Heat Exchanger Expert

Before Starting

1. Which exchanger type? (shell and tube, plate, air cooler)
2. New design or rating of existing exchanger?
3. Which fluids and operating conditions?

Core Expertise Areas

Heat Exchanger Design

Overall heat transfer coefficient: 1 over U = 1 over hi + rf_i + t over k + rf_o + 1 over ho. LMTD method: Q = U times A times LMTD times F, F is correction for non-counterflow. Effectiveness-NTU: use when outlet temperatures unknown, useful for rating. TEMA standards: Tubular Exchanger Manufacturers Association, designates shell and tube types.

Shell and Tube Design

Tube side: fluid in tubes, higher pressure service, easier cleaning. Shell side: fluid outside tubes, baffles direct flow, lower pressure drop. Baffle design: segmental baffles, 25% cut standard, spacing affects heat transfer and pressure drop. Tube bundle: fixed, floating head, or U-tube for thermal expansion accommodation. TEMA types: E, F, G, H, J, X shells with different flow configurations.

Fouling

Fouling resistance: rf added to thermal resistance, reduces effective U. Types: particulate, crystallization, corrosion, biological, polymerization fouling. Mitigation: velocity above 1 m/s, smooth surfaces, chemical treatment, periodic cleaning. Oversurface: design with extra area to account for fouling over run length.

Heat Integration

Pinch analysis: identify maximum energy recovery from process hot and cold streams. Minimum utility: set by pinch temperature, determines minimum heating and cooling. Heat exchanger network: match hot and cold streams to minimize utility use. Above and below pinch: never transfer heat across pinch point.

Best Practices

• Use TEMA fouling factors appropriate for fluid and service
• Verify tube velocity above minimum to prevent fouling and below maximum to prevent erosion
• Check thermal expansion accommodation in fixed tubesheet design
• Perform vibration analysis for shell-side cross flow over tubes

Common Pitfalls

Pitfall	Fix
LMTD correction factor too low	Consider different configuration or multiple shells in series
Excessive pressure drop	Optimize baffle spacing and tube count
Ignoring nozzle pressure drop	Include nozzle losses in hydraulic design
No provision for cleaning	Design removable bundle or cleaning access for fouling service

Related Skills

• heat-transfer-expert
• process-design-expert
• process-simulation-expert