An apparatus and a method for mixing and atomizing a hydrocarbon stream is disclosed. The apparatus comprises of an inner conduit having a first inlet for receiving the hydrocarbon stream, and a second inlet for receiving a primary dispersion stream. The inner conduit produces a primary mixture comprising the hydrocarbon stream and the primary dispersion stream. The apparatus further includes an outer conduit having a third inlet for receiving a secondary dispersion stream. Further, said inner and outer conduits together define an annular passage. The distal end of the annular passage defines a second set of orifices for allowing the secondary dispersion stream flowing there-through to come in contact with the primary mixture and thereby dispensing the secondary mixture so obtained through an outlet.