JPS59196742A - Regeneration of selectively hydrocracking catalyst - Google Patents

Abstract

PURPOSE:To efficiently regenerate a catalyst having activity deteriorated, by decontaminating said catalyst using liquid saturated or unsaturated hydrocarbon which does not contain sulfur. CONSTITUTION:In regenerating a palladium-based catalyst for selectively hydro- cracking an acetylenic compound in olefin, said catalyst is decontaminated under a temp. condition of 0-80 deg.C with 1-30kg/cm<2>G using liquid hydrocarbon, e.g. saturated or unsaturated aliphatic hydrocarbon, liquefied petroleum gas, a 3-4C fraction or liquefied butane, which does not contain a sulfuric compound. Hence, the efficiency of removing acetylene with the catalyst having activity deteriorated and a loss of butadiene can both be regenerated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the use of a distillate containing mainly olefin hydrocarbons having 3 to 4 carbon atoms (hereinafter referred to as C
It is called the 3-4 fraction. ) is a method for selectively hydrogenating an acetylene compound under pressurized liquid phase conditions. The present invention relates to a method characterized by washing and regenerating using saturated or unsaturated hydrocarbons.

The 03-4 fraction obtained by cracking petroleum products mainly consists of propylene, ]-1,3-butadiene isobutene, n-butene (butene-1, butene-2), propane, and butanes, and contains impurities. Contains small amounts of acetylene compounds such as acetylene, methylacetylene, ethylacetylene, and vinylacetylene, and
In some cases, allene (propadiene) as an impurity,
It may also contain diene compounds such as methyl allene.

When separating these 03-4 fractions and using them as raw materials for rubber, plastic, and other chemical industries, the acetylene compounds contained as impurities pose various obstacles.
It must be removed by appropriate treatment in advance so that the concentration is below a certain level.

Conventionally, as a method for removing acetylene compounds in the 03-4 fraction range, acetylene compounds are removed by suppressing hydrogenation of olefins and diolefins, which are the main components, as much as possible under gas phase or liquid phase conditions in the presence of a catalyst. A selective hydrogenation method is being used.

However, in the conventionally known methods, it is very difficult to selectively and sufficiently hydrogenate only the acetylene compounds while suppressing the hydrogenation of the olefins and diolefins, which are the main components, as much as possible. Especially in the case of C4 fractions, there is generally little difference in reactivity between 1,3-butadiene and impurity acetylene compounds, and the concentration of acetylene compounds to be hydrogenated is extremely low compared to the concentration of butadiene. For this reason, hydrogenation of butadiene should be carried out as much as possible.
It is very difficult to selectively and sufficiently hydrogenate only the acetylene compound while suppressing the hydrogenation. For example, in the gas phase method, the reaction is usually carried out at a concentration of about 150 to 200°C.
In such a high temperature reaction, hydrogenation and polymerization of butadiene are severe, and a considerable amount of butadiene is inevitably lost, and the catalyst is also significantly deteriorated due to adhesion of polymeric substances. On the other hand, in the liquid phase method, the reaction is usually carried out at a relatively low concentration of 100°C or less, so there are fewer drawbacks such as catalyst deterioration compared to the gas phase method, but on the other hand, hydrogenation of the acetylene compound is completely eliminated. It is also unavoidable that a considerably large amount of hydrogen must be used for the hydrogenation of butadiene, resulting in a large number of :1i1j reactions in the hydrogenation of butadiene.

Even in the liquid phase method, depending on the properties of the C3-4 fraction, if the catalyst is used for a long period of time, catalyst poisoning components such as polymers and water will gradually accumulate with Ai, reducing the catalyst activity and causing loss of bucdiene. may increase. Various methods are known for regenerating the pJ of a catalyst whose activity has decreased. For example, known methods include performing firing in air, burning off the polymers accumulated on the catalyst, and then re-reducing and activating the catalyst, or washing and dyeing using an appropriate solvent. However, catalysts that can be regenerated by combustion using air must have heat resistance, and excellent catalysts with high activity and low butadiene loss have low heat resistance and cannot be used in such regeneration methods. In many cases, it cannot be removed, and it is desired to develop a method for recycling it.

In view of the current situation, the present inventors have developed an effective method for producing a radium metal salt or metal oxide solid catalyst, which selectively hydrogenates acetylene compounds in C3-4 fractions. As a result of various studies to develop the catalyst, we have discovered that there is an excellent method for regenerating the catalyst whose activity has decreased by washing it with a liquid saturated or unsaturated hydrocarbon containing substantially no sulfur. I found it.

The main component of the catalyst used in the present invention is palladium, and co-catalysts include other metal salts or metal oxides, such as inorganic acid salts of copper, silver, gold, tin, zinc, cadmium, or lead. Organic acid salts, oxides, etc. can be used. As a carrier,
Although various metal oxides such as alumina, silica, titania, and silica-alumina can be used, alumina is particularly preferred, and among them r -Al2O3, η-Aβ203, θ-A
1203 etc. are suitable. As for the catalyst composition, the ratio of palladium to support is 0.05 to 5% by weight, preferably 0.
The ratio of co-catalyst component to palladium is 01-101, preferably 05-101 as the metal atomic ratio.
The range is 8.

When selective hydrogenation of acetylene compounds in the C3-4 fraction is carried out using a palladium-metal salt or metal oxide solid catalyst, the catalytic activity ffi is considered to be a combination of palladium-metal salts, and 4 It is estimated that !1 body contributes to increasing the effective surface area.

Even in the case of liquid phase hydrogenation, the reason why the catalyst activity gradually decreases is thought to be that polymers and oligomers smaller than dienes and acetylene attach to the active sites and reduce the effective product.

According to the present invention, by washing a catalyst whose activity has been reduced with a liquid saturated or unsaturated hydrocarbon containing substantially no sulfur compounds, the catalyst has the same performance as a fresh catalyst. Can be regenerated into catalyst.

Liquid hydrocarbons used for catalyst regeneration include saturated and unsaturated aliphatic hydrocarbons, liquefied fossil aJ+gas (LPG), and C
3 to 4 fractions, liquefied butane, etc. are particularly preferred,
C4 fraction, liquefied butane, and n-hegisano can be used.

Liquid hydrocarbons used for catalyst regeneration may contain sulfur compounds, but it is best to use them after desulfurization with an appropriate desulfurization agent. Case B where sulfur compounds become poisonous substances When washing with liquid hydrocarbons that do not desulfurize, the accumulation of sulfur compounds takes precedence over poisoning, so the washing effect is markedly 4c.
There are cases where it is not possible.

Regarding the concentration of sulfur compounds in the liquid hydrocarbons used for rlj raw material, analysis by gas chromatography (detection 8
(ii) using a frame photolytic technique), it is desirable that the detection limit be below the detection limit.

There are no strict restrictions on the regeneration conditions when carrying out the method of the present invention, but the regeneration conditions are generally as follows.

Regarding the washing temperature and 11-power, when using liquid hydrocarbons at room temperature, normal pressure and below the boiling point are preferable, and in the case of liquefied scum etc., 1 to 3 kg, ', 7Q, preferably 13 to
To 20! Under pressure of J/ciG, O~5o0c, c,.

Preferably a temperature range of 5 to 600C is preferred. The washing time can be appropriately selected depending on the degree of catalyst deterioration.

11) When raw dyeing is carried out, it can be carried out in a fixed bed in either a flow type or batch type, or it may be taken out of the system and washed.

・l11ijf of the catalyst produced by the method of the present invention:;
Although there is not necessarily a strict 4f limit to the reaction conditions for carrying out the r·I reaction, the following conditions are generally used.

Reaction) The quality is in the range of 0 to 80'C, preferably 5 to 60°C, and the reaction pressure is in the range of 2 to 30 kg/v*G, preferably 3 to 20 kg/crj, G (1,) range. The molar ratio of σ1'', iI, and the acetylene compound is O]~1
5. The reaction humidity is preferably in the range of 05 to I(), and the reaction humidity is in the range of 2 to 80 hr, preferably 4 to 40 hr. and radial pressure.

The H2 used in the present invention may be pure or may be diluted with an inert residue such as methane.

There is no particular limitation on the content of the 04 acetylene compound in the C3-4 fraction used in the present invention. (Hydrogenation removal is possible even when the total 1f1 concentration of the various acetylene compounds present is in the range of 05 to 3 wt%.

The reaction type is a fixed bed reaction, and either a flow-down type or an overflow type can be adopted to perform a fixed bed reaction in a liquid phase.

Another reaction? Either isothermal or adiabatic types can be used.

The method of the present invention has the unique advantage of being able to regenerate both the acetylene removal rate and butanene loss of a catalyst whose activity has deteriorated.

Hereinafter, the method of the present invention will be explained in more detail by showing typical examples. However, these are just examples;
It goes without saying that Ikukomyo is not limited to these.

Example 1 (1) Raw material hydrocarbon composition Butanes 6.7wt%, Butenes 22-6wt%,
Isobutyne 25-9wt%, 3-butadiene 4
3-8 wt%, l,2-butadiene 0.1 wt%
't Ethyl acetylene 0.2 wt%, vinyl acetylene 0.7 wt%, methyl acetylene, propadiene, C5 hydrocarbon (2) Hydrogenation conditions Temperature ° 20 °C 1 pressure crab 8 kg/iG, H2 molar ratio:
5 (for acetylenes), LH8V: J 5hr-1z
Reaction type/Adiabatic type (3) Catalyst (used for 1500 hours) Pd-
Pb(CH3CO2)2-Ag2O3, Pb/Pd atomic ratio -3, Pd-containing J ratio (:!A'Al2O3) = 0.
35 wt% (4) Catalyst 1 Ojo method In n-hexane, boiling point 'F% 3 hrs) After heating in 4 streams, the extract was separated and the catalyst was heated at 100°C for 13 hrs.
Vacuum dried.

For catalysts with decreased activity, the above regeneration is performed in (a), 0), (
The table shows the results when hydrogenation removal reaction of Cjj° cetylenes was carried out using the C4 fraction and hydrogenation conditions corresponding to 2).

Example 2 A C4 fraction desulfurized under the following conditions was used to wash and dye a catalyst with decreased activity at room temperature and under pressure, and then a hydrogenation reaction was carried out in the same manner as in Example 1. The results are shown in the table.

Desulfurization conditions Desulfurization agent dioxide ++] r lead, desulfurization Miflα
, room temperature, pressure crab 6kL/iG, LH8V + 2
hr-1 Example 3 The catalyst with decreased activity was washed and dyed in exactly the same manner as in Example 2 except that liquefied butane was used instead of the C4 fraction, and then the hydrogenation reaction was carried out in the same manner as in Example 1.

The results are shown in the table.

Comparative Example 1 Example 1 for a catalyst with reduced activity without any regeneration
A hydrogenation reaction was carried out in the same manner. The results are shown in the table.

Table Reaction results

Claims (1)

[Claims] Palladium metal as carrier and copper, gold, silver, tin as promoter,
In a method for regenerating a catalyst for selective hydrogenation of an acetylene compound in an olefin, which supports at least one of an inorganic acid salt, an organic acid salt, or an oxide of zinc, cadcium, or lead, the catalyst whose activity has been reduced is substantially removed. A method characterized by washing and regenerating using a liquid saturated or unsaturated hydrocarbon that does not contain sulfur.