A customized BlueLine OCC stock preparation line for Papierfabrik Palm goes above and beyond the leading papermaker’s expectations for sustainability. Unrivalled low energy consumption and a comprehensive AquaLine Flex mill-wide water management system ensure the new Palm Aalen plant sets industry standards in resource efficiency.
The Project Manager at Voith justifiably trusts the best-in-class design to reduce both energy and water consumption at the plant, while also ensuring fiber loss is kept to the minimum required for the desired product quality. And the customer? Stephan Gruber, Chief Technology Officer at Papierfabrik Palm, shares his confidence:
As one of the largest and most advanced systems worldwide, the entire BlueLine stock preparation line delivers a reliably high production 24/7, 365 days a year at Palm Aalen, and therefore plays a critical role in the annual production of 750,000 metric tons of containerboard to the defined standards and quality. The total stock preparation capacity is designed for 2,700 metric tons from recovered paper each day and will handle reject contents typical for European recycling grades. Up to 500 metric tons will be produced in an adjacent pulping unit, where Voith’s new pulping technology, the Green Pulping Concept, leads to a significantly more energy-efficient pulping of broke from various Palm converting facilities.
Moreover, the complete AquaLine Flex water management system for the new plant, incorporating the wet-end process of the paper machine, was designed and installed with the full-line supplier expertise of the Voith and Meri team. “Given that sustainability takes center stage at Palm Aalen, the requirements were understandably demanding,” explains Dr. Michael Trefz, President Projects at Voith Paper.
Breaking down the energy savings
The key to the BlueLine resource-efficiency lies with the intricate combination of tried-and-tested sub-systems, proven machinery and advanced automation. The outcome is a well-balanced stock production. The BlueLine OCC solution is a seamlessly coordinated process, which avoids the intermediate chests, additional tanks and agitators that often disrupt operations in conventional systems. This simplified process leads to lower investment costs in pumps, piping and valves and requires less pumping energy overall. Such energy efficiency translates to savings of more than 20% compared to conventional facilities. For a plant the size and scale of Palm Aalen, this may result in savings well above half a million euros each year.
Targeting water consumption and yield
While high energy efficiency is one priority, another is reduced water consumption. To this end, Voith has implemented its automated water management system for both the stock preparation and the wet-end process of the paper machine. “This was a smart move,” believes Rauch.
What’s more, the water management process in combination with a special disc filter configuration ensures that only super clear filtrate, with less than 150 mg/l total suspended solids, is discharged to the effluent treatment plant. This allows the anaerobic effluent treatment to operate even without a primary clarifier. “Our approach has the added benefit of keeping fibers in the papermaking process,” adds Rauch, “which increases the overall yield of the plant.” Another unique design feature that targets fiber loss is the grouping of no fewer than four stages of IntegraScreens with C-bar Q. In coarse screening, IntegraScreens with slotted baskets are installed, a concept that is already well established in Voith plants that have recently been started up. The slotted baskets combine good screening efficiency, maximum throughput and substantial energy savings.
All for ease of operation and maintenance
“The robust BlueLine set-up is also very easy to use,” highlights Tomislav Druzinec, the Start-up Engineer at Voith for the Palm Aalen project. As the head of the start-up team since the beginning, Druzinec has come to know the operators and their needs up close. The maintenance-free InfiltraDiscfilter with BaglessPlus technology is appreciated on both a service and sustainability level, while the simple design of the InfiltraScrewpress ensures easy maintenance.
Another popular topic of conversation at the mill is the ease of operation of the BlueLine system. “This is not accidental,” explains Druzinec. “It allows to take advantage of an important feature of the overall design: the start/stop control.” Essentially, this combines a strict counterflow principle with smart water cycle separation that is the secret to a fast start-up after any scheduled or unplanned shutdown of the paper machine. At start-up, the key is to set the parameters correctly so that a chain of events seamlessly cascades to ensure smooth start/stop sequences.
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