June 15, 2012. Pakistan State Oil's (PSO) two-year old plan to enter the refining business has finally made some headway as Khyber-Pakhtunkhwa (K-P) has agreed to allot 400 acres of land to set up a refinery. The proposed PSO refinery will produce 40,000 barrels per day, only 7,000 barrels less than Pakistan Refinery Limited. Pak-Arab Refinery Company is the largest player in the refinery business while the other main companies are Pakistan Refinery, National Refinery, Attock Refinery and Byco. As on June 13, PSO's total receivables stand at'217.45 billion and payables at'182.89 billion, showing the intensity of the circular debt.