HU207118B - Process for improving the quality of petrol obtained by thermal splitting - Google Patents

Abstract

The invention relates to a process for the treatment of gasolines from the thermal decomposition of Erdoelrueckstaenden that are not usable without aftertreatment as a gasoline fuel component. According to the invention, the refinement of these gasolines is carried out in the following process combination: 2-stage partial condensation, hydrorefining of the heavy gasoline component together with vacuum distillate, joint separation of the gasoline fractions from the hydrorefining and the hydrocatalytic conversion of the vacuum distillate, mixing of these gasoline fractions with the light gasoline component from the partial condensation.

Description

The present invention relates to a process for improving the quality of gasoline obtained by thermal cleavage of petroleum residues.

Thermal cleavage of petroleum residues is known to produce a certain amount of gasoline, but is reduced in value by properties (Hydrocarbon Processing, September 9, 1980; Bland and Davidson, Petroleum Processing Handbook, McGraw-Hill, 1967, 3 / 62-3 / 74; SW Martin and LE Vili, Advances in Petroleum Chemistry and Refining, Vol. II, 1959, 357-433).

Petrol produced by thermal cleavage of petroleum residues is unstable, corrosive and knocks relatively quickly during storage. Therefore, it cannot be used as a fuel component without post-treatment.

Hydroaffinification and subsequent reformation are commonly used (Oil Gas Journal, 24, 1, 1972; Cherry Point Refinery and Oil Gas Journal, 23.4, 1973).

Due to the high content of olefins and nitrogen, this process combination is relatively complex and can only be used in combination with a large amount of straight-run gasoline with reduced efficiency.

Hydro-refining of thermally cleaved petrols has the disadvantage of having to use special solvents to control the highly exothermic reaction at high hydrogen consumption and of decomposing the olefin components that improve the octane rating of the gasoline to a very low level (e.g. ROZ 73 to ROZ 40).

The use of such petrol as a fuel is burdensome for the economy and causes significant cost losses.

When refined petroleum naphtha is catalytically reformed as described in the literature to improve octane, vigorous conditions have to be applied due to the high nitrogen content of the gasoline, which increases costs. Due to the low number of ring compounds in the split gasoline, the technical and economic yield of the reforming is very low.

Removal and / or conversion of mercaptans in thermally cleaved gasoline (e.g., U.S. Patent Nos. 2966453, 2999806, 3039855, and 3423,180) and blending with other fuels (Erdői und KohlenErdgas-Petrolchemie, 22, 1969, 1, 11; Oil) Gaz Journal, 31-3, 1971, 49-53 and Oil Gas Journal 7, 6, 1971, 76-82) are relatively expensive and do not change the octane number of the unleaded component, only reducing the amount of sulfur compounds with the amount of extractable mercapto. Due to the residual sulfur content by weight, gasoline can only be blended with other fuel components at a very poor rate in order to meet quality standards, and it also significantly reduces the lead sensitivity of the fuel blend.

Changes in petroleum production are leading to increased use of thermal cleavage, and the disadvantages listed are becoming increasingly important.

The object of the present invention is to provide a technically and economically improved process for the processing of gasoline obtained by thermal cleavage of heavy stone oil residues.

It is an object of the present invention to provide a head product of the main fractionation column of a thermal splitter to obtain low sulfur gasoline that does not cause octane reduction when mixed with other fuels.

According to the invention, a mixture of strip vapor and about 480 K boiling point hydrocarbon vapors formed at the head of a main fractionating column used to separate the thermal cleavage reaction products at a pressure of 0.1 to 0.5 MPA and a head temperature of 60 to 90 MPa. At a temperature lower than K, the first step of a two-stage partial condenser is separated into a gas phase and a liquid phase consisting of a heavy gasoline component and an aqueous phase.

The heavy gasoline component is treated with a vacuum distillate of hydroaffinification on a sulfide nickel / molybdenum support catalyst at a pressure of about 5 MPa and 610680 K with a residence time of 1-3 m ³ / m ³ and a gas / product ratio of 300-500 m ³ / m ³ . From the reaction mixture, the gasoline component is separated with the gasoline formed during the hydrocatalytic conversion of the vacuum distillate by separation and distillation. From the gas partial phase of the first partial condensation step, the light gasoline component is separated from the gas phase in the second step. This light gasoline is blended with the gasoline component separated from the hydroaffinification product prior to being added to the fuel, which prior to blending is blended with the light gasoline or the finished blend with the gas generated during the thermal cleavage step and subjected to standard two-step mercaptan extraction and conversion.

Execution examples

l. Example I (Comparative Example I)

In a small process refiner, Visbreaker gasoline is hydroaffinated on a sulfurized Ni / Mo supported catalyst at a pressure of 5 MPa, a temperature of 630 K, and a residence time of 3 m ³ / m ³ h and a gas / product ratio of 400 m ³ / m ³ . As a result of the treatment, the properties of gasoline change as follows:

quality initial material hidroraffináll petrol ROZ (clear) 73 41 MOZ (clear) 66 39 Sulfur content (% by weight) 1.27 0.0001 Mercaptan content (ppm) 3720 1 Nitrogen content (ppm) 63 10 Bromine number (grams bromine / 100 grams) 61 0.2

Due to its low octane content in the raffinate, only special conditions exist as a fuel component1

EN 207 118 (such as low octane fuel types or extreme blending ratios).

The raffinate has an aromatic content of 8% by weight and a naphthenic content of 15% by weight (of which 10% cyclopentane and 51% cyclohexane).

Due to its properties, the product is not suitable for use in a reformer, even if its nitrogen content is reduced to 1 ppm for use with a reformer under more stringent refining conditions. If the process is used at a large technological scale, temperatures of about 200 ° C due to the exothermic nature of the olefin hydrogenation would cause considerable difficulties.

Examples 2a and 2b (Comparative Example 2)

Visbreker gasoline is treated in a two-stage mercaptan removal and conversion device (German Patent Publication No. 2116158). The mercaptans soluble in the sodium hydroxide in the extraction portion are extracted with sodium hydroxide containing the catalyst, oxidized to the disulfide by air in the alkaline generation, and removed as such. The poorly soluble or insoluble mercaptans remaining in the Visbreaker gasoline are reacted with air in a solid catalyst reactor in the presence of sodium hydroxide. The resulting disulfides remain in the gasoline. The properties of gasoline change as a result of the treatment as follows:

Example 2a: Visbreaker gasoline has a boiling point of 453 K

quality initial material treated petrol ROZ (clear) 73 72 MOZ (clear) 66 66 Sulfur content (% by weight) 1.27 0.97 Mercaptan content (ppm) 3720 5

Example 2b: Visbreaker gasoline has a boiling point of 483 K

quality initial material treated petrol ROZ (clear) 71 71 MOZ (clear) 65 64.5 Sulfur content (% by weight) 1.25 1.04 Mercaptan content (ppm) 3540 20

The Visbreaker gasoline has a sulfur content of about 1% by weight. If the maximum amount of Visbreaker gasoline was to be mixed with 1500 kt / fuel at 65 kt, the sulfur content of Visbreaker gasoline would reach 0.04% by weight, which is 0.03% by weight above the applicable specifications. would further reduce the lead sensitivity and thus the octane rating.

Example 3

Example 3 relates to the process of the invention.

(Figure 1) A mixture of a Strip Vaporizer of a Visbreaker A, consisting of "Steam" Steam and 483 K Upper Boiling Hydrocarbon Steam at a pressure of 0.25 MPa and a temperature of 65 K below the head temperature of a two-stage condenser (2). ) is separated into two liquid phases consisting of (3) heavy naphtha and (9) an aqueous phase having a density of 0.765 g / cm ³ at 20 ° C. The (three) heavy naphtha component relative to összbenzinre% of (8) szulfidozott together vákuumdesztillátummal Ni ₃ / Mo supported catalysts 5 MPa, 630 K temperature, 3 m ³ / m ³ h residence time and 400m ³ / m ³ to about 50 weight gas / product ratio (C) in a refiner. The reaction product separates the heavy gasoline components by separation and distillation, together with the cleavage gasoline (5) formed during the vacuum distillate refining.

The gaseous phase (2) the second step of the condensation of (B ₂₎ at 20 DEG C. 0.705 g / cm ³ density (4) light benzinkomponenst together separated from hidroraffinálóban (C) (5) benzinkomponenssel single (D) a stabilizing column of the thermal cracking (10 ) gas mixture. The stabilized gasoline mixture (6) is subjected to a two-step treatment in the apparatus (E) as described in Example 2 to remove and convert the mercaptans. In this process, the soluble mercaptans enriched in the light gasoline component (4) are washed in the extraction step and discarded after conversion to the disulfide. The remainder of the insoluble mercaptans is treated in a reactor.

The gasoline thus obtained has the following characteristics:

ROZ (clear) 66 MOZ (clear) 62 Sulfur content (% by weight) 0.3 Mercaptan content (ppm) 4 Bromine number (grams per 100 grams) 36.5

While the sulfur content decreases as desired, the gasoline octane number shows a much smaller decrease than expected. Mixture of visbreaker gasoline, light naphtha (boiling point below 373 K) and heavy naphtha (boiling above 373 K) obtained by distillation of the laboratory gasoline, with heavy naphtha refined before blending, showing the following octane number:

ROZ (Clear) 59

MOZ (Clear) 55

This represents a double octane reduction compared to the process of the present invention.

Based on the achieved sulfur content and octane number, the Visbreaker petrol can be used in the blend without any problems. The procedure is economical and ru3

HU 207 118 Β galmas. It is easily adapted to fuel specifications and allows full utilization of the upper end of the boiling point.

Claims (3)

PATENT CLAIMS 1, A process for processing gasoline obtained by thermal cleavage of heavy petroleum residues into a fuel component, characterized in that a two-stage partial condensation and removal of water from the head fraction of the main fractionation column for separating the reaction products of thermal cleavage and strip vapor and hydrocarbon vapors. separating the gasoline from the reaction product of the hydro-refining process, before light gasoline or the mixture itself is thermal is contacted with the gas formed during the cleavage and subjected to a two-stage mercaptan extraction and conversion known per se. A process according to claim 1, wherein the head fraction of the main fractionator column is comprised of "strip" vapor and 480 K boiling point hydrocarbon vapor at a pressure of 0.1-0.5 MPa and 60-90 K below the head temperature. at a temperature, the first step of partial condensation is separated into a gas phase and a liquid phase consisting of heavy gasoline and an aqueous phase, and the light gasoline is separated from the gas phase obtained in the first step of the second partial condensation. 3. A process according to claim 2, wherein the naphtha and vacuum distillate obtained by thermal cleavage of the petroleum residue have a residence time of 1-3 m ³ / m ³ h on a sulfurized nickel / molybdenum supported catalyst at 610-680 K and It is hydroaffinated at a gas / product ratio of 300-500 m ³ / m ³ .