Compressed air treatment at a beverage industry plant

The eight bottling lines of RheinfelsQuellen are supplied through two separate compressed air systems pressurized by two independent compressor stations. The conventional processing air system includes five screw compressors with capacities of between 90 and 120 kW. A frequency-controlled compressor provides the basic air flow, while the other units are automatically switched on and off as required.

The second, smaller system is pressurized by a 50-kW oil-free compressor and supplies oil-free compressed air to dedicated consumption points. Compressed air of this high quality is required in sensitive sections of the bottling plant. De-pending on the application, the oil-free compressed air needs to be sterile, for instance at fillers where products free of CO₂ are transferred into containers or tanks, and the carbon dioxide at the top of is to be replaced with sterile air. Oil-free compressed air is also required in date printers at filling stations to prevent the ink from blocking the minute print nozzles. It is equally indispensable for the operation of precision valves used for the highspeed transport of bottles or the labelling of pallets.

By running a single oil-free compressor, they have eliminated all unnecessary redundancy in this small compressed air system. In the event of a compressor failure, there is no need to panic, as their innovative catalysis technology provides a safety net.

The catalysis technology enables Rheinfels Quellen to feed the oil-free compressed system from our five conventional screw compressors without any risk of oil contamination. This is achieved by means of a switchover unit installed between the two compressed air systems. In other words: they can always supply all consumption points with perfectly oil-free compressed air, irrespective of the compressor type.

This is made possible by the BEKOKAT solution developed by BEKO TECHNOLOGIES GmbH, a compressed air system supplier based in Germany. The BEKOKAT is a compact unit that removes hydrocarbons from the compressed air through total oxidation, breaking them up into carbon dioxide and water

In the BEKOKAT, a special granular material serves as the catalyst. This material is heated by heating elements to an operating temperature of around 150° C. The oil molecules are broken down into compounds that only contain a single carbon atom. In the final phase of the catalysis, the oil molecules are oxidized to H₂O and CO₂.

The entire catalytic process is performed over seven steps. Initially, the sub-stances to be removed, i.e. the oil molecules in the contaminated compressed air, are diffused to the surface of the granules. Subsequently, the reactants are diffused into the pores and absorbed. This process is followed by a surface reaction. In a next step, the reaction products are desorbed and subsequently diffused from the pores. Diffusion into the homogeneous phase concludes the process.

For the process to be effective, the hydrocarbon chains that form the oil molecules must be completely broken up into carbon dioxide and hydrogen. The BEKOKAT has no problems doing this and can break up hydrocarbon chains of any lengths, whether they originate from the ambient air or the compressor lubricants. In the same catalytic process, the BEKOKAT also eliminates polar compounds such as olefins, alcohols, glycols and ketones. The purified compressed air is subsequently cooled to a temperature that is approx. 10 to 15 K below the inlet temperature, and is now ready for use.

The BEKOKAT is the only system in the world ensuring a constant supply of oil-free compressed with a maximum residual oil content of as little as 0.003 milligram per cubic meter. The compressed air treated in the BEKOKAT thus meets the stringent requirements of the medical, pharmaceutical, food processing and packaging industries. The catalytic system is not only highly efficient but also cost-effective, as the special granular material used in the BEKOKAT only needs to be changed every 20,000 operating hours.