MOSCOW (MRC) -- Private equity company Carlyle Group will increase its stake in Varo Energy by buying out one of two other partners in the Swiss refining firm, the companies said, said Hydrocarbonprocessing.Carlyle is part owner of Varo with Dutch investment firm Reggeborgh and energy trader Vitol. Varo said Carlyle would raise its share by acquiring Reggeborgh's interest.Varo owns Switze