Delta Air Lines Inc is preparing to market gasoline from a refinery it owns outside Philadelphia, signaling a shift in strategy toward managing the plant as a commercial refiner rather than a dedicated jet fuel supplier. Delta became the first airline to own a refinery when it bought the shuttered plant in 2012, hoping to turn the facility into its own jet fuel supplier and capitalize on cheap oil supplies from a boom in U.S. shale output. Instead of marketing the gasoline and diesel from the 185,000 barrels per day Monroe Energy plant, until now Delta has swapped the billions of dollars of motor fuel for jet fuel under a contract with Phillips 66 that is set to expire next year. Now, Monroe is ramping up to sell […]