Patent ID: 7586018

Claim:
A process for producing light olefins from an oxygenate-containing feedstock, the process comprising: contacting the oxygenate-containing feedstock in an oxygenate conversion reactor with an oxygenate conversion catalyst and at reaction conditions effective to convert the oxygenate-containing feedstock to an oxygenate conversion effluent stream comprising light olefins and C 4 + hydrocarbons, wherein the oxygenate-containing feedstock is selected from the group consisting of methanol, ethanol, dimethyl ether, diethyl ether, and combinations thereof, the light olefins comprise a quantity of ethylene and the C 4 + hydrocarbons comprise a quantity of diolefins and a quantity of butenes including a quantity of 1-butenes; separating the oxygenate conversion effluent stream in a separation zone and forming a first process stream comprising at least a portion of the quantity of ethylene from the oxygenate conversion effluent stream; dimerizing at least a portion of the quantity of ethylene from the first process stream in a dimerization zone to produce a dimerized stream comprising a residual quantity of ethylene, a quantity of butenes including a quantity of 1-butenes and a quantity hexenes; metathesizing at least a portion of the residual quantity of ethylene from the dimerized steam with at least a portion of the quantity of hexenes from the dimerized stream in a first metathesis zone to produce a first metathesis effluent stream comprising a quantity of butenes including a quantity of 1-butenes, and a quantity of propylene; isomerizing at least a portion of the quantity of 1-butenes from the first metathesis effluent stream in an isomerization zone to produce isomerized stream comprising a quantity of 2-butenes; metathesizing at least a portion of the quantity of 2-butenes from the isomerized stream with ethylene in a second metathesis zone to produce a second metathesis effluent stream comprising propylene; and recovering propylene from the second metathesis effluent stream.