Process for preparing an olefin stream for oligomerization with selective hydrogenation

1 . A process for processing an olefin stream comprising:

converting methanol to provide an olefin stream;

fractionating said olefin stream to provide a gas stream and an olefin rich stream;

selectively hydrogenating said olefin rich stream to convert diolefins to mono-olefins and provide a mono-olefin stream; and

oligomerizing said mono-olefin stream over an oligomerization catalyst to provide an oligomerized stream.

2 . The process of claim 1 further comprising absorbing oxygenates from said olefin rich stream into a water wash stream to provide an oxygenate rich water wash stream and a washed olefin rich stream and the olefin rich stream that is selectively hydrogenated is said washed olefin rich stream.

3 . The process of claim 2 , wherein the oxygenates absorbed from said olefin rich stream comprise one or more of dimethyl ether, methanol, and acetaldehyde.

4 . The process of claim 1 wherein said fractionating step comprises demethanizing said olefin stream to provide said light gas stream and said olefin rich stream.

5 . The process of claim 4 further comprising fractionating said olefin rich stream to provide a fractionated olefin rich stream and an ethylene stream and the olefin rich stream that is selectively hydrogenated is said fractionated olefin rich stream.

6 . The process of claim 5 further comprising absorbing oxygenates from said fractionated olefin rich stream into a water wash stream to provide an oxygenate rich water wash stream and a washed olefin rich stream and the olefin rich stream that is selectively hydrogenated is said washed olefin rich stream.

7 . The process of claim 5 further comprising converting acetylenes in said ethylene stream to ethylene in the presence of hydrogen to provide a concentrated ethylene stream.

8 . The process of claim 7 further comprising oligomerizing said concentrated ethylene stream.

9 . The process of claim 8 further comprising oligomerizing said concentrated ethylene stream and said mono-olefin stream together.

10 . The process of claim 5 wherein said olefin rich stream comprises C3 to C8 olefins.

11 . The process of claim 4 further comprising absorbing oxygenates from a fractionated olefin rich stream into a water wash stream to provide an oxygenate rich water wash stream and a washed olefin rich stream, and the olefin rich stream that is selectively hydrogenated is said washed olefin rich stream.

12 . The process of claim 1 further comprising absorbing oxygenates from said mono-olefin stream before oligomerizing said mono-olefin stream.

13 . The process of claim 1 further comprising compressing a product olefin stream produced from the methanol to provide a compressed product olefin stream; stripping said compressed product olefin stream to provide a light olefin stream and a heavy olefin stream; and selectively hydrogenating said heavy olefin stream with said olefin rich stream to convert diolefins to mono-olefins to provide said mono-olefin stream.

14 . The process of claim 13 , wherein the olefin rich stream is a demethanized olefin rich stream.

15 . The process of claim 1 wherein the olefin stream is taken from an oxygenate conversion reactor.

16 . The process of claim 1 wherein said olefin rich stream is a demethanized olefin rich stream comprising C2 to C8 olefins.

17 . The process of claim 1 wherein said lighter gas stream includes carbon monoxide, carbon dioxide, nitrogen, hydrogen, and methane.

18 . A process for processing an olefin stream comprising:

converting methanol to provide an olefin stream;

fractionating said olefin stream to provide a gas stream and an olefin rich stream;

absorbing oxygenates from said olefin rich stream into a water wash stream to provide an oxygenate rich water wash stream and a washed olefin rich stream;

selectively hydrogenating said washed olefin rich stream to convert diolefins to mono-olefins and provide a mono-olefin stream; and

oligomerizing said mono-olefin stream over an oligomerization catalyst to provide an oligomerized stream.

19 . The process of claim 18 further comprising compressing a product olefin stream produced from methanol to provide a compressed product olefin stream; stripping said compressed product olefin stream to provide a light olefin stream and a heavy olefin stream; and selectively hydrogenating said heavy olefin stream with said washed demethanized olefin rich stream to convert diolefins to mono-olefins to provide said mono-olefin stream.

20 . A process for processing an olefin stream comprising:

sending a vaporous olefin stream and a liquid olefin stream to a fractionation column;

fractionating said vaporous olefin stream and said liquid olefin stream to provide a gas stream and an olefin rich stream;

selectively hydrogenating said olefin rich stream to convert diolefins to mono-olefins and provide a mono-olefin stream; and

oligomerizing said mono-olefin stream over an oligomerization catalyst to provide an oligomerized stream.