Product category:
Industrial Drives/Controls
News Release from: BSL Engineering | Subject: Siemens Masterdrives
Edited by the Engineeringtalk Editorial
Team on 29 May 2001
Electrical usage cut by 32% at coating
plant
By replacing a complex mechanical damping system with a Siemens Masterdrive, BSL Engineering has enabled Lafarge Aggregates to reduce electrical energy usage by 32%
By replacing a complex mechanical damping system with a Siemens Masterdrive, BSL Engineering has enabled Lafarge Aggregates to reduce electrical energy usage by 32% at its North Yorkshire coating plant The improvement in control introduced by the Siemens Masterdrive has also resulted in fuel savings, achieved through more precise regulation of the oil burner that produces heat for the process
The coating plant itself is essentially a 2.5m wide by 20m long drum that takes in mixed stone aggregate, heats and then coats it with bitumen to produce asphalt.
The aggregate is heated as it enters the drum, removing moisture and fine dust to create an ideal bonding surface for the bitumen.
A large fan, situated at the base of the chimney stack draws air through the system.
The particulates are collected in a bag house and recycled.
Previously, the fan operated at a constant speed and a complex series of moveable baffles in the air ducting system were used to control air flow and pressure.
Due to the abrasive nature of the general atmosphere, the baffle control mechanism required frequent maintenance.
BSL Engineering was contacted to help provide an automated solution when the baffle system became too unreliable.
BSL Engineering provided a 75kW Siemens Masterdrive to use in a closed loop system with a Foxboro pressure controller and pressure switch.
The system operates automatically through the control loop, but also provides manual override for fine-tuning and adjustment to settings.
By using a variable speed drive in the system, the fan no longer has to run at a maximum 1460 rpm and the average motor speed has been brought down to 1000 rpm at 38Hz.
Working on a nine hour daily shift and a five day week, the new system has resulted in a 32% reduction in electricity usage, a cost saving of ?5,560 since it's commissioning.
Additional energy savings have also been made by increasing the efficiency of the combustion process, now regulated by the main fan.
Control of the burner is crucial to fuel economy and also to the consistency of the final product.
Both have been improved with a more precisely regulated air flow and more even draw through achieved using the variable speed drive system.
Lafarge Aggregates Electrical Engineer, Barrie Pitt, responsible for electrical systems across the UK (including 20 additional coating plants) commented: "The technical advice and service offered by BSL gave us the confidence to go ahead with this project.
As a result of making the changes we have improved the running of the Dry Rigg plant and make significant energy savings, both on electricity and fuel oil.
We are now surveying each of our coating plants to see if the improvements and savings can be repeated".
"Providing a drive based control system for saving energy on the operation of large fans and pumps is typical of the work we are doing to help customers offset the costs of the Climate Change Levy" said Gary Kitchin, Operations Manager - Systems at BSL Engineering.
"The payback time for investment in these applications can now be as little as twelve months.
The Dry Rigg installation is also a good example of the additional benefits accruing from greater control, including reduced maintenance, smoother running and improved plant performance".
• BSL Engineering: contact details and other news
• Email this article to a colleague
• Register for the free Engineeringtalk email newsletter
• Engineeringtalk Home Page
