RU1813095C - Method of heavy oil fraction reprocessing - Google Patents

Abstract

Essence: a heavy oil fraction containing less than 3 wt.% Of asphaltene components together with a hydrogen-containing gas is passed through a reaction zone containing a non-acid catalyst at a temperature of 400-550 ° C, a partial pressure of hydrogen of 10-60 bar. 13 tab.

Description

The invention relates to a method for converting a heavy oil fraction, in particular a heavy oil fraction containing a limited amount of asphaltene components, into lighter components.

The aim of the invention is to reduce coke formation and increase the yield of target products.

This is achieved by the described method of processing a heavy oil fraction into lighter fractions in the presence of a hydrogen-containing gas and a non-acidic catalyst that activates hydrogen, in which a feedstock containing less than 3 wt.% Of asphaltene components together with a hydrogen-containing gas is passed through a reaction zone containing a catalyst and the process is carried out at 400 -50 ° C, with a partial pressure of hydrogen of 10-60 bar.

Thermal cracking of the molecules of the starting material has a significant effect on the decrease in molecular weight. Thus, unlike catalytic cracking and hydrocracking, the new process is independent of the presence of acid points on the catalyst, which must remain -active during the cracking cycle or the life of the catalyst. Due to the presence of hydrogen, even at relatively moderate pressure, a very small amount of coke is deposited on the catalyst, which allows operation in a fixed bed (e.g. swinging reactor) or moving bed (e.g. bunker flow reactor).

The resulting middle distillates are of good quality due to the greater amount of p-paraffins and the small amount of olefins, despite the presence of a certain amount of aromatic compounds. The consumption of hydrogen in the process is relatively low, since aromatic compounds are poorly hydrogenated. Another advantage is that, depending on the catalyst, the sulfur available in the feedstock is substantially

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the heat can be converted to hydrogen sulfide, resulting in a product containing a relatively small amount of sulfur.

Residual product i.e. a product with a boiling point higher than the boiling point of middle distillates is of high quality (viscosity, carbon residue and sulfur content) and can be used as a valuable additive for liquid fuels. Such a product is an excellent starting material for a fluidized bed catalytic cracking reaction. Compared to conventional feedstocks for a fluidized bed catalytic cracking reactor, e.g., direct distillate evaporated distillate, the gasoline quality is similar. Compared to the residual product obtained from the distillate thermal cracking reactor as a starting material for the fluid catalytic cracking process, a significantly higher yield of gasoline is achieved.

Compared to a conventional thermal cracking process, a comparable middle distillate is obtained provided that the thermal cracking product is further hydrotreated. However, the quality of the untreated fraction of the product obtained in the described process is significantly higher compared to the untreated fraction of thermal cracking.

Thanks to the presence of activated hydrogen during. reactions of the heavy fraction T obtained in the present process,

It has low viscosity, low content of polyaromatic compounds and low sulfur content.

Compared with the conventional catalytic cracking process, the described-process does not depend on the presence of acid points on the catalyst. This process can be carried out with a significant or even complete absence of acid points in the catalyst. Thus, feeds containing a significant amount of basic nitrogen or sulfur compounds / can be processed without difficulty. Due to the presence of activated nitrogen, only a very small amount of coke is deposited on the catalyst, and in catalytic cracking in a fluidized bed, a significant amount of coke is deposited on the catalyst, which requires continuous regeneration of the catalyst. The products obtained by the present process are mainly middle distillates of good quality along with a heavy unreduced fraction relative to

good quality. The main product obtained by liquid catalytic cracking is a component for mixing with gasoline, along with a small amount of medium-low quality light recycle oil, since aromatic compounds form the majority of this light fraction. During the process of the invention, there are almost no hydrogen transfer reactions associated with the formation of (field) aromatics and paraffins from naphthenes and olefins.

Compared to conventional processes

The hydrocracking process of the invention is independent of the presence of acid points on the catalyst. In this regard, this process is relatively sensitive to impurities of the starting materials. Since the process

according to the invention can be conducted for a long time at a relatively low pressure of hydrogen, the investment is significantly reduced compared to a conventional hydrocracking process. Ras- (.

the course of hydrogen in the process is relatively low. Regarding the iso-normal ratio of paraffins, it should be noted that due to the radical type of cracking in this process, the relatively normal paraffins are low, which favorably affects the ignition characteristics of gas oils. The classic hydrocracking process gives a high iso-normal ratio due to the reaction mechanism.

ion-carbonyl, which has a beneficial effect on the quality of middle distillates, in particular on the ignition characteristics of gas oil.

Corresponding process feed

of the invention is a low heavy oil fraction. asphaltene components. Vacuum distillates and / or deasphalted oils from any source may be used.

and without restrictions on the content of sulfur and nitrogen. Similarly, the asphaltene content of the feed is less than 3 wt.%, Preferably less than 2 wt.%, More preferably less than 1.5 wt.% And most preferably less than 1 wt.%. By these asphaltic components we mean asphaltenes C, i.e. asphaltene fraction removed from the heavy oil fraction

by pre-precipitation with heptane. This feed may contain a significant amount of carbon residue, less than 15 wt.%, Preferably less than 10 wt.%, More preferably less than 6 wt.%. The amount of sulfur in the feed

less than 10% by weight, preferably less than 6% by weight, more preferably less than May 4. % The amount of nitrogen is less than 6 wt.%, Preferably less than 4 wt.%.

Similarly, a vacuum distillate or evaporated distillate can be used as a feed with a boiling point in the range of 370-520 ° C. Another suitable feed is deas. falt residual oil (DOM), for example a deasphalted narrow or wide residual fraction of propane, butane or pentane.

In addition, distillates and / or synthetic de-decontaminated oils, which, for example, are obtained at refineries, can be used as a feed in the present process. The most suitable source of such a synthetic feed contains the so-called hydroconversion process of residual oil fractions, e.g., a narrow residual fraction. Such a hydroconversion process preferably comprises a hydrometallization step followed by a hydrodesulfurization hydrodenitrogenation step and / or a hydrocracking step. It should be noted that, as a rule, synthetic evaporated distillates or synthetic deasphalted oils are processed in the process of catalytic cracking. However, it is mainly gasoline that is obtained, not kerosene or gas oil of acceptable quality. Conventional hydrocracking of such a feed is hardly possible due to the pronounced refractory characteristics of nitrogen compounds and the need for a feed with a low nitrogen content during the hydrocracking process.

An acceptable feed for the process described is obtained in a light cracking process, e.g. a narrow residual fraction. The thermal cracking field of the heavy residual fraction, followed by a single evaporation or distillation of the product, can produce a distillate with a boiling point in the range of 350-520 ° C, which is an excellent raw material for the process of the invention.

Mixtures of relatively heavy and relatively light raw materials, such as DOM or evaporated distillate, can be used due to reduced coke formation.

The hydrocatalytic thermal cracking process can be carried out at a reaction temperature of 400-550 ° C, preferably 410-530 ° C, more preferably about 450 ° C. Please note that

a higher degree of conversion is achieved at a higher temperature, since the rate of thermal cracking of hydrocarbons will be higher at a higher temperature. To obtain a similar conversion rate, you should use a (slightly) higher temperature for the raw material, which is less susceptible to thermal cracking, for example

0 raw material containing a large number of cyclic compounds, compared with a raw material that is easily crackable.

The volumetric feed rate in the described process is 0.1-10 l / l / h, preferably 0.5-6 l / l / h, more preferably 1.0-5 l / l / h. The partial pressure of hydrogen, at

which is carrying out the present process, is 10-60 bar, preferably 20-40 bar, more preferably about 25 bar. Typically, the total pressure in the reactor is 16-65 bar and preferably 24-45 bar, more preferably about 30

5 bar. In this regard, it should be noted that the partial pressure of hydrogen at the outlet of the reactor is usually 3-10 bar higher than at the inlet of the reactor.

Catalysts designed for

For use in the process of the invention, should provide a hydrogen activating function. Suitable catalysts contain one or more metals of groups IVa, VI or VIII. Suitable catalysts 5 contain one or more Group IVa, VI or VIII metals. Suitable substrates are silica, alumina,

 aluminum phosphates, spindle compounds, titanium dioxide and zirconia.

0 Combinations of common metals of Groups VI and VIII may be used. It should be noted that in this description the term non-acidic indicates an almost complete absence of one or more active

5 acid points in the catalyst that can accelerate the cracking reaction of hydrocarbons based on carbon-ion chemistry. Under the initial reaction conditions, certain acid points may be present. However, these acidic points are rapidly deactivated due to the formation of coke and adsorption of basic nitrogen, while the nitrogen activation fraction remains substantially unchanged.

5 If the catalyst contains a noble metal of group Vlli, the use of palladium or platinum is preferred. If the catalyst contains a metal of group IVa, tin is preferably used. If the catalyst contains metal

Group VI, molybdenum, chromium or tungsten is preferably used. If a base metal of Group VIII is used, it is preferable to use iron, cobalt or nickel,

It was found that very good results can be obtained using molybdenum-based catalysts, in particular catalysts containing silica as a carrier and having a surface area in the range of 125-250 m2 / g. The use of such catalysts provides good hydrodesulfurization along with a slight coke formation.

Preferred catalysts are those that give a pronounced but limited hydrodesulfurization. These catalysts produce very little coke formation along with relatively good product quality for the middle distillate fraction.

/. The hydrogen / feed ratio of the process of the invention can vary over a wide range. A suitable hydrogen / delivery ratio is 50-5000 nl / kg, in particular 100-2000 nl / kg. Preferably, a hydrogen / feed ratio in the range of 100-500 nl / kg is used, more preferably 200-400 nl / kg. Using these preferred hydrogen-coke deposition ratios, the coke on the catalyst is very low. In addition, a high cracking conversion is achieved. Compared to a conventional hydrocracking process, the hydrogen-feed ratio is significantly lower in the process of the invention, which has a beneficial effect on the economics of the process. The typical hydrogen-feed ratio in the hydrocracking process is 700-1500 ml / kg. Typically, during hydroprocessing, high hydrogen feed ratios are required to suppress coke formation and increase the conversion rate. In the described process, a low gas rate is not only acceptable but also favorably on coke formation and conversion.

In a preferred embodiment of the invention, said preferred hydrogen-feed ratio of 200-400 nl / kg is used in combination with a catalyst containing a noble metal of group VIII. preferably palladium and / or platinum. Using the indicated hydrogen-feed ratio in combination with this catalyst gave a very low coke formation rate, and the amount of sulfur on the catalyst was also low.

In another preferred embodiment, the hydrogen-containing stream comprises a mixture of hydrogen and hydrogen sulfide. Carrying out the reaction with a mixture of hydrogen and hydrogen sulfide also leads to an increase in the level of conversion and selectivity to middle distillates. The amount of hydrogen sulfide in the mixture in the reactor is up to 50 vol% of the amount of hydrogen. Preferably, the amount of hydrogen sulfide is 1-30%, more preferably 5-25%, and most preferably about 10%.

The process according to the invention is carried out under conditions of a fixed bed, for example in a reactor with a nozzle layer with a jet stream of liquid. Due to the need for periodic regeneration of the catalyst, preferably two or more fixed beds are used, which are used in a swing mode. The process is usually carried out in an upstream fixed bed catalyst, in particular when relatively light raw materials are used. The use of an upflow reactor in this case results in a reduced coke deposition rate on the catalyst, which accordingly increases the interval between catalyst regeneration. A decrease in the amount of coke-on upstream catalyst may be 50 rel.% Or more as compared to the downstream mode. Other preferred modes of carrying out the method of the present invention include the use of a moving bed, for example a fluidized bed bunker reactor.

The products obtained in the described method can be used as such or can be subjected to further processing. For example, part or all of the products may be desulfurized, in particular hydrodesulfurized, to adjust the sulfur content of the product to the desired value. Further, part or all of the products (hydrodesulfurized) may be hydrotreated, if necessary, before or after distillation of the hydrodesulfurized product. In addition, a portion of the unconverted material present in the product is recycled to the reactor.

Catalyst regeneration can be carried out by burning carbonaceous material deposited on the catalyst using oxygen and / or vapor-containing gas. When using a fixed bed, catalyst regeneration can be carried out about the cracking reactor itself. When using a bunker flow reactor, regeneration is usually carried out in a separate regenerator.

The invention is illustrated by the following examples.

PRI me R 1. The choice of catalyst.

The distillate of a single distillation of Kuwaiti oil is subjected to a hydrocatalytic thermal cracking process. The feed characteristics are presented in table 1.

The reaction is carried out in a microflow reactor with a catalyst bed with a jet stream of liquid, with a downward flow under isothermal conditions. Catalysts are prepared using conventional pore volume impregnation methods, unless otherwise indicated. Carriers used by industry (silica or alumina) are used (catalysts 1-12 and 19-21). In experiments 13-18, commercially available catalysts are used — as such or somewhat modified. The properties of the media are described in table 2. Inorganic intermediates are used to prepare catalysts 1-12 and 19-21 (e.g. metal nitrates, ammonium molybdenum). Tin is applied as an organometallic compound. Before use, the catalysts were calcined at 350-450 ° С (with the exception of NiMo (Si02) catalysts, followed by grinding no smaller particles (30-80 mesh). A review of the catalyst compositions is shown in Table 3.

The catalysts were subjected to sulfidation before use. When using molybdenum-containing catalysts, this is the preferred technique since otherwise, an excessive amount of coke will be formed in the first hours of the experiment.

 Two sulfidation techniques are used. The first technique involves heating the catalyst together with sulfur-containing raw material and hydrogen. At a rate of 75 ° C / h to 375 ° C and keeping it at this temperature overnight. After that, the temperature is increased to 400 ° C, held for 6 hours, raised to 425 ° C and again kept overnight, followed by heating to 450 ° C. Another sulfidation and start-up procedure is applied using HaS. The catalyst is exposed to a mixture of H2 (H2S) 7 (1 by volume) at a pressure of 10 bar and the temperature is increased at a rate of 75 ° C / h to 375 ° C. Then raw materials are served.

and the temperature is increased at a rate of 75 ° C / h. It was found that they provide similar characteristics of the catalyst, for example, the formation of coke,

When using noble metal catalysts, it was found that reduction using hydrogen prior to testing also gives satisfactory results.

0 Reactions were carried out at 450 ° C and the total pressure was 30 bar. Hourly volume - the fluid velocity is approximately 1 l / l / h. The feed ratio is 850-11-00 ml / kg. Reaction time varies

5 from 170 to 220 hours

Analyzes and data processing. The liquid product is analyzed according to the distribution of boiling points using methods for determining true

0 boiling point. Moreover, an GLC analysis for flue gas was performed. Based on these analyzes, conversion and selectivity are determined. Conversion is determined by the net removal (%) of material with

5 with a boiling point above 370 ° C. The solid product is split into gas (Ci-Ci), naphtha (Cg-150 ° C), middle distillates (150-370 ° C) and coke. Selectivity is determined by the amount of product tested divided by the total number of products (material with a boiling point below 370 ° C and coke). Hydrogen consumption

 determined by mass spectrometry analysis, combustion of starting material and liquid product 5, and gas analysis. The hydrodesulfurization activity (constant second-order rate) is determined by the sulfur content of the liquid product. The experimental results are presented in 0 of table 4,

The properties of the obtained middle distillates are described in Tables 4a and 46. The product properties of the residual fractions are described in Tables 4c. 5 Example 11. Pressure effect.

The effect of the total pressure was examined under the general reaction conditions of Example 1. The results are shown in Table 5.

PRI me R 3. Comparison of the catalyst with 0 different activity of desulfurization.

Under the general reaction conditions described in Example 1, the relationship between the hydrodesulfurization activity and the coke 5 selectivity of certain catalysts is determined. The results are presented in table.6.

Example 4. The effect of temperature. Using the reaction conditions of Example 1, the effect of temperature is investigated. Catalyst 16 is used in experiment 1-3. Catalyst 12 - in experiment 4. The results are presented in table.7.

Example 5. Effect of duration.

Under the general reaction conditions of Example 1, the effect of the duration at the low 5th H2 / feed ratio is followed.

A catalyst 11 is used for all experiments. The results are presented in Table 8.

PRI me R 6. The effect of the composition of the catalysis-10 ora on the deposition of sulfur.

Using the general reaction conditions of Example 1, the effect of the composition of the catalyst on sulfur deposition is investigated. The results are presented in table 9.15

PRI me R 7. The influence of raw materials; rial. ...:. . . .

When using the general conditions re-. the stock of example 1 compares three different raw materials. - The properties of the 20 raw materials are described in the table. The distillate of a single distillation of Kuwaiti oil is described in more detail in Table 1, Deasphalted Kuwaiti Oil Represents co. narrow butane deasphalted battle: 25 residual fraction. A synthetic distillate of May a one-time distillation is obtained by means of methydylation and hydroconverting; these narrow residual fractions of Ma. I ate food more and more often. The results of the GZO experiments are presented in Table. eleven.

Example 8. The effect of HaS on the feed / hydrogen. ;::;: /. . ;:

Using the general reaction conditions of Example 1, the effect of 35 HzS on the hydrogen supply was investigated. Use catalyst 3. The results are presented in table.12. :: -,, -. . .-. - :. -.-; .

Example 9. The use of non-converted material in the process in catalytic fluidized bed cracking.

The process is carried out at 450 ° С, pressures of 30 bar, ratio, Н2 / feed of 900 nl / kg and hourly volumetric flow rate of the fluid 1.0 / l / h using catalyst 45 1B and: supply of distillate of a single reconquered oil. Non-transformed material, i.e. a fraction with a spike temperature greater than 370 C, use 5T as a feed for the catalytic 50 cracking reaction in a fluidized bed. The fluidized-bed catalytic cracking reactor operates with a constant coke yield and separation efficiency. The second reactor is run using distillation unit 55 of a single distillation of Kuwaiti oil. Characteristics of the feed and output are presented in table.13.

PRI me R 10. The use of distillate single distillation after heat

cracking as a feed for the process of the invention.

After thermal cracking, a single distillation distillate obtained from the heavy fraction of Arab oil is used as a feed for the experiment, which was carried out at 450 ° C at a pressure of 30 bar, a fluid hourly space velocity of 1 l / l / h, a H2 / feed ratio of 250 nl / kg and the duration of the process 161 h using a catalyst 12.

Properties of the raw material: specific gravity d 70 / 4,0,9139 may.% Sulfur. May 2.22. % nitrogen, 0.4% by weight of resins. The net conversion is 42.7%. The results are as follows: Selectivity,% Ci-Gi3.9 С5-150 ° С 11.5 150-25р ° С 21.6 250-370 ° С 62.9 Coke,%, 0.05 - Total Н2, wt.% 0.22 PRI me R 11. The use of feed with a high content of asphaltenes.

A wide bcurate fraction of Kuwaiti oil is used as a feed for the experiment, which is carried out at 450 ° C, 50 1 bar, hourly fluid volumetric rate of 1 l / l / h, Na / feed ratio of 1000 nl / kg and a duration of 50 hours using a catalyst 12 The properties of the raw material: specific gravity d 70 / 4-0.9139, sulfur 3.69 wt.%, Nitrogen 0.1.5 wt.%: Metals 42 ppm resins 5.1 wt.%, asphaltenes C 2.4 wt.%. The net conversion is 45%. Selectivity, wt.%: Ci-C4 8; St 150 ° C 11.1, 150-370 ° C 80.1; coke 0.7.

li Example 12. A heavy residue of Arab oil containing 10.5 wt.% of asphaltenes C is brought into contact with catalyst 11. Described in table 3 at 480 ° C, a pressure of 50 bar and a volumetric flow rate of 1 l / liters per hour. Total conversion is 50 May.% liters. The selectivity is, wt%: fraction (Ci-C) 18, fraction Cs 370 ° C 73, coke 9.

Claims (1)

A comparison of the results obtained in this example and example 11 shows. that get a significantly smaller amount. coke at almost the same level of conversion. SUMMARY OF THE INVENTION A method of processing a heavy oil fraction into lighter fractions in the presence of a hydrogen-containing gas and a non-acid catalyst that activates hydrogen at elevated temperature and partial pressure of hydrogen in the reaction zone, characterized in that, in order to reduce coke formation and increase the yield of target products, the feedstock containing less than 3 mes.% of asphaltene components, together with a hydrogen-containing gas is passed through the reaction zone containing the catalyst and the process are carried out at 400-550 ° C and a partial pressure of hydrogen of 10-60 bar. Properties of the Distillation Material of a Single Distillation of Kuwaiti Oil Table 1 table 2 Table 3 Study of experimental catalysts used in the processing of distillate single distillation of Kuwaiti oil  The bulk density of the crushed catalyst. Pore volume is determined using water. Surface area is determined using nitrogen. Table 4 Continuation of the table. 4. Quality characteristics of kerosene fractions 150-350BC And about. - Not defined. The ratio of N / feed -250 ml / kg Characteristics of quality {fractions of gas oil 250-370 ° C And about. - Not decided, Table Table 46 Residual fraction quality characterization 370 ° С And about. - Not defined .. Table 4c Table 5 Table 6 Continuation of the table. 6 Table 7 Table 8 ) At an hourly volumetric flow rate of a liquid - 0.5 l / l 1 And about. - Not defined. Table 9 Table 10 Table 11 Table 12 Table 13