Efficiency of heterogeneous reactions is influenced by kinetic conditions with an emphasis on reactants in different phases to have effective interactions. Optimal interactions of reactants rely on the rational design of the equipment and engineering parameters for the reaction process, especially for the process on a large scale. 188W production at the Oak Ridge National Laboratory is such an example. In processing the irradiated 186W metal target for the 188W product, two of the heterogeneous reactions are essential ones: (1) the gas–solid reaction of O2 + W to form WO3 and (2) the gas–liquid reaction of OsO4 being absorbed by the NaOH sorbent. Better understanding of the two reactions has led to revisions to the design of the quartz reaction vessel (gas–solid reaction) and the scrubbing system (gas–liquid reaction). The optimized quartz vessel resulted in less heating hours, whereas a more efficient OsO4 scrubbing system ensured that all volatile OsO4 was qualitatively captured.