Mills House automation project executed in 2019.

1. Mill House Automation
Waqas Mahmood
Senior Engineer (I&C)
Layyah Sugar Mills

2. Mill House
Automation
Agenda
Introduction to Mill House Operation
Purpose of Mill House Automation
Cane Feeding Control Strategy
Milling Control Strategy
Mill 4: Planetary Gear System
System Elements
System
Architecture
Graphical User Interface
Advantages of Automation
Conclusion

3. Introduction to Mill House
Operation
✔ The initiation point for all sugar processes is the Mill
House
✔Efficiency of Mill House directly affects:
▪ Increase in crushing capacity
▪ Juice extraction efficiency
▪ Reduction of moisture percentage in bagasse
▪ Bagasse Pol loss
▪ Low wear and tear
▪ Low energy consumption and low torque
PROCESS
HOUSE
BOILER
POWER
HOUSE

4. ✔ Basic Requirements
▪ Safety of the cane feeding and milling equipment
▪ Prevention of overloading of feeding and milling
equipment
▪ Prevention of jams and choking
▪ Early indications of faults
✔ Optimization
▪ Maintaining optimum load on preparatory devices
and mills
▪ Maintaining continuous feeding at all times.
▪ Maintaining uniform steam/power demand over
entire mill house
▪ Early indications of faults
Purpose of Mill Automation

5. Cane feeding control
Strategy

7. Milling control Strategy

9. ✔ Scheme
▪ All gears are driven by induction motors
▪ Top roller is driven by two motors 250kW each
▪ Speed of feed and discharge rollers is determined by
top roller speed (Ratio control)
▪ VFDs are installed for all motors
▪ Water circulation pumps for gears’ oil cooling
✔ Operational Safeties: System trips whenever
▪ Any of the four motors trips
▪ Cooling fan of a motor trips
▪ Gear oil high temperature switch is activated
▪ Gear oil high pressure switch is activated
▪ Both water circulation pumps of any gear are tripped
Mill 4: Planetary Gear System

11. ✔ Distributed Control System
▪ Plant cruise C-300 controller by Honeywell
▪ Redundant Power Supply
▪ Server and Operator workstations
✔ Network
▪ Fault Tolerant Ethernet Switches Honeywell
▪ Redundancy
✔ Instruments
▪ Pressure Transmitters and Gauges
▪ Level Transmitters
▪ Temperature Transmitters and Gauges
▪ Load Cells
▪ Chute Height Sensors
▪ Proximity Sensors
System Elements

12. System
Architecture

13. Graphical User Interface
✔ User interface provides
▪ Larger display of process parameters
▪ Multi-window support
▪ Data Recording
▪ Trends
▪ Alarms and Events

16. Advantages of Automation
✔Continuous and un-interrupted feeding reduces down time.
✔Elimination of choking at preparatory devices, mills, chutes and carriers.
✔Optimum mill speeds with respect to loads and levels ensure good milling
results at all times.
✔ Constant Load on Preparatory Devices ensures Better Cane Preparation
resulting in better extraction, RME, Reduced Bagasse Pol and Moisture.
✔ Constant Load on Mills and Level in all Donnelly Chutes results in Power and
Steam Savings.
✔Constant Load on Mills also results in Lesser Mechanical Wear & Tear.

17. Conclusion
s
✔Regularity in cane feeding is the key to operational efficiency.
✔Global practice of automated systems is the surest way to achieve uniformity
and control over all critical parameters.
✔Reduction in product losses and Increase in crushing capacity are worth the
justifiable investment, resulting in a smooth payback over a short period of
time.
✔Energy conservation in electricity, fuel and other resources.

18. Question & Answers
Thank You for Your Valuable
Time