US2080088A - Method of lowering pour points of mineral oils - Google Patents

Description

Patented May 11, 1937 aosonss 1 METHOD JOE LOWERING POUR POINTS 01 MINERAL OILS Franz Rudolf Moser, Amsterdam, Netherlands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application October 25, 1933, Serial In the Netherlands November 2,

'13 Claims. (01. 196-1) The invention relates to a process for reducing pour points of hydrocarbon oils, particularly of lubricating oils.

It has been found that the pour point of vis- 5 cous hydrocarbon oils can be lowered by adding polymerized Edeleanu extracts and similar extracts of'mineral oils. By polymerized Edeleanu extracts and the like are meant Edeleanu'extracts or other'extracts rich in non-paraflinic hydrocarbons obtained by extraction of mineral oils with solvents, such as furfural, phenol, nitrobenzene, BB'dichloroethyl ether (chlorex), etc.', which. extracts have been cracked or exposed to heating in the presence or absence of catalysts 55 and have thereby acquired pour point-reducing properties. tracts were found to be far more effective as pour point-reducers, or as sources of pour pointreducing substances, derived in the manner here- 90 inafter disclosed, than any other cracked'oils,

tars, residues or pitches. In principle, any extract can be used, but as a rule extracts of lubri cating oils are to be preferred in view of their better yield of polymerization products.

Inthe application of polymerized extracts for lowering the pour points of lubricating oils, which, for example, have high pour points by reason of their high paraffin wax contents, difficulties are often encountered. due to the fact 0 that these extracts do not dissolve readily in the oil and sometimes have an unfavourable efiect on the colour of the lubricating oils. 7

It has now been found that these drawbacks do not occur when the components of the darkest colour and least soluble in hydrocarbons poor in aromatics are first separated from the polymerization product by means of precipitating agents in which these components are insoluble.

A highly suitable precipitating agent is a kero- 40 sene poor in aromatics, while lighter'distillates, such as straight run gasoline poor in aromatics, may also be used, as well as a lubricating oil poor in aromatics. suitable for precipitation of undesirable darkcoloured substances, such as mixtures of alcohol and ether, ethyl acetate and amyl alcohol.

' In some cases the use of a lubricating oil poor in aromatics as precipitating agent may have its advantages.

lighterdistillate is used as precipitating agent the resulting dilute oil solution usually has to be concentrated by distillation (with steam or under vacuum, if desired) and the resultant residue applied, as such or dissolved in oil, as a Such activated or polymerized ex Many other liquids are also For example, when kerosene or a pour point-reducing agent; howevenwhen a lubricating oil poor in aromatics is used as the precipitating agent the resulting oil solution can be added directly to the oil whose pour point is to be reduced. The effective quantity to be used in each case can be readily ascertained by tests.

In many cases it may be considered preferable to add the polymerized Edeleanu extract treated in the above manner in the form of a solution, so as tofacilitate dosing. For. instance, if the pour point of a lubricating oil has to be reduced, then a similar lubricating oil may also be used as a solvent for diluting the polymerized extract freed of the undesirable dark coloured substances.

By choosing the right precipitating agent and by regulating its quantity and the treating temperature, it may be assured that substantially only undesirable components are removed from the oil, i. e. those which are least soluble and darkest in colour. These undesirable components, which are removed in the described manner, may be referred to as an asphaltene fraction. Therefore, it is the least soluble and darkest coloured asphaltenes that are removed from the polymerized Edeleanu extract and the like, thus leaving the so-called maltenes and the. lighter coloured asphaltenes dissolved in the precipitating agent. The remaining, i. e. not precipitated, portion (further concentrated or not) of the polymerized extract may be referred to as the active portion of such extracts.

Before applying the above described refining treatment to the polymerized Edeleanu extract and the like, these materials may be concentrated by distilling off more volatile components (with steam or under vacuum, if desired, so as to avoid cracking at this stage) and/or reheated, thereby increasing the content of pour point-reducing components. The reheating can be done, for instance, at a mild cracking temperature, such as about 350 C.

The active pour point-reducing substances may be concentrated in the rafiinate obtained by distillingofi morevolatile components from said rafiinate substantially without causing the cracking of the resulting distillation residue. The raflinate may be further activated by reheating same substantially without distillation or cracking e. g. by prolonged heating at a temperature of about 350 C.

Example tion, was heated for 4 hours to 400 C. under a pressure of about 5 atmospheres. The polymerization product, which was obtained with a yield of was concentrated by steam distillation to a residue of 15-20% calculated on the original extract; it had the appearance of a hard asphalt or pitch. This residue was mixed at about C. with 2 volumes of kerosene containing about 8% aromatics. After being cooled, the solution was decanted (it could be filtered) and the kerosene evaporated with steam. The resulting residue (6% of original extract) was the desired product which was used for reducing pour points of mineral oils.

When this product was added to three different lubricating oils with pour points 0 C., +1 C. and -6 C. in proportion of 1%, the pour points were reduced by 12, 10 and 9 C., respectively.

In order to obtain a liquid product, a suitable quantity of a lubricating oil can be added before evaporating the kerosene or other precipitant; the distillation (carried out at non-cracking temperatures) is so controlled then as not to distil off the added lubricating oil, so that it remains in the residue and the final product (residue) is obtained in the liquid form.

Instead of a kerosene also a lubricating oil fraction poor in aromatics can be used as the precipitating agent, such, for instance, as an Edeleanu raffinate, which may have been treated with an acid. After filtering or centrifuging the resulting product can be used directly as a pour point-reducing agent.

I claim as my invention:

1. In the process of lowering the pour point of a mineral oil, the steps of precipitating asphaltenes from a polymerized extract derived by extracting mineral oil with a selective solvent for non-parafiinic hydrocarbons by adding a liquid precipitant for asphaltenes to said polymerized extract, removing the precipitate and the precipitant from the unprecipitated portion, thereby concentrating active pour point-reducing substances in the unprecipitated portion, and adding the said concentrated pour point-reducing substances to the mineral oil.

2. The method of lowering the pour point of a viscous mineral oil, which comprises the step of incorporating into said oil an eifective quantity of a polymerized S02 soluble mineral oil extract rich in non-parafiinic hydrocarbons, substantially free from substances which are insoluble in light saturated aliphatic hydrocarbons.

3. In the process for preparing pour point reducing substances, the steps or" adding a liquid precipitant for asphaltenes to a polymerized S02 soluble mineral oil extract rich in non-parafiinic hydrocarbons, thereby dissolving a portion of said polymerized extract in the precipitant and precipitating asphaltenes from the dissolved portion, and separating the precipitate from the unprecipitatedportion of the polymerized extract.

4. The process according to claim 3, in which the liquid precipitant is a light hydrocarbon rich in saturated aliphatic hydrocarbons.

5. The process according to claim 3, in which the liquid precipitant is a lubricating oil which is poor in aromatics.

6. The process according to claim 3, in which the liquid precipitant is a mixture ofv alcohol and ether.

'7. In the process for preparing pour point re ducing substances, the steps of adding a liquid precipitant for asphaltenes to a polymerized S02 soluble mineral oil extract rich in non-parafilnic hydrocarbons, thereby dissolving a portion of said polymerized extract in the precipitant and precipitating asphaltenes from the dissolved portion, separating the precipitate from the solution of precipitant and unprecipitated polymerized extract, separating the precipitant from the unprecipitated portion of the polymerized extract by distillation, and then distilling oil the relatively more volatile components of said unprecipitated portion substantially without causing the cracking of the resulting distillation residue, thereby concentrating active pour point reducing substances in said residue.

8. In the process for preparing pour point reducing substances, the steps of adding a liquid precipitant for asphaltenes to a polymerized S02 soluble mineral oil extract rich in non-parafllnic hydrocarbons, thereby dissolving a portion of said polymerized extract in the precipitant and precipitating asphaltenes from the dissolved portion, separating the precipitate from the solution of the precipitant and unprecipitated portion of the polymerized extract, removing said precipi tant from said solution by distillation, and activating the resulting unprecipitated portion of the polymerized extract by heating the same at 1 about 350 C.

9. In the process for preparing pour point reducing substances from a polymerized S02 soluble hydrocarbon oil extract containing the same, the steps of concentrating said polymerized extract rich in non-parafiinic hydrocarbons by distilling it to remove the relatively more volatile components, adding a liquid precipitant for asphaltenes to the resulting distillation residue, thereby dissolving a portion of said residue in the precipitant and precipitating asphaltenes from the dissolved portion, and separating the precipitate from the unprecipitated portion of said distillation residue.

10. In the process for preparing pour pointreducing substances, the steps of adding a hydrocarbon fraction which is poor in aromatic hydro-.

carbons to a pyrogenous polymerization product of an S02 soluble mineral oil extract rich in non-parafiinic hydrocarbons, thereby dissolving a portion of said polymerization product and precipitating asphaltenes, and removing the precipitate from the unprecipitated portion of the polymerization product.

11. As a new composition, a Wax-bearing lubricating oil containing the asphaltene-free portion of a polymerized liquid sulfur dioxide soluble extract from mineral oil.

' 12. As a new composition, a wax-bearing lubricating oil containing that portion of polymerized S02 soluble mineral oil extractwhich is soluble in light saturated aliphatic hydrocarbons, and substantially free from substances which are insoluble in light, saturated aliphatic hydrocarbons.

13. As a new composition, a wax-bearing lubricating oil containing that portion of a pyrogenous condensation product of S02 soluble mineral oil extract which is soluble in light saturated aliphatic hydrocarbons, and substantially free from substances which are insoluble in light saturated aliphatic hydrocarbons.

FRANZ RUDOLF MOSER.