A systematic engineering study on continuous synthesis of bismuth metal nanoparticles by vapor condensation in tube flows is presented. Simulations of aerosol nucleation, condensation and coagulation are cast in a design diagram format to guide experimental Studies on the effect of process parameters on product nanoparticle characteristics. Flow visualization, tracer gas analysis and computational fluid dynamics are used to unravel the effect of particle residence time distribution on product morphology during evaluation of alternate quenching designs for the metal vapor. Bismuth nanoparticles of average diameter 12-37 run, as determined by nitrogen adsorption and X-ray diffraction, were made by controlling the quenching gas flow rate, carrier gas flow rate and process pressure.