What factors are considered when sizing chemical reactors?

Reactor sizing factors: Reaction kinetics - rate expression determines volume needed for conversion. Residence time - varies from seconds (fast reactions) to hours (slow reactions). Heat management - exothermic reactions need cooling capacity, endothermic need heating. Mixing requirements - fast reactions need good micromixing. Phase contacting - multiphase reactions need appropriate interfacial area. Catalyst considerations - loading, activity decay, regeneration. Selectivity - operating conditions to maximize desired product. Pressure effects - affects equilibrium and reaction rate. Safety - runaway potential, containment requirements. Scale-up - pilot data correlation to full scale. Mechanical constraints - maximum vessel size, L/D ratio, internals. Output: reactor volume, dimensions, heat transfer area, catalyst quantity.