Polydeck’s polyurethane compound WXP combats premature panel failure caused by hydrolysis and microbial degradation, extending the life of the media. Above, Polydeck panels at the Sugar Camp coal mine. (Photo: Polydeck)

The top dewatering solutions offer improved productivity and product characteristics while requiring minimal labor

By Jesse Morton, Technical Writer

The top solutions used to dewater coal offer several benefits. Top among those is low labor requirements. This is achieved through parts and equipment longevity, ease of maintenance or replacement, and the ability to operate consistently with minimal manual control or oversight. Further, the suppliers offer to customize their solutions and to help in maintaining and servicing them.

Low labor requirements is a benefit high in demand right now. It ranks just behind improved productivity, improved product characteristics, and the ability to help with sustainability goals, which are also among the top benefits offered.

Dewatering Panels Go Green

Polydeck said it is developing a product line that will be made of 100% recycled material. “Part of our effort to support our customers is by developing products that are designed and manufactured with the environment in mind,” said Trey Rollins, director of marketing. “We are very excited about being a part of the solution that makes our planet more sustainable for future generations.”

The company’s injection molded panels have a long history of offering critical benefits, such as improved production and helping a company meet sustainability goals. Many of those benefits trace back to capabilities that make injection-molded panels superior in performance to cast-molded competitor panels.

“Injection molding produces a highly precise and consistent aperture opening,” said Daniel Anderson, regional sales manager. “So, when you are producing fine aperture panels, the injection molding process allows material to fill even very intricate details of a mold, enabling the production of precise and consistent aperture sizes.”

Greater precision means injection molding “generally has tighter tolerances, making it well-suited for producing panels with smaller, consistent aperture sizes,” he said. “That, the fact that we make our dies in-house, and our ability to fine-tune the design of a screen panel to match the application it’s used in, sets us apart from our competition.”

Proprietary polyurethane compounds ensure longevity. “Because we invest heavily in material science development, we have been able to develop material compounds that are more durable in targeted applications, are resistant to wear and tear, and offer a longer lifespan in abrasive conditions compared to other materials like steel,” Rollins said.

“Our proprietary polyurethane compound WXP was specifically designed to combat premature panel failure caused by hydrolysis and microbial degradation,” he said. “WXP mitigates chemical interactions within the polyurethane, extending the life of the media and saving our customers money at the end of the day.”

For coal dewatering, the Polydeck MAXI panel offers “multiple custom solutions,” said Anderson. “The MAXI style panel offers the highest open area available on the market in modular synthetic screen media, with sizes ranging all the way down to 150 mesh, or 0.105 mm.”

The Polydeck MAXI panel is a customizable solution, can feature specialized aperture shapes, thickness and compounds. “Polydeck’s application knowledge allow us to provide a custom solution for each customer that is specific to their requirements and situation,” Anderson said.

“We understand that each site has its own unique challenges, and we are able to combine the application knowledge we’ve gathered across multiple sites and industries to deliver a custom solution that will help our customers increase efficiencies,” he said. “These custom solutions have proven to allow better water flow, retaining a maximum amount of coal while allowing water to pass through.”

The benefits offered are numerous. “Using all our product configurations helps us reduce customer downtime and cut maintenance costs,” Anderson said. “The efficiency gains result in a drier coal output.”

The high wear life allows the customer to “focus on other areas during maintenance times,” Anderson said.

The lower costs “and increased productivity directly affect the bottom line of a mine,” he said. “We work hand in hand with our customers to provide a media solution that will help them increase profitability.”

To help the customer hit sustainability goals, the panels are biodegradable, Rollins said. “In a few years in the environment, UV light will break down our panels.”

The solution is backed by a service and support network that helps ensure performance and results. “Part of what makes Polydeck unique and able to win against our competition is the combination of our custom solutions along with our reliable supply of products and the application knowledge of our field staff and in-house engineering team,” Anderson said.

“We understand that ensuring our customers have the parts they need when they need them is half the battle,” he said. “That’s why we have established five distribution centers across the country stocked with parts that can be delivered at a moment’s notice in case of an emergency at a customer site.”

A fully automated Decanter Centrifuge produces a solid cake material that is suitable for mechanical handling as well as immediately reusable process water. (Photo: McLanahan)

Labor-saving Solutions See Demand

McLanahan Corp. reported seeing an uptick in requests for information on its filter presses and Decanter Centrifuge. Part of the demand is rooted in the fact that the equipment requires minimal personnel to operate, the company said in a prepared statement.

In March, McLanahan acquired Diefenbach, an Italian manufacturer of filter presses and thickeners. The companies had previously partnered on projects, and the acquisition was driven by a trending focus in industry on water conservation. With the acquisition, Diefenbach became an McLanahan brand.

McLanahan offers overhead beam and side beam units. The overhead beam plates are available in sizes from 630 x 630 mm to 2 x 2 m. Plate sizes available for the Side Beam Filter Press range from 630 mm to 1.5 m.

Compared to the Side Beam Filter Press, the Overhead Beam Filter Press has a bigger opening for better cake release. It also provides “better cleaning and maintenance access,” said Dennis Zink, global product manager.

McLanahan offers recessed chamber-style plates, and membrane filter plates. McLanahan Membrane Plates can deliver a pressure of up to 15 bar.

In interviews earlier this year, McLanahan described its filter presses as capable of producing “a drip-free cake.” They “can address many typical issues associated with fine material processing, including full slurry ponds and dams, high material handling equipment repair costs, limited expansion capabilities, environmental permit restrictions, high waste material handling costs and limited water availability,” Zink said.

McLanahan Filter Presses use fewer chemicals than do belt presses, and feature the Smart Hydraulic System for online monitoring and assistance. The system controls “operating pressure and mobile plate position for fast, precise opening and closing,” company literature said.

“The system can be designed for higher slurry feed pressure to meet specific application requirements,” McLanahan said. “The McLanahan Smart Hydraulic System is monitored and controlled via the standard Allen Bradley PLC or a customer-preferred control system with remote capabilities and assistance via ethernet.”

Last year, the company reported its Decanter Centrifuges use high-gravity forces and a screw conveyor to move slurry particles to the discharge. “The tapered end of the screw allows the solids to dewater as they make their way toward the discharge,” the company said. “The water freely moves to the other end of the machine and discharges via ports.”

The units produce a solid cake material that is suitable for mechanical handling. They also produce immediately reusable process water, the supplier said. “They discharge a solid material somewhere between that of a Thickener and Filter Press,” McLanahan said. And potentially helping companies operate amid staffing shortages, “Decanter Centrifuges are fully automated and enclosed for cleaner operation.”