Patent ID: 6303841
Filing Date: 2001-10-16
Classification: C07C,Y02P

Abstract:
A process for the production of an ethylene product stream from an oxygenate conversion effluent stream comprising hydrogen, carbon dioxide, water, methane, ethylene, ethane, propylene, propane, and C.sub.4 -plus olefins said process comprising:a) passing the oxygenate conversion effluent stream to a carbon dioxide removal zone to remove at least a portion of the carbon dioxide to produce a carbon dioxide depleted stream;b) passing the carbon dioxide depleted stream to a dryer zone containing a solid desiccant to remove water to produce a dry deethanizer feed stream;c) passing the dry deethanizer stream to a deethanizer zone to provide a light hydrocarbon feedstream comprising hydrogen, methane, ethylene and ethane, and a deethanized stream comprising propylene, propane, and C.sub.4 -plus olefins;d) passing the light hydrocarbon stream to a demethanizer zone operating at a demethanizing temperature greater than about -45.degree. C. to provide a bottom stream comprising ethylene and ethane and an overhead stream comprising hydrogen, methane, and ethylene;e) passing the overhead stream at effective adsorption conditions to an adsorption zone containing at least two adsorption beds, each of said adsorption beds containing a selective adsorbent to adsorb the ethylene on adsorption to produce an adsorber effluent stream comprising hydrogen and methane, and on desorption to produce a desorbed stream comprising ethylene and immediately following adsorption withdrawing a vent stream comprising hydrogen and methane in a cocurrent depressurization step which is terminated prior to the breakthrough of ethylene;f) regenerating the dryer zone with at least a portion of the adsorber effluent stream and at least a portion of the vent stream;g) passing the bottom stream to a C.sub.2 splitter zone to produce the ethylene product stream and an ethane stream; andh) combining the desorbed stream with the oxygenate conversion effluent stream prior to passing the oxygenate conversion effluent stream to the deethanizer zone.