Calumet Specialty Products Partners L.P.s board of directors named Timothy Go CEO effective Jan. 1, 2016. Go most recently served as vice president of operations for Flint Hills Resources, L.P. Previously, he spent nearly 20 years in senior level operations and management roles at ExxonMobil. Bill Hatch will remain interim CEO of Indianapolis-based Calumet until Dec. 31, and then remain an executive advisor to the partnership.