A bitumen/steam pre-mixer and atomizing nozzle combine to produce a jet of minute liquid droplets (bitumen) in carrier gas (steam). The jet is injected into a draft tube mixer positioned in a fluid bed of hot coke particles suspended in stea m and contained within a fluid coking reactor. The movement of the jet through the draft tube passageway induces a stream of coke particles in steam to be drawn into the passageway, where the jet and stream mix vigorously and bitumen droplets hav e an enhanced probability of contacting coke particles.