RU2186090C2 - Method for production of liquid hydrocarbons by hydrogenation and demetallization of heavy oil feedstock - Google Patents

Abstract

FIELD: petroleum processing and petrochemistry. SUBSTANCE: heavy oil residues are subjected to hydrogenation using as catalyst iron polyphosphate with gel or xerogel structure containing 92.0-97.0 wt % ferric oxide ate P₂O₅/Fe₂O₃ ratio between 0.5:1 and 1.5:1 and no more than 4 wt % transition metals of V-VIII groups, each of the metals being present in quantities 0.001 to 1.0 wt % and the rest of catalyst being composed by water Ca, Si, Na, and Mg oxide impurities. Process is conducted during 0.5 to 2.0 h at 380-450 C and hydrogen pressure 2-6 atm. EFFECT: increased yield of lube oil fractions. 2 cl, 6 tbl, 19 ex

Description

 The invention relates to the field of oil refining and catalysis of processes for producing hydrocarbon fractions from heavy petroleum feedstocks used to produce liquid motor fuels, and can also be applied in the petrochemical and organic synthesis industries.

 In connection with the increase in the content of tar-asphalt and sulfur compounds in modern produced oils all over the world, the problems of advanced processing of heavy oil residues - tars containing a significant amount of tar-asphaltene substances, sulfur secondary tars, heavy viscous pyrolysis resins, etc. .

 Currently, for the advanced oil refining in order to obtain additional quantities of gasoline, a low-efficiency coking process is used, where the yield of gasoline fractions is 20%.

 Catalytic processes for the production of liquid hydrocarbon feedstocks from heavy distillates, for example, hydrocracking, are currently used for the processing of relatively light fractions, for example, gas oils and high boiling oil oils (1. Smidovich E.V. Petroleum technology, part II. Destructive oil refining. M., Chemistry, 1968, 375 p.).

The disadvantages of these processes regarding the use of tar as a raw material in them are, firstly, the transfer of raw materials to the liquid-vapor phase, which is almost impossible if viscous fractions with a boiling point of more than 500 ^o С are involved in the process and, secondly , the need for frequent cyclic regeneration of the catalyst.

 Known processes for producing liquid products from coal and their mixtures with heavy oil fractions (2. Krichko A.A., Lebedev V.V., Farberov I.L. Non-fuel use of coal. M., Nedra, 1978. 215 p.3. Yulin MK Hydrogenation of brown coals of the Kansk-Achinsk basin under low hydrogen pressure into synthetic liquid fuel. Abstract of thesis for the degree of Doctor of Technical Sciences M., Moscow Art Institute named after DI Mendeleev, 1990 4. Maloletnev A.S., Krichko A.A., Garkusha A.A. Obtaining synthetic liquid fuel by hydrogenation of coal. M., Nedra, 1992, 128 pp.).

 The disadvantage of these processes is the use of high pressures, the introduction of significant amounts of elemental sulfur (3. Yulin M.K. Hydrogenation of brown coals of the Kansk-Achinsk basin under low hydrogen pressure into synthetic liquid fuel. Abstract of dissertation for scientific degree. Science M., Moscow Art Theater named after DI Mendeleev) or the need for complex catalyst regeneration due to the inclusion of noble metals (4. Maloletnev A.S., Krichko A.A., Garkusha A.A. Synthetic liquid fuel by coal hydrogenation. M., Nedra, 1 992, 128 p.).

In the processing of petroleum fractions, solid acid catalysts are used, for example, based on polyvalent metal phosphates (5. US Patent 3,088,908.). The closest analogue to the proposed solution to the problem of obtaining liquid products from heavy oil residues is the method (5. US Patent 3,088,908.) Hydrocracking high-boiling mineral oils (Bp. Less than 500 ^o C) in the presence of H ₂ using phosphates of polyvalent metals - 40-80 % A1P0 ₄ ; 35% Fe ₃ (P0 ₄ ) ₃ phosphates in xerogel form with 5-10% sodium fluoride.

 When hydrocracking high-boiling mineral oils, which differ significantly from tars with a lower molecular weight of compounds, fewer tar and asphalt compounds, and compounds of heavy metals and heteroatoms, under the conditions stated in the patent, gas 15-20%, gasoline 30-25%, oils 45 -50% and resins 5-15 (wt.%).

 The disadvantage of the methods is not only the impossibility of using viscous tars as a raw material on stationary catalysts, but also the catalyst deactivation by heteroorganic (especially sulfur-containing) compounds, and the thermal instability of the used catalyst during regeneration after coke formation on the surface.

 The objective of this method is to provide the possibility of processing straight-run tar, sulphurous secondary tar, heavy viscous pyrolysis resins, etc. heavy refinery residues.

 To solve this problem, a method for producing liquid products by hydrogenation of heavy oil feedstock in the presence of hydrogen and a catalyst based on iron polyphosphate in the amount of 4-6 wt.% Of the total amount of the feedstock is proposed.

The difference between the proposed method and the known ones is that iron polyphosphate of a gel or xerogel structure is used as a catalyst — 92-97 wt. % with a ratio of P ₂ O ₅ : Fe ₂ O ₃ = 0.5-1.5 and transition metals of groups V-VIII in an amount of not more than 4 wt.% in total of the composition of the catalyst, with each metal present in an amount of 0.001-1,000 wt. %, the rest is water and impurities of the oxides Ca, Si, Na, Mg. The difference also lies in the fact that the process is carried out at T = 380-450 ^o C, a hydrogen pressure of 2-6 MPa, a contact time of 0.5-2.0 hours. Thanks to such a combination of features, it becomes possible to carry out the above task - hydrogenation of heavy crude oil mainly into oil.

 To improve the rheological properties of the reaction mass and phase contact, a continuous process is carried out in the presence of 1-3 wt.% Surfactant.

The method of producing catalyst
The catalyst introduced into the tar (example 1-15), fuel oil (example 16), a mixture of tar and Parex resin (example 19) are obtained by urea precipitation of iron salts from a solution containing the calculated amount of orthophostoric acid and salts of metal-cocatalysts - Mo, Co, Ni, Cr, Cu, Ti, with a molar ratio of phosphorus pentoxide to iron oxide P ₂ O ₅ : Fe ₂ O ₃ = 0.5-1.5. In this case, after “maturing” and aging of the gel, a phosphate xerogel is formed (Example 1), the dried catalyst contains, according to atomic absorption analysis, iron orthophosphiphosphates and metal-cocatalysts (Table 2).

The catalyst, as follows from the derivatographic analysis, is thermostable to high temperatures, Δg at T = 850 ^o C - 10 wt.%. However, its reuse is impractical because after coke annealing, as shown by x-ray phase and microscopic analysis, its phase composition changes, iron oxides are formed.

The process is carried out in the following way:
Example 1
The tar, the characteristics of which are presented in Table 1, is heated to a temperature of 90 ^o C and passed through a dispersant, where 6 g of the catalyst (6 wt.%) Is introduced - iron phosphate xerogel containing metal group additives (the composition of the catalyst CT-1 is presented in table .2).

After dispersion, the tar with the catalyst is subjected to a destructive hydrogenation process at T = 450 ^° C, P _H2 = 5.0 MPa for 0.5 hours in a rotating autoclave.

After the experiment, the gas is throttled through a gas clock and analyzed by gas-liquid chromatography on an LHM-8MD instrument at room temperature, the carrier gas is helium, and the detector is a katharometer; H ₂ , CH ₄ , CO — analyzed on a column L = 1 m, d = 4 mm on zeolite Max; С0 ₂ , NH ₃ and С ₂ С ₄ - on a column L = 9 m, d = 4 mm, filled with a spherochrome-2 with 10 wt.% N-hexadecane. The gas composition, with the exception of H _{2, is used to} calculate the gas density and its yield during the hydrogenation of tar (G).

 Solid and liquid hydrogenation products are analyzed according to the methods adopted in oil refining for the study of oil residues (6. Diyarov I.N., Batueva A.N., Sadykov A.N., Solodova N.L. Petroleum Chemistry. L., Chemistry, 1990. 240 s.). The solid residue on the filter is extracted with toluene in a Soxhlet apparatus, dried to constant weight, ashed, and the yield of solid products (carbenes, carboids and coke - wt.%) Is determined by the difference in weights.

Asphaltenes - (A, wt.%) Are sequentially isolated from liquid products by the VNIINP method by gasoline deposition in gasoline and oils (M, wt.%), Non-polar and polar resins (С _Н and С _п , wt. %).

 In the total liquid hydrogenate, the sulfur content is determined (7. GOST 1437-75. Accelerated method for determining sulfur.) - wt.% And calculate the degree of sulfur removal (% beats).

 The amount of polar resins in the initial tar and in the liquid product characterizes the removal of heteroorganic compounds.

Example 2 (comparative)
The tar is heated to a temperature of 90 ^o C and passed through a dispersant, at a temperature of 450 ^o C, a hydrogen pressure of 5.0 MPa, hydrogenation of the tar is carried out for 0.5 hours in a rotating autoclave.

 The results of the analyzes are presented in table 4.

 As follows from a comparison of the results of Op. 1 and 2, the destructive hydrogenation reaction in the presence of a catalyst - iron phosphate dispersed in the tar passes selectively with the formation of mainly oils - 60.3 wt. %, the most valuable fractions for the production of liquid motor fuels. At the same time, coke formation and gas production decrease significantly - from 19.2 to 7.6% - from 30.7 to 11.3 wt.%. It should also be noted a high degree of desulfurization of tar - 59.6%.

Examples 3-4
The experiments and analysis are carried out similarly to op.1, changing the process time. As follows from the data in Table 3, an increase in the time of the process leads to a deeper destruction of the organic matter of the tar, the amount of gas formed increases, however, the oil yield up to τ = 2 hours remains at least 40%, which corresponds to the parameters of the prototype. Significantly increases the degree of removal of sulfur - 80 wt.%.

Examples 5-6
In experiments 5, 6, 1, the process temperature varies T = 380-450 ^o C. In the indicated temperature range, a significant (more than 80%) yield of liquid products remains, however, the selective yield of oils is slightly reduced - from 60.3 to 45.5 wt. %

Examples 7-9
A significant effect on the process is exerted by the hydrogen pressure P _H2 . A decrease in P _H2 below 2.0 MPa is impractical because the content of asphaltenes and resins in the liquid hydrogenate increases, the degree of sulfur removal decreases to 31.6%. An increase in the hydrogen pressure P _H2 above 6 MPa is also impractical, since the yield of gaseous products increases (almost 2 times) and the total yield of liquid products decreases (by 10%).

Examples 10-11
The concentration of the catalyst - xerogel of iron phosphate P ₂ O ₅ : Fe ₂ O ₃ = 0.5-1.5 metal-containing cocatalysts: Mo, Co, Ni, Cr, Cu, Ti, in the studied range has a significant effect on the oil yield - the greatest the oil yield in the liquid hydrogenation product is 70.4 wt.% at Scat = 8 wt. %, P _H2 = 3.0 MPa, τ = 0.5 hours. However, while the total yield of liquid products is slightly lower than at Skat = 6 wt.% (Example 7), at the same time, the degree of sulfur removal remains at the same level. Thus, it is not economically feasible to increase the concentration of the catalyst above 6 wt.%. A decrease in the concentration of the catalyst to 4 wt.% And lower sharply reduces the yield of the oil fraction and worsens the performance of desulfurization.

 The results of experiments 1-11 indicate the possibility of changing the process conditions depending on the purpose of processing tar, obtaining gasoline, oils, and removing hetero-organic compounds.

Examples 12, 13
The result of the replacement of iron phosphate with iron orthopoliphosphates with a ratio of P ₂ O ₅ : Fe ₂ 0 ₃ = 2.0-2.5 despite a decrease in the total yield of liquid products (op. 1-81.1%, op. 12, 13-72 , 1% and 77.0 wt.%, Which is probably associated with a decrease in the content of iron in the catalyst - KT-2, KT-3 - Table 2), is an increase in the destruction of heteroorganic compounds, the content of sulfur and polar resins is reduced almost to the level of accuracy analysis - 0.2 wt.%.

Example 14 (Prototype)
As a prototype of the selected method (5 US Patent 3.088.908.). Hydrocracking of high-boiling mineral oils using a catalyst of the following chemical composition:
A1PO ₄ - 60 wt.%
Fe ₃ (PO ₄ ) ₂ - 35 wt.%
SiF ₄ - 5 wt.%.

 Since high boiling mineral oils are significantly different from tar with a lower molecular weight of compounds, fewer tarry and asphaltene compounds and compounds of heavy metals and heteroatoms, the use of a catalyst obtained by the method described in (5. US Patent 3,088,908.) Leads to increased coke formation and low yield of both gasoline and oil fractions.

 For comparison, the results are shown in table.3.

Thus, the introduction of a xerogel solid-acid catalyst (polymetallic iron-orthopolyphosphate) makes it possible to hydrogenate the processing of tar under hydrocracking conditions T = 380-450 ^o С, Р _Н2 = 2.0-6.0 MPa into the liquid fractions of oils used for the production of motor fuels in quantities not lower than in the prototype.

Example 15
The specified method of processing tar can be carried out in a continuous process.

The tar, the characteristics of which are presented in Table 1, is heated to a temperature of 90 ^o C and passed through a dispersant, where catalyst and additives of 2 wt.% Surfactant are introduced to improve the rheological properties of the feedstock.

 As surfactants use the most cheap substances of a number of polyethylene glycols, or other compounds that do not impair the composition of hydrogenation products (Table 3).

After dispersing the additives, the tar is subsequently heated under pressure to a predetermined temperature (T = 425 ^° C, P _H2 = 5.0 MPa, bulk velocity of the feed is 1.0 hour ^-1 ).

 After throttling and separating the hydrogen-containing gas, the hydrogenate is fed into a hot separator, from the upper part of which the hydrogenate is taken for fractionation, from the lower part the hydrogenate, enriched in the catalyst in an amount of 1-10%, is sent for recycling to the dispersant. In this case, up to 70% of the fresh catalyst can be continuously introduced from a given value. The solid residue is periodically removed from the separator, centrifuged and sent either to burn out coke deposits or to gasification.

The performance of the continuous process is slightly higher than for a batch process in autoclaves, probably due to improved contact between hydrogen and a viscous reaction mass under conditions of flow installation: the oil yield at T = 450 ^° C and P _H2 = 5.0 MPa is 63.2 wt .%, the degree of sulfur removal - 75.4 wt. %

Example 16
The proposed method can be used for processing fuel oil. The fuel oil is heated to 80 ^o C and passed through a dispersant, where the catalyst is introduced in an amount of 4.2 wt.% On raw materials. After dispersing the catalyst, the fuel oil is heated under pressure to a predetermined temperature (T = 425 ^o C, Pn ₂ = 2.5 MPa, a volumetric feed rate of 1.0 h ^-1 , a hydrogen supply of 1000 l / kg of feedstock. Next, as in Example 15. the proposed process is higher than for a typical method for processing heavy fractions - catalytic cracking + hydrotreating.The yield and composition of the products are shown in table 5.
Example 17 (comparative)
As a comparison method, the process of catalytic cracking of vacuum gas oil of sulphurous oil on a zeolite-containing catalyst was carried out, followed by hydrotreating of the catalysis.

Catalytic cracking is carried out at a temperature of 500-530 ^o C and a pressure in the reactor of 0.2-0.3 MPa, a volumetric feed rate of 1.0 h ^-1 . Hydrotreating of catalysis is carried out at a temperature of 425 ^o With a pressure of 2.5 MPa, a volumetric feed rate of 1.0 h ^-1 , a hydrogen supply of 1200 lN ₂ / kg of raw material.

 The yield and composition of the hydrogenate are presented in table 5.

 From the table it is seen that during the processing of fuel oil by the proposed method, the yield of hydrogenate is increased, compared with the prototype method, to 89.9% (and the yield of light fractions: gasoline and diesel fractions is 68.7%). In addition, the gas yield is reduced to 2.6% and coke recovery to 1.5%.

Example 18
In addition to tar and fuel oil, it is possible to involve resins, for example, high-sulfur resin of the Pareks process, into processing by the proposed method.

The experiment is carried out analogously to example 1, except that when dispersed in the tar is introduced resin of the process "Parex" in a ratio of 1: 1. The composition of the high-sulfur resin of the Parex process: H ₂ S0 ₄ free - 29.4%; H ₂ 0 - 11.0%; the rest is sulfonic acids, aromatic hydrocarbons, resins. The yield and composition of the obtained products are presented in table 6.

Example 19 (comparative)
The experiment is carried out analogously to example 2, except that when dispersed into the tar, the resin of the Parex process is introduced in a ratio of 1: 1. The yield and composition of the products are presented in table 6
From the data in table 6 it is seen that when hydrocracking a mixture of tar and tar from the Parex process in the presence of a catalyst, the amount of coke deposits decreases from 37.7% to 8.92%, the yield of liquid products increases compared with the thermal process from 33.96% to 87.57%, moreover, the yield of gaseous products decreases, even compared with hydrocracking of one tar, from 9.22% to 7.5%.

 It should also be noted that when processing the mixture, the maximum yield of oil fractions is observed - 83.35% with a minimum yield of asphaltenes.

Claims (2)

1. The method of producing liquid products by hydrogenation and demethalization of heavy crude oil in the presence of hydrogen and a catalyst based on iron polyphosphate, characterized in that the catalyst is used iron polyphosphate xerogel structure in the amount of 4-6 wt. % on raw materials; the catalyst contains 92-97 wt. % iron polyphosphate with a ratio of P ₂ O ₅ : Fe ₂ O ₃ = 0.5-1.5, transition metals of V-VIII subgroups of not more than 4 wt. % in total of the composition of the catalyst in an amount of from 0.001 to 1.0 wt. % of each, the rest is water and impurities of oxides of Ca, Si, Na, Mg, the process is carried out at a temperature of 380-450 ^o C, a hydrogen pressure of P _H2 2-6 MPa for 0.5-2.0 hours  2. The method according to p. 1, characterized in that the process is carried out continuously in the presence of a catalyst and 1.0-3.0 wt. % surfactant introduced into the raw material by dispersion.

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