»
Optimisation & Design
Comparative analysis: Splash baffles vs. demisters
Design and operation Splash baffles rely on turbulence and gravity to separate larger droplets within the heat exchanger, making them a passive, low-maintenance solution. Demisters, positioned at the outlet, use structured surfaces to capture fine droplets through impaction and interception, offering superior separation but requiring more complex designs.
Performance:
• Droplet size: Splash baffles are effective for bulk liquid separation but struggle with fine mists. Demisters, particularly fiber bed types, can capture droplets as small as 0.1 microns, making them ideal for highpurity requirements.
• Efficiency: Demisters achieve higher separation efficiency, especially in applications demanding minimal entrainment. Splash baffles provide adequate performance for less stringent processes.
• Pressure drop: Splash baffles introduce negligible pressure drop, while demisters, particularly mesh types, can increase resistance, impacting energy efficiency.
Cost and maintenance Splash baffles are cheaper to install and maintain due to their simplicity. Demisters, while more expensive upfront, offer long-term benefits in applications requiring high efficiency. However, their maintenance needs( e. g., cleaning mesh pads) can increase operational costs.
Selection criteria Choosing between splash baffles and demisters depends on system priorities:
• For minimal pressure drop and cost: Splash baffles are preferable in heat exchangers where bulk separation is sufficient.
• For high-efficiency mist removal: Demisters are the better choice for applications requiring fine droplet capture, such as chemical processing or pollution control.
• For comprehensive separation: Combining splash baffles( for bulk liquid) and demisters( for fine mist) can optimize performance in complex systems.
Key design considerations include droplet size distribution, gas velocity( typically 1 – 4 m / s for demisters), material compatibility, and fouling risks. Engineers must also balance pressure drop against separation efficiency to meet process goals.
Industry perspectives In heat exchanger applications, splash baffles are favored for their simplicity and effectiveness in kettle-type designs, particularly in oil and gas processing. However, industries like petrochemicals and refining often prefer demisters for their ability to ensure high vapor purity, critical for downstream processes. In chemical plants, demisters are standard in separators to recover solvents and prevent contamination. The choice ultimately hinges on process constraints, maintenance capabilities, and efficiency requirements.
Figure 4. Wire mesh-type mist eliminator for kettle heat exchanger.
Conclusion Splash baffles and demisters play complementary roles in vapor-liquid separation, each addressing specific needs in heat exchangers and chemical engineering systems. Splash baffles offer a cost-effective, low-maintenance solution for bulk liquid separation, ideal for simpler heat exchanger designs. Demisters provide superior efficiency for fine droplet capture, making them essential in high-purity applications across industries. By carefully evaluating system requirements— such as droplet size, pressure drop tolerance, and maintenance feasibility— engineers can select or combine these technologies to optimize performance, enhance process reliability, and reduce operational costs.
About the author
Ali Dehghani is a Junior Mechanical Engineer with expertise in the design and analysis of heat exchangers. He holds a master’ s degree in mechanical engineering with a focus on thermal management of small satellites using phase change materials, heat pipes, and Nano fluids. Ali has over three years of industry experience and is currently working at EIED( Energy Industries Engineering and Design). He has contributed to several projects involving passive thermal control and advanced heat transfer systems. He can be reached at Ali. dehghani1372 @ gmail. com.
About the co-author
Sara Kafashian is a Senior Mechanical Engineer with nearly 17 years of experience in the oil, gas and energy industries, specializing in heat transfer and thermal systems. My work focuses on design, optimization, and performance analysis of heat exchangers across various industrial applications. With hands-on expertise in engineering and project management, I am passionate about advancing efficient, innovative, and sustainable thermal solutions.
36 Heat Exchanger World July 2025 www. heat-exchanger-world. com