| 摘要 |
A process for maintaining the activity level of a nickel catalyst bed when used for catalytic cracking of gaseous or liquid hydrocarbons with steam or with steam and air, especially in cyclic processes, comprises feeding a hydrocarbon solution of a hydrocarbon-soluble salt of an organic acid into the plant during gas-making simultaneously with the injection of the hydrocarbon feedstock, the said introduction being carried out either continuously throughout all periods of injection, or intermittently during part of each or any period of injection of the feedstock. The salt is decomposable under the operating conditions to produce nickel or nickel oxide together with other compounds similar to those produced by cracking the feedstock. The nickel salt may be the nickel salt of a fatty acid having from 7 to 17 carbon atoms in the hydrocarbon chain or of an alicyclic carboxylic acid having 5 carbon atoms in the ring, e.g. nickel oleate, nickel myristate, nickel linoleate, or a nickel salt of a naphthenic acid. The nickel salt may be dissolved in the feedstock or added thereto in solution, or may be separately injected as a solution on to the catalyst. The amount of nickel added amounts to 0.002% to 0.05% by weight of the feedstock in a given phase, and delivery of the solution may be automatically controlled from the gas-making plant. Specification 772,787 is referred to.
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