(54a) New Route to Paraxylene

Traditional methods for producing paraxylene use naphtha as the exclusive feedstock source. The naphtha is catalytically reformed to mixed xylenes, from which paraxylene is recovered and the other C8 aromatics are recycled through isomerization to generate additional paraxylene. Because the equilibrium concentration of paraxylene in the mixed xylenes is on the order of 22 ? 24%, the xylenes-based route to PX requires large recycle streams and consequently high capital and operating cost. Additionally, naphtha is derived from crude oil, which is in relatively lower supply than natural gas.

New technology is introduced to use methanol as a raw material for producing paraxylene. The methanol is selectively reacted with toluene to paraxylene at high concentration, which greatly reduces the recycles required by the traditional method. Also, the long-term raw material costs of the methanol and toluene will be lower than mixed xylenes. This permits a favorable economic prospect for paraxylene producers.

This presentation gives an update on the toluene methylation technology, how it is applied in grassroots or revamp applications, and an economic comparison to conventional methods for paraxylene.