Process for producing light olefins from crude methanol

A process for the production of light olefin from a hydrocarbon gas feedstream comprising methane and ethane, said process comprising:

• a) passing said feedstream in combination with a water stream to a syngas production zone to produce a synthesis gas stream comprising hydrogen and a carbon oxide and passing said synthesis gas stream to a methanol plant to produce a crude methanol stream comprising methanol, light ends, water, and fusel oil;
• and
• b) passing said crude methanol stream in the presence of a diluent to an oxygenate conversion zone containing a SAPO catalyst selected from the group consisting of SAPO-34 and SAPO-17 to produce a light olefin product comprising ethylene, propylene, butylene, and water;
• c) separating said light olefin product to provide a by-product water stream, an ethylene product, a propylene product, and a butylene product;
• and
• d) returning at least a portion of said by-product water stream to said syngas production zone to provide a portion of said water stream and at least a portion of said diluent.

A process for the production of light olefins from a hydrocarbon gas feedstream, comprising methane and ethane, said process comprising:

• a) passing said feedstream in combination with a first water stream to a syngas production zone to produce a synthesis gas stream and passing said synthesis gas stream to an oxygenate formation zone to produce an oxygenate product stream comprising at least one of methanol or dimethyl ether;
• b) passing at least a portion of the oxygenate product stream in the presence of a diluent to an olefin production zone containing a SAPO catalyst selected from the group consisting of SAPO-34 and SAPO-17 to produce a light olefin stream consisting essentially of olefins having 2 to 4 carbon atoms per molecule and a second water stream;
• c) admixing at least a portion of said second water stream with a make-up water stream to provide a water admixture and passing at least a portion of the water admixture to said syngas production zone to provide said water stream and at least a portion of said diluent;
• d) passing said light olefin stream to a first fractionation zone to provide a methane stream, an ethylene product stream, and a C.sub.3.sup.+ stream;
• e) passing said C.sub.3.sup.+ stream to a C.sub.3.sup.+ /C.sub.4 fractionation zone to provide a crude propylene stream, and a C.sub.4.sup.+ stream;
• and,
• f) passing a portion of said crude propylene stream and a portion of said second water stream to a first etherification zone to form a first ether product comprising diisopropyl ether and a first light ends stream.

A process for the production of light olefins and high octane ether from a hydrocarbon gas feedstream comprising methane and ethane, said process comprising:

• a) passing said feedstream and a first water stream to a syngas production zone to produce a synthesis gas stream comprising hydrogen and a carbon oxide, passing said synthesis gas stream to a methanol formation zone to produce a methanol product stream, and passing at least a portion of methanol product stream in the presence of a diluent to an oxygenate conversion zone containing SAPO catalyst at conditions effective to produce an effluent stream comprising olefins having 2 to 4 carbon atoms per molecule and water;
• b) separating said effluent stream into an olefinic hydrocarbon stream and a second water stream and recycling at least a portion of said second water stream to said syngas production zone to provide a portion of said first water stream and at least a portion of said diluent;
• and
• c) fractionating said olefinic hydrocarbon stream by successive distillation to provide an ethylene product stream, a crude propylene stream, and a C.sub.4.sup.+ stream and etherifying said crude propylene stream with another portion of said second water stream to produce a diisopropyl ether stream.