Mineral oils: processes and products – Refining – Halogen contaminant removal
Patent
1996-05-13
1998-07-21
Myers, Helane
Mineral oils: processes and products
Refining
Halogen contaminant removal
2082621, 208179, 585820, C10G 1700
Patent
active
057830681
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for dechlorination of a spent oil fraction.
BACKGROUND OF THE INVENTION
It is known that spent lubricating oils recovered in garages or service stations represent considerable tonnages which in France, for example, are as high as 100,000 metric tons and even 120,000 metric tons per year.
For a long time, therefore, attempts have been made to avoid disposing of these spent oils, as this would contribute substantially to environmental pollution. Currently, these oils are therefore usually subjected to a regeneration treatment.
Said treatment is costly, however, because these spent oils contain a large amount of various metals and chlorine, and the regenerated oils are practically as costly as new oils coming from the refinery.
This has provided a stimulus for looking for other uses for these spent oils, for example as fuels, particularly in cement plants. In this application, however, the presence of large amounts of chlorine (about 400 to 2000 ppm) also presents problems.
Hence, it has been proposed to recycle these spent oils to refineries to subject them to distillation, optionally in admixture with other feedstocks, so as to recover at least a fraction of the valuable compounds they contain.
Preliminary tests carried out to this end have shown that in such a utilization the chlorine compounds contained in the oils once again present serious problems. These compounds are in fact organic chlorides stemming from oil additives usually containing chlorinated compounds, particularly chlorinated polyisobutenes. During a distillation operation, even at relatively low temperature and particularly in the presence of steam, the molecules of these chlorinated compounds decompose with formation of, in particular, hydrochloric acid which exerts a strong corrosive effect on the refinery equipment.
OBJECTS OF THE INVENTION
Hence, the purpose of the present invention is to bring the chlorine content of spent oils to a level compatible with recycling such oils to refineries, and to this end the invention proposes to use solid compositions capable of binding chlorinated ions and already known industrially for use in other applications and under different conditions.
In fact, industry already uses special compositions known as chlorine metal hydroxides, such as CaO, Na.sub.2 O, K.sub.2 O, MgO and the corresponding hydroxides, to eliminate the chlorine present in liquid or gaseous streams of process units, particularly reforming and isomerization units.
In general, said compositions have a special particle size of 0.5 to 3 mm usually used at room temperature or at the most at 100.degree. C. and atmospheric pressure, and they usually retain about 15% of the chlorine present in the treated stock.
SUMMARY OF THE INVENTION
Applicant has now found that such chlorine scavengers are very well suited to partial dechlorination of spent oils to be performed upstream of any recycling operation in refineries and particularly of any vacuum distillation and that, unexpectedly, the chlorine fixation capacity of such scavengers increases markedly with the temperature of the treated oils, said scavengers being capable of retaining at a temperature from 300.degree. to 400.degree. C. and atmospheric pressure at least 40% of the chlorine present in the treated oil.
As will be seen in the following, it is of course also possible to operate at a different temperature and/or pressure.
This chlorine quantity that exceeds 40% represents approximately the fraction of chlorinated compounds that decompose, with formation of hydrochloric acid, in the course of recycling spent oils or of chlorinated compounds oils that distill in a vacuum fractionating column for spent oil. The invention therefore proposes, in simple fashion, to subject spent oils to dechlorination upstream of any recycling operation.
Hence, the invention is embodied by a process for dechlorinating a fraction of spent lubricating oil, optionally in admixture with another hydrocarbon feedstock, said process being characterized by the fact that,
REFERENCES:
patent: 2481300 (1949-09-01), Eingel
patent: 3761534 (1973-09-01), Sun et al.
patent: 4612404 (1986-09-01), Thyagarajan
patent: 4639309 (1987-01-01), Lalancette et al.
patent: 5096600 (1992-03-01), HQCH
Dolbecq Philippe
Laborde Michel
Myers Helane
Total Raffinage Distribution , S.A.
LandOfFree
Process for dechlorination of a spent oil fraction does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for dechlorination of a spent oil fraction, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for dechlorination of a spent oil fraction will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1643676