Heat Exchangers Types of heat exchangers Constraints on temperature differences Materials Costing

Shell-and-Tube Heat Exchanger

Double-Pipe Exchanger

Spiral Heat Exchanger

Plate Heat Exchanger

Shell-and-Tube Heat Exchanger

Shell and Tube Exchanger Terms Fanaritis, J.P., Bevevino, J.W. "Designing shell and tube heat exchangers". Chemical Engineering, 83(13), 62-71, Bayonet type - floating inner tubes and floating heads for large temperature differences

Heat Exchanger Selection Brown, 1985

Air-Cooled Exchangers Design for worst case - summer air temperatures of  C Typical approach temperature is 50 C  Maximum process fluid temperature ca. 260  C Typical inlet process fluid temperature < 150  C Ganapathy, 1978; Ulrich, 1982

Air-Cooled or Fin-Fan Exchanger

Air Cooling vs Water Cooling Air cooling (+) corrosive water pollution water consumption maintenance Water cooling (tower) (+) temperature control space freeze up noise achievable T power

Heat Integration Temperature profiles –crossovers –phase changes –correct delta T Keeping heat in the process saves utility costs –integrated processes save money –heat exchangers (always) leak

T cross

Design Equation Q=amount of heat transferred (from process design) A=heat exchanger area MTD=mean temperature difference=f  T LM f=correction factor for exchanger geometry f=1 for true counter-current; f<1 when cross-flow