RIYADH - Yanbu Aramco Sinopec Refining Co (Yasref) is operating its refinery at full capacity, its chief executive said on Wednesday, after the plant reduced run rates earlier this month. “From our perspective, we operate based on refining margins. We had very low margins in August so we took advantage of it and did some pending maintenance. But in September margins improved and now we see better margins,” Mohammad Alshammari, chief executive of Yasref, told Reuters by telephone. “Now the refinery is working at full capacity,” Alshammari said. This month, sources told Reuters that Yasref was operating at 75 percent capacity, potentially boosting product margins as several plants in Asia and the Middle East undergo maintenance. The refinery, which began operations at full capacity in July, is a joint venture between Saudi Aramco and China’s Sinopec.