RU2095395C1 - Method for production of diesel fuel - Google Patents

Abstract

FIELD: production of diesel fuel; oil processing industry. SUBSTANCE: hydrogenation treatment of origin oil raw materials is carried out in three steps on various catalysts, the process is carried out in aggregate contour, pressure of hydrogen in reaction zone being 3.0-4.8 MPa. Quantities of hydrogenation catalyst, hydrorefining catalyst and catalyst of destruction dearomatization are 30-65 %, 10-25 % and 25-45 % respectively. Proposed method makes possible to produce ecologically pure diesel fuel. EFFECT: improved quality of desired product. 4 cl

Description

 The invention relates to methods for producing diesel fuel and can be used in the oil refining industry.

 A known method of producing diesel fuel by deep hydrogenation of gas oil by catalytic cracking in the presence of sulfide Nickel-tungsten catalyst.

Hydrogenation is carried out at a pressure of 25-30 MPa and a temperature of 360-400 ^o C. As a result, from raw materials containing up to 1.5 wt. sulfur and up to 60 wt. sulfonated hydrocarbons (totally unsaturated and aromatic) receive a product characterized by a sulfur content of 0.01-0.02 wt. and up to 10 wt. aromatic hydrocarbons (no unsaturated hydrocarbons). The specified product meets the technical specifications for environmentally friendly diesel fuel (ECDT) with a sulfur content of up to 0.05 wt. and aromatic hydrocarbons up to 10 wt. [one]
The disadvantage of this method is the possibility of its implementation only under a pressure of 25-30 MPa, which entails increased metal consumption, as well as significant capital and operating costs. Also known is a method of producing diesel and jet fuels by two-stage hydrogenation of petroleum distillates boiling in the temperature range 150-310 ^o C. The method consists in preliminary hydrotreating the feedstock on conventional industrial catalysts to obtain a residual sulfur content in the hydrogenate at a level of 50-100 rpm and subsequent dearomatization of hydrogenate in the presence of a platinum (palladium) catalyst. The method is carried out at a pressure of 5-7 MPa and a temperature of 300-400 ^o C. The technological scheme is framed in the form of two autonomous stages with separate hydrogen-containing gas circulation systems.

The result is a product containing less than 12 wt. aromatic hydrocarbons and less than 0.03 wt. sulfur [2]
The disadvantages of the method are: the need to use two autonomous systems for the circulation of hydrogen-containing gas (two stages); the use of palladium (platinum) catalysts in the second stage, which are very sensitive to sulfur compounds; the need to apply pressure of 5-7 MPa (which is slightly higher than the working pressure of typical hydrotreatment plants).

 All of the above methods significantly complicate the technological scheme of the process and increase the cost of production.

Closest to the claimed is a method for producing diesel fuel, including two-stage hydrogenation of straight-run distillates or mixtures thereof with cracking gas oils in the presence of nickel-tungsten or nickel-molybdenum catalysts at a pressure of 5.08-10.15 MPa and a temperature of 316-329 ^o C. allows you to reduce the content of aromatic hydrocarbons from 19-33 to 5-18 wt. with a deep decrease in sulfur content. At the first stage, the feedstock is pretreated in the presence of a nickel-molybdenum catalyst to a residual sulfur content of 100-200 ppm, and then the obtained hydrogenate is subjected to hydrogenation treatment in the presence of a nickel-tungsten catalyst. In this case, a reduction in the content of aromatic hydrocarbons to 5-15 wt. [3] The disadvantage of this method is both the use of two autonomous stages and relatively high pressure (5.08-10.15 MPa). Both of these circumstances significantly increase the cost of hydrogenation due to increased capital and operating costs.

 An object of the invention is to improve the environmental and operational characteristics of the target product while reducing hydrogen pressure in the process of hydroprocessing.

 This problem is solved by the fact that in the proposed method for producing diesel fuel, the feedstock is subjected to hydrogenation treatment in three stages on different catalysts in the general circuit of a hydrogen-containing gas at a hydrogen pressure in the reaction zone of 3.0-4.8 MPa.

In the first stage, the feedstock is subjected to hydrogenation, while the conversion reactions of the most reactive polycyclic aromatic hydrocarbons and some of the unsaturated hydrocarbons occur. Process conditions: temperature 300-390 ^o C, pressure 3.0-4.8 MPa, the volumetric feed rate of 3-7 h ^-1 . Two sequentially loaded catalysts are used as a catalytic composition: aluminum-cobalt-molybdenum (AKM) (20% of the load) and aluminum-nickel-molybdenum (ASM) (80% of the load). The composition of the aluminum-cobalt-molybdenum catalyst, wt. cobalt oxide 3-6, molybdenum oxide 16-19, aluminum oxide the rest. The composition of aluminum-Nickel-molybdenum catalyst, wt. nickel oxide 3-6, molybdenum oxide 16-19, aluminum oxide the rest.

In the second stage, the hydrogenated feedstock is subjected to hydrotreating, while the reactions of transformation of sulfur compounds and unsaturated hydrocarbons occur. Process conditions: temperature 330-400 ^o C, pressure 3.0-4.8 MPa, the volumetric feed rate of 2.5-12.0 h ^-1 . As a catalyst using cobalt-molybdenum composition of the following composition, wt. cobalt oxide 2-5, molybdenum oxide 13-20, aluminum oxide the rest.

At the third stage, destructive dearomatization is carried out. In this case, the reactions of deep conversion of aromatic hydrocarbons and partial destruction of paraffin hydrocarbons occur. Process conditions: temperature 320-400 ^o C, pressure 3.0-4.8 MPa, the volumetric feed rate of 4.0-12.0 h ^-1 . As a catalyst using a zeolite-containing composition of the following composition, wt. nickel oxide 15-25, molybdenum oxide 30-50, silicon oxide 8-15, rare earth oxide (REE ₂ O ₃ ) 5-15, Al ₂ O _{3 the} rest. The catalyst loading ratio is: hydrogenation catalysts 30-65% hydrotreating catalyst 10-25% dearomatization catalyst 25-45% Moreover, from direct distillate feed raw materials or mixtures thereof with secondary gas oils (sulfur content up to 1.5 wt. Of aromatic hydrocarbons up to 30 wt.% Receive diesel fuel characterized by a sulfur content of less than 0.05 wt. And aromatic hydrocarbons of less than 20 wt. (And even less than 10 wt.).

Example 1. Hydrogenation treatment is subjected to straight-run diesel fraction (sulfur content of 1 wt. Aromatic hydrocarbons 22 wt.). In the first stage (hydrogenation), sequentially loaded aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts are used. The composition of the AKM catalyst, wt. cobalt oxide 3, molybdenum oxide 16, aluminum oxide the rest. The composition of the ASM catalyst, wt. nickel oxide 3, molybdenum oxide 16, aluminum oxide the rest. Process conditions: pressure 3 MPa, temperature 300 ^o C, the volumetric feed rate of 7.0 h ^-1 .

In the second stage (hydrotreating) use a cobalt-molybdenum catalyst containing, by weight. cobalt oxide 2.0, molybdenum oxide 13.0, aluminum oxide the rest. Process conditions: pressure 3 MPa, temperature 330 ^o C, the volumetric feed rate of 12 hours ^-1 .

In the third stage (destructive dearomatization), a zeolite-containing nickel-molybdenum catalyst of the following composition is used, wt. nickel oxide 15, molybdenum oxide 50, SiO ₂ 8, REE ₂ O ₃ 5, aluminum oxide the rest. Process conditions: pressure 2 MPa, temperature 320 ^o C, the volumetric feed rate of 12 h ^-1 .

The catalyst loading ratio is: hydrogenation catalysts 65% hydrotreating catalyst 10% destructive dearomatization catalyst 25%
The result is an ESDT containing less than 0.05 wt. sulfur and less than 20 wt. aromatic hydrocarbons.

 Example 2. A mixture of straight-run diesel fraction and catalytic cracking gas oil (sulfur content of 1.3 wt. Aromatic hydrocarbons 28 wt.) Is subjected to hydrogenation treatment.

In the first stage (hydrogenation), sequentially loaded aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts are used. The composition of the AKM catalyst, wt. cobalt oxide 4.5, molybdenum oxide 18.0, aluminum oxide the rest. The composition of the AMM catalyst, wt. nickel oxide 4.5, molybdenum oxide 18.0, aluminum oxide the rest. Process conditions: pressure 4 MPa, temperature 330 ^o C, the volumetric feed rate of 5.0 h ^-1 .

In the second stage (hydrotreating) use a cobalt-molybdenum catalyst containing, by weight. cobalt oxide 3.5, molybdenum oxide 16.0, aluminum oxide the rest. Process conditions: pressure 4 MPa, temperature 355 ^o C, volumetric feed rate of 5.5 h ^-1 .

In the third stage (destructive dearomatization), a zeolite-containing nickel-molybdenum catalyst is used containing, by weight. nickel oxide 20, molybdenum oxide 40, SiO ₂ 10, REE ₂ O ₃ 10, aluminum oxide the rest. Process conditions: pressure 4 MPa, temperature 340 ^o C, the volumetric feed rate of 7 h ^-1 .

 The ratio of the catalyst loading by stages is: hydrogenation catalysts 50% hydrotreating catalyst 15% destructive dearomatization catalyst 35% As a result, an ECPT containing less than 0.05 wt. sulfur and less than 20 wt. aromatic hydrocarbons.

 Example 3. A mixture of straight-run diesel fraction and thermal cracking gas oil is subjected to hydrogenation treatment (sulfur content of 1.7 wt. Aromatic hydrocarbons 31 wt.).

 In the first stage (hydrogenation), sequentially loaded aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts are used. The composition of the AKM catalyst, wt. cobalt oxide 6.0, molybdenum oxide 19.0, aluminum oxide the rest. The composition of the AMM catalyst, wt. nickel oxide 6.0, molybdenum oxide 19.0, aluminum oxide the rest.

Process conditions: pressure 4.8 MPa, temperature 390 ^o C, the volumetric feed rate of 3 h ^-1 .

In the second stage (hydrotreating) use a cobalt-molybdenum catalyst containing, by weight. cobalt oxide 5.0, molybdenum oxide 20.0, aluminum oxide the rest. Process conditions: pressure 4.8 MPa, temperature 400 ^o C, the volumetric feed rate of 2.5 h ^-1 .

At the third stage (destructive dearomatization), a nickel-molybdenum catalyst is used containing, by weight. nickel oxide 25, molybdenum oxide 30, SiO ₂ 15, REE ₂ O ₃ 15, the rest is aluminum oxide. Process conditions: pressure 4.8 MPa, temperature 400 ^o C, the volumetric feed rate of 4 h ^-1 .

The ratio of catalyst loading by stages is: hydrogenation catalysts 30% hydrotreating catalyst 25% destructive dearomatization catalyst 45%
Thus, the proposed method allows to produce environmentally friendly diesel fuel by hydrogenation treatment at a moderate pressure of hydrogen and using a fairly simple technological scheme.

Claims (4)

 1. A method of producing diesel fuel, comprising the step of hydrogenating petroleum feedstock at elevated temperature and pressure in the presence of catalysts, characterized in that the feedstock after hydrogenation is subjected to hydrotreating followed by destructive dearomatization and the hydrotreatment process is carried out at a pressure of 3.0 4.8 MPa in the following the ratio of the load of catalysts, wt. hydrogenation catalysts 30.0 65.0; hydrotreating catalyst 10.0 25.0; destructive dearomatization catalyst 25.0 45.0. 2. The method according to claim 1, characterized in that the hydrotreating is carried out at 330 - 400 ^o C, the volumetric feed rate of 2.5 to 12.0 h ^{- 1} on a catalyst containing 2 to 5 wt. cobalt oxide, 13 20 wt. molybdenum oxide, aluminum oxide the rest. 3. The method according to p. 1, characterized in that the destructive dearomatization is carried out at 320 400 ^o C, the volumetric feed rate of 4.0 to 12.0 h ^{- 1} on a catalyst containing 15 to 25 wt. nickel oxide, 30 to 50 wt. molybdenum oxide, 8 to 15 wt. silicon oxide, 5 to 15 wt. rare earth oxide, aluminum oxide the rest. 4. The method according to claim 1, characterized in that the hydrogenation is carried out at 300 - 390 ^o With a volumetric feed rate of 3 to 7 h ^{- 1} in the presence of aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts.