Formosa Petrochemical Corp., Taiwan's only publicly traded oil refiner, will shut its No. 2 crude distillation unit in November for maintenance.

The closure will last between 40 and 50 days, company spokesman Lin Keh Yen said by telephone in Taipei today. The Mailiao-based refiner will also shut an 80,000-barrels-a-day vacuum distillation unit and a 36,000 barrels-a-day delayed coker.

Formosa Petrochemical has three crude distillation units, each with a capacity to process 180,000 barrels a day. These units, which comprise the bulk of refineries, heat crude oil to separate it into different fuel products.

The delayed coker processes asphalt produced at the vacuum distillation unit, Lin said. The vacuum distillation unit turns heavier fuels into higher-value, lighter petroleum products