RU2667920C1 - Catalyst for hydroisomerization of hydrocarbon fractions and method of its application - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to the field of oil refining, in particular to a hydroisomerization catalyst for hydrocarbon fractions and a method for using it. Hydroisomerization catalyst of the hydrocarbon fractions contains 0.05–8.0 % by weight at least one metal or metal compound selected from the series: platinum, palladium, rhenium, nickel, cobalt, chromium, manganese, molybdenum, tin, lead, zirconium, lanthanum, 5–75 % by weight crystalline ferroaluminosilicate or ferrogallium aluminosilicate with ZSM-5 or ZSM-11 zeolite structure and aluminium oxide is the rest. When the catalyst is used in the hydroisomerization of hydrocarbon fractions, the process is carried out at a temperature of 260–360 °C, a pressure of 0.1–5.0 MPa, volume feed rate of liquid feed 0.5–10 h, molar ratio of hydrogen to hydrocarbons 1–12.EFFECT: technical result consists in lower temperature of the complete burning out of the catalyst coke at the stage of catalyst regeneration.6 cl, 3 dwg, 2 tbl, 18 ex

Description

The invention can be used in the refining and petrochemical industries and relates to zeolite-containing catalysts for hydroisomerization of various hydrocarbon fractions.

The processes of isomerization of paraffin hydrocarbons are increasingly used in the fields of petrochemicals and oil refining. So, along with the traditional processes of isomerization of n-butane, n-pentane, hexane and gasoline fractions, intended for the production of raw materials for petrochemical and organic synthesis, as well as for the production of high-octane gasoline components, catalysts have been recently developed for isomerization (isodeparaffinization) of more heavy hydrocarbon fractions - kerosene, diesel and oil, in order to lower their cloud point and solidification temperature.

To increase the efficiency of isomerization processes, the catalysts used are constantly being improved by changing the nature and concentration of metals used as active components and / or promoters, as well as by changing the ratio of dehydrogenating and acid functions. One way to change the ratio of the dehydrogenating and acidic functions of the isomerization catalyst is to introduce a zeolite component into its composition, moreover, zeolites of various structural types are used for this, zeolites ZSM-5 and ZSM-11. Moreover, the catalysts may contain simultaneously several zeolites of various types (for example, [US Pat. RF 2549617, B01J 29/072, 29/076, 29/16, 29/14, 29/46, 29/48, 21/04, 27 / 185, 27/188; С10G 45/08, 2015]), as well as zeolites of only one structural type.

A known catalyst and method for the isomerization of hydrocarbons [US Pat. U.S. 6124516, B01J 27/22, 29/40; C10G 35/095, 45/64, 2000]. According to this method, the isomerization catalyst contains metal carbide (pre-carbonized metal) and zeolite in a mass ratio of from 0.0001: 1 to 1: 1. In this case, tungsten, molybdenum, chromium, iron, ruthenium, manganese, rhenium, cobalt, rhodium, iridium, nickel, palladium, platinum, hafnium, titanium, zirconium, vanadium, niobium, tantalum or their can be used as a metal or its compound combinations. The catalyst may contain any of the following zeolites - ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-35, ZSM-38, or combinations thereof. The isomerization of C ₄ -C ₁₀ hydrocarbons on such a catalyst is carried out in the reaction temperature ranges of 200-800 ° C at a pressure of up to 10 MPa and bulk feed rates of up to 1000 h ^-1 .

A known catalyst for the hydroisomerization of oil fractions and a method for its preparation [US Pat. RF №2162012, В01J 29/44, 37/02; C10G 35/095, 2001]. The catalyst for hydroisomerization of various hydrocarbon fractions contains 10-50% wt. zeolite CVM (analogue of zeolite ZSM-5) in the H-form, 0.2-0.6% platinum, 0.05-1.0% indium and alumina - the rest.

Known zeolite-containing isomerization catalyst and method for its use [EP No. 1593429, BJ 29/064; 29/74; C07C 5/27; C10G 45/64, 2005]. The catalyst contains one of the zeolites selected from the following series: beta, mordenite, faujasite, ferrierite or ZSM-5, in a zeolite / alumina ratio of 1-9, and 0.01-5% of Group VIII metals, one of which is at least platinum or palladium. The process of isomerization of C ₄ -C ₉ paraffins is carried out at a temperature of 150-400 ° C, a pressure of 0.1-10 MPa, a mass feed rate of 1-6 h ^-1 and a molar hydrogen / hydrocarbon ratio of 1-8.

Known catalysts for isomerization of n-hexane [US Pat. Rep. Kazakhstan No. 16384, B01J 23/24, 21/16, 23/44, 29/40, 21/04; 2005] and [Pat. Rep. Kazakhstan No. 16385, B01J 21/04, 23/24, 29/40, 21/16, 23/44; 2005]. These catalysts contain 0.20-0.35% wt. palladium, 0.8-1.0% tungsten oxide, 9-12% clay from the Taganskoye deposit, 10-15% zeolite ZSM-5 and aluminum oxide - the rest. Between themselves, the catalysts differ in the composition of the zeolite ZSM-5 used - in different silicate modules, equal to 30 for the first and 50 for the second catalyst, respectively.

Known catalyst for isodeparaffinization of oil fractions [US Pat. RF 2320407, B01J 23/652, 29/44, 23/62, 21/04, 37/02; C10C 5/27; C10G 35/095, 2008]. This catalyst contains 0.15-0.60% wt. platinum, 0.24-0.97% indium oxide, 1-4% tungsten oxide, 5-40% zeolite and alumina - the rest. As the zeolite catalyst component used zeolite ZSM-5 having a molar ratio SiO ₂ / Al ₂ O ₃ equal to 25-80, or zeolite beta having a molar ratio SiO ₂ / Al ₂ O ₃ equal to 25-40.

A known catalyst for the isomerization and desulfurization of naphtha (gasoline-naphtha fractions) [CN No. 106582793, BJJ 29/44, C10G 35/095, 45/12, 2017]. The catalyst contains 25-35% zeolite ZSM-5 with a molar ratio of SiO ₂ / Al ₂ O ₃ = 65, 15-25% zeolite ZSM-5 with a molar ratio of SiO ₂ / Al ₂ O ₃ = 50 and 45-55% zeolite ZSM -5 with a molar ratio of SiO ₂ / Al ₂ O ₃ = 90, while the zeolites used contain 0.2-0.3% palladium, 1-2% zinc, 2-3% potassium and 3-8% aluminum chloride.

The closest in its technical essence and the achieved effect is a catalyst and a method for hydroisomerization of normal hydrocarbons C5-C8 with its use [Pat of the Russian Federation No. 2658018 B01J 29/46, 37/30; C10G 45/64; C10C 5/27; 2018]. According to the selected prototype, the catalyst contains 20-50% α-alumina or silicon binder, 0.2-1.0% platinum and / or palladium and one or more promoter metals selected from the group Zn, Cu, Co, Cr, Fe, Ni, La, and zeolite are the rest. As zeolite, ZSM-5 zeolite (MFI structure) or beta (BEA) with a molar ratio of SiO ₂ / Al ₂ O ₃ from 25 to 130 is used. In this case, promoter metals are introduced into the zeolite from an aqueous solution in the form of cations. The process of hydroisomerization of linear C ₅ -C ₈ paraffins in hydrocarbon fractions is carried out at a mass feed rate of 1-8 h ^-1 , a hydrogen / feed molar ratio of 1.1: 1 to 6: 1, a temperature of 240-300 ° C and a pressure of 0 1-3.0 MPa. As raw materials, it is possible to use both individual n-paraffins C ₅ -C ₈ and hydrocarbon fractions boiling in the range of 20-215 ° C.

The main disadvantages of the prototype and the above analogues are the relatively high temperature of the burning of coke formed on the zeolite component of the catalyst and the incomplete depth of its burning at moderate temperatures of catalyst regeneration.

The objective of the invention is to develop a catalyst for the hydroisomerization of hydrocarbon fractions with a reduced temperature for the complete coke burn-up formed on the zeolite component of the catalyst under the process conditions while maintaining a high level of catalyst activity, as well as a method for its use in isomerization processes of hydrocarbon fractions.

The problem is achieved in that the catalyst for hydroisomerization of hydrocarbon fractions contains 0.05-8.0% wt. at least one metal or metal compound selected from the series: platinum, palladium, rhenium, nickel, cobalt, chromium, manganese, molybdenum, tin, lead, zirconium, lanthanum, 5-75% crystalline ferroaluminosilicate or ferrogallium aluminosilicate with a ZSM- zeolite structure 5 or ZSM-11, and alumina - the rest.

The task is achieved in the same way that the ferroaluminosilicate has a molar ratio of SiO ₂ / Al ₂ O ₃ in the range of 38-310 and contains 0.1-1.5% by weight. iron, and ferrogallium aluminum silicate has a molar ratio of SiO ₂ / Al ₂ O ₃ in the range of 61-320 and contains 0.1-1.2% iron and 0.1-1.5% gallium.

The goal is also achieved by the hydroisomerization of hydrocarbon fractions carried out on the catalyst described above at a temperature of 260-360 ° C, a pressure of 0.1-5.0 MPa, a volumetric feed rate of liquid raw materials of 0.5-10 h ^-1 , the molar ratio of hydrogen to hydrocarbons 1-12.

During the processing of hydrocarbon raw materials, a gradual coking of any catalyst occurs, leading to a decrease in its catalytic activity, which in turn leads to a decrease in the yield of isomerized hydrocarbons. To restore the initial level of activity of the catalyst, its regeneration is carried out, which consists in the controlled burning of coke deposits from the surface of the catalyst with a regenerating gas with a certain oxygen content. However, the burning of coke on the metal component of the catalyst located on alumina occurs more fully and at lower temperatures than the burning out of coke formed inside the crystals of the aluminosilicate (zeolite) component, since polyvalent metal cations (Pt, Pd, Ni, etc.) do not penetrate into zeolite crystals of the ZSM-5 and ZSM-11 type and therefore do not affect the burning process of catalyst coke inside zeolite channels. As a result of this, coke deposits inside zeolite crystals may not completely burn out at moderate regeneration temperatures and gradually accumulate from regeneration to regeneration, leading to a decrease in the level of activity and / or to a reduction in the inter-regeneration run of the catalyst. At the stage of hydrothermal synthesis, the introduction of iron and gallium atoms into the zeolite crystalline framework during the synthesis of ferroaluminosilicate or ferrogallium aluminosilicate with the structure of ZSM-5 and ZSM-11 leads to the formation of active centers in the volume of their crystals that accelerate the reactions of burnout of catalyst coke, which in turn leads to lower temperature and increase the depth of burning of coke in the zeolite component of the catalyst while maintaining a high level of activity of the catalyst.

The main distinguishing feature of the proposed method is the use of crystalline ferroaluminosilicate or ferrogallium aluminosilicate with the structure of zeolite ZSM-5 or ZSM-11 having the structural types MFI and MEL, respectively, in the composition of the catalyst.

The hydroisomerization catalyst for hydrocarbon fractions is prepared by known methods. Before the process of hydroisomerization of hydrocarbon fractions, the catalyst can be reduced in a stream of hydrogen at a temperature of 350-550 ° C.

The essence of the proposed method and its practical applicability is illustrated by the following examples. Examples No. 2-15 illustrate the method of hydroisomerization of hydrocarbon fractions using the proposed catalyst, example No. 1 is similar to the prototype and is shown for comparison with the proposed method. The compositions of the catalysts are shown in table 1, the conditions and test results of the catalysts for hydroisomerization of hydrocarbon fractions in table 2.

To illustrate the attainability of the goal - to reduce the temperature of burning of catalyst coke and increasing the completeness of its burning on a zeolite-containing catalyst carrier, examples No. 16-18 and FIG. 1-3. Example No. 16 and FIG. 1 show the burnup depth of coke formed on a carrier of a catalyst containing, like a prototype, zeolite ZSM-5, and examples No. 17-18 and FIG. 2-3 illustrate the burnout of coke on the catalyst carrier of the proposed method, in all cases - before applying any metal to the catalyst.

Example 1 (for comparison).

The carrier of the hydroisomerization catalyst contains 30% wt. γ-Al ₂ O ₃ and 70% decationized zeolite ZSM-5 in the H-form with a molar ratio of SiO ₂ / Al ₂ O ₃ = 91, is prepared similar to the prototype. After the introduction of platinum and lanthanum onto the carrier, the resulting catalyst contains ~ 70% wt. zeolite ZSM-5, 0.3% platinum, 0.05% lanthanum and alumina - the rest.

The test of the catalyst in the hydroisomerization reactions is carried out in a laboratory setup with a tubular isothermal reactor. The catalyst is tested in the process of isomerization of n-hexane. Before testing the catalyst, it is activated in a stream of air for 1 hour at a temperature of 450 ° C, then purged with nitrogen and restored in a stream of hydrogen at a temperature of 450 ° C for 4 hours. The test of the catalyst is carried out at a temperature of 300 ° C, a pressure of 3.0 MPa, a volumetric feed rate of liquid feed of 2.0 h ^-1 and a molar ratio of hydrogen to hydrocarbons H ₂ / CH = 10. Under these conditions, the conversion of n-hexane is 61%, the yield of C ₆ isoparaffins is 54.1% by weight.

Example 2

The hydroisomerization catalyst carrier contains 30% by weight. γ-Al ₂ O ₃ and 70% crystalline ferroaluminosilicate with a ZSM-5 zeolite structure in a decationized H form having a molar ratio of SiO ₂ / Al ₂ O ₃ = 96 and containing 0.5% wt. gland. After the introduction of platinum onto the support, the resulting catalyst contains ~ 70% wt. ferroaluminosilicate with the structure of zeolite ZSM-5, 0.3% platinum and alumina - the rest.

The test of the catalyst in the hydroisomerization reactions is carried out analogously to example 1. The conditions of the hydroisomerization process of n-hexane and the test results of the catalysts are shown in table 2.

Example 3

The hydroisomerization catalyst carrier contains 25% by weight. γ-Al ₂ O ₃ and 75% crystalline ferrogallium aluminosilicate with the structure of zeolite ZSM-11 in a decationized H form having a molar ratio of SiO ₂ / Al ₂ O ₃ = 105 and containing 0.4% wt. iron and 0.1% gallium. After the introduction of platinum and rhenium onto the carrier, the resulting catalyst contains ~ 75% wt. ferrogallium aluminum silicate with the structure of zeolite ZSM-11, 0.2% platinum, 0.3% rhenium and aluminum oxide - the rest.

The test of the catalyst in the hydroisomerization reactions is carried out analogously to example 1. The conditions of the hydroisomerization process of n-hexane and the test results of the catalysts are shown in table 2.

Examples 4-14.

Similar to example 1. The compositions of the catalysts are shown in table 1. The conditions of the process of hydroisomerization of n-hexane and the test results of the catalysts are shown in table 2.

Example 15

Similar to example 1. As a raw material of the hydroisomerization process, a kerosene fraction containing 33.2% by weight is used. n-paraffins and having the following fractional composition, ° C: n.k. - 152, 10% vol. - 162, 50% - 189, 90% - 251, c.k. - 267. The catalyst used is the catalyst of Example No. 2. (the composition of the catalyst are given in table. 1). The test of the catalyst is carried out at a temperature of 340 ° C, a pressure of 1.0 MPa, a volumetric feed rate of liquid feed of 2.0 h ^-1 and a molar ratio of hydrogen to hydrocarbons H ₂ / CH = 1. Under these conditions, 15.2% wt. fractions C ₁ -C ₄ and 89.4% of the fraction C ₅₊ . Due to isomerization (deisoparaffinization) reactions, the content of n-paraffins in liquid products decreases to 13.6% by weight.

Example 16 (for comparison).

The study of the burning process of catalyst coke of a coked sample is carried out by controlling the change in mass of 0.2 g of sample in a reactor close to isothermal. Coke burning is carried out by contacting with a catalyst a regenerating gas containing 1.3% vol. oxygen in a mixture with nitrogen, which is carried out at atmospheric pressure, a temperature of 500-600 ° C and a gas flow rate of 50 l / h.

The coke is burned out by the catalyst support of Example 1, which has worked for 15 hours as a catalyst for processing a C ₆ -C ₈ hydrocarbon fraction and containing 5.1% by weight. coke.

Coke burning starts at a constant temperature of 500 ° C and is carried out for 60 minutes until the mass of the catalyst sample is stabilized; As a result of the oxidative treatment of the catalyst, 39% of the initial coke content was removed. After raising the regeneration temperature to 520 ° C and subsequent burning of coke for 60 min until the mass stabilization of the catalyst sample, another 22% of the initial coke content was removed. At a temperature of 550 ° C another 8% of coke was removed. Residual coke in the amount of 31% of the initial coke content burned out at a temperature of 600 ° C in 70 minutes. The total coke burning time was ~ 250 min. The curves of sample weight loss over time due to coke burnout in a coked catalyst are shown in FIG. one.

Example 17

Similar to example 16 with the difference that the carrier of example 2 was subjected to coke burning, which worked for 15 hours as a catalyst for processing the C ₆ -C ₈ hydrocarbon fraction and containing 5.2% by weight. coke.

Coke burning starts at a constant temperature of 500 ° C and is conducted for 85 minutes until the mass of the catalyst sample is stabilized; As a result of the oxidative treatment of the catalyst, 62% of the initial coke content was removed. After raising the regeneration temperature to 520 ° C and subsequent burning of coke for 75 min until the mass stabilization of the catalyst sample, another 28% of the initial coke content was removed. Residual coke in the amount of 10% of the initial coke content burned out at a temperature of 550 ° C for 20 minutes. The control temperature increase to 600 ° C did not lead to a further change in the mass of the sample, which confirms the complete removal of coke at a temperature of 550 ° C. The total coke burning time was ~ 180 min. The curves of sample weight loss over time due to coke burnout in a coked catalyst are shown in FIG. 2.

Example 18

Similar to example 16 with the difference that the carrier of example 3 was subjected to coke burning, which worked for 100 hours as a catalyst for processing the C ₆ -C ₈ hydrocarbon fraction and containing 10.2% by weight. coke.

Coke burning starts at a constant temperature of 500 ° C and lasts 80 minutes until the mass of the catalyst sample is stabilized; As a result of the oxidative treatment of the catalyst, 81% of the initial coke content was removed. After raising the regeneration temperature to 520 ° C and subsequent burning of coke for 60 min until the mass stabilization of the catalyst sample, another 13% of the initial coke content was removed. Residual coke in the amount of 6% of the initial coke content burned out at a temperature of 550 ° C for 20 minutes. The control temperature increase to 600 ° C did not lead to a further change in the mass of the sample, which confirms the complete removal of coke at a temperature of 550 ° C. The total coke burning time was ~ 160 min. The curves of sample weight loss over time due to coke burnout in a coked catalyst are shown in FIG. 3.

As can be seen from the above examples No. 16-18 and FIG. 1-3, the proposed catalyst has the ability to remove coke deposits from the surface of the zeolite component of the regenerated catalyst under milder conditions, consisting in lowering the temperature of complete burning of coke from 600 ° C to 550 ° C and reducing the total regeneration time. Moreover, it is highly active in the hydroisomerization of hydrocarbon fractions (see examples No. 1-15). In addition, under identical conditions of the hydroisomerization process with the prototype, the proposed catalyst produces isoparaffins with a higher yield than the prototype catalyst (see examples 1 and 2 in Table 2, respectively), which is associated with additional leading isomerization reactions of Fe and Ga containing active centers formed by the introduction of iron or iron and gallium in the composition of the zeolite.

Claims (7)

1. The catalyst for hydroisomerization of hydrocarbon fractions containing alumina, zeolite and at least one metal or metal compound selected from groups III, VI, VIII of the periodic system of elements, characterized in that the catalyst contains zeolite crystalline ferroaluminosilicate or ferrogallium aluminosilicate with a zeolite structure ZSM-5 or ZSM-11 and has the following composition,% wt .: metal or its compound  0.05-8.0 (in terms of metal) specified zeolite  5-75 aluminium oxide  rest 2. The catalyst according to claim 1, characterized in that the ferroaluminosilicate has a molar ratio of SiO ₂ / Al ₂ O ₃ in the range of 38-310 and contains 0.1-1.5% wt. gland. 3. The catalyst according to claim 1, characterized in that the ferrogallium aluminum silicate has a molar ratio of SiO ₂ / Al ₂ O ₃ in the range of 61-320 and contains 0.1-1.1% wt. iron and 0.1-1.5% wt. Gaul. 4. The catalyst according to any one of paragraphs. 1-3, characterized in that the catalyst contains at least one metal or metal compound selected from the series: platinum, palladium, rhenium, nickel, cobalt, chromium, manganese, molybdenum, tin, lead, zirconium, lanthanum. 5. The method of hydroisomerization of hydrocarbon fractions by contacting them in the presence of a hydrogen-containing gas at elevated temperatures and overpressure with a catalyst, characterized in that the catalyst according to any one of paragraphs is used as a catalyst. 1-4. 6. The method according to p. 5, characterized in that the hydroisomerization of hydrocarbon fractions is carried out at a temperature of 260-360 ° C, a pressure of 0.1-5.0 MPa, a volumetric feed rate of liquid raw materials of 0.5-10 h ^-1 , the molar ratio hydrogen to hydrocarbons 1-12.

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