HYDRAULICS & PNEUMATICS
FEATURE
A-LM pump units have been chosen for fibre separation
Suitable for use in the toughest liquid
pumping applications, 28 pumps from Sulzer have been specified for a potato starch plant. Here we find out why
L
ocated in Mjällby, Southern Sweden, the Lyckeby potato starch plant produces native and specialty starches along
with valuable by-products such as fibres, proteins and biofertilisers for the global food and paper industries. A factory modernisation project in 2022, with a
focus on energy savings, expanded production to 40,000 tons of commercial starch annually. With efficient, reliable and cost-effective equipment necessary here, the company turned to Sulzer for the toughest liquid pumping applications.
MEETING THE CHALLENGES There are technical challenges at every stage of starch production – from raw material washing and rasping to fibre and fruit juice separation, and finally starch washing and drying. In addition, problems are faced when pumping liquids prone to foaming, caused by the protein content of liquids and because the different raw material components are separated mechanically. The
INNOVATIVE LIQUID PUMPING
fibre pulp separation stage is particularly critical, as the liquids pumped can contain over 40% air. Conventional centrifugal pumps cannot
operate with such high gas content as capacity is reduced dramatically and pumping becomes unstable, the company explains.
STABILISING THE PROCESS After rasping, the slurry mixture of pulp, starch and potato juice passes through rotating conical sieves for pulp fibre separation. In close collaboration with Lyckeby and the centrifugal sieves supplier, Sulzer provided seven AHLSTAR A-LM pumping units for transferring or recirculating starch and fruit juice, and fibres and water. The AHLSTAR A pumps with LM integrated liquid ring pump degassing units are specifically designed to handle foamy suspensions effectively and reliably, ensuring trouble-free operation and a steady process. Even for viscous slurries, the A-LM pumps with built-in vacuum system can separate most of the air from the liquids, maintaining a constant flow. According to the
DIGITAL VALVE CONTROLS SPECIFIED FOR ALASKAN OIL PIPELINES SNS pump units are
company, the AHLSTAR A-LM pump units stabilise the entire process, optimising the operation of upstream and downstream equipment. Furthermore, the internal degassing device in the A-LM pumps removes most air bubbles from the impeller eye, significantly increasing pump efficiency. This saves energy and benefits the
used for starch washing
With effective monitoring critical to ensuring the safety and efficiency of pipelines, 15 QuickTrak Digital Valve Control System and Positioners are being supplied by IMI for one of the world’s largest oil pipelines which spans approximately 800 miles across Alaska. The QuickTrak system features pneumatic
digital valve control technology, combining a microprocessor-based control system with an integrated valve positioner. It will provide the Alaskan pipelines with the control and performance of a hydraulic system, but without the storage and environmental requirements. The system is capable of operating in temperatures ranging from -40˚C to 70˚C. It features three sequential layers of safety
through integrated software, firmware and mechanical systems. It also benefits from a probe consisting of Magnetostrictive linear
position transducers located within the actuator stem to provide fast and highly accurate control feedback. Additionally, it features a custom designed actuator with larger ports to accommodate the feedback probe. QuickTrak systems are engineered, designed and built to robust, fail-safe designs and, as such, are ATEX, IECEx, CSA and UL certified. These qualities and certifications make them well-suited to demanding operating conditions. They also incorporate digital control, using a closed-loop system based on the value and spool position to control the stepper motor, adjusting the actuator’s chamber pressure to achieve the desired valve position. Patrick Deane, business development director at IMI, said: “Building trust and showcasing expertise are essential to the success of innovative products like the QuickTrak systems. These new controllers deliver significant benefits including enhanced performance, reduced maintenance and exceptional reliability. Their deployment in Alaska is a testament to the dedication, ingenuity and engineering excellence of our team, as well as the collaborative effort that brought this project to life.”
IMI
www.imi-critical.com MARCH 2025 DESIGN SOLUTIONS 37
environment. Added to this, reduced air in the system also enhances the efficiency of other process devices, plus the use of expensive antifoam agents is greatly minimised.
PROJECT DATA The new full starch line includes 28 Sulzer single-stage overhung process pumps in duplex material and with double mechanical seals: • Seven AHLSTAR A pumps with LM integrated liquid ring pump degassing units, and open impellers
• 21 SNS pumps with open impellers. Most pump units are equipped with VFD for higher flexibility and efficiency. The AHLSTAR and SNS pump units are now
working smoothly on site, complementing the older installed Sulzer pumps that have given full satisfaction for decades.
Sulzer
www.sulzer.com
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