Clean-in-place optimization using swirl pipe and ultrasonic monitoring

Clean-in-place (CIP) is a method of cyclic cleaning of production equipment and pipelines in a closed loop without the need for dismantling and is commonly used in the food and drink sector. The consumption of energy and water resources in the CIP process has always been a significant problem with negative environmental and economic impacts. This study introduces a swirl pipe to enhance CIP efficiency by generating a swirl flow that enhances the mean wall shear stress and its fluctuation, both critical for fouling removal. An ultrasonic measurement system was employed for real-time monitoring to detect the endpoint of the ketchup fouling cleaning process. Results showed that the swirl pipe improves CIP efficiency, achieving a 38.7 % increase in cleaning efficiency at a flow velocity of 0.7 m/s and a 42.7 % increase at 1 m/s at the swirl pipe outlet. Higher flow velocities further amplify the swirl effect, enhancing cleaning efficiency. As industrial CIP systems typically operate at higher velocities, the improvement in cleaning efficiency is expected to be more significant in practical applications. Although the swirl pipe effectively reduces cleaning time, its performance is influenced by the downstream distance, with impact diminishing as the distance increases. To address this limitation in industrial settings, the use of multiple swirl pipes can maintain the swirl flow and ensure consistent cleaning performance across extended pipelines. These findings offer actionable insights for optimizing CIP processes, potentially reducing water, energy, and chemical consumption, thereby improving sustainability and operational efficiency in industrial applications.