Accurate Process Model= Winning Solution
A southern US mill installed a new Kraft digester, dramatically increasing their pulping capacity. However, the existing screening system was undersized for the new production rate.
Our applications team utilized SimAudit™ balances to model the current system and provide recommendations to meet new production goals. New GHC rotors and MacroFlow cylinders were part of the solution, replacing OEM LP rotors and milled slotted baskets.
Startup of the screening system was seamless. Production goals and performance warranties were met….all accomplished without adding costly new capital equipment.
What was the Science Applied behind this success? Accurate process modelling facilitated the application of the right solution. This included GHC rotors with proper foil height operating at a speed recommended for their process, and MacroFlow cylinders with the correct slot size and wire (contour/pitch) to maximize throughput and runnability. The upgrade from milled to MacroFlow baskets resulted not only in higher production but also doubled cylinder life.
Kevin Burkett, Sales Representative
Cure screen plugging
A small southern Brazilian corrugating medium producer invested in a new complete OCC plant a few years ago. Since start-up, their coarse screening operation was unstable, resulting in low capacity and high fiber losses. Life was very hard on everyone at the mill.
The primary coarse screen cylinder plugged daily. A spare cylinder was kept beside the screen to improve cylinder time changing! As a consequence of troubled primary operation, the secondary screen – CombiSorter – performed poorly, resulting in high fiber losses!
To overcome these serious issues, AFT designed a GHC2 rotor to replace the OEM rotor in the primary position. Since installation, capacity is at a higher level than designed and a trouble free operation is the rule. Energy costs are lower too.
Orlando Matteoni, Regional Manager, Brazil
The Real Cost to Own
A small Brazilian corrugating medium producer needed a competitive edge. They were open to changes in refining for better product properties and cost savings. But “high cost” from AFT refining solutions was cost prohibitive. Or not?
From a big picture standpoint, they expressed a need to reduce chemical and energy costs, improve quality, and cut time for maintenance. In fact, AFT know-how and Finebar plates with higher specific edge length and proprietary technology proved valuable to deal with all of these concerns.
R$5 per ton were saved in reduced wet strength resin, surface starch, enzymes and retention aids. RCT and burst were improved. Energy costs dropped. Finebar plates lasted three times longer. According to this producer, too expensive proved to be a myth.
Nicolau Portela, Applications Engineer
No Plugging Please
To support a mill’s need for clear water or clear black liquor, AFT designs filters to achieve smooth flow and no plugging - even with just one filter. By contrast, when too high a feed PPM results from improper hole size, trouble will follow.
Proper filtering always helps improve processes downstream. Similar to filtering for wastewater treatment, our approach concept for a series of filters delivers peak performance.
Dan Mueller, Applications Support Manager
Brownstock Line Sustainability
A Scandinavian brown stock pulp producer suffered from high reject volumes in their screen plant. Equally challenging, valuable fiber flowed out with the rejects. Switching to AFT MacroFlow screen cylinders in combination with AFT GHC rotors enabled them to improve selectivity of fibers and reduce loss of good fibers from 50% to only 10%.
Enhanced performance wear component design and function results from AFT's understanding of screening fundamentals, screening processes and limitations of screen capability. Saving energy, saving valuable fibers or maximizing fiber yield is a result of understanding process conditions, the function of key processes and equipment parameters together with selection of right equipment.
Our new technology of screening components made it possible to cut energy consumption by 50%, and double the life of cylinders and rotors. The GHC rotor, with optimized shape of rotor elements, is the most efficient rotor in the world. Besides a strong and accurate construction, the essential scientific idea with the MacroFlow screen cylinder is the shape of wires. AFT's broad selection of wires enables an optimal match for different applications.
Simo Koskell, Sales Manager Sweden
OCC line more robust
"Replacement parts for OCC pulping are reduced because our new stock preparation systems are robust. Cylinders and rotors have a longer life. This saves Fajar Paper and other Indonesian producers money. In addition, maintenance is much lower so operators can spend their time optimizing rather than simply maintaining.”
Herman Handoko, AFT General Manager, Sales South-East Asia
POM - So reliable it's dull
Stora Enso Varkaus counts on AFT for their POM system, screens and cleaners. They understand the importance of POM running smoothly with much lower water and energy usage.
Their leadership believes that POM is largely about what it’s not. No contaminant build up. Less time for grade changes. Less air to disrupt the process. Fewer defects and subsequent complaints from customers. They tell us that AFT’s POM is almost dull, because it’s so reliable!
Similarly, the Science Applied of POM at Stora Enso Ostroleka saved millions from equipment not put in place, like seal pits, silos, deckles, etc. Consistency and optimization efficiency keep saving money, while quality output meets or exceeds targets.
Risto Nykanen, Project Manager
An Approach to Reduce Equipment
"The benefit of eliminating one or more headbox screens to improve runnability and save energy is easy to see. But how you do it requires many observations, calculations, and capabilities.
We often help customers shut down refiners, yet maintain equal or greater productivity. This means putting more load on the remaining refiners. Optimization of plate geometry happens because of our Finebar® manufacturing flexibility.
When Navigator Setúbal sought to achieve higher throughputs, we moved to an even finer plate pattern. Our plates have very high bar edge lengths, which contribute not only to excellent fibrillation, but also to high flow capacities. In addition our material selection and low-intensity aspects lead to very long plate life.”
Carlos Bayarri, AFT representative in Iberia.
Process Audit - Review & Runnability Fixed
At Modern Karton, our team of specialists began an intensive study to determine the root cause of the stock preparation runnability problems. Two specific tools, AFT’s SimAudit™ process simulation and a mechanical audit, were used in the analysis.
SimAudit revealed in detail the potential for optimizing existing processes and sizing equipment. A mechanical audit determined the condition of the wear components to help achieve a more effective maintenance program.
When the internal components, rotors and cylinders, allow fiber to build up and plug the screen, there is no way a mill can experience smooth and continuous operation. The AFT audits revealed some good news for Modern Karton. The simulation showed that changing out the OEM wear components would allow Modern Karton to regain full capacity and save energy. They did just that and more.
Bulent Sendag, AFT representative, Turkey
Fix it now! Stop it from repeating
Despite the predictive and preventative efforts of the best mill maintenance departments, unplanned failures usually happen at the worst time.
With experience from over 550 different screen models, we have been able to help many mills with a short term fix or a swap-out of a critical wear component. Step 1 - fix it now. After the emergency has passed, we get the best reviews with mills that let us work with them to examine failure cause and then plan a longer-term rebuild or monitoring process. This longer term plan may include many elements such as:
Whatever you may decide, we are best known for helping mills find a solution to the true cause of the failure - not just another patch until the next unplanned downtime.
Jeff Hartman, Director of Services - Americas
Solutions to prevent downtime
Pulp mills want to run up to 2 years between maintenance shutdowns. Each day of a shutdown costs a mill up to 1 MEUR in lost production.
Because mills need solutions for wear life and preventive maintenance, AFT offers mechanical audits, chroming, hard wear coating, improved cylinder fit, screen body reconditioning, screen drive, seal and bearings condition analysis, and process improvements to reach the long interval between shutdowns.
Some mills suffer from cylinder breakages in their brown stock screening. AFT analyzes root cause for the breakages, reconditions screen bodies, and improves cylinder fit and optimizes rotors. As a result, cylinders don’t break anymore.
Screen body long life requires expertise and high precision measurement to localize problems, and apply the knowledge to design the correct solution. Currently AFT is delivering on site screen body reconditioning, which again reduces the need for downtime.
Risto Weckroth, Vice President, European Operations