Södra Cell’s pulp mill in Mönsterås, Sweden is one of the world’s most modern facilities of its kind. It is also the largest operated by Södra, the international forest industry group, with a production capacity of 750,000 tonnes per year of softwood and hardwood pulp. In 2019, the mill was the first operation in Sweden to be awarded ‘World-class maintenance’ status by the auditor Trivalo. The maintenance team has now taken its operations to the next level by deploying ABB Ability™ Smart Sensors to provide remote, wireless condition monitoring of electric motors in the pulp dryer.
The safe and reliable operation of its large fleet of electric motors is critical for the productivity of the whole Mönsterås mill, and especially its pulp dryer. Regular manual vibration monitoring to determine the health of the motors was established as a key element in the plant’s maintenance regime. But manual vibration monitoring is time-consuming and costly. It is also challenging to perform in areas of the plant where access is restricted. Those factors persuaded Södra Cell to be an early adopter of the ABB smart sensors as part of a continuous, condition-based monitoring program.
The pulp dryer is the last stage in the pulp making process. It features 140 motor-driven fans arranged in two banks of 70. Initially, half the motors were fitted with smart sensors. Following a successful trial, the remaining 70 motors are also being fitted with smart sensors.
Because of the way that the banks of fans are stacked, maintenance engineers needed an aerial work platform to access the motors to make manual vibration measurements. This involved significantly monthly costs for the hire of the access platform, the qualified engineer, and the vibration analysis equipment.
The smart sensors now provide remote tracking of the health and performance of the motors. Under a service agreement with ABB, they are monitored constantly, with key data collected every hour, round the clock – in contrast to the manual monitoring that could only provide measurements once a month.
The smart sensors provide Södra Cell with a clear indication of how each motor is performing at different operational speeds and at different times of the day, enabling the operations team to optimize their pulp drying process. Continual monitoring will also raise any alerts if, for instance, unusual vibration patterns are identified that might lead to premature failure.
The smart sensors are attached, quickly, simply, and without any wiring, to the outer casing of the motors. The sensors are used to track the motor’s speed, vibration levels, sheath temperature, frequency of starts/ stops, operating time, and power consumed, which is then analyzed via a secure cloud service.
Andreas Eriksson, the Maintenance Technician at Södra Cell, says. “With the smart sensors maintenance can now be planned according to current needs rather than based on general schedules. It extends the life of the equipment, reduces maintenance costs, and reduces or eliminates unplanned downtime. In addition, we obtain new data that can be used for systematic investigations to identify problem sources and improve the process or reliability of the system.”