Method and apparatus for controlling effluent composition in oxygenates to olefins conversion

A process for controlling a circulating fluid bed methanol to olefin reactor to provide a substantially consistent effluent composition, which process comprises:

• contacting a methanol-containing feedstock in a reaction zone within a riser in the presence of a molecular sieve methanol to olefins conversion catalyst under conditions sufficient to provide an olefins-containing effluent containing methanol and dimethyl ether;
• analyzing within about five minutes a single gas phase of said olefins-containing effluent containing methanol and dimethyl ether to determine methanol concentration and dimethyl ether concentration of said effluent, from a time said single gas phase is provided from said olefins-containing effluent;
• adjusting reactor conditions as a function of said determined methanol concentration and said determined dimethyl ether concentration as necessary to provide said substantially consistent effluent composition, wherein said adjusting of reactor conditions is carried out by one or more of:
• a) varying WHSV within said reaction zone;
• b) varying the level of coke which deposits on said conversion catalyst within said reaction zone;
• c) varying the reaction temperature within said reaction zone;
• d) varying the amount of said methanol-containing feedstock provided to said reaction zone as a liquid, relative to the amount of said methanol-containing feedstock provided to said reaction zone as a vapor;
• or
• e) varying heat input to a feed pre-heater used for pre-heating said methanol-containing feedstock prior to said contacting with said conversion catalyst;
• and
• wherein said analyzing is carried out under conditions sufficient to permit said adjusting based on said analyzing to occur within about fifteen seconds from the time said effluent is provided.