PX spreads dipped to below $300 per ton in 2014 due to supply increase amid sluggish demand, after staying between $500 and $700 per ton in the early 2010s. The break-even point for local refiners is estimated at some $250 per ton.

Paraxylene, derived from crude oil, is used as a raw material in producing polyester.

The recent surge in PX spreads is caused by some foreign rivals suspending their production facilities due to technical glitches.

No. 1 oil refiner SK Innovation and its affiliates have a total PX capacity of over 3 million tons, followed by S-Oil with 1.8 million tons, Hanhwa Total with 1.77 million tons, GS-Caltex with 1.35 million tons and Hyundai Oilbank with 1.18 million tons, sources said.

Last year, despite global oil prices hitting a multi-year low due to a supply glut, local oil refiners pocketed decent earnings on the back of improved cracking margins.

The country's four major oil refiners -- SK Innovation, GS Caltex, S-Oil and Hyundai Oilbank -- logged a combined operating income of 4.79 trillion won ($3.99 billion) last year, which presents a four-year high and marks a sharp turnaround from the previous year's almost 1 trillion won operating loss. (Yonhap)