4.2 Resources CO2
Fig.1 depicts the principle of chemical energy transmission system.
Fig.2 explain the Eva-Adam process.
5. Thermodynamics of CO2 reforming of methane It is essential to understand the thermodynamic of CDRM represents as follow:
CH_4+CO_2 □(→) 2CO+〖2H〗_2 ∆H_298=247 KJ⁄(mol ) (1)
∆G^o=61770-67.32 T
This reaction above is highly endothermic which is favored by low pressure but, requires a higher temperature. A reverse water-gas shift reaction occurs as a side reaction as below
CO_2+H_2 □(→) CO+H_2 O ∆H_298=41 KJ⁄(mol ) (2)
∆G^o=-8545+7.84 T
Under conditions of stoichiometric CO2 reforming, carbon deposition …show more content…
Catalysts
6.1. Methods of synthesis catalysts
NO. Name of author Journal, volume, year Name of method Briefly about his work
1 Ashcroft et at.[10]
Science,352, 1991 Vacuum 'incipient wetness' technique It is studied effect vacuum wetness method, and it is demonstrated that highly dispersed noble metal catalysts; thus leads to maintaining the efficiency for CO2 reforming of CH4 with suppressing carbon deposition.
2 Gadalla and Sommer[11]
J. Am. Ceram. Soc., 72, 1984. Coprecipitation
Method They investigated synthesized three catalysts with various compositions (NiO, MgO, and Al2O3).Those demonstrated high CH4 conversion in dry reforming reaction.
3 Chang et al[12]
Stud. Surf. Sci. Catal., 84, 1994. solid-state reaction They researched two methods to prove catalytic activity (solid-state reaction and incipient wetness method) the results show the KNiCa/ZSI catalyst was produced by incipient wetness method gave much less activity than the one prepared by solid-state. That could be melting effect of metallic precursor mixtures.
6.2. Metal activity
Table 2 illustrates some experimental results that related to reforming methane with CO2 over group VIII …show more content…
It is found that the influence of support (metal oxides) on the efficiency of the catalyst as order TiO2 > Al2O3 > SiO2 for coupling CO2 with the CH4 conversion. On the other hand, the turnover frequency for CH4 conversion, the order of performance was TiO2 > Al2O3 > SiO2. It was deduced that the synergetic effect of metal oxides might be due to a direct activation of CH4 or CO2 by metal oxides and the difference of particle size of the metal.[16]
6.2.4. Carbon formation and activity
Deposition of carbon is assigned to from the CO2 molecular route, but a minimal amount of carbon deposited on catalyst surface is derived from the CH4 molecular direction.56,60 There are types of carbonaceous in which has different reactivity (α-C,β-C, and γ-C).
NO. Name of author Journal, volume, year Briefly about his work
1 Zhang and Verykios[17]
J. Chem. Soc., Chem. Commun. 1995, It is studied effect found that carbon is originating from the CH4/CO2 over Ni/La2O3 catalyst. It is demonstrated that promoting the reaction via its interaction with a component migrated from the La2O3
Fig.1 depicts the principle of chemical energy transmission system.
Fig.2 explain the Eva-Adam process.
5. Thermodynamics of CO2 reforming of methane It is essential to understand the thermodynamic of CDRM represents as follow:
CH_4+CO_2 □(→) 2CO+〖2H〗_2 ∆H_298=247 KJ⁄(mol ) (1)
∆G^o=61770-67.32 T
This reaction above is highly endothermic which is favored by low pressure but, requires a higher temperature. A reverse water-gas shift reaction occurs as a side reaction as below
CO_2+H_2 □(→) CO+H_2 O ∆H_298=41 KJ⁄(mol ) (2)
∆G^o=-8545+7.84 T
Under conditions of stoichiometric CO2 reforming, carbon deposition …show more content…
Catalysts
6.1. Methods of synthesis catalysts
NO. Name of author Journal, volume, year Name of method Briefly about his work
1 Ashcroft et at.[10]
Science,352, 1991 Vacuum 'incipient wetness' technique It is studied effect vacuum wetness method, and it is demonstrated that highly dispersed noble metal catalysts; thus leads to maintaining the efficiency for CO2 reforming of CH4 with suppressing carbon deposition.
2 Gadalla and Sommer[11]
J. Am. Ceram. Soc., 72, 1984. Coprecipitation
Method They investigated synthesized three catalysts with various compositions (NiO, MgO, and Al2O3).Those demonstrated high CH4 conversion in dry reforming reaction.
3 Chang et al[12]
Stud. Surf. Sci. Catal., 84, 1994. solid-state reaction They researched two methods to prove catalytic activity (solid-state reaction and incipient wetness method) the results show the KNiCa/ZSI catalyst was produced by incipient wetness method gave much less activity than the one prepared by solid-state. That could be melting effect of metallic precursor mixtures.
6.2. Metal activity
Table 2 illustrates some experimental results that related to reforming methane with CO2 over group VIII …show more content…
It is found that the influence of support (metal oxides) on the efficiency of the catalyst as order TiO2 > Al2O3 > SiO2 for coupling CO2 with the CH4 conversion. On the other hand, the turnover frequency for CH4 conversion, the order of performance was TiO2 > Al2O3 > SiO2. It was deduced that the synergetic effect of metal oxides might be due to a direct activation of CH4 or CO2 by metal oxides and the difference of particle size of the metal.[16]
6.2.4. Carbon formation and activity
Deposition of carbon is assigned to from the CO2 molecular route, but a minimal amount of carbon deposited on catalyst surface is derived from the CH4 molecular direction.56,60 There are types of carbonaceous in which has different reactivity (α-C,β-C, and γ-C).
NO. Name of author Journal, volume, year Briefly about his work
1 Zhang and Verykios[17]
J. Chem. Soc., Chem. Commun. 1995, It is studied effect found that carbon is originating from the CH4/CO2 over Ni/La2O3 catalyst. It is demonstrated that promoting the reaction via its interaction with a component migrated from the La2O3