What are the key design considerations for a shell-and-tube heat exchanger?

Key considerations include: Tube-side vs shell-side fluid placement (corrosive, high-pressure, fouling fluids typically tube-side), TEMA standards selection (R for refinery, C for commercial, B for chemical), baffle design (segmental, disc-and-doughnut) affecting shell-side flow pattern and pressure drop, tube arrangement (triangular for better heat transfer, square for easier cleaning), number of shell and tube passes for desired approach temperature, material selection for corrosion resistance and thermal expansion, and proper venting/drainage. Pressure drop constraints often limit velocities (tube: 1-2.5 m/s for liquids, shell: 0.3-1 m/s) balancing heat transfer enhancement.