Until now, absolutely oil-free compressed air for sensitive applications could only be produced using relatively costly, often interconnected compressor- and filter-based technology. In many cases not entirely re-liably. Now a newly developed and effective catalysis method and an extremely reliable residual-oil monitoring system point the way to the future of permanent high-quality compressed-air processing and moni-toring.
In numerous fields of application, class 1 compressed air which, according to DIN ISO 8573-1, is technically oil-free, is far from clean enough. In accor-dance with this guide-value classification, the maximum oil content (including oil vapour) must not exceed 0.01 mg/m? compressed air. This amount is already so minuscule that it can hardly be detected.
Nevertheless, for many compressed-air applications, this amount is still completely unacceptable, for example for medical engineering, phar-maceutics, measurement technology, food processing, and for the packaging of foodstuff and medicaments, or the provision of certain breathing gases.
In these fields, absolutely oil-free compressed air with a residual-oil content of partially less than 0.003 mg/m? is required.
Up to now, two technical solutions have mainly been used to try and achieve this aim: oil-free-functioning or oil-lubricated compressors, followed by com-pressed-air processing using activated carbon. However, specific weaknesses of these methods continue to exist. Even oil-free-compressing compressors, for example, do not guarantee reliability under most application conditions as compressed-air quality may be affected, depending on the inlet air. This will be the case, for instance, when oil vapours escape during the ventilation of the gearbox casing, an almost permanent effect that can be observed with large compressors. The downstream systems are not always capable of reducing the residual oil content in the system to the required extent – not to mention an effective continuous residual-oil monitoring.
In most cases, a considerable uncertainty regarding a permanent, absolutely reliable quality of the processed "oil-free" compressed air remains, in spite of all efforts.
A new catalysis method, developed by Beko Technologies GmbH, the Ger-man compressed-air specialist, makes all these weaknesses of previous solu-tions a thing of the past. And a residual-oil monitoring system ensures perma-nent process reliability.
Absolutely oil-free compressed air in a single process step
What do we mean by this? In summary, the Bekokat system effects total oxi-dation of hydrocarbons which actually results in oil-free compressed air. And this in a concentrated, comprehensive process step after compression, mean-ing that the complete oil removal from compressed air takes place in only one individual plant component. This functions independently of the ambient condi-tions, of the initial oil concentration and of the relative humidity of the com-pressed air.
Bekokat treats all contaminations in the compressed air supplied by the com-pressor. These are usually lubricants, oils, sulphur dioxide, carbon monoxide etc. They exist in the form of gases, vapours and aerosols. Via the Bekokat method, such air components are completely converted into carbon dioxide and water.
Effective and environmentally friendly
In the Bekokat, granular material serves as the catalytic converter, which is heated up to an operating temperature of approx. 150 °C by means of heating elements. In the catalytic converter, the oil molecules are broken down until only one carbon atom remains. In the final catalysis phase, the oil molecules are oxidised down to H2O and CO2.
In the next stage of the process, the purified compressed air is cooled down in a heat exchanger to approx. 10 to 15 °C above the inlet temperature, and is available for the respective application.
With Bekokat, it is for the first time possible to constantly achieve absolutely oil-free compressed air with a barely measurable maximum residual-oil con-tent of 0.003 milligram per cubic metre of compressed air. This is the quality required in the most demanding fields of medicine, pharmaceutics, food proc-essing and food packaging.
Even the condensate which accumulates during the cooling of the com-pressed air is completely oil-free thanks to the catalytic method, and can be introduced into the sewerage system without being processed. So the Bekokat principle is not only highly efficient but also fully environmentally friendly.
The enormously long service life of the special granular material of the Beko-kat is also extremely advantageous as far as profitability is concerned: it only needs to be replaced after a good 20,000 hours.
Controlled performance for tested quality
Solid quality monitoring of the oil-free compressed air is as important as its constantly reliable processing, in particular in the aforementioned sensitive fields of application. However, up to now there has been a lack of solutions which were also feasible and efficient, primarily with regards to the high-precision online test during running operation.
With the innovative Oil Control residual-oil monitoring system, Beko has also achieved substantial progress in this respect. Thanks to this system, the pre-viously oft-practised procedure with time-consuming samplings and laboratory evaluations which were only temporarily representative, belongs in the past.
Instead, the Beko system allows permanent online oil-content monitoring of the flowing compressed air via measurements using an ion-exchange method. The sensitivity of the Oil Control sensor guarantees early detection of an in-creasing oil content caused, for example, by a defective filter. This reliably prevents consequential damage to machines and products.
The fact that the device easily copes with the maximum requirements on the monitoring quality regarding medical and foodstuff-related compressed air applications is remarkable and characteristic of the efficiency of Oil Control. To be more concrete: even the most extreme limit values of a residual-oil content of 0.001 mg/m? can be continuously monitored online with Oil Control during running operation.
Three versions
Beko Instruments offers three Oil Control versions: the Oil Control OCC for a compressor monitoring up to 100 mg/m?, the Oil Control OCF for the monitor-ing subsequent to compressed-air processing from 20 mg/Nm? to 0.01 mg/Nm?, and the Oil Control OCA for the monitoring of the compressed air downstream of activated-carbon filters and catalytic converters from 1.0 mg/Nm? to 0.001 mg/Nm?. The scope of delivery includes a probe, a metering cell and an evaluation unit and, optionally, a data logger and software.
The Oil Control monitoring system corresponds to ISO 8573. It functions relia-bly in a temperature range between 0 and +60 °C, independent of varying flow rates and unaffected by humidity. The admissible operating overpressure is 10 bar as standard), 16 and 45 bar are optionally possible.
A new evolution stage of compressed-air processing
By combining both, the Bekokat catalysis method and the Oil Control residual-oil monitoring system technologies, compressed air processing reaches a new quality level.
A quantum leap in evolution which guarantees users in demanding fields sig-nificantly more process reliability and profitability for the application of abso-lutely oil-free compressed air.
