The Methyl Tertiary Butyl Ether (MTBE)  

Built in 1993

Capacity 18,000 BPD 

Designed to process a mixed  butanes - butenes feed producing MTBE  product by a selective reaction of  isobutene and methanol.  The unit can  be divided into five sections a) Feed  Section, b) MTBE Reactor Section, c)  MTBE Recovery Section, d) Methanol  Extraction Section, and e) Methanol  Recovery Section (Figure 1.0).  The feed preparation system consists of  a water wash tower (T-7701) which  reduces the basic nitrogen content of the  feed. Nitrogen is poisonous to the MTBE  catalyst. A coalescer is used to prevent  water carryover into the reactor system.   Methanol is added to the feed on ratio  control and the mix flows through the two  reactors in a series flow (R-7701 and R 7702).  As the feed/methanol mix flows  through the Cationic (Acidic) resin beds,  the isobutene and methanol react to form  MTBE.  The MTBE Unit is designed to  convert 96% of the isobutene to MTBE  with approximately 80-90% of the  conversion taking place in the first  reactor.  The reactor system effluent  flows to the debutanizer (T-7702) where  the unreacted butanes and methanol are  taken overhead and the finished MTBE  flows from the tower bottom to storage.   The butane/methanol mix from the  overhead flows to the methanol recovery  system.  The mix is fed to the bottom of  the methanol extractor (T-7703). The  methanol is removed using water flowing  down the tower.  The methanol-free  butanes flow from the top of the tower  through a coalescer and on to the  Alkylation unit for further processing.   The methanol rich water from the  extractor bottom flows into the methanol  stripper (T-7704) where the methanol is  removed overhead to be re-injected into  the incoming feed. The methanol-free  water is circulated back to the extractor  to complete the cycle.  Fresh methanol is  brought in on level control to replace the  methanol consumed in the reaction  forming MTBE