SU1600832A1 - Method of recovery of catalyst for dehydration of alkenes c4 - Google Patents

Abstract

The invention relates to catalytic chemistry, in particular, a method for regenerating a catalyst for dehydrating C ₄ alkenes. The goal is to increase the selectivity of the catalyst and increase the interregeneration period. The process is carried out by blowing the catalyst with an air-steam mixture (for burning coke), followed by additional treatment with an air-steam mixture containing a reducing agent in a concentration below the lower explosive limit. The reducing agent is selected from the group of: hydrogen, methane, carbon monoxide, abgas. The regenerated catalyst, for example, reduced by methane, has a selectivity after 3 hours of operation of 92.5-93.2% and can be used to dehydrogenate for 7 hours against respectively 88.5% and 5.5 hours for the catalyst regenerated in a known manner. 1 tab.

Description

The invention relates to the field of and catalytic processing of hydrocarbons, in particular, to methods for the regeneration of a catalyst for the dehydrogenation of C4 alkenes.

The aim of the invention is to increase the selectivity of the catalyst and increase the interregeneration period.

Example 1. A spent chromium-iron-zinc catalyst with a volume of 10 ml after a dehydrogenation cycle of 5.5 hours under the conditions:

Feed rate

raw materials, l / h8

Volumetric feed rate, 800 Dehydrogenation temperature, C 580

The degree of dilution with steam,

mol / mol1: 10

The amount of evaporated water, g / h 64 and the composition of the raw material, May. %: butene-1 28.3; cis-butene-2 30, O + H-butane 8.8, has the following indicators,%: conversion 11.4} elector whining 1e 95.0 J output of divinyl 10.8,

The catalyst is regenerated under the following conditions.

O5

00 iOO

The supply of hydrocarbons is stopped and the reactor is blown with steam for 5 minutes, during which time the temperature of the catalyst decreases to. After purging, air is added to the steam in the amount of 8 l / h (volumetric flow rate of 800) By burning up the coke on the catalyst surface, it is heated to 650 ° C. To prevent further decomposition of the catalyst, air flow is controlled and maintain the desired temperature. After 30 minutes after the start of regeneration, the reducing agent — hydrogen — is added to the air to a concentration of 0.7% in air (which is 0.2 of the lower limit of hydrogen explosiveness in air) and the regeneration is continued for another 30 minutes. After 1 hour from the start of the regeneration, the air mixture is stopped, the reactor is blown with steam for 5 minutes, simultaneously reducing the catalyst temperature to 580 ° C, and the dehydrogenation cycle begins. The catalyst thus regenerated is characterized by the following indicators (Table 1),

Table 1

Example 2. The spent catalyst with the activity specified in example 1 is subjected to regeneration in

specified conditions. The concentration of the reducing agent — hydrogen — is 0.7% by volume, which is 0.2 of the lower explosive limit of hydrogen in air. And 30 minutes

The catalyst is regenerated with a vapor-air mixture, and in the next 30 minutes a hydrogen reducing agent is added to it. The generated catalyst is characterized by the following indicators (Table 2).

table 2

Time, h Converts,% Selectivity

Increasing the yield of divinyl over a certain period during regeneration in the presence of a reducing agent allows an increase in the duration of the dehydrogenation cycle.

Example A. A spent catalyst with the activity indicated in Example 1 is subjected to the regeneration described in Example 1. Concentration

Example 3. The spent catalyst with specified in example 1, the activity is subjected to regeneration, described in example 1. (trigenated catalyst is characterized by the following indicators (Table 3).

Table 3

: .l

Output, %

five

the reducing agent carbon monoxide is 2.5 vol.% (0.2 of the lower explosive limit of carbon monoxide in the air). Moreover, the catalyst is regenerated by the vapor-air mixture for 30 minutes, and in the next 30 minutes a reducing agent, carbon monoxide, is added to it. The regenerated catalyst is characterized by the following indicators (Table K),

Table 4

.. Example 5. The spent catalyst with the activity indicated in Example 1 is subjected to the regeneration described in Example 1. The concentration of the reducing agent — carbon monoxide — is 11.0 dB (0.9 from the lower explosive limit of carbon monoxide in the air). Moreover, the catalyst is regenerated by the vapor-air mixture for 30 minutes, and in the next 30 minutes a reducing agent, carbon monoxide, is added to it. The regenerated catalyst is characterized by the following indicators (Table 5).

Examples 8 and 9. The catalyst regenerated by the proposed method with activity as in examples 5 and 7 (respectively, examples o and 9), and the catalyst regenerated. Table 5

Examples 6 and 7. The spent catalyst with the activity specified in Example 1 is subjected to regeneration as described in Example 1. Methane is used as a reducing agent. The concentration of the reducing agent is 1% (0.2 of the lower explosive limit, methane in air, example 6) and k, 5% (0.9 of the lower explosive limit of methane in air, example 7). The catalyst is characterized by-. following indicators (Table 6).

Table 6

in a known manner (incomplete burning of coke), is subjected to a dehydrogenation cycle 45. Change of parameters is given in table. 7

Table. 7

Conversion, by example

 Selectivity,%, pi examples

eight

Famous

, 0 O .5, 0

,50

.0, 0

26.4 16.6 13.5 13.0 11.4 Regeneration

28.9 28.4 26.5 27.6

21.220,8

19.318.8 16.9 16.7 14.7 14.6

12.5 12.3 Regeneration

88.5 94.5 94.2

94.7 95.0 Regeneration

92.5 94.0 95.3 95.5 95.6 95.8

93.2 94.8 95.8 96.0 96.0 95.8

96.0 96.0 Regeneration

Example 10 and 11. The spent catalyst with the activity indicated in Example 1 is regenerated under the conditions described in Example 1. The regeneration temperature

Indicators Through 0.33 h on average for 3 h on

examples of examples

10 I 11 -10 I 11

Conversion,% 23.8 22.6 2b, 2 25, Selectivity, 78.0 68.2 85.3 72, t Output of divinyl,% 18.6 15, 22.3 B, k

Example 12. Regeneration with air mixture with reducing agent EZod t under the conditions of example 1, total 30 minutes.

1Erem-regeneration for 1 hour, of which steam- As a reducing agent, using an air mixture - 30 minutes, methane evaporates (Table 9) Table 9

Time h Methane concentration in the air 3.3 OBD

Conversion,% Selectivity,% Output,%

26.5 27.0 27.6

Continued tabl, 7

Output,%, by examples

eight

Famous

22.3 15.7 12.7 12.2 10.8 Regeneration

26.7 25.0 20.2 18, it 16.2 1.1

26.5 26.0 19.8 18.0 16.0 1A.O

12.0 11.8 Regeneration

 (example 10) and (example 11). The regenerated catalyst is characterized by the following indicators (Table 8).

Table8

88.5 90.4

23.4 25.0

Continuation of table 9,

g g w ---- “. - - - ----- -

Time, the concentration of methane in the air 3.3 vol.%

Conversion,% Selectivity,% Output,%

1,528.2 91 725.9

2,027,192.9 25.2

2,527,09,025,

3,025,295,52,1

Average for

3 hour

cycle 26,090,323,5

 I

As a reducing agent (common table, OBD: Hj Bl, 3; COj 10,

10) use abgas (secondary pro z. 4 3, C production of divinyl) next-C 1.3.

Table 10

Time, h The concentration of exhaust gas in the air 4.00 vol.%

Conversion,% Selectivity,% 1 Output,%

26.9

27.6

28.7

29.7

26.7

24.15

20.6

Claims (1)

The use of the proposed catalyst regeneration method in comparison with the existing ones provides greater selectivity for useful products, especially in the initial period of catalyst operation, a greater yield of useful products, a longer period between regenerations. Invention Formula A catalyst regeneration method for the dehydrogenation of C alkenes, including 23.5. 25.7 27.07 28.0 25.8 22,8 20.1 Coke burning by blowing the catalyst with a vapor-air mixture, characterized in that, in order to increase the selectivity of the catalyst and increase the inter-regeneration period, the catalyst is further treated with an air-vapor mixture containing a reducing agent. selected from the group comprising hydrogen, methane, carbon monoxide, abgas, in a concentration below the lower explosive limit.