Although the majority of dewaxing units in the U.S. refineries use MEK), some advantages of using propane as a solvent compared to MEK include the following [2]:
- Propane is used both as a diluent and as a refrigerant
- Lower capital investment
- Refrigeration energy savings
- Higher filtration rates
- Rejection of asphaltenes and resins in the feed
- Higher VI than ketone dewaxing
What is dewaxing in lube oil? The goal of dewaxing is to remove hydrocarbons that would potentially increase the pour point of the lube oil base stock to a desirable range of -9 o – 14 o F. There is two different processes that result in this marketable lube oil: solvent dewaxing and catalytic dewaxing.
What is Solvent Dewaxing? The Bechtel Hydrocarbon Technology Solutions (BHTS) solvent dewaxing process uses a mixture of MEK and toluene to aid in the crystallization and filtration of wax from the lube oil stocks. Several recent developments have led to improved filtration rates, energy efficiency, water management, and operability of solvent dewaxing units.
How is lube oil made? There is two different processes that result in this marketable lube oil: solvent dewaxing and catalytic dewaxing. Solvent dewaxing is a physical process that uses refrigeration, scraping techniques, and methyl ethyl ketone (MEK) and propane solvents to separate the feedstocks and produce a valuable product.
What are the solvents used in wax extraction? Usually two solvents are used: toluene, which dissolves the oil and maintains fluidity at low temperatures, and methyl ethyl ketone (MEK), which dissolves little wax at low temperatures and acts as a wax precipitating agent.
What is dewaxing in lube oil?
What is dewaxing of lubricating oil base stocks? Dewaxing of lubricating oil base stocks is necessary to ensure that the oil will have the proper viscosity at lower than ambient temperatures. Two types of process are used; selective hydrocracking and solvent dewaxing. In the formar, one or two zeolite catalysts are used to selectively crack the wax paraffins. The latter is more prevalent.
What is Solvent Dewaxing? Solvent dewaxing is more prevalent. In solvent dewaxing the oil feed is diluted with solvent to lower the viscosity, chilled until the wax is crystallized, and then filtered to remove the wax. Solvents used for the process include propane and mixtures of methyl ethyl ketone (MEK) with methyl isobutyl ketone or MEK with toluene.
How is lube oil made? There is two different processes that result in this marketable lube oil: solvent dewaxing and catalytic dewaxing. Solvent dewaxing is a physical process that uses refrigeration, scraping techniques, and methyl ethyl ketone (MEK) and propane solvents to separate the feedstocks and produce a valuable product.
What is the feedstock of dewaxing? The feedstocks to dewaxing include DAO from deasphalting, and HVGO from vacuum distillation as shown in Figure 5.11 along with some compositional characteristics of the feedstock and the dewaxing product. Note that wax (long-chain paraffins) obtained in dewaxing is a marketable by-product.