Fundamental studies of catalytic gasification: Quarterly report, April 1, 1987-June 30, 1987
Our results indicate that there is a strong interaction between nickel and potassium in the steam gasification of carbon solids leading to a ternary oxide compound formation. Nickel and potassium, however, can potentially also interact with other components present in the char, mainly calcium and alumino-silicate compounds. We have previously reported that the nickel/calcium mixed catalysts are much less active than the nickel/potassium mixture for steam gasification of graphite. The nickel/calcium interaction may therefore be a reason for the loss of catalyst activity. Most of the ash components in the char can be extracted by treatment in aqua regia, and this treatment does prevent the loss of catalyst activity with carbon conversion. The same treatment, however, may also affect the char structure and composition, which in turn can be responsible for the results observed. For example, this treatment strongly oxidizes the carbon surface, and the resulting surface oxygen groups may interact with the catalysts, changing their spreading characteristics and thereby the deactivation process. To distinguish between these two possibilities for catalyst deactivation, that is, interaction with the indigenous components of the char, or change of carbon-catalyst contact, further experiments are being performed. First, pretreatment of the char in HF, instead of aqua regia, can extract the mineral content of the char without oxidizing the carbon surface. Comparison of the results obtained after these two pretreatments can distinguish between these two possible explanations for the catalyst deactivation.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6141542
- Report Number(s):
- LBL-23649; ON: DE87013963
- Country of Publication:
- United States
- Language:
- English
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