AU608502B2 - Conversion of acetylene to aromatic hydrocarbons - Google Patents

Description

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AUSTHALIA 6 850 2 Form PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: This document contains the amen dments made Under Sectio 49 and is correct for printing.

Lodged: 0 o 0 o o 9 ce o 00 060 0 0 -Complete Specification-Lodged: 0 0 Accented: ArTflnfrl 00 0

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0U 0 riority: Lapsed: Published: o ea 0 0 0 A Related Art: 0o o O* a." 0 00 0 90 d *00 DIVIDED FROM AUSTRALIAN APPLICATION No.73920/81 Name of Applicant: O 0 a o Address of Applicant: Actual Inventor: TO BE COMPLETED BY APPLICANT THE BROKEN HILL PROPRIETARY COMPANY LIMITED and COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH

ORGANISATION

140 William Street, Melbourne, Victoria, Australia and Limestone Avenue, Campbell, A.C.T Australia respectively.

Noam WHITE Douglas Alan KAGI Jack Graham CREER Peter TSAI Address tor S Complete Spe ervice: CLEMENT HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

ecification for the invention entitled: CONVERSION OF ACETYLENE TO AROMATIC HYDROCARBONS statement is a full description of this invention, including the best method of performing it known IF/2/80 ~VL~3lii~r~rrr~-i~l :li i I- 0 0 10 *0 o o 0e 0 09 0090 0I 99 00 9 a 0 0, This invention relates to the production of hydrocarboncompounds, including aromatic hydrocarbons, useful as fuels.

The production of aromatics is of particular importance because lighter aromatics which boil in the normal gasoline range have very high octane numbers and are therefore excellent gasoline blend stocks. In addition, benzene, toluene and xylene are important for their chemical uses and as chemical feedstocks.

The uncertain availability and fluctuating price of petroleum for gasoline and chemical manufacture has directed increased attention to the potential of methane (natural gas) and coal as major alternative raw materials for these uses. Using the route developed by Mobil,the production of aromatic gasoline from natural gas and coal depends upon the production of methanol as an intermediate, and routes to methanol from coal and methane depend on the production of synthesis gas (hydrogen and carbon monoxide mixture).

It has long been known that coal can be converted via gasification to mixtures of carbon monoxide and hydrogen (synthesis gas). The carbon monoxide-hydrogen mixture may be adjusted in ratio using the water gas shift reaction followed by removal of CO 2 and methanol can then be produced.

O 0 0 0 O0 00 9 0 0 0 00 00 0000 a0 20 2 27/1/V r The gasification reaction may be represented as:coal H20->H 2 CO (also CH CO2) coal 02 CO 2 The latter reaction is required to generate heat for the gasification reaction and results in carbon loss.

The water gas-shift reaction is

CO--H

2

CO

2 Methanol may then be produced by the following S 10 reactions:- 9* o o 2H, CH 3

OH

o o3H 2 CO2- CH30H So Overall products are methanol and carbon dioxide.

It has also been known that synthesis gas can be produced from methane by steam reforming, in 0o accordance with the reactions CH H20---3H 2

CO

Soo CH 20 CO 2H 0 4 2 2 2 Some methane is reacted with oxygen to generate heat for the steam reforming and this results in carbon loss.

0 0 Since methanol conversion requires the reaction 2H 2 CO--CH3OH the reforming step produces a deficiency of carbon for this conversion and this deficiency is usually made up by the addition of carbon dioxide. This carbon 3 16/1/V _L lit. I dioxide is available from the combustion of the methane. However, in practice there is wastage of carbon as carbon dioxide.

The use of crystalline aluminosilicate zeolites as catalysts for the conversion of methanol to hydrocarbon products has been proposed in the Mobil process. This produces a hydrocarbon product of the following approximate composition:- 0 Wt 10 methane ethane ethylene 0 0 propane 5.6 isobutane .0 n-butane 2.9 °o propylene butenes 4.7 15 C nonaromatics 49.0 aromatics 27.3 oa 100.0

C

5 fraction 76.3 4 16/1/V II The most valuable products from this Mobil process are the aromatics, but these comprise only about 30% of total products.

Existing technology has thus established a route from either coal or natural gas to aromatic gasoline via methanol; but the abovementioned processes have serious shortcomings.

The disadvantage of the use of coal as the raw material is the very high cost of plant for the coal gasification and the introduction of oxygen into the 0", S process produces loss of carbon as carbon dioxide.

Q o The disadvantage of the route from methane via 0 00 o° methanol is the loss of methane to carbon dioxide and water due 00 to the introduction of oxygen.

A further disadvantage of the Mobil methanol to gasoline conversion over zeolite catalysts is the 0°o low proportion (about 30%) of valuable high octane too a 0 aromatic product and the consequent high proportion of o less valuable lower octane materials. Yet another disadvantage is that water produced during the methanol conversion is entrained in the product, so requiring 0 a 0 a later separation step. In addition, any unreacted methanol is difficult and expensive to separate from the product stream, so operating conditions need to be biased towards maximum conversion of methanol at the expense of 29/7/V i, -L -i -1 :i I Il;; ili 6 00 00 o 00 o 0 0 b40 00 0 00 0 0° a o0 00 oO o 0o ot o0 0 o a e 0o 0 01 0 0J 0 00 0 0 0 better selecting the composition of the product stream.

Also, there is substantial loss of weight due to the elimination of water.

It is an object of this invention to provide a novel process for production of useful hydrocarbon fuels, including aromatic ring compounds.

In a general aspect the invention provides a process for the production of useful hydrocarbon fuels, including aromatic ring compounds, from acetylene, either alone or in admixture with other compounds.

In accordance with the invention it has been found that useful hydrocarbon fuels including aromatic ring compounds may be produced by contacting acetylene either alone or in admixture with certain other compounds, with a zeolite catalyst. An advantage of this process over the conversion of methanol is that any unreacted acetylene is far easier to separate from the product stream than is methanol, so making more viable a trade-off of a lower degree of conversion for a more desirable liquid product mix.

The invention accordingly provides a process for the production of aromatic hydrocarbons, which comprises contacting a feed stream containing acetylene with a crystalline zeolite catalyst having a silica to alumina molar ratio of at least 35, at a temperature up to 5500C and a pressure of from 0.5 to 50 atmospheres, and at least a weight hourly space velocity of 0.1 to 20 hr

I

to produce a reaction product containing aromatic hydrocarbons.

6a The preferred catalysts for use in the process of this invention are zeolites with a crystal framework structure similar to the ZSM-5 type zeolites. Zeolite catalysts of this type are disclosed in U.S. Patent 3,702,886. Other zeolites of the ZSM-5 type are disclosed in Australian Patent Specification AU-A 35237/78. Another zeolite with a framework 4 9 *0 0 00 e oo 0 «0 o 00 o oo So a o o o structure similar to that of ZSM-5 is described in U.S. Patent 4,104,294 and in an article by E.M. Flanigen et al in Nature, vol. 27; p.512, 1978, and is known as silicalite. One characteristic of these zeolites is their silica to alumina ratio.

The preferred range of silica to alumina disclosed in U.S. Patent 3,702,886 is between 5 and 100.

Silicalite has a much higher silica to alumina ratio.

In U.S. Patent 4,104,294, the silica to alumina ratio S 10 has a lower limit of 800. Zeolite catalysts with e too 0 *9 a crystal framework structure similar to the 00 0 a type zeolites may be prepared with a very large 00 o r. silica to alumina ratio, but in practice it is 9 0 believed that these catalysts are never entirely free of alumina, even though no alumina may be Sa deliberately added during preparation thereof.

In the course of our continuing research into *o the catalytic production of useful hydrocarbon fuels from starting materials including acetylene, we have now found that advantages are obtained by use 0o 0 of a zeolite catalyst having a crystal framework structure similar to the ZSM-5 type zeolites, and having a high silica to alumina ratio, preferably at least about 100. Improved catalyst life is one of the advantages achieved by the process of the present invention.

7 16/1/V -i ;I~~ly P4 0 60 0*1 0 00 0 A preferred embodiment of this invention comprises contacting a mixture of gaseous acetylene and one or more other gases (which may be inert, for example helium and/or nitrogen) with the preferred zeolite catalysts, or alternatively, in a further embodiment the feed may consist of gaseous acetylene and water. Water may be substituted in this process by alcohols such as methanol, ethanol or higher alcohols. Further, contact of a gaseous mixture of acetylene and methane or ethane or ethylene or hydrogen, or acetylene alone, with the preferred catalyst produces a useful product containing a mixture of aromatic compounds.

Processes are available for the conversion of methane to acetylene and for the conversion of coal to acetylene. Processes may be chosen which are electrically based and suffer no loss of feedstock carbon due to the introduction of oxygen as do the synthesis gas processes outlined above. Thus economic sources of acetylene for use in the process of the present invention are available and it is to be expected that further developments in acetylene production technology from coal or methane will accelerate the adoption of acetylene as a key intermediate in future fuel technology. An advantage of the present invention is -8o o 00 0 0 4D 0 00 020 0 0," 0414 ,0 0 29/7/v I _i .L J;-l that hydrogen used in the process could be obtained as a by-product of methane to acetylene conversion.

The catalysts employed in this invention may be in the hydrogen form and/or they may be exchanged and/or may be impregnated to contain a metal cation complement.

Further the catalyst may be modified by the inclusion of one or more metals other than aluminium in the crystal structure. It is normally desirable to calcine the catalyst before use.

The metal cations that may be present may include Poo °one or more cations of the metals of Group I through ato Group VIII of the periodic table.

The zeolite, with or without impregnation may be o vo 6 combined, dispersed or otherwise intimately mixed with an inorganic oxide matrix in such proportions that the 4 04 resulting product contains 1% to 95% by weight of the O °zeolite in the final product. Matrices which impart desirable properties to the zeolite such as increased strength and attrition resistance are preferred.

20 The process can utilize either a fixed or fluidized bed of catalyst.

In a preferred embodiment of the invention the catalyst is a crystalline aluminosilicate zeolite having a silica to alumina ratio of 35 to 500, preferably having a silica to alumina ratio of 80 to 300.

In a preferred embodiment of the invention a process comprises converting acetylene, in the presence of one or more other gases as noted above, to a predominantly -9 2 29/ 7/V i-Y ~UI- Da~- i aromatic mixture in the presence of a catalyst as described above at an elevated temperature up to 550 0 C, preferably about 260 450 0 C, carrying out said conversion at between 0.5 and 50 atmospheres, and a weight hourly space velocity (WHSV) of 0.1 to hrl with the other gas comprising from 0 to 95 volume percent of the feed stream.

Experimental To illustrate the preparation of the catalyst ao S 10 type the following experimental procedure has been 06 0 0 included. Fifty six gram of sodium silicate solution 0 6 o (.29.1 wt.% Si02, 9.1 wt, Na20) was mixed with 193,6 0 00 gram di.stilled water, To this solution, 1.04 gram of sodium hydroxide was added, followed by the addition 15 of 7.04 gram of tetra n-propyl ammonium bromide.

o.0 o This mixture was thoroughly mixed and 4,9 gram of 98 o 0 weight percent sulphuri.c acid added, After further vigorous mixing the material was placed in a pyrex vessel inside a stainless steel pressure vessel, placed 20 in an oven and held at 175°C for 48 hours. The product from the reaction vessel was filtered; thoroughly washed with distilled water, dried at 110 0 C overnight and calcined at 500 0 C for 16 hours. On cooling a portion of the product was washed with 0,3 M hydrochloric acid at 100°C for 16 hours, The material was then filtered, 10 -C-~lcxxl~ r o e 0 0 0 9 0 a o a o Q 00 0 004 0 p 9 Soo or 09 a a o a washed and dried. X-ray diffraction showed that the material gave a diffraction pattern very similar to that typical of ZSM-5, The catalyst was found to contain a small amount of alumina, although no deliberate addition of alumina wa,s made. The source of this alumina is not definitely known, but it is thought that it may be derived from impurities in the sodium silicate solution. The silica to alumina ratio in this catalyst was 120.

10 To illustrate the preparation of a catalyst modified by the inclusion of a metal other than aluminium in the crystal lattice, the experimental procedure for preparation of an iron modified zeolite catalyst was identical to that given above except 15 that 7.44 gram Fe(NO ).,.9H20 was added with the sulphuric 3K' 2 acid in the reaction mixture.

Examples The following examples are illustrative of this invention and are not to be considered to be limiting on the scope thereof.

In each example the feed stream was passed through an electrically heated reactor tube containing an appropriate aluminosilicate zeolite which had been pelletized and crushed to a particle size of 80-100 mesh.

11 29/7/V illYLLI- -ili- -I- The total pressure was usually one atmosphere and the weight of catalyst was 0.1 gram. The reactor effluent was analysed by gas chromatography (GC) using a 4m x 3mm silicone OVIO1 column in a temperature programmed mode. Parts and percentages are by weight.

In each table BTX is the sum of Benzene, Toluene and Xylenes; C 10 is the aromatics of carbon number> and C 9 is aromatics of carbon number =9.

e 0 0 12 a29/7/V o o a 0 0 0 0 0 0 94 120 0 0 00 0a 0 12 29/7/V I 4 4 *t a <r a a a a a 4 a *a o 4 a« a a a a to a ae ra so t0 4 I ft 4 B 't tQI Examples 1 6 Acetylene and two diluent gases were contacted with zeolites having different silica/alumina ratios. A rise in temperature increases the acetylene conversion and alters the effluent composition as shown in Table 1.

TABLE 1 Variation of Si /AJ (50-120) Variation of Temperature (300-4000C) EXAMPLE 1 2 3 4 5 6 FEED C2H 2 0.3 0.3 0.3 0.3 0.3 0.3 (cc/min) H 2 1.6 1.6 1.6 1.6 1.6 1.6 He 1.9 1.9 1.9 1.9 1.9 1.9 CATALYST H-ZSM-5 H-ZSM-5 H-ZSM-5 H-ZSM-5 H-ZSM-5 Si02/Al203 50 50 80 80 120 120 TEMP (oC) 300 400 300 400 300 400

CONVERSION

of C 2

H

2 10.2 36.4 11.5 57.3 1.1.0 49.4 MHSV (hr 1 of C 2

H

2 0.2 0.2 0.2 0.2 0.2 0.2 PRODUCTS NON-AROMATICS 13.7 23.5 33.8 39.8 33.8 41.3 BTX 43.7 35.0 31.3 41.2 23.9 30.2

C

9 25.6 18.1 16.1 10.1 15.7 10.1 Cl 0 17.0 23.3 18.9 8.8 26.6 18.3 BTX: Benzene, Toluene, Xylenes

C

10 :Aromatics of carbon number

C

9 Aromatics of carbon number 9 13 29/7/V Examples 6 8 Acetylene was subjected to three experiments involving dilution with hydrogen, helium and/or water. Comparison of yields and product distribution for the same crystalline aluminosilicate catalyst were made. The results are summarized in Table 2.

TABLE 2 Variation of Feed (H 2 0, H 2 He) 00 0 0 0 000 o *0 o o 0 040 0 0 00 O 0 0 0 0 *4 00 0 0 00 0 0*0 0 0 00* 4 0 0'~ 00 0 *440 0 *4 0 0 0 00 0 0* o 0 1~400 EXAMPLE 6 7 8 FEDC2 H2 (cc/mmn) 0.3 0.3 0.3 H 2 1.6 1.6 He 1.9 1.9 H 2O3 (g/min) 0.013 0.013 CATALYST H-ZSM.-5 H-ZSM-5 (SiO 2 /A1 2 0 3 120 120 120 TEMP (oc) 400 400 400

CONVERSION

of C 2

H

2 49.4 68.7 85.4 MHSV (hr1 of C2 H2 0.2 0.2 0.2

PRODUCTS()

NON-APROMATICS 41.3 23.0 24.1 BTX 30.2 41.5 51.9 C 9 10.1 8.0 8.9 C 10 18.3 27.0 13.6 0 00 40 0 0*4040 0 0 14 29/7/V Examples 9 Table 3 illustrates the variation in product distribution of the effluent with an increase in the space velocity over at H-ZSM-5 type catalyst, at similar conversion levels.

TABLE 3 Variation of Space Velocity 00 9 090 0 00 00 0 909 0 0 00 00 0 0 00 0 0* 00 0 0 00 .0 00 0 0 0 00.0 0 0 40 00 0 4004 0 00 00 0 0' 00 0 00 0 0 0 00*0 EXAMPLE 9 FEED C 2H 20.3 (cc/min) H2 1.8 7.8 N 2 2.3 8.4 CATALYST H-ZSM-75 H- (SiD /Al 20 3 66.1 66.1 TEMP (oc) 400 400

CONVERSION

Of C 2H 2) 21.8 21.1 MHSV (hf 1 of C 2H 20.2 0.7

PRODUCTS(%

NON-AROMATICS 67.5 52'.2 BTX 20.7 12.8 C 9 5.4 5.6 C 0+6.3 29.7 0900 15 29 /7/v Examples 11 -18 Acetylene and a diluent were passed over zeolites with increasing silica/alumina ratio. The percentage conversion of the acetylene and its product distribution under specific operating condition are shown in Table 4.

TABLE 4 Acetylene and Helium in Feed 0 0 .4 0 00 EXAMPLE 11 12 13 14 15 16 17 18 FEED C 0.5 0.5 0.5 0.5 0.5 0.5 0.7 0.7

H

2 000He 3.6 3.6

CATALYST

SiO 2 /Al 2 0 3 2 2 3 H-tZ SM-Sr 50 H-Z SM-5 50 H-Z SM-5 120 H-Z SM-S 120 H-Z SM-S5 206 H-,Z SM-S5 206 H--Z SM-S 466 H-Z SM-S 486 0 0.

TEMP (OC) 297 400 300 400 300 400 300 400

CONVERSION

of C 2

H

2 MHSV (hr- 0 :6 0 :of C*H 29.4 40.7 4.7 45.1 11.4 34.7 4.5 17.2 0.4 0.4 PRODUCTS NON-AROMATICS 1.2 3.7 8.1 11.3 5.9 1.0 13.0 1.7 BTX 19.6 31.5 40.4 60.4 8.3 22.4 10.0 11.7 C 9 13.4 11.1 19.8 10.5 7.2 12.7 5.8 6.3 C 1 0 +65.7 53.7 31.8 17.9 78.8 64.0 71.3 80.4 16 2 9/7/V on- rA Examples 19 Catalyst activity decreases with product distributions in Table time as shown by yields and TABLE Catalyst Activity with Time c.o O 5 o too o 00 o 0 000 0 0 00 00 0 o 00 o 00 00 .5 0 00 0 00 0 ~00 0 0 00 00 0 0000 0 00 0 0 00 00 00 0 EXAPLE 19 FED C2H2 0.5 (cc/min) H 12 1.0 He 6.0 CATALYST H-ZSM,.5 (Si 2 /Al 2 0 3 120 120 TEMP 400 400 (after 15 min) (after 220 min)

CONVERSION

Of C 2H 2 35.5 19.0 -1 MHSV (hr, of C 2 H 2 0.4 0.4

PRODUCTS(%

NON-AROMATICS 13.1 BTX 55.5 28.1 C 9 25.2 31.3 Cl 6.1 36.0 0 00 L,0 0 000 00~ 0 0 1.7 2 9/7/V I~ -L IIIIIII~C II~I~ -C -*L~i I 0% *I 4 *i 00 00 0 00 0 0% 0 4s 0402 Examples 21 Table 6 demonstrates the effectiveness of a catalyst in which the presence of a metal other than aluminium has been included in the structure of the ZSM-5 zeolite. Further, that the use of different liquid feeds can alter the yield and distribution of aromatized product in the effluent.

TABLE 6 Fe replacing Al in the Zeolite Framework EXAMPLE 21 22 23 23 FEED C2H 2 (cc/min) 0.4 0.4 0.4 0.4' 0.4

H

2 2.2 2.2 2.2 2.2 2.2

N

2 3.0 3.0 3.0 3.0

H

2 0 (g/min) 0.005 0.005 MeOH 0.005 CATALYST Fe-ZSM-5 Fe-ZSM.-5 Fe-ZSM-5 Fe-ZSM-5 Si02/Al 2 0 3 140 140 140 140 140 TEMP (oC) 300 300 400 400 400

CONVERSION

of C 2

H

2 56.3 30.0 86.9 64.2 93.0 MHSV (hr 1 of C2H 2 0.3 0.3 0.3 0.3 0.3 PRODUCTS NON-AROMATICS 9.2 21.5 4.4 28.3 2.4 BTX 31.7 27.3 30.6 24.3 35.1

C

9 10.1 16.0 10.7 13.6 12.2 48.3 35.7 54.3 33.0 50.3 18 29/7/V This application is divided from our copending application 73920/81 and the entire disclosure in the complete specification of that application is by this cross-reference incorporated into the present specification.

0 C o0 0 0) D o o 0o eo 0 00 -19- F186V 0I W -19- 0F 8/6V

Claims (3)

1. A process for the production of aromatic is hydrocarbons, which comprises contacting a feed stream containing acetylene with a crystalline zeolite catalyst

9. having a silica to alumina molar ratio of at least 35, at which a temperature up to 550 0 C and a pressure of from 0.5 to 50 framev atmospheres, and at a weight hourly space velocity of 0.1 to 20 hr -1 to produce a reaction product containing aromatic hydrocarbons. to alt 2. A process according to claim 1, in which the feed 11. stream contains acetylene in admixture with one or more catall j other gases which constitute up to 95 volume percent of other Sthe feed stream. a 012. S 3. A process according to claim 2, in which the other 00 '0 catal gas is an inert gas, water vapour, hydrogen, methane, ,0 ethane or an alcohol. o 13. 0 o, which 0 4. A process according to claim 2, in which the feed "00 stream contains acetylene in admixture with methanol,

14. ethanol or a higher alcohol. tempey a 5. A process according to claim 2, in which the feed 0 stream contains acetylene in admixture with helium and/or 0 hereir nitrogen. :000 Exampl J 6. A process according to claim 1, in which the feed a stream consists of acetylene alone. 00+o 7. A process according to any one of claims 1 to 6, in which the silica to alumina ratio of the zeolite catalyst is 35 to 500. -r i 21 8. A process according to any one of claims 1 to 6, in which the silica to alumina ratio of the zeolite catalyst is 80 to 300. 9. A process according to any one of claims 1 to 8, in which the catalyst has a ZSM-5 type zeolite crystal framework structure. A process according to claim 9, in which the silica to alumina ratio of the zeolite catalyst is at least 100. 11. A process according to claim 9 or 10, in which the catalyst is modified by inclusion of one or more metals ,other than aluminium. .0 12. A process according to claim 11, in which the catalyst is modified by inclusion of iron. o 0 o. 13. A process according to any one of claims 1 to 12, in oO 0 which the temperature iS 260 0 C to 550 0 C. 14. A process according to claim 13, in which the temperature is from 260 0 C to 450 0 C. ao 0 °0 15. A process according to claim 1 substantially as hereinbefore described with reference to any one of the Examples. o So DATED THIS 9TH DAY OF JANUARY 1991 THE BROKEN HILL PROPRIETARY CO. LTD and COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION By their Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia. I