RU2290996C1 - Method of regenerating catalytic systems of hydrogenation processes - Google Patents

Abstract

FIELD: petroleum processing.

SUBSTANCE: method is accomplished by burning out carbon-containing compounds in oxygen-containing gas medium and comprises stages: desorption of hydrocarbons from catalyst surface performed in plant reactor and burning out of hydrocarbon thickening products performed on a special installation in indirect-heating rotary kiln at 450-550°C and excessive pressure 0.4-1.0 bar. Desorption of hydrocarbons from catalyst surface is carried out in a hydrogen-containing gas medium with 60-80 vol % H2, while gradually raising temperature from 200-220°C to 380-400°C at a rate 35-30°C/h following by aging of catalysts at 380-400°C until concentration of hydrocarbons in hydrogen-containing gas is no higher than 0.5 wt %, after which temperature is lowered to 100-120°C at a rate 20-25°C/h and active catalyst components are passivated. Passivation is accomplished by treatment at 100-120°C and excessive pressure 4-10 bar with mixture of inert gas and oxygen-containing gas, in particular carbon dioxide and/or air used in amount providing oxygen concentration in gas mixture 0.02-0.5 vol %, which corresponds to consumption of gas mixture 400-600 nm³/m³ catalyst. Treatment is conducted until oxygen concentrations at inlet and outlet of reactor are leveled.

EFFECT: enabled industrially feasible maximally possible restoration of catalyst activity with minimum destruction loss of catalyst.

4 tbl, 7 ex

Description

The invention relates to oil refining, in particular to methods for hydrofining oil fractions.

An increase in the consumption of motor fuels and base oils with a decrease in demand for residual oil products requires an increase in the depth of oil refining [The state of the Russian and world markets for oil, refined products, petrochemicals and chemistry. Moscow: TsNIITEneftekhim, Express-information, 2002, No. 3, p.6-9]. At the same time, the requirements for operational and environmental characteristics of fuels and oils are being tightened, consisting mainly in a significant decrease in the content of sulfur and polycyclic aromatic hydrocarbons in the product [Kaminsky E.F., Khavkin V.A., Osipov L.N. and other Oil refining and petrochemicals, 2002, No. 6, p.17-18].

Tighter requirements for the quality of marketable petroleum products derived from domestic sulfur oils present new requirements for the hydrofining of light and residual petroleum fractions, primarily associated with an increase in the activity and stability of the operation of catalysts in the reactions of hydrogenolysis of organosulfur compounds, hydrogenation of unsaturated, bi- and polycyclic aromatic hydrocarbons with the same technological parameters.

Current technical solutions in the field of production of catalysts for hydrogenation processes [RF Patents No. 2140963, 2103065, 2124400, 2198733, 2216404, 2183505] and technological methods for their operation [RF Patents No. 2229934, 2124042, 2140964, 2225433] allow us to solve these problems when using fresh catalysts .

The operation of catalysts for hydrogenation processes is always accompanied by a decrease in their activity.

The duration of the period during which the catalyst potential is used to the maximum extent possible (the first inter-regeneration cycle) depends on the composition of the used catalyst system and its operating conditions (quality of the processed raw materials, technological parameters) and varies from 4-6 months when processing gasoline and middle distillate fractions of the secondary origin [Oil refining and petrochemistry, 2003, No. 1, pp. 17-20] up to 6 years old during hydrotreatment of straight-run gasoline fractions [Oil refining and petrochemistry, 2004, No. 4, p. 47 -51].

Partially, the activity of catalysts for hydrogenation processes can be restored by oxidative regeneration, the process of controlled burning of the products of compaction of hydrocarbon-containing compounds with oxygen-containing mixtures at catalysis temperatures and above [Masagutov RM, Morozov BF, Kutepov BI Catalyst regeneration in oil refining and petrochemicals. - M.: Chemistry, 1978, p. 3. 103-105].

The activity of the catalysts after regeneration and the period of their further operation depends on the conditions and duration of operation, as well as the method and conditions of the regeneration process.

Depending on the composition used in the regeneration of an oxygen-containing mixture, steam-air and gas-air regenerations are distinguished.

For example, a method of regeneration, consisting in passing through the spent adsorbent at a temperature of 121-399 ^{° C} regeneration gas stream comprising a mixture of inert gas and carbon oxides, hydrogen and steam [Application №97112457 / 04, date of publication 10.08.1998]. . The method described above relates to steam-air regeneration.

The most significant drawback of the steam-air regeneration method in relation to catalysts of hydrogenation processes is the risk of watering the catalyst in the initial period of regeneration, when the catalyst is not sufficiently warmed up. With a further increase in temperature, instantaneous evaporation of water occurs, which is accompanied by the destruction of the catalyst granules.

The use of water vapor also leads to a partial leaching of compounds of active metals, which during further operation affects the activity of the catalyst.

It is possible to minimize the loss of activity and strength during gas-air regeneration.

A known method of gas-air regeneration, the main feature of which is the use of nitrogen as inert and coolant [Technology of catalysts. Edited by IP Mukhlenov, - L .: Chemistry, 1974, p.69].

Air-gas regeneration can be carried out:

- or in the reactor of a process unit,

- or outside the reactor of a process plant in a specialized regeneration plant.

Maximum recovery of activity with minimal loss of strength of the catalyst is achieved during the regeneration reactor is a dedicated process plant at the installation in a rotary indirect heating furnace at a temperature of 450-550 ^C and a pressure of 0.4-1.0 atm [Masagutov RM, Morozov B .F., Kutepov B.I. Catalyst regeneration in oil refining and petrochemicals. - M.: Chemistry, 1978, p. 3. 108-110].

When carrying out regeneration in a specialized installation, it is necessary to take into account that all catalysts of hydrogenation processes during operation acquire pyrophoric properties. Uncontrolled ignition of the catalyst leads to an irretrievable loss of its activity and a decrease in strength, which makes its further operation impossible.

Precautions must be taken when unloading the catalyst to prevent ignition of the catalyst in contact with air. For this purpose, the passivation of the catalyst is recommended. The essence of the passivation operation is to block, under mild conditions, the active components in the form of finely dispersed sulfides and metals contained on the surface of the spent catalyst, which are highly flammable in air, after which the catalyst practically loses its pyrophoric properties.

The closest to the proposed technical solution to the technical essence and attainable result is a method of catalyst regeneration by burning out condensation products of hydrocarbons in the environment of oxygen-containing gas in the temperature range ^of 260-600 C, at a pressure of 0,45-3,5 bar [RF patent №2053843] .

This regeneration method relates to gas-air regeneration, but does not provide for the passivation stage of the catalysts and, therefore, can only be carried out in the reactor of the technological installation. Carrying out the regeneration of catalysts in the reactor of a technological installation is always accompanied by a significant temperature difference throughout the reactor volume, which leads to the destruction of a part of the catalyst located in the high temperature zone and incomplete burning of the products of hydrocarbon compaction to the part of the catalyst located in the low temperature zone.

The aim of the invention is to develop a technical solution that allows to carry out in industrial conditions the maximum possible restoration of the activity of catalysts of hydrogenation processes with minimal loss of catalyst due to destruction.

This goal is achieved by implementing the method of regeneration of catalysts and catalytic systems of hydrogenation processes by burning carbon-containing compounds in an oxygen-containing gas environment, which includes the stage of desorption of hydrocarbons from the surface of the catalysts carried out in the reactor of the technological installation, and burning products of their compaction on a specialized installation in an indirect rotary kiln heating at a temperature of 450-550 ^C and a pressure of 0.4-1.0 psig, provided that the desorption of hydrocarbons from the n catalyst surface is carried out in a medium with a hydrogen-containing gas hydrogen concentration of 60-80 vol.% at temperatures gradually rise from 200-220 ^C to 380-400 ^C at a rate ^of 25-30 C / hour, followed by aging the catalyst system at a temperature of 380- 400 ^о С until the concentration of hydrocarbons in the hydrogen-containing gas reaches not more than 0.5 wt.% And the temperature drops to 100-120 ^о С at a speed of 20-25 ^о С / h, followed by passivation of the compounds of the active components of the catalysts by processing at a temperature of 100- 120 ^° C and a pressure of 4-10 atm with a mixture of gas with an oxygen-containing component, which is carbon dioxide and / or air taken in an amount that provides an oxygen concentration in the gas mixture of 0.02-0.50 vol.%, with a flow rate of 400-600 nm ³ / m ^{3 of} catalyst leveling the oxygen concentration at the inlet and outlet of the reactor.

The distinguishing feature of the proposed technical solution is that the desorption of hydrocarbons from the surface of the catalysts is carried out in a medium hydrogen-containing gas with a hydrogen concentration of 60-80 vol.% At temperatures gradually rise from 200-220 ^C to 380-400 ^{° C} with a rate ^of 25-30 C / hour, followed by aging the catalyst system at a temperature of 380-400 ^o C to achieve a concentration of hydrocarbons in the hydrogen-containing gas is not more than 0.5 wt.% and a decrease in temperature to 100-120 ^{° C} at a rate of 20-25 ° ^C / hour, with subsequent passivation connected s active components of catalysts by treatment at a temperature of 100-120 ^C and pressure of 4-10 atm in a mixture of inert gas with an oxygen-containing component which is used as carbon dioxide and / or air is taken in an amount to provide an oxygen concentration in the gas mixture 0 02-0.50 vol.% With a flow rate of 400-600 nm ³ / m ^{3 of the} catalyst to equalize the oxygen concentration at the inlet and outlet of the reactor.

The specified restrictions on the concentration of hydrogen in a hydrogen-containing gas and the selected temperature regime of the stage of hydrocarbon desorption from the surface of the catalysts described in the claims of the invention allow eliminating the reduction reactions of the compounds of active components from the surface of the catalyst of hydrocarbons, the implementation of which significantly reduces the activity of the catalyst.

The technological parameters specified in the formula of the invention for the passivation stage of the compounds of the active components of the catalysts allow, at comparatively low temperatures, the compounds of the active components of the catalyst surface to be blocked by an oxide film, which prevents combustion of the catalyst upon contact with atmospheric air when the catalyst is unloaded from the reactor of the technological unit and delivered to a specialized regeneration unit.

The use of carbon dioxide as an oxygen-containing component or its mixture with air allows the use of process gases for the passivation stage, which helps to increase the environmental friendliness of the process.

The use of the previously described technical solutions in the regeneration of catalysts for hydrogenation processes is not known.

Thus, the present invention meets the requirements of "novelty" and "significant difference".

The proposed method for the regeneration of catalysts for hydrogenation processes is as follows.

After stopping feed to the catalyst loaded in the reactor is set hydrogen concentration in the feed to the reactor the hydrogen-containing gas of 60-80 vol.% And the reactor temperature was 200-220 ° ^C gradually at a rate of 25-30 ^C / hour, the temperature is raised in the reactor up to 380-400 ^о С. Determine the concentration of hydrocarbons in a hydrogen-containing gas. Catalyst is maintained under these conditions until the concentration of hydrocarbons in the hydrogen gas is not more than 0.5 wt.% And then reduce the reactor temperature to 100-120 ^{° C} at a rate ^of 20-25 C / h. At a reactor temperature of 100-120 ^C. replace hydrogen gas on an inert, for example nitrogen, and the reactor pressure set 4-10 atm. After complete displacement of hydrogen from the reactor, an oxygen-containing component is introduced into the inert gas at a flow rate of 400-600 nm ³ / m ^{3 of} catalyst in an amount providing an oxygen concentration of 0.02-0.50% by volume of the gas mixture. Carbon dioxide and / or air are used as the oxygen-containing component.

After aligning the oxygen concentration at the reactor inlet and the reactor outlet temperature of the reactor was lowered to 40-60 ^{° C} and the catalyst is carried out unloading, transporting catalyst discharged specialized installation and start of regeneration in the rotary indirect heating furnace at a temperature of 450-550 ^C. and a pressure of 0.4-1.0 atmospheres.

The proposed method of regeneration of the catalysts is illustrated, but not limited to the examples below.

Information about the catalysts used to illustrate the proposed method for the regeneration of catalysts and catalytic systems of hydrogenation processes are given in table 1. The same table shows the characteristics of the catalysts after their passivation. The physicochemical properties of the fresh starting catalysts are characterized by the content of compounds of active components in them and the strength of passivated ones by the content of carbon and sulfur.

The conditions for carrying out the stages of hydrocarbon desorption from the surface of the catalysts, passivation of the compounds of the active components of the catalysts and burning of the products of hydrocarbon compaction are given in Tables 2, 3, 4, respectively. Table 4 also shows the physicochemical and operational characteristics of the regenerated, i.e. past all three stages of processing, catalysts. Sulfur conversion, achieved by using these catalysts in the hydrotreating of crude oil, was used as an operational indicator. This indicator gives an idea of the restoration of catalyst activity after regeneration. A very important indicator of regeneration is to minimize catalyst losses during regeneration due to destruction. This indicator is also given in table 4. The carbon content data on the regenerated catalyst indicate the completeness of removal of hydrocarbon densification products from the catalyst, i.e. the effectiveness of the stage of burning products of hydrocarbon compaction from the surface of the catalyst.

Example 1

Regeneration of the catalyst RK-442Ni. The catalyst was in operation at the installation of deep hydrofining vacuum gas oil with a sulfur content of 2.0-2.5 wt.% Without regeneration for three years. The amount of catalyst loaded into the reactor was 108 tons. The main physicochemical and operational characteristics of the fresh catalyst RK-442Ni are given in Table 1.

After stopping feed on RK-442Ni catalyst set the hydrogen concentration in the hydrogen gas 60 vol.%, The reactor temperature was 220 ° ^C gradually at a rate of 25 ^C / hour, the reactor temperature raised to 400 ^C. The concentration of hydrocarbons in the hydrogen gas amounted to 4.2 wt.%. The catalyst was kept in these conditions until reaching a concentration of hydrocarbons in the hydrogen containing gas of 0.5 wt.%, After which reduced the reactor temperature to ¹²⁰ ° C at a rate ^of 20 C / h. At a reactor temperature of ¹²⁰ ° C hydrogen was replaced with nitrogen gas. The pressure in the reactor was 4.0 ati.

After complete displacement of hydrogen from the reactor, air was added to the nitrogen supplied to the reactor in an amount providing an oxygen concentration in the gas mixture of 0.50 vol.%. The flow rate of the gas mixture of 400 nm ³ / m ^{3 of} catalyst was established. After aligning the oxygen concentration at the reactor inlet and the reactor outlet temperature of the reactor was reduced to 40 ^{° C} and the catalyst started to discharge.

After unloading, the catalyst was analyzed for its sulfur and carbon content. The data are given in table 1.

Burning condensation products of hydrocarbons from the catalyst surface was carried out at a specialized installation in a rotary indirect heating furnace at a temperature of 550 ^C and a pressure of 0.4 atm. After screening the regenerated catalyst from dust and chips formed during operation and regeneration, 104 tons of catalyst were obtained, i.e. losses amounted to 3.5%.

Physico-chemical and operational characteristics of the regenerated catalyst are given in table.4.

Comparison of the characteristics of fresh, passivated and regenerated catalyst PK-442Ni shows that there were practically no changes in the chemical composition of the catalyst, the activity and strength of the catalyst decreased slightly. Loss of catalyst due to destruction is minimal. Hydrocarbon compaction products are almost completely removed.

Example 2

Regeneration of the catalyst RK-231Co. The catalyst was in operation at the unit for hydrofining mixed middle distillate fractions with a sulfur content of 1.6-2.0 wt.%, Unsaturated hydrocarbon content of 10-15 wt.%.

The amount of catalyst loaded into the reactor was 40 tons. The main physicochemical and operational characteristics of the fresh catalyst RK-231Co are given in Table 1.

After termination of feed to catalyst RC-231So set the hydrogen concentration in the hydrogen gas is 80 vol.% And the reactor temperature was 200 ° ^C gradually at a rate of 30 ^C / hour, the reactor temperature raised to 380 ^C. The concentration of hydrocarbons in the hydrogen gas amounted to 3.5 wt.%. The catalyst was kept in these conditions until reaching a concentration of hydrocarbons in the hydrogen containing gas of 0.4 wt.%, After which reduced the reactor temperature ^to 100 ° C at a rate ^of 25 C / h. At a reactor temperature of 100 ^{° C} hydrogen was replaced with nitrogen gas. The pressure in the reactor was set to 10 atm.

After complete displacement of hydrogen from the reactor, air was added to the nitrogen supplied to the reactor in an amount providing an oxygen concentration in the gas mixture of 0.02 vol.%. The flow rate of the gas mixture of 600 nm ³ / m ^{3 of} catalyst was established. After aligning the oxygen concentration at the reactor inlet and the reactor outlet temperature of the reactor was reduced to 40 ^{° C} and the catalyst started to discharge.

After unloading, the catalyst was analyzed for its sulfur and carbon content. The data are given in table 1.

The regeneration of the catalyst was carried out at a specialized installation in a rotary indirect heating furnace at a temperature of 450 ^C and a pressure of 0.4 atm. After screening the regenerated catalyst from dust and chips formed during operation and regeneration, 38.8 tons of catalyst were obtained, i.e. losses amounted to 3%.

Physico-chemical and operational characteristics of the regenerated catalyst are given in table.4.

A comparison of the characteristics of the fresh, passivated and regenerated catalyst RK-231Co shows that practically no changes in the chemical composition of the catalyst took place, the activity and strength of the catalyst decreased slightly. Loss of catalyst due to destruction is minimal. Hydrocarbon compaction products are almost completely removed.

The implementation of the proposed method for the regeneration of catalytic systems of hydrogenation processes according to examples 3-6 was carried out in a sequence similar to examples 1-2. Information about the catalysts used in the execution of examples 3-6, technological parameters and the results obtained are given in table 1-4.

It is seen that during the regeneration in accordance with the formula of the invention (examples 1-4), the physicochemical and operational characteristics of the catalysts change slightly. Loss of catalysts in the form of crumbs and dust is minimal.

Conducting regeneration with a deviation of technological parameters from those specified in the formula of the invention (examples 5 and 6) leads to a significant decrease in the activity of the catalyst, the deterioration of its strength properties and large losses.

Regeneration in accordance with the technical solution set forth in the prototype (example 8) is carried out in the reactor of the technological installation. There are no stages of hydrocarbon desorption and passivation of the catalyst surface. As a result, the regenerated catalyst has much lower catalytic activity and strength than fresh catalyst. Catalyst losses during overloading in the form of dust and crumbs are significant. Hydrocarbon compaction products are not completely removed (high carbon content).

From the above data it is seen that the implementation of the proposed method for the regeneration of catalysts and catalytic systems of hydrogenation processes proceeds with minimal loss of their activity and strength.

Table 1.
Information about the catalysts used to illustrate the proposed method for the regeneration of catalytic systems of hydrogenation processes. Example Catalyst grade Recyclable raw materials Interregeneration cycle, month Sulfur Conversion,% Fresh catalyst Passivated catalyst Content, wt.% Strength, Content, wt.% MoO ₃ Soo Nio MPa FROM S Example 1 RK-442Ni vac. gas oil 36 80.0 15.5 - 4,5 0.98 15,5 8.5 Example 2 RK-231Co mixed raw materials 12 95.5 14.8 4.6 - 0.90 18.6 8.4 Example 3 RK-222 + GO-70 * middle distillation fr. 48 96.2 14.5 / 14.2 - / 4,2 4.3 / - 0.96 / 0.88 12.3 / 10.8 8.6 / 8.7 Example 4 RK-231Ni gasoline 24 99.8 15.0 - 4.2 0.86 4,5 9.0 Example 5 TNK-2000 diz. French 24 96.0 15.0 4.3 - 0.78 12.6 8.9 Example 6 GO-70 petrol 60 99.6 14.3 4.0 - 0.80 8.6 8.4 Example 7 (prototype) RK-231Co mixed raw materials 12 95.5 14.5 4.4 - 0.91 17.8 8.6 * RK-222 indicators are given in the numerator, GO-70 in the denominator

Table 2.
The conditions for the stage of desorption of hydrocarbons from the surface of the catalyst. Example The concentration of N ₂ in the WASH, vol.% T-ra of the beginning of the stage, ^about The rate of temperature rise to a maximum, ^o C / hour Maximum temperature, ^о С Conc. hydrocarbon gases in the WASH at the end of the stage, wt.% The rate of decline t-ry, ^about C / hour T-ra end of the stage, ^about With Example 1 60 220 25 400 0.5 twenty 120 Example 2 80 200 thirty 380 0.4 25 one hundred Example 3 75 210 25 380 0.5 twenty one hundred Example 4 70 200 thirty 380 0.3 25 120 Example 5 fifty 230 twenty 410 0.6 thirty 130 Example 6 90 190 35 370 0.8 fifteen 90 Example 7 (prototype) No stage

Table 3.
The conditions for the stage of passivation of compounds of the active components of the catalyst. Example Temperature, ^о С Pressure, ati Oxygen component The oxygen concentration in the gas mixture, vol.% The flow rate of the gas mixture, nm ³ / m ^{3 of} catalyst Example 1 120 four air 0.50 400 Example 2 one hundred 10 CO ₂ 0.02 600 Example 3 110 6 CO ₂ + air 0.25 500 Example 4 one hundred 5 air 0.30 500 Example 5 130 12 air 0.60 350 Example 6 90 3 air 0.01 650 Example 7 (prototype) No stage

Table 4.
Conditions for the stage of burning products of hydrocarbon compaction and the results of the regeneration process. Example Burn Stage Parameters Characteristics of the regenerated catalyst Temperature, ^о С Pressure, ati Loss, wt.% Content, wt.% Strength, MPa Sulfur Conversion,% MoO ₃ Soo Nio FROM Example 1 550 1,0 3,5 15.4 - 4.5 0.2 0.97 79.5 Example 2 450 0.4 3.0 14.8 4,5 - 0.1 0.90 95.3 Example 3 500 0.8 2,8 14.4 / 14.2 - / 4.1 4.2 / - 0.1 0.95 / 0.88 96.0 Example 4 480 0.7 1,0 15.0 4.1 - 0.2 0.87 99.6 Example 5 500 1,0 9.0 14.6 3.9 - 0.2 0.78 91 Example 6 500 1,0 7.0 13.9 3.6 - 0.3 0.71 89 Example 7 * (prototype) 500 0.5 12.0 13.8 3,5 - 1.4 0.4 85 * regeneration is carried out in the reactor of the technological installation in a mixture of air with nitrogen oxides.

Claims (1)

A method for the regeneration of catalysts for hydrogenation processes by burning carbon-containing compounds in an oxygen-containing gas medium, which includes the stages of desorption of hydrocarbons from the surface of the catalysts carried out in the reactor of a process unit, and burning products of their compaction on a specialized unit in a rotary indirect heating furnace at a temperature of 450-550 ° C and a pressure of 0.4-1.0 ati, characterized in that the desorption of hydrocarbons from the surface of the catalysts is carried out in a hydrogen-containing medium basics with a hydrogen concentration of 60-80 vol.%, with a gradual rise in temperature from 200-220 ° C to 380-400 ° C at a speed of 25-30 ° C / h, followed by exposure of the catalysts at a temperature of 380-400 ° C to achieve the concentration of hydrocarbons in a hydrogen-containing gas is not more than 0.5 wt.% and a decrease in temperature to 100-120 ° C at a rate of 20-25 ° C / h, followed by passivation of the compounds of the active components of the catalysts by processing at a temperature of 100-120 ° C and pressure 4-10 atm with a mixture of inert gas with an oxygen-containing component, which is used as dioxide leroda and / or air is taken in an amount providing oxygen concentration in the gas mixture 0,02-0,50% vol., at a rate of 400-600 Nm ³ / m ³ catalyst to equalization of the oxygen concentration at the inlet and outlet of the reactor.