Condition monitoring for the pulp and paper industry
The pulp and paper industry has existed since the sixth century, and although modern technology has made the production of paper hugely more efficient, there’s still one major way that paper mills can increase efficiency and output. And that’s through the reduction of unplanned production downtime.
Condition monitoring of critical pulp and paper production processes can alert the maintenance team to a developing fault before that fault causes unplanned downtime. By reducing unplanned downtime, you can increase industrial output without expanding your plant, ultimately helping you to make more paper for less.
Below are a number of critical processes in the pulp and paper industry, combined with an explanation of how condition monitoring can make that process more reliable.
The hydrapulper is a machine that uses an agitator to mix waste paper and water together to create recycled pulp.
Hydrapulper agitators are often driven by AC motors. Although the machine requires little maintenance, when it does break down, it can have a direct impact on production.
Applying traditional vibration-based condition monitoring techniques is often impossible because the agitator motor is difficult to reach. That’s why many maintenance professionals are turning to SAM4, which is installed inside the motor control cabinet rather than on the motor itself.
The bleaching system in a paper mill relies on a number of multistage centrifugal pumps, both to feed the process and expel wastewater. Because of the toxicity of the chemicals involved, a fault in this process could create a health hazard.
Condition monitoring will ensure that any developing fault is detected early (up to 5 months in advance), giving your maintenance team sufficient time to correct the fault before a health hazard does occur.
The paper machine can be split into a number of individual processes, many of which are crucial to the production process. These include:
Headbox pulp pumps
The headbox uses powerful pumps to propel the pulp at high speeds into the gap former. Although they aren’t overly expensive to replace, if a pulp pump breaks unexpectedly, the resultant downtime can be costly.
By installing condition monitoring software, maintenance teams can be alerted to any developing fault in the pulp pumps, so they can be replaced before a pump failure causes downtime.
The pressing section uses a number of high-power rollers to remove water from the paper. Pressing is an important part of the production process, so if the motors that power the rollers break down, the effect on production output can be immediate.
After pressing, the paper enters the drying section, which uses heated cylinders to remove the rest of the water and strengthen the paper.
The rollers used in the drying section run at high temperatures, and this can create problems when trying to install on-asset condition monitoring sensors. The heat could damage the sensors and ultimately lead to a missed fault.
SAM4 requires sensors to be installed inside the motor control cabinet, which is a safe and temperate place for condition monitoring sensors. No sensors need to be placed on or near the hot rollers.
In the calender (not to be confused with calendar) section, the paper is fed through two rollers to give the paper a consistent thickness. These rollers are heavy, so the motor that moves them needs to be powerful (and is therefore quite expensive to replace). Periodically replacing a powerful roller motor as part of a preventive maintenance strategy can significantly reduce your overall equipment effectiveness (OEE).
SAM4 can detect a developing fault in a motor, and report that fault to your maintenance team. This means your maintenance team only needs to replace the roller motor when it’s necessary, and not before—increasing OEE and optimizing your maintenance schedule.
Once the paper leaves the paper machine, it’s fed into the sheeter. As the name suggests, the sheeter is used to cut large sheets of paper into smaller sheets, which are then stacked onto pallets ready for transportation. If a paper mill needs to create a high volume of smaller-sized paper, then sheeter downtime can significantly hamper production.
By monitoring the rollers in the sheeter with SAM4, production levels can be maintained regardless of the paper sizes being produced.
Unplanned downtime in the pulp industry is no fiction
Paper producers such as Sappi and Crown Van Gelder use SAM4 to reduce unplanned downtime events in their paper mills. To learn more specifically about how Crown Van Gelder uses SAM4, read the case study here.
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