The U.S. sanctions on Chinese tanker firms and the increased tensions in Middle Eastern waters have spoiled what many refiners had anticipated could be a bumper Q4 quarter just ahead of the new rules on cleaner shipping fuel taking effect in January 2020. The global shipping industry has seen freight rates soar over the past few weeks as traders and shippers stay away from booking oil tankers owned by Chinese tanker companies that came under U.S. sanctions for dealing with oil from Iran. The cost of chartering supertankers to carry crude oil from…