JPH04352731A - Method for manufacturing olefin-containing hydrocarbon mixture - Google Patents

Abstract

PURPOSE: To obtain an olefin-contg. mixture of hydrocarbons in high yield of lower olefins and in a small ratio of ethylene to propylene by bringing a hydrocarbon supply source material into contact with a specified zeolite catalyst under specified conditions.

CONSTITUTION: The hydrocarbon supply source material is brought into contact with a zeolite catalyst under conditions of 5 to 150 weight ratio of catalyst/ supply source material, preferably 10 to 100 weight ratio, at temp. higher than 480°C, preferably 480 to 900°C, especially preferably 500 to 750°C, and under 1 to 10 bar pressure. The catalyst used is a zeolite having 0.3 to 0.7 mm pore diameter, preferably 0.5 to 0.7 mm and <2 μm average crystal size, preferably <1 μm, and more preferably 0.1 to 0.5 μm, and the zeolite preferably consists of a crystalline (metallo)silicate, ferrierite or erionite having a ZSM-5 structure or a mixture of these. The reaction is carried out preferably on a moving bed so as to obtain an olefin-contg. mixture which is rich in lower olefins, especially propylene.

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a process for producing olefin-containing mixtures of hydrocarbons.

0002

BACKGROUND OF THE INVENTION There is considerable interest in the production of olefins, particularly ethylene and propylene. Because,
Unlike lower value paraffins, its reactivity makes it suitable for conversion into other products. It is known to convert hydrocarbon feedstocks, such as light cuts, in particular to products rich in lower olefins, such as ethylene and propylene, by high temperature steam pyrolysis. Typical product slates obtained with this type of steam pyrolysis process are not completely suitable for the requirements of the chemical industry in that they exhibit relatively high methane production levels and high ethylene to propylene ratios. Recently, for example, EP03
No. 47003, EP0392590 and EP038
Alternative processes have been developed to produce lower olefins from a wide range of hydrocarbon feedstocks, as described in the '5538 publications. These processes have been found to provide surprisingly high yields of lower olefins, small amounts of methane, and low ethylene to propylene and C4 olefin ratios compared to conventional steam pyrolysis processes. Ethylene and propylene are valuable starting materials for chemical processes, whereas C4 olefins have applications as starting materials for alkylation and/or oligomerization processes to produce high-octane gasoline and/or middle distillates. has. Isobutene is methyl t-
Up to butyl ether can advantageously be converted. Surprisingly now, the much higher yield of lower olefins and the lower ratio of ethylene to propylene have been shown to improve
It has been found that the use of a zeolite catalyst consisting of a zeolite having a specific zeolite size can be obtained in comparison with the above-mentioned method.

0003

SUMMARY OF THE INVENTION Accordingly, the present invention provides for the production of olefin-containing mixtures of hydrocarbons by contacting a hydrocarbon feedstock with a zeolite catalyst at a temperature greater than 480° C. for a period of less than 10 seconds to reduce the amount of catalyst/feedstock. The weight ratio is in the range of 5 to 150, and the zeolite catalyst is in the range of 0.
The present invention relates to a process for the production of olefin-containing mixtures, characterized in that they are composed of zeolites with a pore size of 3 to 0.7 nm and an average crystallite size of less than 2 μm. Preferably, the zeolite catalyst to be used in the process according to the invention consists of zeolites with an average crystallite size of less than 1 μm. More preferably, the zeolite is 0.01 to
It has an average crystallite size in the range of 0.5 μm. The term crystallite size as used herein is to be considered as the size of individual zeolite crystals. These individual crystals can aggregate into clusters of 3 to 10 or more individual crystals each. Preferably, the zeolite consists of separate individual crystals. The zeolite catalyst to be used is 0.3-0.7 nm, preferably 0.
．． It can be composed of one or more zeolites with a pore size of 5 to 0.7 nm.

The term zeolite as used herein is not to be understood as consisting only of crystalline aluminosilicates. This term refers to crystalline silica (silicalite), silicoaluminophosphate (SAPO), chromosilicate, gallium silicate, iron silicate, aluminum phosphate (AL
PO), titanium aluminosilicate (TASO), boron silicate,
Also included are titanium aluminophosphate (TAPO) and iron aluminosilicate. A suitable example is crystalline silica (silicalite)
, silicoaluminophosphate (SAPO), chromosilicate, gallium silicate, iron silicate, aluminum phosphate (
ALPO), titanium aluminosilicate (TASO), boron silicate, titanium aluminophosphate (TAPO) and iron aluminosilicate. Examples of zeolites are U.S. Pat. No. 4,44
SAPO-4 and SAPO described in No. 0,871
-11, ALPO-11 described in U.S. Patent No. 4,310,440, TAPO-11 described in U.S. Patent No. 4,500,651, U.S. Patent No. 4,254,29
TASO-45 described in No. 7, aluminum silicate,
For example erionite, ferrierite, Θ- and Z
SM-type zeolites, such as ZSM-5, ZSM-1
1, ZSM-12, ZSM-35, ZSM-23 and ZSM-38. Preferably 0.3 to 0.7
The zeolite with a pore size of nm is selected from the group consisting of crystalline (metallo)silicates with the ZSM-5 structure, ferrierite, erionite and mixtures thereof. Preferably, the zeolite with a pore size of 0.3 to 0.7 nm consists of a crystalline (metallo)silicate with a ZSM-5 structure. Suitable examples of crystalline (metallo)silicates having the ZSM-5 structure are e.g.
These are aluminum silicate, gallium, iron, sicandium, rhodium and/or chromium described in Japanese Patent No. 10,559.

After the production of the zeolite to be used in the process of the invention, significant amounts of alkali metal oxides are generally present in the ready-made zeolite. Preferably, the amount of alkali metal is determined by methods known to those skilled in the art (e.g. ion exchange followed by
(optional calcination) to produce zeolite in its hydrogen form. Preferably, the zeolite used in the method of the invention is substantially in its hydrogen form. The catalyst preferably also includes a matrix of refractory oxide, which acts as a binder. Suitable refractory oxides are alumina,
Includes silica, silica-alumina, magnesia, titania, zirconia and mixtures thereof. The matrix can also include natural or synthetic clays. The weight ratio of refractory oxide and zeolite is preferably 10:90 to 9.
The ratio is 9:1, preferably 50:50 to 90:10. The zeolite catalyst can also contain up to 40% by weight of other zeolites with pore sizes greater than 0.7 nm. Suitable examples of zeolites of this type include faujasite-type zeolites, zeolites β, zeolites ω, especially zeolites X and Y. This zeolite catalyst is 0.3
It consists of zeolite with a pore size of ~0.7 nm. Preferably, the zeolite catalyst consists of ZSM-5 and zeolite Y.

[0006] The hydrocarbon feedstock is contacted with the zeolite catalyst for a period of less than 10 seconds. Preferably, the minimum contact time is 0.1 seconds. Very good results are obtained when the hydrocarbon feedstock is contacted with the zeolite catalyst for 0.2 to 6 seconds. This method is carried out at relatively high temperatures. The preferred temperature range is 480-900°C, more preferably 500-750°C. The pressure to be used in the method of the invention can vary within a wide range. Preferably, however, the pressure is such that the resulting mixture of hydrocarbons is substantially in the gas phase at the prevailing temperature or is brought into the gas phase by contact with the catalyst. This is advantageous because it does not require expensive compressors and high pressure vessels, as well as other equipment. A suitable pressure range is 1 to 10 bar. Although reduced pressure is possible, it is not preferred. It is economically advantageous to operate at atmospheric pressure. Other gaseous substances such as water vapor and/or nitrogen may also be present during the conversion of the hydrocarbon feedstock. Olefin production is facilitated in the absence of hydrogen or hydrogen donors. The invention is therefore advantageously carried out without the addition of hydrogen. Of course, small molecules such as eg hydrogen molecules can also be produced during the reaction. However, this amount is generally negligible and less than 0.5% by weight of the product.

The process according to the invention can be carried out in a fixed bed. However, this means that very high space velocities are required to achieve short contact times. Therefore, the invention is preferably carried out on a moving bed. The bed of catalyst can move upwardly or downwardly. If the bed moves upwards, a process similar to fluid catalytic pyrolysis is obtained. In the process of the invention some coke forms on the catalyst. It is therefore advantageous to regenerate the catalyst. Preferably, the catalyst is regenerated by treatment with an oxidizing gas, such as air. Continuous regeneration similar to that carried out in fluid catalytic pyrolysis is particularly suitable. Coke formation does not occur at very high rates. Accordingly, methods can be provided in which the residence time of the catalyst particles in the reaction zone (eg, moving bed) is longer than the residence time of the feedstock in the reaction zone. Of course,
The contact time between feedstock and catalyst should be less than 10 seconds. Contact time generally corresponds to the residence time of the feedstock. Preferably, the residence time of the catalyst is 1 to 20 times the residence time of the feedstock.

The weight ratio of the catalyst used to the hydrocarbon feedstock to be converted (catalyst/oil ratio, g/g) varies over a wide range;
That is, it can vary from 5 to 150 kg of catalyst per kg of hydrocarbon feedstock. Preferably, the weight ratio of catalyst to hydrocarbon feed is from 10 to 100, more preferably from 20 to 100. In addition to a substantial increase in lower olefin production, it has been found that much less coke is produced using small crystal zeolites than when using large crystal zeolites at (relatively) high catalyst/feed weight ratios. Attractively high conversions to olefins and low coke formation are made possible by the combination of particularly high temperatures and short contact times with the use of specific small crystal catalysts and (relatively) high catalyst/feedstock weight ratios. It's a combination. The hydrocarbon feedstock to be contacted with the zeolite catalyst in the process of the invention can vary within a wide boiling point range. Examples of suitable feedstocks are relatively light petroleum fractions, such as feedstocks consisting of C3-4 hydrocarbons (eg LPG), naphtha, gasoline fractions and kerosene fractions. Heavy feedstocks include, for example, vacuum cuts, long residues, deasphalted residues, and atmospheric cuts, such as gas oil and vacuum gas oil. Other attractive feedstocks consist of mixtures of hydrocarbons obtained by Fischer-Tropsch hydrocarbon synthesis.

[0009]

[Examples] The present invention will be further explained below with reference to Examples. Experiment 1 The hydrocarbon feedstock in this experiment was a hydrowax with the following properties: IBP, °C 29820 wt% 38850 wt%
43390% by weight
495FBP
552 density 70/4
0.8057kg/1 nitrogen
The 1.0 ppmw feedstock was contacted in a downflow reactor by moving cocurrently downward with the flow of catalyst particles. The catalyst was ZSM-5 in a silica-alumina matrix (weight ratio ZSM-
5/silica-alumina, 25:75). ZS
M-5 had an average crystallite size of 0.1 μm. The experiment was carried out at a pressure of 2 bar. Other process conditions and results obtained are shown in Table 1 below. Experiment 2 was carried out for comparative purposes substantially similar to Experiment 1, except that in this case ZSM-
5 was used. The results obtained are shown in Table 1 below.

0010

Table 1 Experiments 3 and 4 were conducted substantially the same as Experiments 1 and 2, respectively. The results obtained are shown in Table 2 below.

[0011]

Table 2 As is clear from the above, the results obtained in the experiments according to the invention are more attractive in terms of lower olefin yield and coke formation than those obtained in the comparative experiments.

Claims (13)

[Claims] 1. In producing an olefin-containing mixture of hydrocarbons, a hydrocarbon feedstock is contacted with a zeolite catalyst at a temperature above 480° C. for a period of less than 10 seconds, and the catalyst/feedstock weight ratio is between 5 and 10 seconds. 150 and the zeolite catalyst is comprised of a zeolite having a pore size of 0.3 to 0.7 nm and an average crystallite size of less than 2 μm. 2. The method of claim 1, wherein the zeolite has an average crystallite size of less than 1 μm. 3. A method according to claim 2, wherein the zeolite has an average crystallite size in the range 0.01 to 0.5 μm. 4. A method according to claim 1, wherein the zeolite has a pore size of 0.5 to 0.7 nm. 5. A process according to claim 1, wherein the zeolite is selected from crystalline (metallo)silicates having the ZSM-5 structure, ferrierite, erionite and mixtures thereof. 6. A method according to claim 1, wherein the zeolite is essentially in hydrogen form. 7. A process according to claim 1, wherein the feedstock is contacted with the zeolite catalyst for 0.2 to 6 seconds. 8. The method according to claim 1, wherein the temperature is 480 to 900°C. 9. The method according to claim 8, wherein the temperature is 500 to 750°C. 10. A method according to claim 1, wherein the pressure is between 1 and 10 bar. 11. The catalyst/feedstock weight ratio is 10 to 1.
11. The method according to any one of claims 1 to 10, wherein: 00. Claim 12: Claims 1 to 1 wherein the process is carried out using a moving bed of catalyst.
1. The method according to any one of 1. 13. A hydrocarbon product or a fraction thereof obtainable by the process according to any one of claims 1 to 12.