Ultrasonic cleaning against fouling

 2 min

Ultrasonic cleaning is an innovative technology for preventing deposits and fouling in industrial pipe systems. Fouling refers to unwanted contamination that settles on surfaces due to raw materials contained in liquids or materials added from outside. These deposits are caused, for example, by salts in water, paraffins in crude oil or organic substances such as sludge and sand. The particles continuously settle on pipe surfaces and impede both the flow velocity and heat transfer. This contamination leads to a measurable reduction in system efficiency due to reduced performance. Various industries are affected across all sectors, from the energy sector to mineral oil processing and paper manufacturing to the food industry.

Economic and ecological effects of contamination

Studies show that performance losses due to fouling lead to economic losses amounting to approximately 0.25 percent of the gross domestic product of industrialised countries. These losses amount to billions and represent an underestimated global phenomenon. Contamination in heat exchangers alone accounts for one to 2.5 per cent of global carbon emissions. As contamination progresses, the inlet pressure must be continuously increased to achieve a consistent output. The pressure increase has a negative effect on efficiency. Further clogging makes costly cleaning unavoidable, often requiring the dismantling of large assemblies.

This results in production interruptions lasting several days, combined with the use of large quantities of chemicals and water. Conventional cleaning methods include mechanical cleaning, high-pressure water jet cleaning or drilling out the pipes. However, these methods require the equipment to be opened and at least partial dismantling of the pipe systems. Water jet cleaning also relies on high pressures, which result in considerable water consumption and a significant risk of injury.

Vibration-based Fouling Prevention in Practice

Ultrasonic vibration technology takes a preventive approach to avoiding deposits. Ultrasonic vibrators are permanently attached to metal pipe systems and generate highly efficient micro-vibrations using frequencies in the kilohertz range. This technology of ultrasonic cleaning prevents deposits and fouling on surfaces from the outset and is easy to retrofit.Ultrasonic technology is already being used successfully in cement production and for silo discharge of powder or granulate. Active component excitation prevents clogging at outlets and hoppers. Smart control technology ensures an optimal vibration process and prevents damage to process equipment, weld seams or the loosening of screw connections.

A practical example from the specialty chemicals industry demonstrates the effectiveness of the technology: deposits in a heat exchanger led to efficiency losses within a short period of time and to increased energy consumption due to the additional pump pressure required. After installing four vibration systems at the top and bottom of the unit, fouling was significantly reduced and the service life under full load was increased by more than 30 percent.

This new system of ultrasonic cleaning resulted in significantly higher volume flow, better heat transfer and increased output. At the same time, costs were reduced considerably due to lower pump flows and less cleaning work. The system has been in operation since the beginning of 2021 and has delivered over 140 million ultrasonic pulses without failure. Long-term operation confirmed that no damage to the heat exchanger or the surrounding peripherals occurred. The ultrasonic transducers can be installed on existing pipes, equipment or heat exchangers using the plug-and-play principle. The active ultrasonic systems operate during ongoing production without interrupting production processes.

Source: Trade journals ‘Chemie Technik’ / ‘PORCESS’

Photo: Jack