Pressing for Wider Profit Margins

Swedish company Drinor has developed a machine it believes could be a game-changer for pellet production.
By Anna Simet | May 23, 2018

In the bioenergy sector, the most promising of concepts can be incredibly challenging to successfully scale, and many end up in the proverbial graveyard of innovative ideas. But for Sweden-based Drinor, the light at the end of the commercialization tunnel is visible. And, in their opinion, it’s very bright.

Drinor’s patented technology, which squeezes water out of biomass via a mechanical process involving a pair of rollers and a perforated steel sheet, has been evolving the past seven years. It’s a simple concept—perhaps nearly too simple to believe without skepticism that it will make the incredible difference in operational costs that Drinor believes it can.

Sefan Sobota of Switzerland is the man behind the initial concept, having realized the idea after seeing large stacks of residuals in Swedish Forests.

The intention wasn’t always to focus on the pellet industry—at the beginning, the impetus was to figure out a way such that the Värmland region’s robust pulp and paper industry could save money, beginning with a team of engineers, economists and forestry experts, and resulting in development of Drinor AB. “The idea began as a way to reduce transportation costs, allowing a wider transport range,” explains Alexander Thelander, sales executive. “In Karlstad, everyone breathes pulp and paper, and biomass.”

 “The pellet [sector] doesn’t have big profit margins, and there is a demand for a solution to increase profits,” he continues. “It’s hoped that the dewatering press will be able to contribute to this in particular—we think it will be most effective here. Our goal for past three years has been to prove, with a full-scale industrial machine installed in a pellet mill, that it works.”

Proving the Concept
Traditional drying methods draw water out of biomass via heat, Thelander says, but with Drinor’s technology, material is pressed at about 13,000 psi in a roller nip, allowing for about half of the water to be squeezed out, prior to sending it to the dryer. He compares the technology to hanging a saturated rag out to dry, versus tightly wringing it out, then setting it out to dry.

At its R&D headquarters in Karlstad, a pilot continuous dewatering press (CDP) is available for testing, and tailor-made trials.  And using a Swedish Energy Agency grant of SEK 4 million ($467,000), the small team at Drinor—just three, for now—implemented a large-scale demonstration unit at a pellet plant, Rindi Pellets, and has results to share. “It’s a 70,000-ton-per-year mill, and we installed it in February,” Thelander says. “The goal was to make sure we covered their needs, by processing about 20 tons of material per hour, and reaching the low 40 percent moisture content range.”

Testing, which is being done in partnership with Karlstad University and the Swedish Energy Agency, has indicated moisture ranges as low as 37 percent, and the machine is now running continuously. “When you put a new machine into place, you think there might be a lot of problems—there always are when you go from very small-scale to much bigger—but we have had great results so far, and we expect a lot from the trials,” Thelander says.

What might be of particular interest to producers located in regions that experience harsh winter conditions is how the machine has handled frozen material. “We weren’t sure how it would test,” Thelander says. In -20 degrees Celsius (-4 degrees Fahrenheit), with an efficiency loss of only about 3 to 4 percent, the water still leaves the material. “It’s great for regions where things are difficult in the winter, and they experience a loss in capacity,” he adds.

Talking Numbers
Overall, Drinor believes that, when retrofitting an existing pellet plant with a CDP—removing 55 to 60 percent of moisture—operational costs can be reduced by about half. At least, for a typical pellet plant in Sweden. “It’s mostly with the dryers—that energy use that goes away,” Thelander explains. “The energy need for our machine is almost nothing, which makes a big difference in the numbers,” Thelander says.

The machines have a small footprint—about 25 square meters—and another benefit is that once material has been processed, it’s much softer. “We’re doing trials with hammer mills right now, to study the effects,” Thelander says. “The operational costs we talk about are all across the process—including the dryers, hammer mills, and material handling, as it gets lighter.”

Pellet tests and comparison between dewatered and nonprocessed sawdust have been performed, and so far, results show equal or better quality and performance in comparison to conventionally dried biomass—in particular, ash content. Pellets made from material processed by the CDP have tested at a 20 percent reduction in ash content. “We wondered why that was initially,” Thelander says. “But it became obvious—if you dry saltwater, the salt is still left there. Since we squeeze the water out, a lot of stuff comes out with the water, the things that usually become ash, so now that’s handled in the water stream.”

An additional benefit of installing a CDP in a retrofit situation is upscaling capacity, according to Thelander. “It’s much faster, pressing the water out, so you can upscale your dryer and almost double the capacity.”

For a new build, the capital costs—considering the smaller space requirements, less handling of equipment, and reduced expenditures for RTOs and thermal dryers, Thelander says a 50 percent cost cut in capital costs could be achieved—about $30 million in cost savings on a $100 million plant. “If you put the press first in the whole [supply] chain, it will affect all of the process steps,” he adds. “A question that we got recently was, how could this affect the actual cost of pellets—we think it could be up to 30 percent, which would have a great effect on the market, especially private markets—we’re not only focusing on industrial use. If the costs can be cut like that, perhaps it will have an effect on demand for pellets, as a result.”

And the pellet market isn’t the only industry the CDP could have implications on. Besides chips, sawdust has been successfully tested, as well as bagasse, and Drinor sees sawmills, biomass contractors, heat and power plants, as well as ethanol and biogas plants as other potential markets. The combination of force and pressure—resulting in a much softer material, as aforementioned—affects materials in such a way that it makes it particularly suitable for  enzymatic treatment before biomass is processed into industrial sugars or biogas, as the enzymes or other additives have access to the core of the material, and the cracked cell structure will increase the process yield, Drinor believes. The water pressed out of the material contains carbohydrates, the level of which depends on the chosen process, and the water itself can work as an substrate for biogas production.

Jonas Berghel, an environmental and energy systems professor at Karlstad University, has followed the technology for the past several years, and believes in it. “Drinor has moved the border of possibilities for mechanical dewatering of biomass,” he says. “I’m sure this will be a difference-maker for energy use within a couple of years.”

Maybe even sooner. Right now, an initial zero series of machines are being developed and produced for customers signed up on a queuing list, manufacturing of which is being done by an experienced European machine developer working with Drinor, which hopes to replicate this business model elsewhere. “We’re a small company, so we’re not looking to do everything ourselves,” Thelander says. “It’s a patented technique, so we’re looking for partners around the globe to license it. We want to further develop the process, because there are other possibilities for the machine—so many interesting fields. In the U.S. and Canada, we want to tell everyone what we’re doing, but we would like to find people to do this with.”

“It’s an intensive phase, but we’ve had so much fun moving this forward,” adds Carl Romlin, financial executive at Drinor. “We’re planning for the next move regarding investment, focusing on building a strong know-how in terms of our R&D, and letting others help us with manufacturing and installation.”
But realistically, how soon could a CDP be available? “We hope to get more machines in the market during the fall,” Thelander says. “When it comes to the American market, it’s just getting our partner agreements together—it won’t be too long.”

Author: Anna Simet
Editor, Pellet Mill Magazine
[email protected]