RU2638159C1 - Method for oxidizing regeneration of oil feedstock hydrofining catalysts - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method of regeneration of used catalysts includes stages for unloading from the reactor, screening, performing oxidative regeneration, additional separation from dust and filling the catalyst. Oxidative regeneration is carried out in cascade furnaces in flue gas medium in two stages. At the first stage the granules are subjected to heat treatment in flue gas medium in a vertical cascade shaft furnace with gradual temperature rise at the outlet to 350°C, flue gas composition is nitrogen, carbon dioxide and water vapours, the total content of which is 98-99%. Then, heat treatment of catalyst granules is performed in a rotating tubular furnace with internal cascade partitions, where dosed atmospheric air is supplied to flue gas, the oxygen content based on the total amount of flue gas can reach up to 5 vol. %.

EFFECT: invention makes it possible to carry out oxidative regeneration of crude oil hydrofining catalysts with maximal activity recovery without further treatment and considerably simplify the regeneration of crude oil hydrofining catalysts and further use thereof depending on requirements of hydrogenation processes.

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Description

The invention relates to a method for carrying out oxidative regeneration of deactivated hydrotreating catalysts for petroleum feedstocks.

With a decrease in crude oil resources and their availability in the world practice, two trends have emerged - an increase in the depth of oil refining and refining of sour crude to meet needs. In this regard, environmental protection requirements have become tougher, namely the reduction of unwanted emissions into the atmospheric basin. Following European countries, Russia began producing low-sulfur fuels for the domestic and foreign sales markets. In Russia, the EURO-3 standard (350 ppm sulfur) began to operate in 2011, EURO-4 - from 2013, and EURO-5 - from 2016. The production of such ultra-low-sulfur fuels is possible only with the use of the latest generation hydrotreating catalysts, which are supported systems — an alumina carrier impregnated with salts of active components. Over time, hydrotreating catalysts during operation lose their activity due to blockage or poisoning of the active components. The decrease in activity in some cases is reversible. And for a number of catalysts, recovery of activity to 95% of the initial activity is possible. The activity of the equilibrium catalyst is always lower than the activity of fresh catalyst, therefore, the restoration of the activity of the spent catalyst to the level of its equilibrium state will extend the life of the catalyst. Since hydrotreating catalysts are expensive, replacing the spent catalyst with a fresh one is not economically feasible. There are two possible solutions to the use of deactivated catalysts. The first option includes regeneration and their further use, but already for less critical hydrogenation processes. The second option involves the regeneration of the catalysts with further reactivation so that they can be reused in the hydrotreating of crude oil, without loss of quality of the resulting product. In any of these cases, it is necessary to carry out oxidative regeneration of the hydrotreating catalyst. Oxidative regeneration of hydrotreating catalysts makes it possible to restore their activity by approximately 85-95%. Carrying out oxidative regeneration under optimal conditions will allow to restore the initial activity as much as possible and reduce the total costs to achieve full activity in comparison with a fresh catalyst. In addition, currently in Russia there are no industrially developed technologies for the complete regeneration of modern supported hydrotreating catalysts.

A known method of regenerating a hydrotreating catalyst [SU 738660] by grinding spent catalyst into fine powder, treating with a solution of nitric acid powder and molding granules. After the stages of drying, drying and calcination, impregnation of additional amounts of active components to achieve activity. The disadvantage of this method is multi-stage, energy-intensive technology, the presence of stages of grinding of granules and re-molding.

The known method [RU 2299095], when the spent catalyst is subjected to heat treatment at a temperature of 550-600 ° C in an atmosphere of air, mechanical activation in a vibratory mill, grinding into powder, further mixing with future components of the catalyst during processing with a solution of nitric acid, then molding, drying and calcining . The disadvantage of this method is the multi-stage, energy-intensive technology, the presence of stages of grinding of granules and re-molding.

Of practical interest is the oxidative regeneration of spent catalyst with the maximum recovery of the initial activity and the absence of a stage of grinding of the catalyst. Therefore, this method is taken as a prototype.

A known method of regeneration of a hydrotreating catalyst [RU 2316579, US 3235511, US 4202865], when the coked catalyst is subjected to regeneration in a stream of oxygen-containing gas directly in the hydrotreating reactors. The disadvantages of the proposed method are the need for a long shutdown of the reactor during regeneration, a low degree of recovery of catalyst activity, the presence of additional stages of unloading from the reactor and screening of the catalyst from dust after regeneration.

The aim of the invention is to develop a method for carrying out oxidative regeneration of a spent catalyst for hydrotreating petroleum feedstocks with a maximum recovery of the initial activity, which would have fewer process steps and would allow to maintain high catalyst activity.

The goal is achieved as follows. The spent catalyst for hydrotreating petroleum feedstock after discharge from the reactor and screening is subjected to oxidative regeneration in cascade furnaces in a flue gas environment. At the first stage, the granules are subjected to heat treatment in a flue gas environment in a vertical cascade shaft furnace with a gradual increase in temperature to 350 ° C at the outlet of the furnace. The composition of the flue gases is: nitrogen, carbon dioxide and water vapor, the total content of which is 98-99%. After that, the catalyst enters a rotary tube furnace with internal cascade partitions, where atmospheric air is dosed into the flue gas. The oxygen content in terms of the total amount of flue gases can reach up to 5 vol.%. After the rotary tube furnace, the catalyst is additionally screened out from the dust and packaged in metal barrels.

Thus, a significant difference of the proposed method is the implementation of oxidative regeneration outside the reactor with heat treatment in cascade furnaces, first in the environment of flue gases, and then with the supply of atmospheric air to the composition of flue gases for burning coke.

The industrial applicability of the proposed method of oxidative regeneration of catalysts for hydrotreating petroleum feedstocks is confirmed by the following examples.

Raw Material:

1. Spent catalyst A (catalyst RK 242 M, used in the processes of hydrofining of fractions of secondary origin, residual fractions, solid paraffins).

2. Spent catalyst B (catalyst RK 720 M, used in the hydrofining of medium distillate fractions in order to obtain components of jet and diesel fuels with improved low-temperature characteristics).

Equipment:

1. Vibrosieve two-shelf.

2. Vertical cascade shaft furnace.

3. Rotary tube furnace.

In the above examples, the spent catalyst for hydrotreating petroleum feed is pre-sown through a two-shelf vibrating screen to separate dust, broken and fused granules.

Example 1

A portion of spent catalyst A is subjected to heat treatment in a rotary tube furnace with internal cascade baffles in a flue gas environment with a gradual rise in flue gas temperature to 350 ° C for 1.5-2 hours and dosed air supply. The oxygen content in terms of the total amount of flue gases can reach up to 5 vol.%.

Example 2

The process is carried out analogously to example 1, but with a gradual increase in the temperature of flue gases to 550 ° C.

Example 3

A portion of spent catalyst A is subjected to heat treatment in a vertical cascade shaft furnace with flue gases with a gradual rise in temperature to 350 ° C at the furnace outlet for 1-1.5 hours, then in a rotary tube furnace with internal cascade baffles in a flue gas environment with a gradual rise flue gas temperatures up to 350 ° C for 1.5-2 hours and dosed supply of atmospheric air. The oxygen content in terms of the total amount of flue gases can reach up to 5 vol.%.

Example 4

The process is carried out analogously to example 3, but with a gradual rise in flue gas temperature to 550 ° C in a rotary tube furnace.

Example 5

The process is carried out analogously to example 1, but as used catalyst take B.

Example 6

The process is carried out analogously to example 2, but B. is taken as a spent catalyst.

Example 7

The process is carried out analogously to example 3, but B. is taken as a spent catalyst.

Example 8

The process is carried out analogously to example 4, but B. is taken as a spent catalyst.

The obtained samples were then determined by the mechanical strength of the granules and catalytic activity. The results of the determinations are shown in table No. 1.

Analysis of the materials presented allows us to conclude that the proposed technical solution makes it possible to carry out oxidative regeneration of hydrotreating catalysts for crude oil with maximum recovery of activity without additional treatments.

The proposed method will significantly simplify the regeneration of hydrotreating catalysts for petroleum feedstocks and ensure their further use depending on the requirements of hydrogenation processes.

Claims (1)

A method of regenerating spent catalysts for hydrotreating petroleum feedstock, including the stages of unloading from the reactor, sieving, conducting oxidative regeneration, additional screening from dust and filling of the catalyst, characterized in that the oxidative regeneration is carried out in cascade furnaces in a flue gas environment in two stages, where the first the granules are subjected to heat treatment in a flue gas environment in a vertical cascade shaft furnace with a gradual rise in temperature to 350 ° C at the outlet, the composition of the flue gases is flax: nitrogen, carbon dioxide and water vapor, the total content of which is 98-99%, then heat treatment of the catalyst granules - in a rotary tube furnace with internal cascade partitions, where atmospheric air is dosed into the flue gas, the oxygen content in terms of the total amount of flue gases can reach up to 5 vol.%.