Patent ID: 7371916
Filing Date: 2008-05-13
Classification: C07C,Y02P

Abstract:
1. A continuous process for selective conversion of a methanol feed to propylene comprising the steps of: a) contacting the methanol feed with an acidic alumina catalyst in a first reaction zone at etherification conditions effective to form a DME-containing effluent stream and to shift at least 10% of the exothermic heat of reaction liberated when methanol is converted to propylene from the subsequent propylene synthesis step to this etherification step, thereby heating the DME-containing effluent stream to a temperature of about 250 to 450° C. and producing by-product water in an amount of at least 0.5 mole per mole of methanol converted; b) adjusting the temperature of the resulting DME-containing effluent to a range of about 375 to 525° C. and adding diluent thereto to produce a heated mixture of DME, unreacted methanol and diluent; c) reacting the resulting heated mixture with dual-function catalyst particles containing a molecular sieve, having the ability to convert the oxygenates contained therein to C d) passing the propylene-containing effluent stream to a separation zone and therein cooling and separating this effluent stream into a vaporous fraction rich in C e) recycling at least a portion of the water fraction recovered in step d) to step b) to provide at least a portion of the diluent added therein; f) separating the vaporous fraction into a C g) recycling at least a portion of the C h) withdrawing coke-containing dual-function catalyst particles from the second reaction zone, oxidatively regenerating the withdrawn catalyst particles in a regeneration zone and returning a stream of regenerated catalyst particles to the second reaction zone.