Catalytic Thermal Decomposition and Stem Reforming of Methanol over Alumina Supported Metal of VIII group

Abstract

For the purpose of exploring the prooess to prepare synthesis gas (CO+H₂) or H₂ from methanol, thermal decomposition (CH₃OH→CO+2H₂) and steam reforming (CH₃OH+H₂O→CO₂+3H₂) were investigated on Al₂O₃ supported metal (Pt, Pd, Ru, Rh, Co, Ni, Fe) catalysts.
The experiment was carried out by using a flow fixed bed reactor under an atmospheric pressure and at 300°-550°C. The inlet gases were 10%CH₃OH-N₂ and 10%CH₃OH-40%H₂O-N₂, and the total feed rate was 500 Ncm³/min Per 1ml of each catalyst of average diameter 0.9mm (space velocity: 3.0×10⁴ hr^-1).
The following informations were obtained:
1) Decomposition of CH₃OH under the absence of catalyst occurred at above ca. 700°C according to CH₃OH→CO+2H₂, but the decomposition under the presence of catalysts except Ru and Fe occured at low temperatures below 300°C.
2) Catalytic steam reforming was considered to be the consecutive reactions of CH₃OH→CO+2H₂ and CO+H₂O→CO₂+H₂O. Ru and Fe gave a litlle activity.
3) Pt was the most active for both reactions, and gave no formation of CH₄.
4) Pd was very high active for decomposition of CH₃OH, but low active for shift reaction of CO.
5) Rh was active for both reactions, but accompanied the formation of a considerable amount of CH₄.
6) Co gave the formation of equimolal CH₄ and CO₂ besides CO and H₂ at decomposition of CH₃OH, and was very high active for shift reaction of CO as well as Pt.
7) Ni promoted considerably the methanation reactions in both reaction systems.