What are the design considerations for a multitubular reactor with highly exothermic reactions?

Key considerations: tube diameter (smaller improves radial heat transfer but increases tube count and cost), tube length (conversion vs pressure drop), coolant selection and flow pattern (co-current vs counter-current vs isothermal bath), coolant temperature optimization (higher improves kinetics but may create hot spots), number of tubes for required capacity, hot spot temperature prediction (parametric sensitivity), runaway avoidance (operating diagram), and catalyst activity profile (consider graded activity). Use 2D pseudo-homogeneous or heterogeneous models for detailed design.