Oil-free compressors with energy recovery aid plant efficiency

The installation uses hot water from the compression process together with latent heat from the automated plant's boilers and refrigeration units to pre-heat its CIP water that is used to clean and sterilise the product lines and bulk storage tanks after they have been emptied during the bottling procedure.

By any measure, the vital statistics at Accolade Wines' Avonmouth plant are impressive: each of the two high-speed bottling lines is capable of producing over half a million bottles of wine a day running at the rate of 400 bottles per minute and totalling 200 million bottles per year. In addition, there are three bag-in-box lines producing 45 boxes per minute in various volume formats from 2.25 litre to 10 litre. Overall, Accolade Wines fills the equivalent of 21 million nine-litre cases of wine each year, 18 million of which are for the company's own brands such as Hardy's and Echo Falls, with an additional three million for producers and retailers, including a leading supermarket's own-label products.

Compressed air is an essential part of the plant control pneumatics involved in the bottling line filling operations, and this is met by an Atlas Copco compressed air installation comprising two water-cooled ZR90 VSD oil-free rotary screw compressors together with a fixed-speed ZR75 machine.

Within a large-scale facility such as Accolade Wines' Avonmouth plant, production and energy efficiency is paramount and was a key factor when choosing the compressor installation. Julian Rainbow, the plant's Utilities & Process Engineering Manager, explains: "It was designed from the outset to minimise energy usage by employing the best available techniques, which is why we chose Atlas Copco ZR oil-free compressors. What's more, the service team are very knowledgeable and the support we have received from them has been outstanding."

There is also an added energy-saving bonus from the heat recovery capability of the three water-cooled ZR compressors: heat from the air compression process is generated and transferred to the cooling water through the compressor's internal components to provide hot water at 80degC. This can be used for process operations such as the cleaning of the 84 bulk storage tanks, each with the capacity to store 55,000 litres of wine that has been transferred from shipping containers.

Certified by the TV

Compressed air users, who, like Accolade Wines, integrate the flow of hot water into their plant processes, are able to recover up to 90-95 per cent of the compressor's electrical energy input as hot water. This is achieved successfully with Atlas Copco's ZR series of water-cooled, oil-free, 55 to 900 kW compressors. These compressors have been certified by the TV, the independent testing and accreditation organisation, as capable of recovering up to 100 per cent of the electrical input energy as hot water under specific design conditions: 40degC, 70 per cent humidity of the intake air, 20degC cooling water inlet temperature and 10 bar(e) working pressure.

For Accolade Wines, Atlas Copco compressors were not only chosen for their energy recovery potential but also to ensure the quality of the consumer products. Because of the vital requirement within the production operations for pure, uncontaminated process air that comes in contact with the finished products, guaranteed 100 per cent oil-free air was a mandatory feature of the installation. This requirement has been assured with the installation of Atlas Copco compressors that have been certified by the TV according to the ISO 8573-1- Class 0 standard.

For more information about Atlas Copco oil-free compressors and energy recovery, visit the website at www.atlascopco.co.uk.