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البحـث الثاني
155
2016
أوابك العلمية لعام
�
ص لبحوث العلمية الفائزة بجائزة
�
عدد خا
مجلة النفط والتعاون العربي
161
العدد
- 2017
أربعون
المجلد الثالث و ال
Re-refining of Used Lubricating Oil and its Economic and Environmental Implications
32
Vacuum distillation:
In this step base oil is recovered as distillate and sent to hydrogenation unit for further
treatment. The vacuum distillation waste is sent through a second extraction, using
propane, which is combined together with the vacuum distillate in the hydrogenation
unit.
Hydrogenation:
In this final stage, base oils with different properties are produced in the
hydrotreatment unit. The bright stock fraction is also recovered from the waste from
vacuum distillation.
4.10.2
Process features and drawbacks
There exists the possibility to produce several base oils with various characteristics. The
PDA bottoms are used in the asphalt production. The solvent is recycled in the process
with minor losses (5~10%).
Figure 17 illustrates the simplified process flow sheet of the SNAMPROGETTI process
Figure 17 Snamprogetti simplified process flow diagram
Source: Snamprogetti
Diluting
fuel
Asphalt
Water+Light
HC
Medium base
oil
Light base
oil
Bright stock
Fuel gas
VGO
Hydrogen
Waste Oil
Vacuum
distillation
Storage
Extraction
using
propane
Hydrofinishing
Propane extraction
Predistillation