Abstract: A nozzle, and hydrocarbon conversion process using the nozzle for atomizing heavy feed to conversion zone, are disclosed. A liquid feed stream is atomized by radial out-to-in impingement of atomizing vapor, discharged onto an imperforate central region of a perforated plate in one end of a nozzle barrel, then sprayed through an outlet in the other end of the nozzle barrel. Preferably two perforate plates are used, a first at one end of the nozzle barrel and a second between the first plate and the outlet, which is preferably an elliptical orifice.