Case study 1- Atlas Copco’s Compression System Audit and upgrade saves plastic moulding specialist 60 tonnes of CO2 a year.
Midas Pattern Company, an award-winning, precision polyurethane moulding manufacturer, utilised a compressor system audit from an Atlas Copco distributor as part of its green initiative project, leading to an equipment upgrade. This both achieved substantial energy savings of £14,554 per annum and reduced the company’s carbon footprint by 60 tonnes per annum.
Midas Pattern Company provides a range of prototype and production volumes of flame-retardant polyurethane moulding solutions. Compressed air plays an essential role within the machining, moulding and product finishing processes. A continuous supply of low-pressure air is utilised for clearing ‘swarf’ from the soft cutting board surface, an essential procedure to prevent the build-up of waste material that can affect the process when equipment is operating unattended. Low-pressure air is also involved in the batching mixing of the polyurethane reaction materials before pouring into composite moulds. After curing, the moulded items are removed to undergo finishing operations, such as fettling and shot blasting in preparation for epoxy or acrylic spray painting. These processes, especially the spray booths and shot blast plants, require a constant, reliable supply of compressed air and are the largest consumers within the moulding and finishing production areas.
The company called upon the services of Anglian Compressors, Atlas Copco’s premier distributor for the area, to conduct a performance survey of their compressed air system. This system was comprised two Atlas Copco 22 kW, fixed-speed rotary screw compressors plus a small VSD unit that had been installed ten years earlier, funded by an interest-free Carbon Trust loan.
This performance survey uncovered that demand fluctuated throughout the week and had changed considerably over the years, the minimum requirement being 12 [litre/second] l/s, and the maximum was 105 l/s. Furthermore, the VSD [variable speed driver] machine had reliability issues and lower output than either of the fixed speed units, meaning at times it did not have enough capacity to provide the full air requirement, so the fixed speed compressors were doing most of the work, running on and offload and wasting energy.
The recommendation was to replace the small VSD machine with a larger 37 kW compressor, from Atlas Copco’s new and extremely efficient VSD+ range. The GA37VSD+ compressor has a free air delivery of 133 l/sec, enough to supply all the air the site requires, thereby reducing energy consumption and service costs. The two fixed-speed compressors, each with an output of 53 l/s, were to be retained as back up.
Another discovery was that the system was running between 9 to 9.9 bar- considered to be too high in relation to the application needs. It was therefore recommended that system pressure on the new VSD machine should be reduced by weekly 0.2 bar increments. At 8.4 bar, this procedure already reduced the energy requirement by 10.5 per cent.
Anglian Compressors advised Midas Pattern Company of the benefits to be derived from sectioning off the factory so that work areas could be shut down when not in use. They also recommended pre-programming the CNC machines with a line of code that shut off the swarf removal air blast once the process was completed. The combined effect of these measures, following the introduction of the VSD+ compressor, saw the night-time usage reduce from 10-35l/s down to just 5-20l/s.
To date, the level of energy used on site for generating compressed air has reduced by about 2/3 to just 78, 104 kW/h, representing a total saving of £14,554 per annum together with an estimated ROI payback of just 1.5 years: an impressive result, but only part of the success story.
The compressed air system upgrade alone has reduced the company’s carbon footprint by some 50 tonnes of CO2, and alongside Midas Pattern Company’s varying efforts as part of the Midas Green Initiative, including zero landfill waste, biogas], and when combined figure is closer to 60 tonnes.
Alan Rance’s final words on the successful outcome of the Atlas Copco compressor installation project were: “Midas Pattern Company, Anglian Compressors and Atlas Copco share the same green principles and a common purpose. They were 100% with me all the way.” Anglian Compressors & Equipment Ltd has been a premier distributor for Atlas Copco since 1977.