using Python 3.8.2. This methodology was recently successfully applied for the thermal decomposition modeling of ZnSO 4 [27], MgSO 4 [28] and potassium alum [57] reaction systems. shows the mass loss curves of pure ammonium sulfate from 25 to 500°C for three heating rates (10,15 and 20°C.min -1 ).…”
Section: Kinetic Modelingmentioning
confidence: 99%
“…In industrial processes, the leach residue is generally not pure since it contains smaller amounts of other sulfates, such as iron, aluminum, and manganese. The decomposition of the eventually precipitated sulfates can be a route to obtain sulfur dioxide and metal oxides [27,28].…”
Simulação termodinâmica e modelagem cinética do processo de decomposição de sulfatos com diferentes níveis de estabilidade Keywords MgSO 4; (NH 4 ) 2 SO 4 ; sulfur water-splitting cycles; thermal decomposition; kinetics;
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