Solvent deasphalting Back

Action Treatment
Method Absorption
Purpose Remove asphalt, increase cracking feedstock
Feedstock Vacuum tower residue

Bitumen (asphalt)
Heavy lube oil
Deasphalted oil

Product(s) goes to

Treating/lube blending
Fluid catalytic cracking

Bitumen (asphalt) is a portion of the residue fraction that remains after distillation operations. It is further processed to reach the specifications required for its final use.

In vacuum distillation, the residue is heated in a column where vacuum is applied to prevent cracking. One subsequent process used to produce asphalt is solvent deasphalting. This is an extraction process in which propane or hexane is used as solvent. Feedstock and liquid propane are pumped to an extraction tower at controlled temperatures and pressures. Separation occurs based on differences in solubility. The products are then evaporated and propane is recovered. Heavy fractions are separated to produce heavy lubricating oil, FCC feedstock and bitumen (asphalt). Deasphalting can also remove some contamination, like sulfur and nitrogen compounds, from the feedstock.

Abbemat HT

The Abbemat HT refractometer is a Heavy Duty line refractometer from Anton Paar. It is designed for work in harsh environments and for special
applications requiring high temperatures or vertical operation to avoid sedimentation on the prism. They feature a hermetically sealed stainless steel housing and no display in order to withstand spillage and dirt.

Measuring range (RI) 1.30 nD – 1.72 nD
Accuracy ± 4×10-5 nD *
Resolution 1×10-6 nD
Temperature Range 10 °C – 110 °C
Pt 1000 temperature sensor accuracy ± 0.03 °C
Control Unit PC

* under standard conditions (20 °C, 589 nm)

Benefits of Abbemat HT at Solvent deasphalting

The refractive index of waxy raffinates at temperatures from 80 °C to 100 °C can be used for quality control and/or process control of the deasphalting process. As long as the melting point of the sample is at least 10 °C below the test temperature, measurements at lower temperatures are possible, too.