CS253410B1 - The method of refining petroleum oils - Google Patents

Abstract

The combined pre-refining and refining of petroleum oils is solved, in which the raffinate solution from the pre-refining is used as a feedstock for the actual refining. This method produces 3 oil refining products: a raffinate with the desired viscosity index, a more or less aromatic extract. Their properties can be adjusted by operating conditions, especially temperature. The procedure is particularly advantageous for expanding production on existing selective oil refining units.

Description

253410

BACKGROUND OF THE INVENTION The present invention relates to a method of saponifying petroleum oils with selective diluents, wherein the raffinate solution from the pre-refining serves as a feed for subsequent refining.

Solvent refining of petroleum oils is a process known and used earlier. The solvents used are mainly phenol, cresol, furfural, and N-methylpyrrolidone (10th World Oropean Congress, Bucharest, 197.9) has recently been recommended. The aim is to obtain, in particular, oil raffinates of the requisite quality and in sufficient yield. The extract is usually less attentive. When processing less quality oils, in order to achieve the desired properties of the produced oils, the raffinate yields, which range from about 20 to 50%, are greatly reduced. As a common technological measure is the use of countercurrent processes, temperature gradients and poor extract flow. In contrast, the technologies mentioned above are not sufficiently effective. It is possible to pre-refine the oils as a separate process, whereby the obtained raffinate is used as a subsequent refining feed. Hydrogenation pre-refining is used for this purpose.

The drawback of such oil production processes is the need for a fund of labor time, the cost of production and, in some cases, the formation of a larger amount of minor by-products.

The process of the present invention overcomes the above drawbacks by pre-refining with an oil-like solvent in which the resulting raffinate solution serves as a subsequent refining feed. By selecting the technological parameters, it is thus possible to obtain the final film with the desired qualitative properties, and the two extracts are noticeably different from those of the broader, respectively. specific uses. The pre-refining extract, which is preferable to do at lower temperatures, has a lower solidification temperature and increased flavor compared to extracts from conventional solvent refinements. Such an extract is preferably used for rubber purposes. From the production point of view, it can substitute the procedure given in the Czechoslovak. A further extract, resulting from its own refining, is less aromatic in comparison with conventional extracts, contains less condensed aromatics, has a viscosity index of 20 to 40 units. Its freezing temperature depends on the refining temperature. After appropriate adjustments, they are suitable for short-term use, eg conventional oil.

In a schematic manner, the process of combining petroleum oil refining and refining is shown in FIG.

The oil 4 is fed together with the solvent 3 to the pre-refining stage 1. The resulting aromatic extract solution 6 is recovered into the recovery part of the apparatus, whereby the solvent is removed therefrom. The pre-refinement solution of the raffinate 5 is fed to the ex-tractor 2 where the solvent 3 is fed to it. The resulting refinery solution 7 and the less aromatic extract 8a are further removed by distillation of the solvent.

As a pre-refining stage, a countercurrent device such as a RDC type or a mixer-type heat exchanger with a heat exchanger for adjusting the temperature of the solutions in the carbon black can be used. In the pre-refining stage, temperatures of 40 to 90 ° C are preferably 50 to 70 ° C to produce more aromatic extracts with reduced freezing temperatures. The weight ratio solvent: oil is 1: 3: 1. The preprafinate solution is refined in countercurrent with an additional amount of solvent in an amount such that the resulting solvent: oil ratio is 1.5 to 3: 1. The temperatures in the refining step are generally higher than in the pretreatment stage, for example 90 to 125 ° C using a temperature gradient of up to 25 ° C. In order to obtain, even from the refining process, extracts with lower freezing points, the working temperatures in this extractor are 50 to 80 ° C.

The solvent is removed from the solutions by distillation to give the raffinate, more or less aromatic extract. Another advantage of the process of the present invention is the need for only 3 recovery lines to remove solvent from the product. Example

The pre-refining of the medium-viscous oil distillate with furfarol gave, at a 50 ° C weight ratio, distillate-furfural1: 2 oils, the properties of which are given in Table 1.

Table 1. distillate unrefined extraktrafinate kinematic viscosity at 100 ° C, mm2. s'1 viscosity index

pour point, ° C density at 20 ° C, kg. m-3

% CA-1 yield,% wt. 4,954 4,651 7,766 75 99 -79 - - —10 914,0 886,5 1,002.0 18.2 12.1 31.4 - 76.8 23.2

Claims (2)

253410 S The pre-refining grade extract complies with its quality parameters for rubber purposes. The raffinate solution from the pre-refining of the oil was subjected to subsequent refining. RDC was fed with a content of 21% by weight of furfural. The furfurane was countercurrently refined, with a total oil: furfural ratio of 1: 1.5. The temperature at the top of the extractor was maintained at 115 ° C and at the bottom at 95 ° C. After distilling off the solvent, the resulting raffinate was obtained in a yield of 52% by weight. The non-paraffinized resulting raffinate had a ki-nematic viscosity at 100 ° C of 4.281 mm 2 · s -1, a viscosity index of 120 units and a content of aromatic carbon (% CA) of 6.5%. After dewaxing, the viscosity at 100 ° C was 4.522mm 2. s_1, viscosity index 97 units and solidification temperature -14 ° C. The extract obtained by the refining step had a viscosity at 100 ° C of 675 mm 2 s -1, a viscosity index of 22 units, a freezing point of + 16 ° C and an aromatic carbon content of 19.7%. OBJECT A process for the refining of petroleum oils with selective solvents, characterized in that the oil is first pre-refined at a temperature of 40 to 90 ° C, preferably 50 to 70 ° C and a weight ratio of solvent: oil of 1 to 3: 1 and the obtained raffinate solution from the pre-refining of the saddle countercurrently refining at 90 DEG to 125 DEG C. with another portion of the solvent, which is in a weight ratio of from 1 to 3: 1. 2. A process according to claim 1, wherein the countercurrent process in the pre-refining and refining step is operated at a temperature gradient of up to 25 ° C. l drawing sheet