Which property is considered undesirable for a solvent selected for dewaxing lube oil?
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Answer: C. Both A. and B.
Explanation
An effective dewaxing solvent must dissolve the liquid oil while leaving solid wax insoluble at low temperatures. If the solvent possessed high wax solubility at chilling temperatures, wax separation would become impossible. Therefore, high solubility of wax in the solvent is an undesirable property for dewaxing operations. Petroleum dewaxing chills lube oil blends to crystallize wax, which is then separated via filtration. Selective solvents must have low wax solubility at chilling temperatures to maximize wax removal efficiency. Complete miscibility with the liquid oil fraction is essential for effective solvent-oil contact.
Refiners select dewaxing solvents carefully to optimize lubricating oil yield and pour point reduction. Understanding phase equilibrium helps engineers design effective chilling and filtration systems. Solvent recovery sections depend on boiling point differences to separate dewaxing solvents from finished lube oil. Complete miscibility with oil is a highly desirable property, making option A incorrect as the sole choice. High solubility of wax is undesirable, so option C correctly identifies both listed properties as problematic. Rejecting both options ignores the fundamental chemical engineering criteria for successful solvent dewaxing.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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