Process for converting methanol or dimethyl ether to olefins

A technology of dimethyl ether and methanol, applied in the field of converting methanol or dimethyl ether into olefins, can solve the problems of reducing the yield of ethylene per pass, reducing the overall efficiency of the method and the like

Inactive Publication Date: 2002-06-05
EXXONMOBIL CORP (US)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Unfortunately, however, operating at low methanol partial pressures necessarily reduces the per-pass ethylene yield, thereby reducing the overall efficiency of the process.

Method used

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  • Process for converting methanol or dimethyl ether to olefins
  • Process for converting methanol or dimethyl ether to olefins
  • Process for converting methanol or dimethyl ether to olefins

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047]This example uses an FCC additive catalyst containing ZSM-5 in a silica:alumina mole ratio of 450:1, a binder to zeolite weight ratio of 60:40, and about 4% by weight P . The catalyst had previously been steamed at 870°C (1600°F) for 4 hours so that the catalyst had an alpha value of about 1, a diffusion parameter of 26, and an n-hexane adsorption value of 38 mg / g. Methanol was converted using this catalyst at 430°C and 15, 90, 120 and 170 psia. The ethylene, propylene, C4+ and total olefin selectivities for each condition are listed in Table 1 at about 70% conversion of methanol. figure 1 A plot of ethylene selectivity versus pressure is given in .

[0048] pressure, psia

[0049] Table 1 and figure 1 The results presented in are surprising in that while the overall olefin selectivity is only reduced by 10%, the selectivity to ethylene is increased by more than 60% by increasing the reactor pressure from 15 to 90 psia methanol. This unexpected increase in ...

Embodiment 2

[0050] Embodiment 2 (comparison)

[0051] A ZSM-5 extrudate catalyst containing 65% by weight silica to alumina in a 55:1 molar ratio of ZSM-5 and 35% by weight alumina binder was steamed at 787°C for 45 minutes such that The steamed catalyst had an alpha value of about 4, a diffusion parameter of 1900 and an n-hexane adsorption value of 35 mg / g. Methanol conversion was performed with steamed catalyst at 430°C and methanol partial pressures of 15 and 90 psia. The ethylene, propylene, C4+ and total olefin selectivities for each condition are listed in Table 2 at about 70% conversion of methanol.

[0052] pressure, psia

15

90

temperature, ℃

430

430

ZSM-5 d / r2

1900

1900

methanol conversion

70

70

Selectivity, wt% of HC

Vinyl

2

4

Acrylic

25

7

C4+ olefins

46

6

other HC

27

83

...

Embodiment 3

[0055] Embodiment 3 (comparison)

[0056] Phosphoric acid, kaolin, and 450:1 silica / alumina ZSM-5 were slurried in water and spray dried to produce a fluidized bed catalyst. The catalyst was calcined at 510°C in air. The final catalyst contained 40% by weight ZSM-5 and 4.5% by weight phosphorus. The catalyst was then steamed at 1050° C. (1920° F.) for 0.75 hours. After the treatment, the alpha value of the catalyst was about 1, the diffusion parameter was 0.5, and the n-hexane adsorption value was 31 mg / g. The catalyst was used to convert methanol at 480°C, 15 psia and 330°C, 15 psia. The ethylene, propylene, C4+ and total olefin selectivities for each condition are listed in Table 3 at about 70% conversion of methanol.

[0057] pressure, psia

[0058] The data in Table 3 show that even with ZSM-5 catalysts with low diffusion parameters, the ethylene selectivity at low methanol partial pressures decreases significantly with increasing temperature. On the contrary...

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Abstract

There is provided a process for converting methanol or dimethyl ether to a product containing C2 to C4 olefins, which comprises the step of contacting a feed containing methanol or dimethyl ether with a catalyst which comprises a zeolite having 10-ring intersecting channels, such as ZSM-5, and which has a Diffusion Parameter for 2,2-dimethylbutane of less than 100 sec-1 when measured at a temperature of 120 DEG C. and a 2,2-dimethylbutane pressure of 60 torr (8 kPa). The contacting step is conducted at a temperature of 370 to 480 DEG C., a methanol partial pressure of 30 to 150 psia and a methanol conversion per pass of less than 95%.

Description

field of invention [0001] The present invention relates to a method for converting methanol and / or dimethyl ether into olefins, especially light olefins rich in ethylene and propylene. Background of the invention [0002] The increasing demand for light olefins, especially ethylene and propylene, in many applications has made it desirable to develop new sources of olefins in addition to the traditional sources of crude oil. One such other source form is methanol and / or dimethyl ether, which can be catalytically converted to olefin-containing hydrocarbon mixtures by certain zeolite catalysts. [0003] For example, USP 3911041 discloses that methanol can be converted to C 2 ~C 4 Olefins wherein the crystalline aluminosilicate zeolite catalyst has a Constraint Index of 1 to 12, such as ZSM-5, and which contains at least about 0.78% by weight phosphorus incorporated within the zeolite crystal structure. [0004] USP 4049573 and 4088706 disclose that methanol can be converted ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C1/20
CPCC07C1/20C07C2529/40Y02P30/20Y02P30/40
Inventor S·H·布朗R·希纳W·A·威伯
Owner EXXONMOBIL CORP (US)
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