DD298522A5 - METHOD FOR PROCESSING ALTOELS - Google Patents

Abstract

The invention relates to a process for working up Altoelen, which is particularly applicable to the regeneration of spent lubricating oils and industrial oils. The process of the present invention is characterized essentially by the addition of an extract obtained by solvent refining of a residual oil with a solvent to the Altoel prior to the refining step, and the Altoel extract mixture is refined with sulfuric acid. The process according to the invention leads to an increase in the raffinate yield and, after working up by distillation, to an increase in the recovery of regenerated material with at least the same regenerated viscosity or to obtain highly viscous regenerates with at least the same recovery of regenerated oil. Industrieoele; waste oils; regeneration; Refining; Sulfuric acid; Solvent refining; Rueckstandsoel; Extract; raffinate; Regeneratviskositaet}

Description

Field of application of the invention

The invention relates to a process for the processing of waste oils, which is particularly applicable in the regeneration of spent lubricating oils and industrial oils.

Characteristics of the known state of the art

It is known to regenerate used oils or waste oil mixtures by workup, whereby high-quality regenerates, especially those with very good oxidation stability and high viscosity index can be produced. In particular, a variety of work-up procedures, which usually differ by the choice of the individual process steps, from the lite; known. Most of the work-up procedures use a pre-purification stage where the mechanical impurities are removed and the distillative removal of the water and light hydrocarbons from the waste oil is carried out. The pre-purification stage is usually followed by the refining stage, where the unwanted

Oil components are removed, for example, by treatment with sulfuric acid. It may also be sine hydrogenating or a solvent refining step. There are also refurbishment procedures, which do without line refining.

The Altölraffinat is then decomposed in a subsequent Fraktionierstufe in the individual vacuum distillates. Target product is a waste oil fraction or are several fractions of a certain (desired) viscosity.

Final stage of the known AufjbeiJungsverfahren is the Nachraffination of Altölfraktionen. This is usually done by treatment with bleaching earth or with hydrogen (hydrofinishing). The waste oil regenerate thus obtained can be used as a lubricating oil component. The use in the lubricating oil range depends mainly on the achieved viscosity level and the achieved quality parameters of the used oil regenerate.

Advantageous is a use in motor oil assortment. Favorable in this respect are the Aufarbsitungsverfahren in which a brightstock component is obtained, for example, in the SNAM-PROGETTI process, which uses a refining stage extraction with propane. In general, in the used oil regenerates compared to the fresh oils, a drop in viscosity, so that the recovery of high-viscosity constituents in the waste oil processing is sought.

More unfavorable in terms of recovering the Grightstock component or the brightstock-containing waste oil regenerate are methods with total distillation stage, where the brightstock vacuum distillation residue is not recycled, for example, the KTI-RELUBE method or the RECYLON method.

The recovery of the high-viscosity brightstock component contained in the waste oil is carried out according to DE-OS 2901090 by predestination of waste oil, subsequent extraction with propane, fractionation of waste oil refinery by means of vacuum distillation and again extraction of the distillation residue with propane and hydrofinishing the fractions thus obtained including the high-viscosity component.

Advantage of the method is a high Regeneratausbeuto, disadvantage is the high equipment and energy expenditure, since the

Double extraction is carried out with large amounts of propane, each again from the oil phase through

Solvent distillation must be separated. According to OD-PS 121337, a work-up procedure for waste oils is proposed, which consists of the steps Grobreinigung, Pre-distillation, two-stage liquid-liquid extraction and post-refining. As a liquid-liquid extraction method

in the first stage the deasphalting and in the second stage the selective refining process is used, where from 1 to 30 parts by weight in% of paraffinic extracts are used for the selective refining of petroleum vacuum distillates before

Selective refining process can be added. The addition of these extracts causes exclusively. ^ '«Improvement of Phase separation (formation of the separation layer) in the extraction column. These extracts are from the same Process stage, in which they are used again, so they are driven without further separation of substances in the circulation. In the regeneration of waste oils, which come from high-quality lubricating oils, the work-up by the rising Content of additives in recent times problematic. The reprocessing procedures must also take this into account. It can

even the case occur that the known process steps are rendered ineffective by the additives contained. For example, the previously mentioned KTI-RELUBE process was adapted to the increasing additive content, where in the

High vacuum distillation a residue consisting of additives and asphalt-like products, is separated from the waste oil. Even the long-known refining process with sulfuric acid can be used with good results. Since the waste oil refining with sulfuric acid to a good cleaning effect with respect to the additives contained, but also to

A loss of oil substance due to the resulting oil-containing acid tere, it has been attempted to improve this basic process by various process changes.

This also takes into account the increasing additive content in the waste oils. In the known MEINKEN process, the refining technology is modified so that for contacting waste oils and Sulfuric acid is used in an intensive mixer, whereby the sulfuric acid consumption and thus the acid tannin

be reduced.

According to US-PS 3639229 is a pre-cleaning of the waste oil with an aliphatic alcohol of chain length C ₄ to C _6th

before the pre-cleaned waste oil is refined with sulfuric acid. According to DE-OS 2813 521 is the

Pre-treatment of the waste oil before refining with sulfuric acid in a mixture with an alcoholic medium and

the separation of the resulting sludge.

According to US-PS 4502948 is known to demold the waste oil in a preliminary stage and then to refine with sulfuric acid. The occurred in the regenerated viscosity drop compared to the fresh oils but by such Pretreatment steps are not balanced. According to DE-OS 2824337 a process for the regeneration of waste oils is proposed, according to the mineral oils for the purpose of White oil production with sulfuric acid or oleum are two stages refined and the separated thin liquid acid tars the

last refining stage for refining a dehydrated waste oil.

After subsequent neutralization and bleaching, the waste oil regenerate is recovered. The aim of this procedure is the use

the excess acid of the thin acid tars and thus a saving of fresh sulfuric acid. Disadvantage of this

Solution is an entry of polymerized, sulfonated products of the acid tere in the waste oil refinery, which is neither

still increase viscosity.

Object of the invention

The aim of the invention is the development of a process for the processing of waste oils, especially used lubricating oils and industrial oils, which is characterized by a low material and energy-economic effort and the recovery of additional lubricating oil components and thus has a high efficiency.

Explanation of the essence of the invention

The invention has for its object to achieve in the workup of waste oils in the stage of refining with sulfuric an increase in the raffinate yield and in the stage of distillative workup an increase in Regeneratausbeute at least the same regenerative viscosity or the recovery of higher-viscosity regenerates at least the same Regeneratausbeute.

According to the invention, the process for the processing of waste oil by pre-cleaning, dewatering and stripping and refining the waste oil with sulfuric acid, separation of the resulting acid resin, neutralization of the acid oil by means of alkaline substances, separation of the resulting neutralization of the raffinate and subsequent distillation and post-treatment of the raffinate by contact bleaching or hydrofinishing essentially characterized in that the waste oil before the Haffinationsstufe a by solvent refining a residual oils obtained by deasphalting and / or Entharzung from the vacuum distillation residue of petroleum, with a polar solvent with or without Antisolvent in a yield of 25 to 55 parts by mass in% obtained extract in an amount of 1 to 10 parts by weight in%, based on the waste oil supplied to the refining stage.

Advantageously, the waste oil obtained is obtained by solvent refining of a dewaxed residual oil obtained by deasphalting and / or softening from the vacuum distillation residue of paraffinic petroleum and subsequent dewaxing. The solvent extract is preferably recovered by solvent refining of a residual oil with phenol with or without water as an antisolvent.

The residual oil extract advantageously has a viscosity of 40 to 1 lOmmVs at 100 ⁰ C and a content

Paraffinic carbon of 35 to 'parts by mass in% of naphthenic carbon of 20 to 35

Parts by mass in% and aromatically bound carbon of 25 to 40 parts by mass in%. Surprisingly

found that the admixture of certain solvent extracts from residual oils to a pre-graded and dewatered waste oil in the refining with sulfuric acid to a higher yield of valuable raffinate oil, without worsing the quality of the raffinate, although the residual oil extracts before actually deliberately from the

Raffinate oil substance were removed. In the selective refining of non-pretreated distillate oils or waste oils with polar solvents, the

aromatic hydrocarbon compounds in the extract.

In the selective refining of residual oils, the extract constituents are mainly highly co-secreted Hydrocarbons, in particular high molecular weight diaromatic and polyaromatic compounds, ie to

Raffinate foreign substances that are unsuitable for lubricating oils.

Surprisingly, it was found that in the process according to the invention, the addition of residual oil to the waste oil

a more selective material separation process by additionally raffinate components are obtained from the waste oil-extract mixture and thus a yield-increasing effect occurs.

The resulting due to the higher raffinate yield larger amount of raffinate causes in the subsequent stage of

distillative workup and post-treatment of the raffinate an increase in the recovery yield, if distilled to a constant Regeneratviscosity. If the distillation is adjusted to an identical reclaimed yield, a higher-viscosity regenerate is obtained by the process according to the invention. The increase in yield of the raffinate then manifests itself in a multiple addition of distilled off light component, for example diesel oil or spindle oil. The method according to the invention has the following advantages over the prior art methods:

- Increase of the recovery rate in the waste oil processing by higher refining of petroleum components,

- Compensation of the viscosity reduction dur 'ι securing a viscosity increase in the used oil regenerates,

- Improve the economics of the waste oil treatment process.

embodiments The invention will be explained in more detail below on some embodiments. example 1 The processing of a mdustriealtöles via the process steps pre-cleaning (decanting), drainage

(Distillation with stripping steam), refining with sulfuric acid, neutralization of the sour oil with sodium hydroxide solution and distillation and contact bleaching of the raffinate.

The waste oil is purified by solvent refining of a dewaxing residual oil prior to refining Deasphalting from the vacuum residue of paraffinic petroleum and subsequent dewaxing recovered

was added, with phenol and with water as an antisolvent in a yield of 38 parts by weight in% extract obtained.

The pre-cleaned, dewatered and stripped waste oil has the following characteristics:

Viscosity at 50 ^° C.: 25.2 mm7s 0.944 g / cm ³ Flash point after 1060mm ² / s Pensky-Martens: 118 ⁰ C 58.1 mmVs Neutralization number: 0,53mgKOH / g -9 ⁰ C Ramsbottom test: 0.45% 312 "C The residual oil extract has the following characteristics: 1.8% Density at 50 ^° C: Viscosity at 5O ⁰ C: 46 mass parts in% Viscosity at 100 C: Pour point: 24.5 parts by mass in% Flashpoint after Marcusson: Ramsbottom test: 29.5 parts by mass in% Salaryan paraffinic bound carbon: Content of naphthenic bound carbon: Content of aromatic ge bound carbon:

(IR spectrometric determination)

It is added in an amount of 5 wt .-% in relation to the refining stage supplied waste oil. The individual process steps of waste oil processing are carried out as follows:

- Refining with sulfuric acid: refining with 8% sulfuric acid based on pre-cleaned, dewatered and stripped waste oils including extract at 25 ° C.

- Neutralization of the sour oil: Wash with 5% methanolic sodium hydroxide solution at 50 ⁰ C.

- Distillation: vacuum distillation for flash point adjustment and viscosity adjustment.

- Contact bleaching: post-refining with 5% bleaching earth (grade Staßfurt B) at a contact temperature of 120 ° C and a contact time of 20min.

The recovered waste oil regenerate has the following characteristics: Viscosity at 50 ° C: 42.4 mmVs Viscosity index: 99 Neutralization number: 0.04 mg KOH / g Flashpoint after Marcusson: 220 ⁰ C Pour point: -24 ⁰ C Ramsbottom test: 0.17%

Noack test: 9.2%

Unit age (18O ⁰ C, 16h, 51 air / h, Cu sheet according to TGL17745): Neutralization number: 0.87 mg KOH / g Ramsbottom test: 0.58% Centrifuge sludge: 0.25% The reclaim yield (at constant hegenerate viscosity) is 66.0 mass parts in% based on the used Waste oil extract Gemlsch. It is thus higher by 1.5 mass parts in% than in the known method of the prior art. Based on the waste oil used for refining, the yield of regenerated material is even higher by 4.8 parts by mass. Example 2 The contaminated, dewatered and stripped waste oil according to Example 1 is added with the addition of the residual oil extract according to Example 1 worked up according to the invention. The residual oil extract is in an amount of 10 wt .-% in% based on the refining stage supplied waste oil

added.

Maintaining the individual process steps according to Example 1 gives a waste oil regenerate with the following Characteristics:

Viscosity at 50 ^° C.: 46.1 mmVs Viscosity index: 96 Neutralization number: 0.17 mg KOH / g Flashpoint after Marcusson : 217V Pour point: -24 ° C Ramsbottom test: 0.27% Noack test: 9.4% Age aging (180 "C, 16h, 51 air / h, Cu sheet after Neutralization number: 0.91 mg KOH / g Ramsbottom test: 0.96% Centrifuges sludge: 0.30%

The Regeneratviskosität (based on the charged waste oil extract mixture at approximately the same Regeneratausbeute) of 46.1 mm ² / s at 50 ⁰ C is around 4.2 MMVs higher than in the known method of the prior art. In relation to the waste oil used for refining, there is also a 6.4% by mass increase in the recovery of regenerated material.

Claims (4)

1. A process for the treatment of waste oils by pre-cleaning, dehydration and stripping and refining of the Aitöles with sulfuric acid, separation of the resulting acid resin, neutralization of the acid oil by means of alkaline substances, separation of the resulting neutralization of the raffinate and subsequent distillation and treatment of the raffinate by contact bleaching or hydrofinishing, characterized in that the waste oil before the refining step by solvent refining of a residual oil obtained by deasphalting and / or Entharzung from the vacuum distillation residue of petroleum, with a polar solvent with or without Antisolvent in a yield of 25 to 55 parts by weight in% extract obtained in an amount of 1 to 15 parts by weight in% based on the refining stage supplied waste oil is added. 2. The method according to claim 1, characterized in that the waste oil is obtained by solvent refining a dewaxing residual oils, which is obtained by deasphalting and / or Entharzung from the vacuum distillation residue of paraffinic petroleum oil and subsequent dewaxing, obtained extract. 3. The method according to claim 1 and 2, characterized in that the waste oil is a residual oil extract having a viscosity of 40 to 110 mmVs at 100 ⁰ C and a paraffinic carbon content of 35 to 50 parts by mass in% of naphthenically bonded carbon of 20 to 35 parts by mass in% and aromatically bound carbon of 25 to 40 parts by mass in% is added. 4. The method according to claim 1,2 and 3, characterized in that the waste oil is obtained by solvent refining a residual oil with phenol with or without water obtained as an antisolvent extract.