Studies on the Catalytic Activity of Alkali Polyaluminate as a Catalyst and Support of Nickel Catalyst for Steam Reforming of Hydrocarbons

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An alkali catalyst and an alkalized nickel catalyst were prepared form β"-Al₂O₃, one of the alkali polyaluminates. The alkali catalyst was used for catalytic cracking of various petroleum fractions, and the alkalized nickel catalyst was used for steam reforming of n-hexane, and the following results were obtained.
Using the alkali catalyst, a maximum yield of ethylene from naphtha was 47.27% at 800°C when the steam/oil ratio and space velocity were 3.0 and 7.0, respectively. From kerosene and gas oil, ethylene yields were 37.51% and 36.69% at 800°C when the steam/oil ratio and space velocity were 3.0 and 5.0, respectively.
In naphtha cracking, the carbon residue on the catalyst was removed by a steam/oil ratio of 1.5 or higher, and in kerosene and gas oil cracking, the ratio of 3.0 was required.
A high quality fuel gas suitable for high calorie town gas was obtained at 750°C or higher.
Composition of the gas produced with the alkalized nickel catalyst at temperatures in the range of from 500 to 800°C with the steam/carbon ratio of 1.5 and under 1∼20kg/cm²•G pressure was close to that of thermodynamical equilibrium. The steam/carbon mole ratio of 3.0 removed the carbon residue deposited under all operating conditions used in this work. Thus, steam/carbon mole ratios in the range of from 2.0 to 2.5 were considered to be most suitable for effective use of the catalyst.
Characteristic actions of these two types of catalysts were also discussed.