RU2794336C1 - Method for passivation of heavy metals on cracking catalysts with boron-containing compounds - Google Patents

Abstract

FIELD: oil refining.

SUBSTANCE: described is a method for passivation of a hydrocarbon cracking catalyst from heavy metals deposited on it, characterized in that the catalyst is impregnated with a solution of a boron-containing passivating agent in an amount of 0.01 to 2.00 % by weight boron in terms of the catalyst, followed by ultrasonic exposure for 0.1-4.0 hours with a frequency 20-40 kHz and calcination at 400-800°C for 0.5-6.0 hours.

EFFECT: increased yield of gasoline, fractions 200-300°C, propane-propylene fraction, reduced yields of coke and hydrogen as a result of heavy oil feedstock cracking.

4 cl, 9 tbl, 7 ex

Description

Technical field

The invention relates to the field of oil refining and relates to the process of catalytic cracking, in particular the method of passivation of heavy metals on cracking catalysts. The invention can be used in the petrochemical industry to increase the depth of oil refining.

State of the art

Catalytic cracking (CC) is one of the first in terms of capacity processes of secondary oil refining in the world. The main raw material of KK is hydrotreated vacuum gas oil. To increase the depth of oil refining, a number of oil refineries use mixtures of gas oil and residues from vacuum and atmospheric distillation of oil and secondary oil refining as raw materials. The involvement of residual heavy feedstock in CC is complicated by a number of scientific and technical problems, in particular, when switching to fuel oils, tars, heavy gas oils, the content of metals in the feedstock increases significantly. Metals accumulate on the catalysts during the cracking of heavy petroleum feedstocks and are the cause of many undesirable side reactions. Nickel, which is the main poisoning agent in cracking catalysts, catalyzes dehydrogenation reactions, which leads to increased coke formation, a decrease in the yield of light fractions, and an increase in the formation of hydrogen in the system.

A possible solution to the problem may be the passivation of the deposited metals on the catalysts. In the prior art, methods are known for the passivation of heavy metals with compounds based on tin (US4321129A, publ. 03.23.1982), antimony (US4255287A, publ. 03.10.1981), bismuth (EP0316431B1, publ. 12.28.1998). The use of these passivators can significantly reduce the poisoning effect of metals deposited on the catalysts. However, as is known (US4235704A, publ. 11/25/1980), tin, antimony, bismuth deactivate CO afterburning promoters, which leads to the increase in the amount of CO in the regenerator during coke combustion, the emission of which into the atmosphere is strictly controlled. A possible alternative would be boron-based passivators, which are more environmentally friendly due to the fact that they do not have a negative effect on CO afterburning promoters (EP0151888A2, published 08/21/1985). There is a known method of using a boron-containing passivator - boron oxide, which is not applied to the cracking catalyst, but is added to the system in the form of separate boron-containing composites (US10683458B2, publ. 06/16/2020, US9895680B2, publ. ). This passivation method has the following disadvantages: firstly, the need to introduce additional particles with a passivator in addition to the catalyst into the cracking unit, and secondly, the passivator is not applied to the catalyst, which greatly complicates the passivator-deactivating metal contact, thereby worsening passivation.

Closest to the claimed method of passivation is a method of passivation of cracking catalysts contaminated with nickel, vanadium and iron, using boron compounds (US4192770A, publ. 11.03.1980). Boron-containing passivators are applied directly to the catalyst surface or introduced together with the feedstock into the cracking unit. Thus, after passivation of 0.27 wt.% nickel and 0.63 wt.% vanadium with boron (0.43 wt.%) on a zeolite-containing catalyst, it is possible to increase the yield of gasoline by 3.8 wt.% as a result of vacuum gas oil cracking. However, the used method of passivation of heavy metals is not a long-term and effective solution due to the fact that the passivator is located mainly on the catalyst surface, and in the process of cracking and regeneration, due to the gradual mechanical wear of the catalyst surface, the passivator is removed from the catalyst, and there is a need for more additional additional loading. passivator.

The technical problem solved by the claimed invention is the development of a method for the passivation of heavy metals, which will provide a more uniform distribution of the passivator over the volume of the catalyst particle in comparison with existing analogues, which makes it possible to increase the increase in yields for gasoline, a fraction of 200-300 ° C, propane-propylene fractions and reduce the yields of coke and hydrogen.

Disclosure of invention

The present invention addresses the problem of heavy metal deactivation of catalysts in a catalytic cracking process.

The technical result of the claimed invention is the development of a method for the passivation of heavy metals on cracking catalysts with boron-containing compounds, which in turn makes it possible to increase the yields of gasoline, fractions of 200-300 ° C, propane-propylene fraction (PPF), reduce the yields of coke and hydrogen as a result of heavy oil cracking. raw materials.

An increase in the yields of gasoline, fractions of 200-300°C, PPF and a decrease in the yields of coke and hydrogen is achieved by passivation of deposited heavy metals on the catalyst and depends on the amount and composition of these deposited metals.

The technical result is achieved by the method of passivation of the hydrocarbon cracking catalyst from heavy metals deposited on it by impregnating the catalyst with a solution of a boron-containing passivating agent in an amount of 0.01 to 2.00 wt.% boron in terms of the catalyst with ultrasonic exposure for 0.1-4.0 hours with a frequency of 20-40 kHz and subsequent calcination at 400-800°C for 0.5-6.0 hours. In this case, solutions of boron-containing passivators are solutions of boron esters, an aqueous solution of boric acid with a boron content of 0.1 to 1.0 wt.%, namely, solutions of ethylene glycol borates in ethylene glycol with a boron content of 0.1 to 3.4 wt.% are used as solutions of boron esters, solutions of propylene glycol borates in propylene glycol with a boron content of 0.1 to 2.7 wt.%, solutions of isopropyl borates in isopropanol with a boron content of 0.1 to 3.6 wt.%. As catalysts, industrial zeolite-containing cracking catalysts with a total content of zeolites from 10 to 90 wt.% are used.

The inventive method is applicable regardless of the technological option for cracking (cracking in a moving, stationary, fluidized catalyst bed, cracking in a riser reactor, etc.). Industrial zeolite-containing cracking catalysts can be used as catalysts (for example, DA-200, DA-250, Reduxion LS-60P, Omsk biceolite and monozeolite catalysts, etc.).

A more uniform distribution of the passivator over the volume of the catalyst particle is confirmed by the stability of the modified catalyst during repeated use. The passivator was applied to the catalysts with (sample 1) and without (sample 2) sonication in an amount of 2 wt.% in terms of B, and the resulting passivated catalysts were repeatedly used in catalytic cracking with regeneration for surface degradation. After 10 cycles of cracking-regeneration, the decrease in the amount of boron, determined by inductively coupled plasma mass spectrometry, on sample 1 was 0.3 wt.%, while on sample 2 - 1.4 wt.%.

The application of passivators to cracking catalysts using ultrasonic treatment made it possible to immobilize the passivator throughout the catalyst volume, which significantly increased the effect of passivation of heavy metals and reduced passivator consumption due to less loss of passivator on the catalyst during regeneration and cracking.

Implementation of the invention

Below is a more detailed description of the claimed method, which does not limit the scope of the claims of the claimed invention, but demonstrates the possibility of carrying out the invention with the achievement of the claimed technical result. The reagents used are commercially available. All procedures are carried out in the temperature range from 18 to 30°C.

The invention is carried out in stages and includes the following stages:

1. Preparation of boron-containing passivators. Organic boron esters (for example, ethylene glycol, propylene glycol, diethylene glycol borates, methyl borates, ethyl borates, isopropyl borates, cyclohexyl borates, etc.) boric acid and boron oxide can be used as boron-containing passivators.

2. Applying a passivator to fresh, equilibrium, and poisoned catalysts. Passivators are applied to the catalysts by diffusion (wet) impregnation in an amount from 0.01 to 2.00 wt.% in terms of boron. For uniform immobilization of passivators throughout the volume of the catalyst, ultrasonic treatment (frequency 20-40 kHz, exposure time 0.1-4.0 hours) is used during application. After deposition of passivators, the catalysts are calcined at 400-800°C in a muffle furnace for 0.5-6.0 hours. Also, the calcination of the catalysts can be carried out in the regeneration zone of the cracking unit. For the passivation of heavy metals under varying cracking conditions, the installation is supposed to be fed with a fresh catalyst with a deposited passivator. The amount of catalyzed passivator added will depend on the degree of heavy metal poisoning of the catalyst in the plant.

To evaluate the effectiveness of passivation, the obtained materials were tested in the cracking of hydrocarbon feedstock. Catalytic cracking was carried out in an ASTM D3907-13 unit using a fixed bed of catalyst at a temperature of 500° C. and a mass feed rate of 14 h ^-1 . The thermocouple stabilization of the catalysts was carried out on a unit that complies with ASTM D4463/D4463M - 96 (2013). Hydrotreated vacuum gas oil with the characteristics shown in Table 1 was used as a feedstock. Industrial cracking catalysts with the characteristics shown in Table 2 were used as catalysts.

Example 1

To prepare a solution of ethylene glycol boric esters, 30 mg of boric acid was dissolved in 5 ml of ethylene glycol at 50°C and diluted with 85 ml of isopropanol. The resulting passivator solution was added to 50 g of equilibrium catalyst 3 with a total content of Ni, V in the amount of 0.07 wt.% and subjected to ultrasonic treatment for 4 hours at a frequency of 20 kHz. After applying the passivator, the catalyst 3 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 500°C for 3 hours. Further, passivated catalyst 3 and equilibrium catalyst 3 were tested in catalytic cracking of hydrotreated vacuum gas oil at 500°C and a mass feed rate of 14 h.^-1. The cracking results are shown in Table 3.

After passivation, an improvement in the catalytic properties was observed, expressed in an increase in the yields of gasoline by 0.67 wt.%, a fraction of 200-300°C by 0.56 wt.%, PPF by 0.52 wt.%, a decrease in the yields of coke and hydrogen by 0.18 wt.% and 0.02 wt. .%, respectively.

Example 2

To poison the catalyst, 1.35 g of nickel naphthenate with 7.4% nickel content and 3.33 g of vanadium naphthenate with 3% vanadium content were dissolved in 70 ml of toluene, the resulting solution was added to 50 g of fresh catalyst 1 and calcined at 600°C in a muffle furnace. The resulting poisoned catalyst 1 was subjected to a thermocouple treatment in an atmosphere of 100% steam at 760°C.

To prepare a solution of propylene glycol boric esters, 280 mg of boric acid were dissolved in 10 ml of propylene glycol at 50°C and diluted with 80 ml of isopropanol. The resulting passivator solution was added to 50 g of poisoned heat stabilized catalyst 1 and subjected to ultrasonic treatment for 3 hours at a frequency of 25 kHz . After applying the passivator, the catalyst 1 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 600°C for 2 hours. Further, the passivated catalyst 1 and the poisoned thermally stabilized catalyst 1 were tested in the catalytic cracking of hydrotreated vacuum gas oil at 500° C. and a mass feed rate of 14 h ^-1 . The cracking results are shown in Table 4.

After passivation, an improvement in the catalytic properties was observed, expressed in an increase in the yields of gasoline by 1.15 wt.%, a fraction of 200-300°C by 0.89 wt.%, PPF by 0.83 wt.%, a decrease in the yields of coke and hydrogen by 0.22 wt.% and 0.05 wt. .%, respectively.

Example 3

To poison the catalyst, 1.35 g of nickel naphthenate with 7.4% nickel and 3.33 g of vanadium naphthenate with 3% vanadium were dissolved in 70 ml of toluene, the resulting solution was added to 50 g of fresh catalyst 2 and calcined at 600°C in muffle furnace. The resulting poisoned catalyst 2 was subjected to a thermocouple treatment in an atmosphere of 100% steam at 760°C.

640 mg of boron oxide was dissolved in 90 ml of water, the resulting solution was added to 50 g of poisoned thermally stabilized catalyst 2 and subjected to ultrasonic treatment for 0.1 hour at a frequency of 40 kHz . After applying the passivator, catalyst 2 was dried at 100°C for 3 hours, followed by calcination in a muffle furnace at 800°C for 0.5 hours. Further, the passivated catalyst 2 and the poisoned thermally stabilized catalyst 2 were tested in the catalytic cracking of hydrotreated vacuum gas oil at 500° C. and a mass feed rate of 14 h ⁻¹ . Cracking results are shown in Table 5.

After passivation, an improvement in the catalytic properties was observed, expressed in an increase in the yields of gasoline by 4.11 wt.%, a fraction of 200-300°C by 1.95 wt.%, PPF by 1.38 wt.%, a decrease in the yields of coke and hydrogen by 0.76 wt.% and 0.13 wt.%, respectively.

Example 4

To poison the catalyst, 2.70 g of nickel naphthenate with 7.4% nickel content and 6.66 g of vanadium naphthenate with 3% vanadium content were dissolved in 140 ml of toluene, the resulting solution was added to 100 g of fresh catalyst 1 and calcined at 600°C in a muffle ovens. The resulting poisoned catalyst 1 was subjected to a thermocouple treatment in an atmosphere of 100% steam at 760°C.

To prepare a solution of ethylene glycol boric esters, 2.8 g of boric acid was dissolved in 90 ml of ethylene glycol at 50°C. The resulting passivator solution was added to 50 g of fresh catalyst 1 and subjected to ultrasonic treatment for 2 hours at a frequency of 30 kHz. After applying the passivator, the catalyst 1 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 400°C for 6 hours. Next, 10 g of passivated catalyst 1 was mixed with 50 g of poisoned catalyst 1, and 10 g of fresh catalyst 1 was also mixed in parallel with 50 g of poisoned catalyst 1. The resulting mixtures of poisoned and passivated catalyst 1, fresh and poisoned catalyst 1, and separately poisoned catalyst 1 were tested in catalytic cracking of hydrotreated vacuum gas oil at 500°C and a mass feed rate of 14 h^-1. Cracking results are shown in Table 6.

After adding a fresh catalyst with a passivator, an improvement in the catalytic properties was observed, expressed in an increase in the yields of gasoline by 1.64 wt.%, a fraction of 200-300°C by 0.81 wt.%, PPF by 0.66 wt.%, a decrease in the yields of coke and hydrogen by 0.29 wt.% and 0.07 wt.%, respectively.

Example 5

To poison the catalyst, 2.70 g of nickel naphthenate with 7.4% nickel content and 6.66 g of vanadium naphthenate with 3% vanadium content were dissolved in 140 ml of toluene, the resulting solution was added to 100 g of fresh catalyst 3 and calcined at 600°C in a muffle furnace . The resulting poisoned catalyst 3 was subjected to a thermocouple treatment in an atmosphere of 100% steam at 760°C.

To prepare a solution of ethylene glycol boric esters, 5.6 g of boric acid was dissolved in 90 ml of ethylene glycol at 50°C. The resulting passivator solution was added to 50 g of fresh catalyst 3 and subjected to ultrasonic treatment for 1 hour at a frequency of 35 kHz. After applying the passivator, the catalyst 3 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 700°C for 1 hour. Next, 10 g of passivated catalyst 3 was mixed with 50 g of poisoned catalyst 3, and 10 g of fresh catalyst 3 was also mixed in parallel with 50 g of poisoned catalyst 3. The resulting mixtures of poisoned and passivated catalyst 3, fresh and poisoned catalyst 3, and separately poisoned catalyst 3 were tested in catalytic cracking of hydrotreated vacuum gas oil at 500°C and 14 h mass feed rate^-1. Cracking results are shown in Table 7.

After adding a fresh catalyst with a passivator, an improvement in the catalytic properties was observed, expressed in an increase in the yields of gasoline by 2.35 wt.%, a fraction of 200-300°C by 1.05 wt.%, PPF by 0.75 wt.%, a decrease in the yields of coke and hydrogen by 0.42 wt.% and 0.09 wt.%, respectively.

Comparative example 1.

To poison the catalyst, 2.70 g of nickel naphthenate with 7.4% nickel content and 6.66 g of vanadium naphthenate with 3% vanadium content were dissolved in 140 ml of toluene, the resulting solution was added to 100 g of fresh catalyst 3 and calcined at 600°C in a muffle furnace . The resulting poisoned catalyst 3 was subjected to a thermocouple treatment in an atmosphere of 100% steam at 760°C.

To prepare a solution of ethylene glycol boric esters, 7.0 g of boric acid was dissolved in 90 ml of ethylene glycol at 50°C. The resulting passivator solution was added to 50 g of fresh catalyst 3 and subjected to ultrasonic treatment for 6 hours at a frequency of 15 kHz. After applying the passivator, catalyst 3 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 900°C for 0.25 hours. Next, 10 g of passivated catalyst 3 was mixed with 50 g of poisoned catalyst 3, and 10 g of fresh catalyst 3 was also mixed in parallel with 50 g of poisoned catalyst 3. The resulting mixtures of poisoned and passivated catalyst 3, fresh and poisoned catalyst 3, and separately poisoned catalyst 3 were tested in catalytic cracking of hydrotreated vacuum gas oil at 500°C and 14 h mass feed rate^-1. Cracking results are shown in Table 8.

After the addition of a fresh catalyst with a passivator, a deterioration in the catalytic properties was observed, expressed in a decrease in the yields of gasoline by 9.83 wt.%, a fraction of 200-300°C by 2.52 wt.%, PPF by 1.54 wt.%, an increase in the yields of coke and hydrogen by 2.33 wt.% and 0.23 wt.%, respectively.

Comparative example 2.

To prepare a solution of ethylene glycol boric esters, 15 mg of boric acid was dissolved in 5 ml of ethylene glycol at 50°C and diluted with 90 ml of isopropanol. The resulting passivator solution was added to 50 g of equilibrium catalyst 3 with a total content of Ni, V, Fe in an amount of 0.07 wt.% and subjected to ultrasonic treatment for 0.05 hours at a frequency of 50 kHz. After applying the passivator, the catalyst 3 was dried at 200°C for 3 hours, followed by calcination in a muffle furnace at 300°C for 7 hours. Further, passivated catalyst 3 and equilibrium catalyst 3 were tested in catalytic cracking of hydrotreated vacuum gas oil at 500°C and a mass feed rate of 14 h^-1. Cracking results are shown in Table 9.

After passivation, no improvement in catalytic properties was observed.

Thus, the passivation of deactivating metals on cracking catalysts under the above conditions makes it possible to reduce the catalyst loading, increase the yields of gasoline by 1–4 wt.%, 200–300°C fractions by 1–2 wt.%, PPF by 1–2%, and yields of coke per 1 wt.% and hydrogen 0.1 wt.%.

Claims (4)

1. A method for passivation of a hydrocarbon cracking catalyst from heavy metals deposited on it, characterized in that the catalyst is impregnated with a solution of a boron-containing passivating agent in an amount of 0.01 to 2.00 wt.% boron in terms of the catalyst, followed by ultrasonic exposure for 0.1-4.0 hours with frequency of 20-40 kHz and calcination at 400-800°C for 0.5-6.0 hours. 2. The method according to claim 1, characterized in that the solutions of boron-containing passivators are solutions of boric esters, an aqueous solution of boric acid with a boron content of 0.1 to 1.0 wt.%. 3. The method according to claim 2, characterized in that solutions of ethylene glycol borates in ethylene glycol with a boron content of 0.1 to 3.4 wt.%, solutions of propylene glycol borates in propylene glycol with a boron content of 0.1 to 2.7 wt.% are used as solutions of boric ethers, solutions of isopropyl borates in isopropanol with boron content from 0.1 to 3.6 wt.%. 4. The method according to claim 1, characterized in that industrial zeolite-containing cracking catalysts with a total content of zeolites from 10 to 90 wt.% are used as catalysts.