US4746761A — Process for coverting methanol to alkyl ethers

Claim 1

Independent Claim 231 words

A process for converting oxygenate feedstock comprising methanol to liquid hydrocarbons comprising the steps of (a) contacting the feedstock with zeolite catalyst in a primary catalyst stage at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 7 olefins and C 8 + liquid hydrocarbons; (b) cooling and separating the primary stage effluent to recover a liquid C 8 + hydrocarbon stream and a light hydrocarbon stream rich in C 2 -C 7 olefins including propylene and C 4 -C 7 isoalkenes; (c) compressing at least a portion of the olefinic light hydrocarbon stream to condense a liquid olefinic hydrocarbon stream rich in C 4 -C 7 isoalkenes and recovering a gaseous stream rich in ethene and propene; (d) reacting the isoalkenes with methanol in a secondary stage etherification zone by contacting the isoalkenes and methanol with an acid etherification catalyst to produce C 5 -C 8 methyl isoalkylethers; (e) fractionating the secondary stage effluent to obtain a liquid ether and C 5 + hydrocarbon stream and an olefinic C 4 stream rich in unreacted butenes and isobutane; (f) reacting the butene-rich olefinic stream from step (e) with isobutane in a catalytic alkylation stage in contact with acid alkylation catalyst to convert at least a portion of olefins to alkylate gasoline; and (g) recycling ethene and/or propene in a gaseous stream to the primary catalytic stage.

Claim 2

Dependent Claim 231 words

A process for converting oxygenate feedstock comprising methanol to liquid hydrocarbons comprising the steps of (a) contacting the feedstock with zeolite catalyst in a primary catalyst stage at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 7 olefins and C 8 + liquid hydrocarbons; (b) cooling and separating the primary stage effluent to recover a liquid C 8 + hydrocarbon stream and a light hydrocarbon stream rich in C 2 -C 7 olefins including propylene and C 4 -C 7 isoalkenes; (c) compressing at least a portion of the olefinic light hydrocarbon stream to condense a liquid olefinic hydrocarbon stream rich in C 4 -C 7 isoalkenes and recovering a gaseous stream rich in ethene and propene; (d) reacting the isoalkenes with methanol in a secondary stage etherification zone by contacting the isoalkenes and methanol with an acid etherification catalyst to produce C 5 -C 8 methyl isoalkylethers; (e) fractionating the secondary stage effluent to obtain a liquid ether and C 5 + hydrocarbon stream and an olefinic C 4 stream rich in unreacted butenes and isobutane; (f) reacting the butene-rich olefinic stream from step (e) with isobutane in a catalytic alkylation stage in contact with acid alkylation catalyst to convert at least a portion of olefins to alkylate gasoline; and (g) recycling ethene and/or propene in a gaseous stream to the primary catalytic stage.

Claim 3

Dependent Claim 38 words

The process of claim 1 wherein primary stage feedstock is converted over HZSM-5 catalyst to provide a light olefinic hydrocarbon vapor stream comprising a major amount of C 3 -C 7 olefins and a minor amount of ethene.

Claim 4

Dependent Claim 37 words

The process of claim 1 further comprising the step of compressing and fractionating gaseous effluent separated from primary stage effluent to recover a recycle gas stream containing at least 90% of ethene from the primary catalytic stage.

Claim 5

Dependent Claim 43 words

The process of claim 1 wherein the primary stage catalyst comprises ZSM-5 type zeolite and ethene is recycled to the primary stage at a rate of about 1 to 10 parts ethene per 100 parts by weight of methanol equivalent in the feedstock.

Claim 6

Dependent Claim 53 words

The process of claim 1 wherein the light hydrocarbon vapor stream separated from the primary stage effluent is compressed in a plurality of compression stges to condense liquid olefinic hydrocarbons, and wherein uncondensed compressed light hydrocarbons are further fractionated to recover a recycle stream containing at least 90 mole percent ethene and propene.

Claim 7

Dependent Claim 35 words

The process of claim 1 wherein isobutane is reacted with butene-1 and butene-2 in the alkylation stage in the presence of a liquid phase acid catalyst at a pressure of about 1500 to 3000 kPa.

Claim 8

Dependent Claim 198 words

A multistage process for producing high octane fuel from lower aliphatic oxygenate feedstock which comprises the steps of (a) catalytically converting oxygenate feedstock in a primary catalyst stage at elevated temperature in contact with zeolite catalyst to predominantly C 2 -C 7 lower olefins comprising C 4 -C 7 isoalkenes, by-product water and a minor amount of C 8 + hydrocarbons; (b) fractionating the C 2 -C 7 olefins to recover a C 2 -C 3 -rich recycle stream for further catalytic conversion in the primary stage and passing C 4 -C 7 olefins to a second catalytic etherification stage for reaction of C 4 -C 7 isolakenes with methanol to produce corresponding C 5 -C 8 ethers; (c) fractionating second stage effluent to recover an ether product, C 5 + hydrocarbon liquid product, isobutane and unreacted n-butenes; (d) further reacting the unreacted n-butenes with isobutane in a third catalytic stage under acid catalysis alkylation conditions; (e) recovering C 7 + alkylate liquid hydrocarbon; (f) recovering propene from step (b) fractionation and reacting said recovered propene with excess isobutane in step (d); and (g) blending the ether with at least one liquid hydrocarbon to produce high octane gasoline.

Claim 9

Dependent Claim 198 words

A multistage process for producing high octane fuel from lower aliphatic oxygenate feedstock which comprises the steps of (a) catalytically converting oxygenate feedstock in a primary catalyst stage at elevated temperature in contact with zeolite catalyst to predominantly C 2 -C 7 lower olefins comprising C 4 -C 7 isoalkenes, by-product water and a minor amount of C 8 + hydrocarbons; (b) fractionating the C 2 -C 7 olefins to recover a C 2 -C 3 -rich recycle stream for further catalytic conversion in the primary stage and passing C 4 -C 7 olefins to a second catalytic etherification stage for reaction of C 4 -C 7 isolakenes with methanol to produce corresponding C 5 -C 8 ethers; (c) fractionating second stage effluent to recover an ether product, C 5 + hydrocarbon liquid product, isobutane and unreacted n-butenes; (d) further reacting the unreacted n-butenes with isobutane in a third catalytic stage under acid catalysis alkylation conditions; (e) recovering C 7 + alkylate liquid hydrocarbon; (f) recovering propene from step (b) fractionation and reacting said recovered propene with excess isobutane in step (d); and (g) blending the ether with at least one liquid hydrocarbon to produce high octane gasoline.

Claim 10

Dependent Claim 24 words

The process of claim 7 wherein substantially the entire product is recovered with C 5 + hydrocarbon liquid as a high octane gasoline stream.

Claim 11

Dependent Claim 21 words

The process of claim 7 wherein unreacted methanol from the etherification stage is recovered with C 5 + hydrocarbon liquid product.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-05-24	1991-11-23	1992-05-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-05-24	1995-11-23	1996-05-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-05-24	1999-11-23	2000-05-24	$7700.00	Window Closed / Lapsed

Process for coverting methanol to alkyl ethers

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