SU1006480A1 - Method of purifying oil fractions of petroleum - Google Patents

Abstract

A method for purifying oil oily fractions by extraction with a selective solvent, characterized in that, in order to increase the yield and improve the quality of the purified oil, 2,5-dimethyl-1,3; 4-oxadiazole or its mixture is used as a selective solvent 8D-90. wt.% furfural.

Description

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42

CX) The invention relates to oil refining industry and can be used to purify oil fractions of oil from polycyclic aromatic hydrocarbons of resinous substances and heterocyclic compounds that impair the performance of oils (, decrease the viscosity index of the oil, impair their thermal and thermal oxidative stability ). Known methods of cleaning oils from undesirable impurities by liquid extraction using as selective solvents phenol, furfural, N-methylpyrrolidone 1. However, these methods are not sufficiently effective due to the low extraction properties of the solvents used (low selectivity, low solubility of the extractants with respect to the separated components). Also known is a method of purification by applying furfural, which consists in contacting the oil fraction with furfural in a ratio of 1: (1.5-5.0) at 50-110 ° C 2 ,. The disadvantage of this method is the low yield of purified oil, due to the insufficient capacity of furfural for the indicated impurities. In addition, the thermal oxidative stability of furfural is low, its ability to grind under the influence of high temperatures and oxygen in the air causes large furur losses in the extraction process and deposition gum formation products on the apparatus. This leads to the need to take special measures to eliminate the contact of the solvent with air, i.e. preliminary deaeration of raw materials; extractive storage under inert gas. The closest to the invention by its technical nature is the method of purification of mineral oil distillates, which consists in treating the oil fraction with a selective solvent — N-acetyloxazolidine or its mixtures with water 2. The disadvantages of this method are the low oil yield (71% ), low viscosity index (109), as well as high energy consumption for oil production, associated with high viscosity of the solvent, its high boiling point and low thermal stability requiring more frequent regeneration solvent. The aim of the invention is to increase the yield and quality of the purified oil, decrease the solvent: raw material ratio and reduce the energy costs of the oil refining process. This goal is achieved by the fact that according to the method of purification of oil fractions by extraction with a selective solvent, 2,5-dimethyl 1, 3,4-oxadiazole or its 8090 wt.% Furfural is used as the latter. 2,5-Dimethyl-1,3,4-oxadiazole of the formula N - N // / - o / - is a colorless liquid with a weak characteristic odor, readily soluble in water, with a boiling point. 178 ° C and a density of d20 1,0963. 2,5-Dimethyl-1,3,4-oxadiazole is obtained from the available raw material — hydrazine hydrate and acetic anhydride, НН2-НН2-, Н20 + (СНзСО) 20ЬОО-350 ° С (СНзСО) 2М-Н (СНзСО) // + СН , COOH + H „0. 00-350 ° 0 - CH3-, 3 2 Thermal stability is determined by boiling in air for 220 hours. The viscosity of 2,5-dimethyl-1,3, 4-oxadiazole remains practically unchanged, which indicates the absence of a gumming process. , while boiling 2,5-dimethyl-1, 3,4-oxadiazole for 100 hours, the viscosity increased by 0.3 cSt, while the viscosity of N-acetyloxazolidine increased by 3 at the same time at 150 ° C. , 0 eSt. Chromatographic analysis of 2,5-dimethyl-1, 3,4-oxadiazole after boiling showed the absence of both low-boiling and high-boiling decomposition products. Thus, unlike N-acetyloxazolidine 2, 5-dimethyl-1,3,4-oxadia, sol exhibits greater thermo-oxidative stability. For its regeneration from the raffinate and extract phases, known methods can be used (rectification, stripping). The extraction properties of 2,5-dimethyl-1, 3,4-oxadiazole and its mixtures, furfural and N-acetyloxazolidine were evaluated on artificial mixtures simulating the composition of oil fractions of oil, and on industrial oil fraction. Example 1. In table. 1 shows the results of a single-stage extraction of p-methylnaphthalene from a mixture with tridecane with a ratio of 1.5: 1 and a weight ratio of solvent and raw materials.

Table 1

35

Furfural

N-acetylox aldidine

35

2,5-Dimethyl-1,3,435 oxadiazole

10% 2,5-dimethyl1, 3.4-6xadiazole + 90%

furfural 35

20% 2,5-dimethyl-1,3, 4-oxadiazole + 80% furfural35 As follows from the table. 1, 2,5-dimethyl-1, 3,4-oxadiazole and its mixtures with furfural are superior to furfural and N-acetyloxazolidine in selectivity to polycyclic aromatic hydrocarbons. as evidenced by the lower content of p-methylnaphthalene in the raffinate and higher selectivity ratios. PRI mme R 2. In table. Figure 2 shows the results of a three-step extraction of the oil fraction 350420 ° C. Characteristic of raw materials: Boiling points, C 350-420 Density at 20 ° С,, 899

79,218 1,220,050 25.4

13.5 1.20 0.035

34.3

85.3 13.1 1.20 0.030

40

81.5 12.8 1.28 0.036

35.1

84.5 12.7 1.31 0.034

38.5 volts + tn 2 Refractive index at 1.4892 Viscosity at, cSt Pour point, ° C Coking ability, wt.% 0.7 Sulfur content, wt.% 0.94 Extraction is carried out at separatory funnels. The raffinate is dewaxed at 0 ° C in a solvent of 75% toluene + 25% acetone. The ratio of dissolved and raw materials - 3: 1. A holding time at minus is min.

Solubilization ratio, 5tl 1.5: 1 l, 5il tel: raw materials

The output of the raffinate phase, wt.% From

80.6 82 raw materials

The output of the raffinate,

69 71 May.% Of raw materials Refractive index at 50 ° С 1.4732 1.4756 before dewaxing Refractive index for after 1.4789 1.4798; dewaxing viscosity at 50 ° C, cSt 14.85 16.58 before dewaxing after dewaxing, 26 18.85 zation

Viscosity at 100 ° C, cSt before dewaxing 4.20 4.60 after dewaxing 4, 26 4.66 Viscosity index (VI)

before dewaxing 104114.5 124

after deparaffin98 109 116,5 123 ozation The data presented in Table. 2, illustrate the possibility of obtaining purified oil using 65

table 2

l, 5tl

1.2: 1

83.6 82

83

73

72

74

130

117

114 1.4711 1.4695 1.4723 1.4765 1.4751 1.4769 15.94 15.33 17.2317.47 4.62 2.5-dimethyl-1.3, .4-oxadiazole with a lower charge (5de solvent 11.2 versus 1.5) Compared with H-acetyl-

oxazolidine and furfural. The quality of the oil is higher than when using N-acetyloxazolidine and furfural (willow 114 against 109 and 98, respectively), and the yield increases by 3% against M-acetyloxazolidine and by 5% against furfural. When using a mixture containing 10-20 wt.% 2, -dimethyl-1,3,4-oxadiazole and I80-90 wt.% Furfural with the ratio; The Scientific Research Institute of Solvent and Raw Materials 1.5: 1 improves the quality of oil (PE 116.5 and 123 against 109) with a slight increase in code (72 and 73% against 71%). The use of the invention allows to improve the technical and economic performance of the process by reducing

the ratio of solvent: raw materials compared with the known method, as well as by improving the quality and increasing the yield of purified oil. Reducing solvent consumption, its lower viscosity and low boiling rate allows to increase the performance of existing plants and reduce energy costs for regeneration and pumping of the solvent. The use of a mixture of 2,5-dimethyl-1,3,4-oxadiazole with furfural can be easily accomplished by simple addition of 2,5-dimethyl-1,3,4-oxadiazole on existing installations of furfural cleaning without any costs.

Claims (1)

METHOD FOR CLEANING OIL FRACTIONS OF OIL by extraction with a selective solvent, characterized in that, in order to increase the yield and improve the quality of the purified oil, 2,5-dimethyl-1,3, 4-oxadiazole or its mixture with 80- is used as a selective solvent 90. wt.% furfural. and w, 1006480