Compressor manufacturer Mattei has installed an AC30sH compressor at an E.ON combined heat and power (CHP) site in Stoke-on-Trent, following a data logging exercise to assess the efficiency of the existing compressed air system. The AC30sH has replaced one of two existing Mattei machines, and, combined with the installation of dew point switching devices for two ancillary dryers, estimated energy savings are in the region of 51 per cent.

 Owned and operated by E.ON UK CHP, the £40 million CHP plant in Stoke-on-Trent comprises a gas turbine, a heat recovery boiler and steam turbine, together being capable of producing around 60MW of electricity and 60 tonnes per hour of steam. The plant supplies both the electricity and steam to a Michelin Tyre factory – which shares the site – on a continuous 24-hour basis, with the steam being used during the manufacturing process.  To ensure Michelin Tyre has complete security of supply, the plant has three standby boilers, which can each produce 20 tonnes of steam per hour, and the local grid provides back-up electricity. Furthermore, the boilers are capable of using fuel distillate as well as gas.

 Mattei recently carried out a data logging exercise for E.ON to determine if a more energy efficient compressed air solution could be provided. The data ­logging exercise enabled Mattei to recommend the replacement of one of the two Mattei AC2030H existing compressors with a more energy efficient AC30sH compressor. This, the smallest of Mattei’s 30kW compressors, was thought to be most suitable for improving efficiency in this application, while offering the best return on investment for E.ON.

The evaluation also highlighted that fitting dew point dependant switching devices to two ancillary desiccant dryers would also achieve energy savings. The dew point dependant switching devices continually monitor the moisture content of the discharged air, so compressed air is only used to purge dry the desiccant when necessary.

The Mattei AC30sH compressor has been operating for several months, and further data logging evaluation proved the system is performing to within 1.5 per cent of the projected energy savings. Neil Price, performance co-ordinator at E.ON, says: “The utilisation of CHP – a microgeneration technology that increases efficiency and reduces carbon emissions – means we run a very efficient operation at Stoke-on-Trent. Therefore we welcomed Mattei’s review of our ­compressed air system, and the fact we’ve been able to improve its efficiency by around 50 per cent.”

 Martin Chitty, business development manager at Mattei, says: “This project is another example of Mattei’s commitment to reducing our customers’ ­energy costs and carbon emissions. At Mattei we are focused on finding appropriate solutions for individual cases, as we know that to operate efficiently, a compressor has to suit the application it’s being installed in. The AC30sH was the most suitable choice for E.ON’s compressed air usage profile – in terms of energy efficiency and cost effectiveness. Though the two existing Mattei machines worked reliably for nearly 10 years, we were certain replacing one of them with an AC30sH would offer increased energy savings – and our subsequent data logging exercise has proven this to be the case.”


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