A system for calcination of oil green coke has a rotating furnace and a rotating cooler, the furnace being serviced by boiler, a combustion chamber and a chimney. There is a feeding system defined by a first mat carrying the green coke into a silo and another mat transporter to feed the furnace. At the end of the silo there are two discharge breadths for the oil green coke, where each breadth has two drawer-like feeders for feeding the green coke onto the mat transporter and, from this to the inside of the rotating furnace through a fall set.