Published September 2003
This Review provides an updated analysis of methanol to olefins conversion technology based on the use of aluminophosphate type molecular sieves. More specifically it focuses on technology disclosed in U.S. Patent 6,534,692 assigned to UOP (issued March 18, 2003) and evaluates its use in a plant sized to consume ~5000 ton/day methanol produced from low cost (50¢/MM btu) natural gas. The patent claims a metalloaluminophosphate catalyst composition with specific crystalline morphology. The evaluation is based on the following performance data provided in the patent for one of the claimed catalyst compositions: C2-C4 olefin selectivity 95 mol%; C2/C3 selectivity 83.7 mol%; C2/C3 mol ratio 1.36; methanol conversion 99%.
Process simulation calculations established the following productivity (lb/yr) for the plant on-stream 8000 hr/yr: ethylene 644,160,000; propylene 711,784,000; butylenes 209,880,000. Total Capital Cost was estimated as $205 MM (Battery Limits $148 MM; Offsites $57 MM) and Product Value at 25% B/T ROI as 20.4 ¢/lb ethylene+propylene. Economics for the project is essentially dependent on three factors: methanol price; ethylene market price; propylene market price. In one pricing scenario, if methanol is priced at 5.46 ¢/lb (estimated transfer price from the 5000 ton/day plant noted above) and ethylene and propylene are priced at their respective last 5 year averages (24.6 and 18.6), the project returns a respectable 29.2 % B/T ROI. If this market trend continues the subject technology clearly can compete with conventional steam cracking routes to the olefins.
