Technology

Heavy Feedstock is diluted with a Light Paraffinic Solvent and then charged to a Vertical Extractor Tower. Within the Tower, a Deasphalted Oil (DAO) Fraction dissolves in the Solvent and the remaining Heavy Components are precipitated. The DAO and Solvent Mixture exits the Top of the Extractor and is heated to create a Supercritical Solvent Phase that is then separated from the Liquid DAO Phase. Any Remaining Solvent is removed in a Stripper Column, and the DAO Product is then typically sent as a quality Feedstock to Fuels Cracking Processes or used in the Production of Lubricating Oils. Pitch with some entrained Solvent is withdrawn from the Bottom of the Extractor and sent to a Pitch Stripping Section. The Pitch can be used in Specification Asphalts, as Fuel, or as Feedstock to Conversion Units such as a Delayed Coker or Gasifier. If desired, a second Extraction Stage is utilized to produce an intermediate Resin Product.

Typical Product yield are:

• 31 vol-% of DAO with 0.9232 API for Lube Application with Propane Solvent Extraction of Feed with 0.995 Specific Gravity.
• 81 vol-% of DAO with 0.997 API for High-Lift Fuel Application with Pentane Solvent Extraction of Feed with 1.047 Specific Gravity.

References

1. Rening Community, SDA – Wood Foster Wheeler / UOP

2. Science Direct, Deasphalted Oil, Maria Magdalena Ramirez-Corredores, Bottom of the Barrel Upgrading Technologies, in The Science and Technology of Unconventional Oils, 2017, 2.1.2 UOP-Foster Wheeler Demex