Two-stage hydrogenation of benzene to form cyclohexane using nickel catalyst

摘要

In a process for carrying out a reaction in a plurality of catalyst zones arranged in series which shows remarkable rise of reaction temperature due to its high initial activity, an improvement is provided by starting the reaction with a first reactor in which its catalyst activity is reduced in advance so as to make it easier to control the reaction temperature; with other reactors in which their catalyst activities are maintained at higher values with an increasing gradient and with a last reactor in which its catalyst activity is made sufficiently larger in order to be able to maintain the initial value of total conversion with all the reactors even at a time when the catalyst activity of the first reactor is reduced to unusable extent, interrupting the reaction when the catalyst activity of the first reactor is reduced to unusable extent, transferring the first reactor to the next to the last reactor after charged with a new catalyst, and repeating the operation in the subsequent run as in the first run except that the order of each of the reactors is advanced by one in each time of the transfer of the first reactor to the last.