|
|
|
|
|
09/12/2010
(Read full story here or download PDF)
 Email to a friend
 Comment on this article
|
More than £25,000 of energy costs per year are being saved by an asphalt production plant, following fitment of ABB variable speed drives.
 Express Asphalt' plant at Darwen, near Blackburn, Lancashire, is the beneficiary – and the saving stems from upgrading its 90kW exhaust fan from fixed speed to variable.
Rick Harbour, works manager with Express, explains that the asphalt production process involves a burner supplying heat to a rotating drum aggregate dryer. Steam and dust are then extracted via the exhaust fan, with the dust captured in filter bags for reuse.
"The dryer exhaust fan creates a pressure to draw the steam and dust out but, because the motor was running at 50Hz constantly, it was doing too much work," he says.
Rick Hinde of Invertech Solutions, which was contracted to look at ways of controlling the fan, says that the solution started with a 110kW ABB standard drive. "The fan had its damper placed in the fully open position and dryer pressure was then controlled via a pressure transmitter feeding back to the drive," he explains.
Invertech also installed a 30kW ABB drive on the dryer. "We experimented with adjusting the speed of the drive to obtain optimum drying. The burner uses kerosene and we found that running the drive at 55Hz gives the optimum drum rotation speed. This meant we used half a litre per tonne less kerosene, saving Express Asphalt £8,000 per annum in burner fuel costs," states Hinde.
Along with other ABB drives on the bitumen pump, the rotating dryer, the hot stone elevator, the mixer and the batch elevator – as well as other energy saving components such as timers – the plant is saving a total of £1,500 a month on its electrical energy costs. So, with the reduction in burner costs of more than £600 a month, total energy costs have fallen by £2,100 per month.
Other benefits cited by Harbour include a 5dB reduction in noise in the asphalt drying area, as well as reduced wear and tear. "Previously, we were getting a lot of breakdowns, because the dryer fan was working so hard. This was losing us up to 20 production days a year. But since the installation of the ABB drive, we have had no more than six lost days," he says.
|
|
| |
Author
Brian Tinham
|
| |
| |
|
| |
This material is protected by SOE copyright 2012.
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.
|
| |
|
|
| |
|