NL8005830A - Aromatic hydrocarbon(s) prepn. from carbon mon:oxide and hydrogen - on two-component catalyst contg. iron silicate - Google Patents

Abstract

Aromatic hydrocarbons are prepd. by contacting a mixt. of H2 + CO with a mixt. of 2 catalysts consisting of (I) a catalyst for the conversion of the H2+CO mixt. into acyclic oxygen-contg. hydrocarbons, and (II) a crystalline Fe silicate which, after calcining for 1 hour in air at 500 deg. C (a) is stable at above 600 deg. C, (b) has a defined X-ray powder diffraction pattern, and (c) has a molar ratio of SiO2:Fe2O3 greater than 10. (I) The catalyst pref. contains Zn and Cr, esp. with an amt. of Zn:Zn + Cr of 60-80%. Catalyst I partic. converts H2+CO to methanol and/or dimethyl ether. (II) The silicate may contain a small amt. of Al. The alkali metal content is less than 0.1wt.% (less than 0.05wt.%). The ratio by vol. of I:II is 1-5:1. The catalyst mixt. has high stability and gives less durene in the prod.

Description

•Resume. - - *

K 5559 NET

PROCESS FOR PREPARING HYDROCARBONS

The invention relates to a process for the preparation of an aromatic hydrocarbon mixture from a mixture of carbon monoxide and hydrogen.

Mixtures of carbon monoxide and hydrogen can be converted into aromatic hydrocarbon mixtures using a mixture of two catalysts, one of which has the ability to catalyze the conversion of an H2 / CO mixture into acyclic oxygen-containing hydrocarbons and the other is a crystalline iron or aluminum silicate which has the ability to catalyze the conversion of acyclic oxygenated hydrocarbons to aromatic hydrocarbons. Said crystalline iron and aluminum silicates are characterized in that, after calcining in air at 500 ° C for one hour, they have the following properties.

a) thermally stable to a temperature above 600 ° C, b) an X-ray powder diffraction pattern containing the reflections listed in Table A, and c) in the formula showing the composition of the silicate expressed in moles of the oxides and in which, in addition to oxides of hydrogen , alkali metal and silicon, which is an oxide of trivalent metal A selected from Al and Fe, the SiOg / Og mol is. ratio more than 10.

8005830 -2- * t

Table A

d (A) _Rel, int.d (A) _Rel. int.

11.1 100 3.84 '(D) 57 10.0 (D) 70 3.70 (D) 31 8.93 1 3.63 16 7.99 1 3.47 <1 7.42 2 3.43 5 6 .68 7 3.34 2 6.35 11 3.30 5 5.97 17 3.25 1 5.70 7 3.05 8 5.56 10 2.98 11 5.35 2 2.96 3 4.98 (D) 6 2.86 2 4, 60 4 2.73 2 4.35 5 2.60 2 4.25 7 2.48 3 4.07 2 2.40 2 4.00 _4_ (D) = doublet 8005830 * '-4 -3-

The crystalline silicates used in the catalyst mixtures were prepared from an aqueous mixture containing the following compounds: one or more compounds of an alkali metal (M), a tetrapropylammonium compound, one or more silicon compounds and one or more iron or aluminum compounds.

The crystalline silicates are prepared by keeping the mixture at an elevated temperature until the silicate is formed, separating it from the mother liquor and calcining it. In the aqueous mixture from which the silicates are prepared, the different compounds should be present in the following ratio, expressed in moles of the oxides: M20: SiO2 = 0.01 - 0.35, 1 '(C3H7) iiNj2G: SiO2 s ° »01“ O »1 *

SiO 2: A 2 O 3> 10, and H 2 O: SiO 2 s 5 - 65

The applicant has conducted a comparative study of the use of the above-described crystalline iron and aluminum silicates as catalyst component in the aforementioned catalyst mixtures intended for the preparation of an aromatic hydrocarbon mixture from an H2 / CO mixture. It has been found that the use of the iron silicates should be preferred over the aluminum silicates because the catalyst mixtures containing an iron silicate exhibit significantly higher selectivity. Although the catalyst mixtures containing an iron silicate exhibit a very acceptable behavior when used for the conversion of the H 2 / CO mixture into an aromatic hydrocarbon mixture, there is still a need to further improve this behavior, especially in terms of stability and durene production. The latter axis 8005830 # * -4-pect is especially important if it is the intention to use the prepared aromatic hydrocarbon mixtures as motor gasoline. In view of the high melting point of dureen, it is desirable that its concentration in the aromatic hydrocarbon mixture be as low as possible.

Applicants have conducted an investigation to determine whether, by altering the preparation of the crystalline iron silicates, products can be obtained which, when used as a catalyst component in the above-mentioned catalyst mixtures, can change the behavior of these catalyst mixtures in the desired direction. It has been found that by replacing the tetrapropylammonium compound with a tetrabutyl ammonium compound or by a tetrabutylphosphonium compound in the aqueous mixture from which the crystalline iron aluminum silicates are prepared, crystalline silicates of different structure are obtained. After calcination in air at 500 ° C for one hour, the crystalline iron and aluminum silicates prepared in this way have an X-ray powder diffraction pattern containing the reflections listed in Table B.

When comparing the X-ray powder diffraction patterns listed in Tables A and B, the following differences appear to exist: a) Table B lacks the following reflections: 8.93; 7.99; 5.35; 4.07; 3.43; 3.25; 2.96; 2.73.

b) In Table A, the following reflections are much more intensive than in Table B: 6.35; 5.70; 4.25; 4.00; 3.63.

c) In Table A, the following reflections are doublets, while in Table B they are singlets: 10.0; 4.98; 3.84; 3.70.

8005830 «* '* · -5-

Table 3 o o d (A) _Rel, int d (A) _Rel. int.

11.1 100 3.84 65 10.0 70 3.70 20 7.42.2 3.63 <.2 6.68 5 3.47 2 6.35 2 3.34 1 5.97 16 3.30 4 5.70 <1 3.05 5 5.56 8 2.98 9 4.98 6 2.86 1 4.60 3 2.60 2 4.35 5 2.48 3 4.25 <1 2.40 2 4.00 _ <1_

It has been found by the Applicant that if in a catalyst mixture containing an iron silicate which, after calcining in air at 500 ° C for one hour, exhibits an X-ray powder diffraction pattern as described in Table A, the silicate is replaced by an iron silicate which, after calcining in air for one hour. at 500 ° C shows an X-ray powder diffraction pattern as shown in Table B, a catalyst mixture is obtained which, when used for the preparation, of an aromatic hydrocarbon mixture from a Hg / CO mixture, exhibits a considerably higher stability and considerably lower duralen production. This is highly surprising considering that in a catalyst mixture containing an aluminum silicate which, after calcining in air at 500 ° C for an hour, exhibits an X-ray powder diffraction pattern as set forth in Table A, the silicate is replaced with an aluminum silicate which after one hour calcining 8005830 -6- in air at 500 ° C exhibits an X-ray powder diffraction pattern as set forth in Table B, a catalyst mixture is obtained which, when used to prepare an aromatic hydrocarbon mixture from an H 2 / CO mixture, has significantly lower stability and significantly higher duralen production shows.

The present patent application therefore relates to a process for the preparation of an aromatic hydrocarbon mixture in which an H2 / CO2 mixture is contacted with a mixture of two catalysts, one of which has the ability to convert an H2 / CO2 mixture into acyclic oxygen-containing hydrocarbons and the other is a crystalline iron silicate which, after calcining in air at 500 ° C for one hour, has the following properties: a) thermally stable to a temperature above 600 ° C, b) an X-ray powder diffraction pattern containing the reflections listed in Table B and c) in the formula representing the composition of the silicate expressed in moles of the oxides, the SiO 2 / Fe 2 O 3 mole ratio is greater than 10.

The process according to the invention is based on an H2 / CO mixture. Such a mixture can very suitably be prepared by 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 H2 / CO mixture whose molar ratio is between 0.25 and 1.0.

6005830 -7-

The method 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 flow rate of 50-5000 and in particular 300-3000 NI gas / 1 catalyst / hour.

In the process according to the invention, a mixture of two catalysts is used, which for the sake of convenience will be 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 iron silicate. Catalysts which are preferably used as catalysts X are those which are capable of converting a% / 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? amounts. Preferably, catalyst mixtures are used which contain, per volume part of catalyst Y, 1-5 volume parts of catalyst X.

Although the crystalline silicates used in the process of the invention are referred to as iron silicates, they may contain a small amount of aluminum in addition to iron. The silicon compounds which are economically suitable for the preparation of crystalline silicates on a technical scale usually contain a small amount of aluminum as an impurity. This aluminum is usually found at least in part in the prepared silicate.

The iron silicates used in the process of the invention are prepared from an 8005830 --- -8- aqueous mixture containing one or more alkali metal compounds. Preferably, a sodium compound is used as the alkali metal compound in the preparation of the iron silicates. The alkali metal ions present in the aqueous mixture from which the iron silicates are prepared, at least in part, end up in the prepared silicates. Using suitable exchange methods, they can be replaced with other cations such as hydrogen ions or ammonium ions. The iron silicates used in the catalyst mixtures preferably have an alkali metal content of less than 0.1 wt. % and in particular less than 0.05 wt. %.

If desired, a binder material such as bentonite or kaolin may be included in the catalyst mixtures.

The process according to the invention can very suitably be carried out by passing the feed upwards or downwards through a vertically arranged reactor in which there is a fixed or moving bed of the respective catalyst mixture.

The process according to the invention can also very suitably be used as the first step of a two-step process for the conversion of H2 / CO mixtures into hydrocarbon mixtures. In this case, carbon monoxide and hydrogen present in the reaction product of the first step, optionally together with other components of this reaction product, are contacted in a second step with a catalyst containing one or more metal components with catalytic activity for the conversion of an H 2 / CO mixture to acyclic hydrocarbons, which metal components are selected from the group consisting of cobalt, nickel and ruthenium, with the proviso that if the feed for the second step is an H2 / CO mol. ratio has less than 1.5, water is added to this feed and a bifunctional catalyst or 8005830-9 catalyst combination is used in the second step, which in addition to the metal components with catalytic activity for the conversion of a Hg / CO mixture into acyclic hydrocarbons, additionally containing one or more metal components with catalytic activity for the conversion of an H2O / CO mixture to a Hg / COg mixture.

The process according to the invention can furthermore be very suitably used as the first step of a three-stage process for the preparation of, inter alia, middle distillates from an H2 / CO mixture. In this case, carbon monoxide and hydrogen present in the reaction product of the first step, optionally together with other components of this reaction product, are contacted in a second step with a catalyst containing 10-40 wt. parts of cobalt and 0.25-5 wt. parts of zircon, titanium or chromium per 100 wt. parts of silica prepared by impregnating a silica support with one or more aqueous solutions of salts of cobalt and zirconium, titanium or chromium, followed by drying the composition, calcining at 350-700 ° C and reducing at 200 ° C 350 ° C, it being understood that if the feed for the second step is an H2 / CO mol. has a ratio of less than 1.5, water is added to the feed and the Co-impregnation catalyst is used in combination with a CO shift catalyst. Of the reaction product of the second step, at least the part whose initial boiling point is above the final boiling point of the heaviest intermediate distillate desired as the final product is subjected to a catalytic hydrotreatment in a third step.

The invention is now illustrated by the following example.

8005830 -10-

Example

Four crystalline silicates (silicates 1-4) were prepared as follows.

Silicate 1

A mixture of NaOH, (03Ηγ) 4Ν0Η, amorphous silica, Fe (NO3) 3 and water with a molar composition of SiO2.1Na20.4.5f (C3H7) 4N [20-0 »I25Fe2O3.450H20 was autoclaved under autogenous pressure. heated at 150 ° C for 24 hours.

Silicate 2

A mixture of NaOH, (C3H7) 4N0H, amorphous silica, NaA102 and water with a molar composition SiQ2.1Na20.4.5 P (C3H7) 4Nj20 * 0 »18Al2 O3.450H20 was autoclaved under autogenous pressure and stirring for Heated at 150 ° C for 24 hours.

Silicate 3

A mixture of NaOH, (C4Hg) 4P0H, amorphous silica, Fe (NO3) 3 and water with a molar composition SiO2.1.5Na20.1.5 [(C4H9) 4p [20. ° 33Fe2O3.450H20] was autoclaved. heated under autogenous pressure at 150 ° C for 48 hours.

Silicate 4

A mixture of NaOH, ^ Hg ^ NOH, amorphous silica, amorphous alumina and water with a molar composition 25 SiO2.1.5Na20.1.5 £ (C4Hg) 4liJ 20.0, 33A1203.450H20 was autoclaved under autogenous pressure for 48 heated at 150 ° C for hours.

After cooling the reaction mixtures, the resulting silicates were filtered off, washed with water until the pH of the 8005830-11 washing water was about 8, dried at 120 ° C and calcined at 500 ° C. Silicates 1-4 had the following properties: a) thermally stable to a temperature above 800 ° C, b) an X-ray powder diffraction pattern for silicate 1 and 2 as listed in Table A and for silicate 3 and 4 as listed in Table B, c) a S1O2 / AI2O3 mol. ratio as follows: silicate 1 SiO 2 / Fe 2 O 3 mol. verb. 130 "2 Si02 / Al203 w w go» 3 Si02 / Fe203 "" 70 "4 Si02 / Al203" 61

From silicates 1-4, resp. the silicates 5-8 prepared by boiling the silicates 1-4 with 1.0 molar NH4NO3 solution, washing with water, boiling again with 1.0 molar NH4NO3 solution, washing, drying at 120 ° C and calcining at 500 ° C. Four catalyst mixtures (Catalyst mixture A-D) were then prepared by mixing a ZnO-Cr 2 O 3 composition with each of the silicates 5-8. The atomic Zn percentage of the Zn0-Cr203 composition based on the sum of Zn and Cr was 70 ^. The catalyst mixtures all contain per wt. part silicate, 10 wt. parts of the Zn0-Cr203 composition.

Catalyst mixtures A-D were tested to prepare an aromatic hydrocarbon or mixture from an H2 / CO mixture. The test was carried out in a 50 ml reactor containing a fixed catalyst bed with a volume of 7.5 ml. In four experiments, an H2 / CO mixture was mixed with an H2 / CO mol. ratio of 0.5 at a temperature of 375 ° C, a pressure of 60 bar and a spatial throughput of 1000 Nl. In all experiments, the aromatic content of the C5 + fraction averaged over 100 hours over 40 wt. %, The other results of the experiments are shown in Table C.

8005830 α> + s -Ρ * HO t.

(0 3 3 a Ό 3 φ Ο Ό 60 ίι Η Ο Ω. Φ Ο c + ό r-> α zrvosrir »Φ LH Ό ****** φ Ο Ή ti · CM · = Τ Ο Ο

U SO 5 3 C Ο> <D

ο · Η 60 Ο 60 Ρ • Η Ο 43

> I

Η 3 +3 Ό Ο Η Ο Ο Ο Ο

I — TTJT-V *. Ο CM ΟΟ CM

VO Ό 00 VO Η · C— ra η ti + 3 ο ιη ο> ο 60 ο Η Ρ Ή Η -Ρ Λ Ο Λ X Ο τ- 43 3 ra ο • Η ti ti Ο η ο φ c ο vo- = rcMcn Η φ> Ο * “43 60 η υ co 43 ra ra 43 Η Η 3 C ra 3 3 43 o

W 43 W

I t tl ι— * _

I HI ί Η 30 CM3-00CM

CM ΦΙ Ο (0 3 0 Lfi νο ΙΛ m r- Λ IC> Ζ r- I (0 1 (0 ο ο hi> η ο * · * 'co «- Φ 60 Η Φ ra ra ti φ tl ι-Ί φ JS 3 0> 4- »<03τ- οο co ο ιη CG Ζ Ο ΙΓ> νΟ νΟ νΟ Ο >> O'-ι ο w« - 43 (0 (0 ο Η tl

HZ ΙΟ VO> CO

Η

CO

Η φ ra 60 c φ

St. Λ. ζ <m ο ο 43 (0 Μ 43

C

φ a Η tl tl φ ζ CM cn Λ α Μ

W.

8005830 -13-

Of the experiments listed in Table C, only Experiment 3 using a catalyst mixture containing an iron silicate with an X-ray powder diffraction pattern according to Table B is an experiment according to the invention. The remaining experiments using catalyst mixtures containing an aluminum silicate or an iron silicate with an X-ray powder diffraction pattern according to Table A are outside the scope of the invention. They are included in the patent application for comparison. The results of Experiments 1 and 2 (both performed using an X-ray powder diffraction silicate according to Table A) show the higher ¢ 5 + 3 selectivity obtained when using an iron silicate compared to an aluminum silicate.

The results of Experiments 1 and 3 (both performed using an iron silicate) demonstrate the higher stability and lower duralen production obtained when using an iron silicate with an X-ray powder diffraction pattern according to Table B compared to an iron silicate with an X-ray powder diffraction pattern according to Table A.

The results of Experiments 2 and 4 (both performed using an aluminum silicate) show the lower stability and higher durene production obtained when using an aluminum silicate with an X-ray powder diffraction pattern according to Table B compared to an aluminum silicate with an X-ray powder diffraction pattern according to Table A.

8005830

Claims (10)

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 300-450 ° C, a pressure of 5-100 bar and a spatial throughput of 300-3000 NI gas / 1 catalyst / hour. if. Process according to any one of claims 1-3, characterized in that the catalyst mixture is composed of a catalyst X and a catalyst Y, wherein catalyst X is able to convert an Hg / CO mixture to mainly methanol and / or dimethyl ether and Catalyst Y is the crystalline iron silicate. Process according to claim 4, characterized in that the catalyst X used is a composition containing zinc together with chromium. Process according to claim 5, characterized in that in the catalyst X the atomic percentage of zinc, based on the sum of zinc and chromium, is 60-80%. Process according to any one of claims 4-6, characterized in that the catalyst mixture contains, per volume part of catalyst Y, 1-5 volume parts of catalyst X. Process according to any one of claims 1 to 7, characterized in that the catalyst mixture contains a crystalline silicate with an alkali metal content of less than 0.05 wt. %. 8005830 A 9 -16- 9. Process according to any one of claims 1-8, characterized in that it is used as the first step of a two-step process of the conversion of H2 / CO mixtures into hydrocarbon mixtures, wherein carbon monoxide and hydrogen are present in the reaction product of the first step, optionally together with other components of this reaction product, are contacted in a second step with a catalyst containing one or more metal components with catalytic activity for the conversion of an H 2 / CO mixture into acyclic hydrocarbons, which metal components are selected from the group formed by cobalt, nickel and ruthenium, it being understood that if the feed for the second step and H2 / CO mol. has a ratio of less than 1.5, water is added to this feed and that in the second step a bifunctional catalyst or catalyst combination is used which, in addition to the metal components with catalytic activity for the conversion of an H2 / CO mixture into acyclic hydrocarbons, additionally contains one or more metal components with catalytic activity for the conversion of an H2O / CO mixture to an H2 / CO2 ·. mixture. 10. Process according to any one of claims 1-8, characterized in that it is used as the first step of a three-step process for the preparation of, inter alia, middle distillates from an H2 / CO mixture, wherein carbon monoxide and hydrogen are present in the reaction product of the first step, optionally together with other components of this reaction product, are contacted in a second step with a catalyst containing 10-40 wt. parts of cobalt and 0.25-5 wt. parts of zircon, titanium or chromium per 100 wt. parts of silica prepared by impregnating a silica support 8005830-17 with one or more aqueous solutions of cobalt and zirconium, titanium or chromium salts, followed by drying the composition, calcining at 350-700 ° C and reduce at 200-350 ° C, it being understood that if the feed for the second is an H2 / CO mol. has a ratio of less than 1.5, is added to the feed and the CO impregnation / catalyst is used in combination with a CO shift catalyst, and of the reaction product of the second step at least the portion of which the initial boiling point is above the final boiling point of the heaviest intermediate distillate desired as the final product, is subjected to a catalytic hydrotreatment in a third step. 11. Process for the preparation of hydrocarbon mixtures, substantially as described above and in particular with reference to Experiment 3 of the example. Hydrocarbon mixtures prepared using a process according to claim 11. 8005830