Bundaberg Walkers

The Saharuang Sugar Factory is located in the central east region of Thailand, approximately 540km from Bangkok. As part of the factory upgrade between 2003 and 2005, Bundaberg Walkers was involved with the supply of the cane preparation and mill extraction equipment. The project was commissioned for the beginning of the 2004-2005 crushing season.
The final scope of works consisted of the following:

  • Associated Specification and Design Services
  • 2438mm wide Chute Magnet Assembly
  • 1100 x 2500 long Shredder Feeder and Drive Assembly
  • 1830 x 2500 long Heavy Duty Shredder
  • Five (5) – only, 1100 Dia. x 2300 long, Heavy Duty 6 Roller Mills.  Nos.1 and 5 with Heavy Duty Pressure Feeders (HDPF) and Nos.2, 3 and 4 with Light Duty Pressure Feeders (LDPF).
  • Five (5) – sets, Mill and Pressure Feeder, Shaft Mounted, Electro-Mechanical Drives, Torque Arms and Reaction Struts
  • Power Supply, Starters, Switch Gear and Variable Frequency Drives  for Shredder Feeder Drives, Mill Drives, Pressure Feeder Drives, Intermediate Carrier Drives, Juice Pumps and Associated Minor Drives.
  • Complete Mill House Control System
  • Installation Supervision and Commissioning Services

The milling tandem was designed for progressive increases in crushing capacity, initial operating conditions were specified as 12,000 tonnes of cane per day at 13.5% Fibre in Cane in accordance with local licensing agreements. By adjusting the mill settings, a crushing rate of 15,000 tonnes of cane per can be achieved and with the installation of a sixth mill and HDPF, approximately 18,000 tonnes of cane per day is anticipated.

For the mill drives, independent shaft mounted electro-mechanical drives were installed on each mill roller. That is, a total of thirty (30) shaft-mounted planetary gearbox and electric motor assemblies were required.  The drives on each mill unit are connected to a Variable Frequency Drive (VFD). Each Mill stand is serviced by a unique Motor Control Centre (MCC), there are five (5) MCC’s for the mill tandem and a separate MCC for the Shredder Feeder and Cane Yard equipment.

Considering that there was a future requirement of co-generation, the electromechanical option had the highest operational efficiency and was the most economical alternative. With electromechanical mill drives, steam is directed to generator turbines in the power house where more power is generated per unit of steam.  Multistage Generator turbines are always more efficient than single stage mill turbines. Other advantages of the electromechanical drives include the ability transmit power independently to each roller allowing greater control. Effective mill control and feedback is provided through the VFD.

In the 2008-2009 season, the mill tandem was achieving 97% extraction with a final bagasse moisture of approximately 48% at a nominal crushing rate of 650 tonnes of cane per hour.

This innovative project was made possible by a highly committed team at Bundaberg Walkers with close cooperation of the planetary gearbox suppliers and electrical equipment supplier and the support of the end user. It has provided the opportunity to further develop a number established milling concepts and gain valuable working information that can be applied to other projects in the future.

For more information on this project and other examples of projects and services available, contact Bundaberg Walkers directly.