Methanol to olefin process with increased selectivity to ethylene and propylene

摘要

A process for converting methanol to light olefins is disclosed and claimed. The catalyst is a metalloaluminophosphate molecular sieve having the empirical formula (ExAlyPz)O2 where EL is a metal such as silicon or magnesium and "x", "y" and "z" are the mole fractions of EL, Al and P respectively and specifically where "x" has a value of about 0.02 to about 0.08. A preferred molecular sieve is one which has predominantly a plate crystal morphology in which the average smallest crystal dimension is at least 0.1 microns and has an aspect ratio of no greater than 5. The process provides greater selectivity to ethylene and propylene versus C4+ byproducts.