NL7811736A - PROCESS FOR PREPARING HYDROCARBONS. - Google Patents

Description

+ 4

K 5468 NET

Applicant: Shell Internationale Research Maatschappij B.V.

Carel van Bylandtlaan 30, The Hague

Short designation: Process for the preparation of hydrocarbons

The invention relates to a process for the preparation of an aromatic hydrocarbon mixture from a mixture of carbon monoxide and hydrogen using a mixture of two catalysts, one of which has the ability to convert an H 2 / CO mixture into acyclic oxygen-containing hydrocarbons and the other is a crystalline silicate which has the ability to catalyze the conversion of acyclic oxygen-containing hydrocarbons to aromatic hydrocarbons. Said crystalline silicates are characterized in that after calcining in air at 500 ° C for 1 hour, they have the following properties a) thermally stable up to a temperature above 600 ° C, b) an X-ray powder diffraction pattern which includes, inter alia, the reflections listed in Table A,

Table A

Radiation: Cu-K α_Wavelength 0.15418 nm 2 Θ relative intensity

7.8-8.2 S

8.7-9.1 M

11.8- 12.1 Z

12.4- 12.7 Z

14.6-14.9 Z

15.4- 15.7 Z

15.8-16.1 Z

17.6- 17.9 Z

78 1 1 7 3 6 * -2- ♦

19.2-19.5 Z

20.2-20.6 Z

20.7-21.1 Z

23.1-23.4 ZS

23.8-24.1 ZS

24.2- 24.8 S

29.7-30.1 M

in which the letters used have the following meaning: ZS = very strong; S = strong; M = moderate: Z = weak; Θ = the angle according to Bragg.

c) after evacuation at 2x10 ^ bar and 400 ° G for 16 hours -2 and measured at a hydrocarbon pressure of 8x10 bar and 100 ° C, the adsorption of n-hexane is at least 0.8 mmol / g, the adsorption of 2 , 2-dimethylbutane at least 0.5 mmol / g and the ratio adsorption of n-hexane ^ _, - j - = - = - -, · - - at least 1.5 adsorption of 2,2-dimethylbutane 2o d) the composition, expressed in moles of the oxides, is the following y (1.0 + 0.3). M20. y. Al ^. SiO2 where M = H and alkali metal and 0 <y <0.1 In a study by the Applicant on the above-mentioned process, it was found that the catalyst mixtures show a higher selectivity as the value of y in the formula representing the composition of the silicate , is lower. It has been determined that in order to achieve a selectivity which is acceptable for commercial application of the process, y should be at most 0.005. This finding is the subject of Dutch patent application No. In further investigation by the Applicant concerning the above method, it has now been found that an acceptable C selectivity can also be achieved with catalyst mixtures containing a silicate of which y is greater than 0.005, provided that the silicate contains one or more elements selected from the group consisting of manganese, calcium, magnesium. and titanium.

78 1 1 7 3 6 * -3-

The invention therefore relates to a process for the preparation of an aromatic hydrocarbon mixture in which a mixture of carbon monoxide and hydrogen is contacted with a mixture of two catalysts, one of which has the ability to convert an E 2 fCO mixture. to catalyze in acyclic oxygen-containing hydrocarbons and the other is a crystalline silicate as defined above, wherein the value of y in the formula representing the composition of the silicate is greater than 0.005 and where the silicate contains one or more elements selected from the group formed by manganese, calcium, magnesium and titanium.

The process according to the invention is based on an E 2 / CO mixture. Such a mixture can very suitably be prepared by steam gasification of a carbonaceous material. Examples of such materials are brown coal, anthracite, coke, crude oil and fractions thereof, as well as oils obtained from tar sand and bituminous slate. The steam gasification is preferably carried out at a temperature between 900 and 1500 ° C and a pressure between 10 and 50 bar. The process according to the invention preferably starts from an E 2 / CO mixture whose molar ratio is between 0.25 and 1.0.

The process according to the invention is preferably carried out at a temperature of 200-500 ° C and in particular of 300-450 ° C, a pressure of 1-150 bar and in particular of 5-100 bar and a spatial throughput of 50-5000 and in particular of 300-3000 NI gas / 1 catalyst / hour.

2q In the method according to the invention a

mixture of two catalysts which will be conveniently referred to as catalysts X and Y. Catalyst X is the catalyst which has the ability to catalyze the conversion of an H 2 / CO mixture into acyclic oxygen-containing hydrocarbons and Catalyst Y

is the crystalline silicate. Preferred catalysts are catalysts X which are able to convert an i / CO mixture into mainly methanol and / or dimethyl ether. Very suitable for the present purpose are catalysts containing zinc together with chromium. * When using such a catalyst, a catalyst is preferably chosen in which the atomic percentage of zinc, based on the sum of zinc and chromium, is at least 60% and in particular 60-80%.

The catalyst mixture used in the method of the invention can be a macro mixture or a micro mixture. In the first case, the catalyst mixture consists of two kinds of macroparticles, one of which consists entirely of catalyst X and the other completely of catalyst Y. In the second case, the catalyst mixture consists of one kind of macroparticles, each macroparticle consisting of a large number of microparticles. of each of the catalysts X and Y. Catalyst mixtures in the form of micro-mixtures can be prepared, for example, by intimately mixing a fine powder of catalyst X with a fine powder of catalyst Y and shaping the mixture into larger particles, for example by extrusion. or pressing. The process according to the invention preferably uses catalyst mixtures in the form of micro-mixtures. In view of the activity of the catalyst mixtures, mixtures are preferably used which contain, per volume part of catalyst Y, 1-5 volume parts of catalyst X.

The crystalline silicate present as catalyst Y in the catalyst mixtures is defined inter alia by the powder X-ray diffraction pattern that the silicate shows after 1 hour of calcination in air at 500 ° C. This X-ray powder diffraction pattern should include the reflections listed in Table A1. The full X-ray powder diffraction pattern of a typical example of a silicate suitable for use according to the invention is shown in Table B

78 1 1 7 3 6 ► '-5- (Radiation: Cu-Κα; wavelength: 0.15418 nm).

Table B

2 β relative intensity description (100. I / Io)

8.00 55 SP

8.90 36 SP

9.10 20 SR

11.95 7 NL

12.55 3 NL

13.25 4 NL

13.95 10 NL

14.75 9 BD

15.55 7 BD

5.95 9 BD

17.75 5 BD

19.35 6 NL

20.40 9 NL

20.90 10 NL

21.80 4 NL

22.25 8 NL

23.25 1001 SP

23.95 45 SP

24.40 27 SP

25.90 11 BD

26.70 9 BD

27.50 4 NL

29.30 7 NL

29.90 11 BD

31.25 2 NL

32.75 4 NL

34.40 4 NL

36.05 5 BD

37.50 4 BD

45.30 9 BD

73 1 1 7 3 6 I = intensity of the magnitude of separate reflection that occurs in the pattern.

-6-

The letters used in table B to describe the reflections have the following meanings: SP = sharp; SR = shoulder; NL = normal; BD = wide: Θ is the angle according to Bragg.

The crystalline silicates used in the catalyst mixtures can be prepared starting from an aqueous mixture containing the following compounds: one or more compounds of an alkali metal (M), one or more compounds containing an organic Ration (R) or from which such cation is formed during the preparation of the silicate, one or more silicon compounds and one or more aluminum compounds. The preparation takes place by keeping the mixture at an elevated temperature until the silicate is formed and then separating the crystals of the silicate from the mother liquor. In the aqueous mixture from which the silicates are prepared, the various compounds must be present in the following molar ratio, expressed in moles of oxides: M20: (R) 2 / n0 = 0.1-20, (R) „0 Si0o = 0.01-0.5, and

SiO 2: Al 2 O 2 <200; n is the valence of R.

The silicates are preferably prepared from a base mixture in which M is present in a sodium compound and S in a tetrapropylammonium compound.

In view of the stability of the catalyst mixtures, in the process according to the invention preference is given to silicates with an average crystallite size of less than 3000 nm and in particular less than 1000 nm. The average crystallite size of the silicates can be controlled using the molar ratio between (R) 2 / nO and SiO2 in the starting mixture, in the sense that silicates of a lower average crystallite size are obtained as the molar ratio 78 1 1 7 3 6 b ί -7- between and S ^ ° 2 * n ^ et ϋ ^ εδ3η§3ιηβη§8β1 is chosen higher.

In the process according to the invention, preference is given to silicates whose value of y in the formula representing the composition of the silicate is 0.01-0.02. The value of y in the formula representing the composition of the silicates can be controlled using the molar ratio of SiO 2 and A 2 O 2 in the starting mixture, in the sense that silicates IQ with a lower value for y are obtained as the molar ratio between SiO2 and in the starting mixture is chosen higher.

The silicates prepared as described above contain alkali metal ions as well as organic cations. Using suitable exchange methods, the alkali metal ions can be replaced by other cations such as hydrogen ions or ammonium ions. Organic cations can very suitably be converted to hydrogen ions by calcining the silicates. The crystalline silicates used in the catalyst mixtures preferably have an alkali metal content of less than 1% by weight and in particular less than 0.05% by weight. If desired, a binder material such as bentonite or kaolin can be included in the catalyst mixtures.

In the process according to the invention, a catalyst mixture must be used, the crystalline silicate coraponent of which contains one or more elements selected from the group formed by manganese, calcium, magnesium and titanium. Preferably, a catalyst mixture is used, the silicate component of which contains one or more of the above-mentioned elements in an amount of 0.1-10% by weight and in particular of 0.5-5% by weight, based on the silicate component in the mixture. The incorporation of the elements in the silicate component can take place in various ways, for example by ion exchange or by impregnation.

The process preferably uses a 78 1 1 7 3 6 -s- 'catalyst mixture' in which the elements have been incorporated into the silicate component by impregnating them with an aqueous solution of one or more salts of the relevant elements, followed by drying and calcining of silicate.

The process according to the invention can very suitably be carried out by passing the feed upwards or downwards through a vertically arranged reactor containing a fixed or moving bed of the respective catalyst mixture. For example, the process may be conducted by passing an upstream feed through a vertically disposed catalyst bed using a gas velocity such that expansion of the catalyst bed occurs.

If desired, the process can also be carried out using a suspension of the catalyst mixture in a hydrocarbon oil. Depending on whether the process is carried out using a fixed catalyst bed, an expanded catalyst bed or a catalyst slurry, catalyst particles with a diameter between resp. 1 and 5 mm, 0.5 and 2.5 mm and 20 and 150 M.

The invention is now illustrated by the following example.

Example

A crystalline silicate (Silicate A) was prepared as follows.

A mixture of SiOjj Na2AlO2 NaOH and / (C ^ H ^ n / OH in water with the molar composition 1.5 Na2O.Al2O. 2.25 / Tc ^) ^ 7 · 37.5 SiO 2 · 675 HjO was left for 48 heated in an autoclave at 150 ° C under 30 autogenous pressure. After cooling the reaction mixture, the oristane silicate was filtered off, washed with water until the pH of the wash water was about 8 and dried at 120 ° C for 2 hours. After calcination in air at 500 ° C for 1 hour, silicate A had the following properties 781 1 7 3 6 V '-9-

a) thermally stable up to a temperature above 800 ° C

b) an X-ray powder diffraction pattern substantially similar to that listed in Table B.

c) after evacuation at 2x10 bar and 400 C for 16 hours -2 and measured at a hydrocarbon pressure of 8x10 bar and 100 ° C, the adsorption of n-hexane is 1.2 mmol / g, the adsorption of 2,2-dimethylbutane 0.7 mmol / g and the ratio adsorption of n-hexane 17 and adsorption of 2,2-dimethylbutane J '10 d) the composition, expressed in moles of the oxides, is the following 0.025 M 2 O. 0.025 A ^ O ^. SiO2 where M = H and Na.

From silicate A having an average crystallite size of 250 nm, a silicate B was prepared by boiling the material calcined at 500 ° C with 1.0 molar NH 2 NO 2 solution, washing with water, boiling again with 1.0 molar NH 2 NO 2 solution and wash, dry at 120 ° C for 2 hours and calcine at 500 ° C for 1 hour.

Seven silicates (silicates C-1) were prepared starting from silicate B, containing 1-3% by weight of one of the following elements: magnesium, calcium, titanium, manganese, molybdenum, chromium and cerium. The preparation was carried out by impregnating samples of silicate B with an aqueous solution of a salt of the element in question, followed by drying and calcining the impregnated material.

Eight catalyst mixtures (i-VIII) were prepared by mixing a ZnO-Cr 2 composition with each of the silicates B-I. The atomic Zn percentage of the ZnO-Cr ^ composition 30 based on the sum of Zn and Cr was 70%. The catalyst mixtures all contain 4 parts by volume of the ZnO-Cr 2 composition per volume part of silicate.

Catalyst mixtures I-VIIII were tested for the one-step preparation of an aromatic hydrocarbon mixture 35 from an H 2 / CO mixture. The test was carried out in a 50 ml 781 1 7 3 6 -10 reactor containing a fixed catalyst bed with a volume of 7.5 ml. A ^ / CO mixture with a mol. ^ / 00 molar ratio of 0.5 xrerd for 48 hours at a temperature of 375 ° C, a pressure of 60 bar and a spatial flow rate of 1000 µl. catalyst.

The results of these experiments are reported below.

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hh§ os 2 -3 υ 2 ε <U «B · Η · ο 'α ο £ η ο thin) so - + E p rt'T.r« m h cui-i.-icsfn-im «i; P ® b hzw U & uuuuu μ ft <ίζ · <781 1736

Claims (17)

1. Process for the preparation of an aromatic hydrocarbon mixture, characterized in that a mixture of carbon monoxide and hydrogen is contacted with a mixture of two catalysts, one of which has the ability to convert an E CO mixture in acyclic oxygen-containing hydrocarbons and the other is a crystalline silicate, which silicate is characterized in that after calcining in air at 500 ° C for 1 hour, it has the following properties IQ a) thermally stable to a temperature above 600 ° C, b ) an X-ray powder diffraction pattern including the reflections listed in Table A, Table A Radiation: Cu-K α_ Wavelength 0.15418 nm 2. Relative intensity 7.8-8.2 S 8.7-9.1 M 11.8-12 , 1 Z 12.4- 12.7 Z 14.6- 14.9 Z 15.4- 15.7 Z 15.8- 16.1 Z 17.6- 17.9 Z 19.2- 19.5 Z 20.2- 20.6 Z 20.7- 21.1 Z 23.1- 23.4 ZS 23.8- 24.1 ZS 24.2- 24.8 S 29.7-30.1 M in which the letters used have the following meaning: ZS = very star k; S = strong; M = moderate: Z = weak; Θ = the 25 angle according to Bragg. “9 oc) after evacuation at 2x10 bar and 400 ° C for 16 hours 781 1 7 3 6 -2 X -13- and measured at a hydrocarbon pressure of 8x10 bar and 100 ° C, the adsorption of n-hexane is at least 0, 8 mmol / g, the adsorption of 2,2-dimethylbutane at least 0.5 mmol / g and the ratio c adsorption of n-hexane. -, - J --3 ----- - "vi -" - r -, - r-r- at least 1,5 adsorption of 2,2-dimethylbutane d) the composition, expressed in moles of the oxides, next y. (1.0 + 0.3). MjO. y. Al ^. SiO2 wherein M = H and alkali metal and y> 0.005, and e) the silicate contains one or more elements selected from the group consisting of manganese, calcium, magnesium and titanium. 2. Process according to claim 1, characterized in that the molar ratio between hydrogen and carbon monoxide in the feed is between 0.25 and 1.0. Process according to claim 1 or 2, characterized in that it is carried out at a temperature of 200-500 ° C, a pressure of 1-150 bar and a spatial flow rate of 50-5000 Nl gas / 1 catalyst / hour. 4. Process according to claim 3, characterized in that it is carried out at a temperature of 300-450 ° C, a pressure of 5-100 bar and a spatial flow rate of 300-3000 Nl gas / 1 catalyst / hour. 5. Process according to any one of claims 1-4, characterized in that the catalyst mixture is composed of a catalyst X and a catalyst Y, wherein catalyst X is able to convert an H 2 / CO mixture to mainly methanol and / or dimethyl ether and catalyst Y is the crystalline silicate. 6. Process according to claim 5, characterized in that as catalyst X a composition is used which contains zinc together with chromium. Process according to claim 6, characterized in that in the catalyst X the atomic percentage of zinc, based on the sum of zinc and chromium, is at least 60%. 78117 36 -14- λ * f Process according to claim 7, characterized in that in the catalyst X the atomic percentage of zinc, based on the sum of zinc and chromium, is 60-80%. 9. Process according to any one of claims 5-8, characterized in that the catalyst mixture contains, per volume part of catalyst Y, 1-5 volume parts of catalyst X. 10. Process according to any one of claims 1-9, characterized in that the catalyst mixture contains a crystalline silicate, the average crystallite size of which is less than 3000 nm. Process according to claim 10, characterized in that the average crystallite size of the silicate is less than 1000 nm. 12. A method according to any one of claims 1-11, with the j ,. characterized in that the catalyst mixture contains a crystalline silicate whose value of y in the formula representing the composition of the silicate is 0.01-0.02. 13. Process according to any one of claims 1-12, characterized in that the catalyst mixture contains a crystalline silicate containing one or more of the elements manganese, calcium, magnesium and titanium in an amount of 0.1-10 wt% based on the amount of silicate in the mixture. 14. Process according to claim 13, characterized in that the elements have been incorporated into the silicate by impregnating it with an aqueous solution of one or more salts of the relevant elements, followed by drying and calcining the silicate. 15. Process according to any one of claims 1-14, characterized in that the catalyst mixture contains a crystalline silicate with an alkali metal content of less than 0.05% by weight. 16. Process for the preparation of an aromatic hydrocarbon mixture, substantially as described above and in particular with reference to Experiments 2-5 from the example. Aromatic hydrocarbon mixtures which have been prepared using a process according to claim 16. 78 1 1 7 3 6 *