| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing lubricating base oil capable of achieving a long lifetime of a hydroisomerization catalyst and stably obtaining the lubricating base oil for a long period of time.SOLUTION: A method for producing lubricating base oil includes a first step of performing an isomerization dewaxing by bringing hydrocarbon oil containing normal paraffin with a boiling point of 360°C or higher into contact with a hydroisomerization catalyst in the existence of hydrogen under a condition where a decomposition rate defined by the following formula (1) is 10 mass% or lower, and a second step of performing the isomerization dewaxing after temporarily switching the condition so that the decomposition rate is 13 mass% or higher. Decomposition rate (mass%)=[(C-C)/C]×100 (1) [in the formula, Crepresents a mass percentage of a fraction with the boiling point of 360°C or higher in the hydrocarbon oil, and Crepresents the mass percentage of the fraction with the boiling point of 360°C or higher in the hydrocarbon oil after the isomerization dewaxing]. |
