DE2112650A1 - Process for the selective hydrogenation of hydrocarbons - Google Patents

Description

Esso Research and (prio US 22 792 - March 26, 70-7972)

Engineering Company

Linden, N.J. / V. St. A. Hamburg, March 10, 1971

Process for the selective hydrogenation of hydrocarbons

The present invention relates to selective hydrogenation of diolefins in a hydrocarbon feed containing monoolefins; the invention particularly relates to selective conversion of propadiene and butadiene, which appear as impurities in propylene and butene, which occurs in alkylation Used in gasoline and aviation fuel production when the feedstock is contaminated with sulfur. The inventive Process is also for the selective conversion of C. Diolefins into monoolefins, such as, for example, the conversion from butadienes to butenes.

The C / C. Fractions used in the alkylation are usually by thermal or catalytic cracking of higher-boiling hydrocarbons or from hydrocarbon coking obtain. This C / C fraction is withdrawn within a practical boiling range so that it is in the

109843/1836

Contains essentially no C hydrocarbons, although smaller amounts can be entrained in one way or another. These C / C fractions generally contain about 0.3 and up to 2.0% by weight or more of diolefins. The C / C fractions obtained from the cracking process included. usually not more than 2% diolefin. This low diolefin content in the feedstock for the. However, alkylation is extremely undesirable, in particular because it also requires a considerably larger acid, and

because tar-like acidic diolefin polymerization products result, which considerably reduce the economics of alkylation processes affect. The proposals made so far for the conversion or removal of the diolefins from hydrocarbons, the still contain mono-olefins have been shown to be unsuitable for use, as they also contain a Loss of monoolefins occurs and the processes are also uneconomical for other reasons.

The Cj / Cr fractions obtained from coking can contain even larger proportions of diolefins, up to 5 % or more. Here these difficulties are even greater, so that it has not been possible to use such fractions for the alkylation up to now.

109843/1836

From US Pat. No. 3,113,983 it is known to selectively convert the diolefins present as impurities to olefins in hydrogenating an alkylation feedstock by using the Feed material passes over a sulfided cobalt-molybdenum catalyst coated on Al O. Using this However, catalysts present considerable difficulties; once must under extremely severe conditions of e.g. 14 to 28 atmospheres and temperatures above 205 C, must also have a high hydrogen / diolefin ratio be worked if the catalyst activity is to remain on the desired range and finally that must be from the The product emerging from the hydrogenation plant is treated in a separate separation process in order to separate hydrogen from hydrogen to enable. The alkylation is carried out in the liquid phase and the presence of larger amounts of hydrogen would make the liquefaction of the reactants difficult or impossible at low temperatures.

In addition, cobalt molybdenum catalysts are not sufficient Selectivity. Supported nickel and palladium catalysts are excellent hydrogenation catalysts in diolefin conversion; however, they are extreme to sulfur in the fresh diolefin feed

109843/1838

sensitive, so that these catalysts can only be used with sulfur-free products.

The present invention has now set itself the task of eliminating the above-mentioned difficulties and the diolefin conversion to carry out with a greater selectivity.

To solve this problem, a process for the selective conversion of diolefins into olefins, in particular sulfur-containing ones, is therefore provided Feed products, proposed, which is characterized in that the hydrogenation in the presence of a Carries out catalyst, which consists of a sulfided nickel-tungsten catalyst on an inert support, such as alumina, Kieselguhr, silica-free clay, bauxite, mullite and preferably alumina.

^ In the process of the invention, the hydrocarbon feed, which has smaller amounts of diolefins and sulfur, over a sulfided nickel-tungsten catalyst passed onto alumina or other support, with a feedstock containing C / C hydrocarbons is particularly interesting.

The catalyst contains 4 to 6 wt. % Nickel, 14 to 20 wt.%

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Tungsten while the remainder is Al O. The ratio of tungsten to nickel is preferably between 4.1 and 5: 1, the catalyst

is sulfided with H_S or CS before use.

u 2

Surprisingly, this catalyst shows a remarkable level of selectivity in that it allows the hydrogenation of diolefins too Monoolefins activated but relatively inactive for hydrogenation from monoolefins to paraffins in the temperature range from 93 to 205 C, at a pressure of 10.5 to 14.1 atti and a hydrogen / diolefin ratio is from 1: 1 to 6: 1.

Although the fiction, contemporary method is best in the Treatment of olefinic C / C hydrocarbons, approximately

j 4

Containing 2 wt.% Butadiene, can be used with the fiction, contemporary method, although sometimes with not always equally good results, with olefinic C / C fractions treat a higher diolefin content, such as a butane-butylene fraction from thermal coking, which can contain up to 5 to 6% diolefins. The inventive method leaves continue to be used in the treatment of butylene-enriched feed streams from the dehydrogenation which contain 1 to 5% diolefin contain. For example, the raffinate enriched in monoolefins is found in the dehydrogenation of butane for production of butadiene and especially after the butadiene has been separated off

109843/1836

Fractionation and extraction of a small butadiene content of a fraction of a percent up to about Z%, depending on the effectiveness of the separation process. These small amounts of butadiene cannot be isolated as such in an economical manner and interfere with further use of the raffinate, for example as feedstock for the alkylation. Furthermore, in processes which are carried out in principle for the conversion of butane into butene, butadiene is produced. If these amounts of butadiene are sufficiently large and are, for example, above about 5 %, the butadiene can be removed in a known manner without difficulty

will. Smaller butadiene amounts of about 3 to 5% leave a Recovery in an economical way is not possible. In all of these cases improvement of the butene is selective Hydrogenation of the diolefins according to the invention of interest.

von'Propadien to the selective hydrogenation / butadiene in a / Mono-

olefin-enriched mixture can be with the invention " carry out appropriate procedures even more easily and economically,

when the proportion of diolefin in the mixture is relatively low and is, for example, about 2%. In these cases it can be catalytic Hydrogenation take place under the mentioned working conditions in an isothermal or adiabatic reactor system, deviating from the optimal process parameters with a slight loss of yield and purity of the product can.

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Eb were two feedstocks with the following composition Hydrogenated at different temperatures with a throughput of 1000 SCFH feedstock without H per 28 l. The throughput of liquid Product per hour fluctuated somewhat and was in a range from 2.8 to 4.0 V / hV. It was used in all cases with a molar ratio worked from H to diolefin from 2.2 to 3.0 to 1, the hydrogen diene ratio fluctuating from 1.0 to 6.0. The pressure at the inlet side of the preheater was 12.3 atm.

The feed was that shown in Table 1 below Composition:

Table 1 Sample 2 Together Sample 1 reduction in wt.% 6.71 propane 6.46 13.75 Propylene 13.24 22.79 η-butane) sn n? ' ^a / 7.16 Isobutane) JU ₁ \ 3 £, 26, 08 Butene (l) 26.30 1.56 Isobutylene 1.61 1.46 Propadien 1.39 2.86 Isopentane 2.94 9.03 trans - butene (2) 9.28 6.41 cis-butene (2) 6.64 0.08 n-pentane 0.08 0.35 3-methylbutene (l) 0.36 0.99 1,3-butadiene 0.93 0.77 Other C _r + hydrocarbons 0.75 100.00 _ 5 substances
All in all 100.00 not determined Carbonyl sulfide ppm 33-57 - not determined Molecular weight 53.8 - not determined, specific density 0.572

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The experimental results obtained were analyzed on the basis of the first-order kinetic reaction equation for calculation the constants KC _ and KC. using the following Equation:

K = S / ~ - In (I-xj7

where S is the throughput rate and χ is the fraction of the reactant that is converted to the product became. The effect of the operating temperature on the hydrogenation of propadiene and butadiene is shown in the graphs P shown in FIGS. 1 and 2, FIG. 1 being a plot

the propadiene conversion and FIG. 2 that of the butadiene conversion according to Arrheriius, where the values in the following tables 2, and 4 are indicated.

In all cases a nickel-tungsten catalyst on Al O used in an amount of 60 ml or 43.2 g.

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175 175 175 '175 Tabel 2 175 169 176 175/55 175/165 175 10 6.56 Pressure in psig 199 205 257 270 175 270 305 283 300 289 356 13.96 Temp. In ° F 56.6 58.9 56.7 56.7 255 48.4 39.7 48.1 40.4 55.8 51.7 23.17 Gas supply in L / h 3.95 4.15 3.96 3.96 53.1 3.39 2.79 3.36 2.84 3.92 3.62 7.40 Liquid supply V / hV 2.8 7.8 2.6 7.8 3.73 7.8 2.6 1.3 2.3 1.3 2.6 24.45 Hydrogen supply L / h 1.77 4.7 1.64 4.9 2.6 5.75 2.32 0.97 2.30 0.84 l.SO 1.86 H / Dien 0.235. 0.372 1.46 0.585 1.77 1.43 1.80 1.19 1.46 1.28 8.35 '0.14 Response value "k" for 0.088 0.134 0.983 0.55 0.334 0.73 1.12 0.52 0.80 0.445 3.36 3.05 ' Propadien 0.381 10 '. 33 Butadiene 7.38 Composition in wt.% 0.37 propane 6.50 6.19 6.38 6.64 6.21 6.55 6.67 6.79 6.49 1.18 Propylene 13.28 12.50 12.89 13.53 6.90 12.62 13.46 13.50 13.97 . 11/13 0 ^ 25 Isobutane 23.13 07/23 23.75 23.59 14.13 23.34 23.43 11/24 23.67 23.78 50.17 n-butane 7.30 7.38 7.39 7.25 23.76 7.45 7.32 7.26 7.22 7.32 ¹ ^ 1.44 Butene (l) 26.29 26.37 26.37 25.96 7.09 26.53 07/26 26.20 25.79 26.30 __> 90.0 isobutylene 1.69 1.80 1.92 1.88 25.75 1.89 1.90 1.89 1.89 1.91 K, 60.5 Propadien 1.31 1.27 0.96 1.20 1.85 0.91 0.73 0.97 0.83 Ί.00 CD Isopentane 2.92 3.19 3.02 2.96 1.27 3.13 2.94 2.71 2.80 2.85 cn t-butene (2) 9.09 9.46 9.05 8.82 2.74 9.33 9.29 8.72 9.06 8.97 CD c ~ $ uten (2) 6.47 ^λ 6.60 6.44 6.26 8.70 6.65 6.60 6.21 6.37 6.38 1,3-butadiene 0.91 0.90 0.72 0.81 6:00 am 0.75 0.62 0.79 0.70 ■ 0.83 Other 1.11 1.27 1.12 1.10 0.84 1.19 1.07 0.95 , 0.91 1.06 H, 0.29 0.85 1.08 0.24 0.92 1.27 0.25 0.134 0.27 0.12 Mole weight 49.48 43.82 41.79 49.71 0.24 40.31 50.16 51.46 49.55 51.67 Diolefin feed L / h 1.58 1.65 1.58 1.58 49.95 1.35 1.12 1.34 1.13 1.55 C 3 - diolefin conversion 5.8 8.6 31 13.7 1.47 34.5 47.5 30.0 40.2 28.0 C. - Diolefin conversion 2.2 3.2 22nd 13th 8.6 . 19.4 33 14.4 . 24.6 10.7 9.7 t

Table 3

Pressure in psig 176 Temp. In ° F 330 Gas supply in L / h 49.4 ' Liquid supply V / hV 3.46 Hydrogen supply L / h 1.3 H ₂ / diene 0.94 Response value "k" for 1 7Λ Propadien X /H
0.522 Butadiene Composition in% by weight propane Propylene 6.30 Isobutane 12.79 n-butane 23.36 Butene (l) 7.41 Isobutylene 26.32 Propadien 1.92
0 84. Isopentane 3 00 t-butene (2) 9.37 c- ^ uten (2) 6.72 1,3-butadiene 0.80 Other 1.17 0.09 Mole weight 51.75 Diolefin feed L / h 1 38 C 3 - Di oil ef in conversion 39.5 C. Diolefin Conversion 14.0

175

348

47.3

3.33

1.3

0.99

6.1

2.81

8.51

14.39

12/24

7.15

23.65

1.82

0.22,

2.66

9.39

6.64

0.41

0.88

0.31
48.69

1.31
84.0
57.0

175

333

46.4,

3.24 \

1.3

1.0

2.35 1.02

6.87

13.85

24.86

7.22

25.58

1.89

0.67

2.60

8.50

6.10

0.68

1.36

0.11 51.64

1.29 51.5 27.0

177

384

52.0

3.65

1.3

0.90

9.95 4.53

7.09

14.41

25.28

7.26

22.69

1.89

0.09

2.57

10.41

7.20

0.27

0.77

0.11 51.82

1.44 93.5 71.0

44.9

3.15

1.04

11.0
4.7

175-130 190 253 246 42.0 54.4 2.90 3.70 3.3 3.3 2.85 3.15 0.61 0.52 0.22 mm V w » mt

7.51 6.35 15.29 12.66 25.99 24 '. 04 7.11 7.41 21.90 26.39 1.87 1.91 0.04 1.13 2.34 2.96 08/10 8.79 6.95 ' 6.36 0.21 0.88 0.68 1.12 0.12 0.27 51.44 49.76 1.25 1.16 97.0 19.5 77.0 7.95

6.15

12.39

23.27

7.41

26.58

1.
1,
3,

, 87
, 23
.06
9.25
6.59
0.95
1.25

0.25
49.71

1.52
12.7

175

256

62.3

4.5 ·

3.3

1.9

0.72 0.39

6.81 13.61 24.86 7.18 23.03

1,
1,
2,

95 19 60

8.19 5.84 0.87 0.87

0.26 49.82

1.73 15.4 8.6

Table 4

Pressure in psig
Temp. In ° F
Gas supply in L / h
Liquid supply V / hV
Hydrogen supply L / h
H_ / Dien

Response value "k" for
Propadien
Butadiene

Composition in % by weight

propane

Propylene

Isobutane

η-butane

Butene (l)

Isobutylene

Propadien

Isopentane

t-butene (2)

c- ^ uten (2)

1,3-butadiene

Other

Mole weight

Diolefin feed L / h

C 3 - Di oil efinum conversion

C. - Diolefin conversion

17S

287

44.7

3.1

3.3

1.62

1.10 0.60

6.88

13.72

25.30

7.18

25.89

1.99

0.99

2.55

8.11

5.80

0.77

0.92

0.27 49.58

1.26 29.8 19.0

175

297

42.49

2y97

3.3

2.8

.1.66
0.86

6.58
12.63
25.98
7.57
26.28
1.91
0.79,
3.12
.57
.90
0.70
0.97

7th
5,

0.23
50.52

1.18
43.2
25.2

175

366

August 47

3.3

3.3

1.9

16.3 6.38

6.78

13.50

25.94

7.55

22.29

1.93

0.01

2.93

10.50

7.50

0.13

1.07

0.20 51.00

1.30 99.5 85.8

175

359

43.54 3.02 3.3

2.05

9.63 3.65

6.93 02/14 25.26 7.34 23.88 1.99 0.06 2.63 9.85 6.95 0.28 0.89

0.21 50.66

1.20 95.7 70.2

When these experiments are repeated in a customary large-scale plant with a feedstock containing from 0 to 4 mol% of butadiene a complete removal of the 1,3-butadiene was achieved.

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Claims (1)

ue: cm Claims , '1. Process for the selective hydrogenation of diolefins contained in * small amounts in a hydrocarbon mixture with a major proportion of monoolefins are present, characterized in that the hydrocarbon mixture passes together with hydrogen through a reaction zone which contains a sulphided nickel-tungsten catalyst and that the selective hydrogenation in a temperature range of 93 to 204 C and preferably between 177 and 204 C and at a pressure between 10.5 and 14.1 atm and a hydrogen / diolefin ratio of 1: 1 to 6: 1 is carried out. 2. The method according to claim 1, characterized in that one as the hydrocarbon feedstock is a C_- to C 3 4 Product used. 3. The method according to claim 1 to Z, characterized in that the diolefin content in the hydrocarbon feed ranges from a fraction of a percent up to 5%. 10 9 8 4 3/1836