Proper baling techniques can help balance customer demands for heavy, dense bales that can travel well.
Strong, heavy, homogenous and stackable. These are some of the qualities, recyclers say, that are crucial to preparing quality bales of recovered fibre that paper mill customers demand.
Baling equipment itself can play a starring role in helping to achieving these requirements, but it is certainly not the only consideration.
Proper feeding of baling equipment also has something to do with the desirability of the bales produced.
Ultimately, it’s a balancing act, recyclers say. Recyclers want to avoid producing bales that are too light and won’t fill up a load, but at the same time they don’t want bales that are too heavy or so large they they risk breaking when being moved.
Achieving these opposing goals can be difficult to do in practice, considering the wide variety of grades and material available.
Johan Boons, a trader with Sha International BVBA based in Belgium says one of the most important considerations for effective baling of paper is making strong, stable bales that can be stacked safely. The family-owned company trades from 20,000 to 30,000 tonnes of recovered paper each month, with much of that going to customers in the Far East.
“There is definitely some pressure to be competitive and with regard to the speed of the baling machine,” Boons observes. He says for example that older baling machines typically offer capacities of around 15 tonnes per hour, compared with today’s machines which can bale around 25 to 30 tonnes per hour. For this reason, says Boons, those packers that have not already upgraded in recent years, are likely to be contemplating it now.
“That’s one reason most packers are changing their baling machines,” observes Boons. “For the speed and also that they can make heavier bales.”
Besides the fact that newer balers allow for speedier baling, they also tend to be more powerful, allowing for the production of heavier bales. Boons explains that newer balers can create bales weighing 800 to 1000 kilograms, compared with 600 to 700 kilogram bales made using older machines.
Boons also says particularly important nowadays is production of strong bales that are stable when stacked, either in shipping containers or at the mill warehouse.
The stackability of the bales may not have much to do with the quality of the commodity, however it can make a competitive difference, industry insiders say. Boons notes that the stackability issue has become even more important in recent months, following news reports of a fatality at a paper mill caused by falling bales of recovered paper.
In Boons’ opinion, the stackability of a bale can depend or vary based upon what is being baled. For example, boxboard cuttings are difficult to bale neatly, as are coated, slippery papers such as old magazines. Therefore, SHA International specifies that its clients crosswire bales of these recovered fibre grades to provide extra stability.
“We ask them to bale it with crosswire, otherwise we don’t buy it anymore because the risk is too high,” he explains.
Boons also refers to a few instances in the past when paper mills have rejected loads if the fibre was determined to be not well baled from a stackability point of view.
“For most paper mills that’s very important,” he says. Loads determined to be not effectively baled are likely to be rejected, Boons says, to lessen or avoid any risk that they’ll be difficult to unloaded safely.
Boons also says ideal paper bales are heavy and dense, but not so long that they end up breaking when moved. This is particularly important when it comes to prepress balers that produce bales of varying lengths. While the size of bales accepted or preferred can vary by country or by mill, SHA International has put policies in place to help standardize bale sizes.
For example German paper mills don’t accept bales longer than 160 centimetres, says Boons, but they also prefer that bales measure at least 140 centimetres long, he says. On the other hand Boons says, the French paper mills will take longer bales, up to 2 metres in length.
To help standardize operations, Boons says SHA requests that customers aim for 160-centimetre long bales, which is acceptable to customers both in France and Germany, he says.
This is not a problem for most clients, Boons says, because most of his suppliers use newer baling machines that are on average between four and seven years old.
“They are quite modern and powerful,” he says.
Marielle Gommans, owner and director of Bel Fibres s.a. based in Mons, Belgium, also describes effective baling as something of a balancing act that operators must learn to master from experience over time. Bales that are not created properly, she says, being either too light or too long for instance, will have to be broken and baled again.
The main or most common challenge of baling, Gommans observes, is filling out the bales properly, which takes experience from an operational point of view.
“If you have a good operator who fills the machines very regularly all the time, you will make a lot more bales,” she says. “Filling out the baling machine is very important.”
The two key feeding problems to watch out for, she says, are making bales that are not dense enough, or on the other hand, feeding the baler with too much paper and creating a bale so long that it’s unwieldy and has to be rebaled.
The company has two recycling depots, one in Mons and the second in Houthalen, which together receive material from throughout Belgium and Northern France, Gommans says.
The Mons depot now operates three fully automated pre-press balers, two of which are 140-tonne capacity models and one with an 80-tonne capacity. One of the balers also has the ability to crosswire bales, which Gommans says is useful for plastics as well as grades of fibre that are difficult to bale, such as smooth grades.
Gommans says it can be difficult to bale fibre cores as well as very large cardboard materials or boxes. She says there are times when the company tries to crush these materials using a crane, as the company doesn’t have a shredder, which would help in that regard.
For Gommon, a key issue is not overfeeding the baler. To prevent this, she says, operators must consider the state of the material as it comes in.
“If it’s precompacted, then you risk [putting] a lot of paper into the baler, and it makes a very long bale,” Gommans explains. “The baler [operator] has to pay attention to that.”
Gommans also points out that bale length can impact the strength of the bale. “If the bale is too long, it will break,” she explains.
Even so, the company has still opted to use variable length prepress-style balers as opposed to cutting balers, says Gomman. These machines operate more quickly, she says. They also require less maintenance and are designed to be more energy efficient.
All machines need regular cleaning and greasing. However cutting balers that will need knife maintenance as well, Gommans points out.
The company’s 80-tonne pre-press baler is useful for the company because it produces smaller bales and allows the company to bale smaller quantities of materials, Gommans says. This is particularly helpful when baling a paper grade of which the company has received lower tonnages or smaller containers.
“We bale about 40 different qualities,” explains Gommans, noting there isn’t room to stockpile all of these grades. The smaller baler allows the company to handle this great variety of grades within the space constraints of its facility.
Harm Douwe Hitzert, manager of Huhtamaki Paper Recycling B.V. located in the Netherlands says the company uses seven balers, both pre-press and cutting models. The company’s balers range in age from four years up to 28, he says.
Hitzert says the cutting balers are used mainly for tough materials such as cardboard, while the pre-press balers are used for medium and high paper grades such as SOP and coated book stock. He says common challenges include the high energy cost along with the cost of baling wire. However he says the company is able to take advantage of high volume energy rates through an arrangement facilitated by the Dutch Recovered Fibre Association. Typical baler maintenance, says Hitzert, includes cleaning of the wiring section, the hydraulic fluids and timely change of the knife of the cutting balers.
He concedes that the intrinsic quality of the grade being baled is important, but so is stackability. “Decent and good stackable bales might give you an edge at the mill upon delivery. Loosely baled and unstackable bales are reasons for mills to bounce loads.”
Besides being safer, stackable bales help deliver productivity. Angus Macpherson, managing director of The Environment Exchange (t2e), based in Edinburgh, Scotland, says one of the key criteria of trading through the company is that buyers and sellers must agree to a specified weight and quality, where the weight is determined based on the grade. T2e is an internet-based marketplace operator that facilitates deals for the buying and selling of OCC and ONP. The company also facilitates the trading of Packaging Recovery Notes.
According to Macpherson, a normal shipping container should weigh at least 24 tonnes, while a normal trailer should weigh 23 tonnes. Macpherson says these weights are achieved or exceeded by just about all sellers nowadays, in part thanks to well-shaped bales.
“With perfectly shaped and sized bales, 26 tonnes can be achieved in a load,” he says.
Bale sizes play a key part, he says, with larger bales weighing around 1,000 kilograms. “If participants wish to trade bale sizes that vary these guidelines, they must notify t2e so that it can be approved by their counterparty,” he says. “Under all circumstances minimum load sizes must be achieved.”
According to Macpherson, “Baling processes matter both from the perspective of standardizing the product, which makes it easier to trade as well as if a dispute arises,” he says. The processes also are geared to increase the operational efficiency of both the seller and the buyer, which he adds, “will result in reduced operating costs and reduced risks.”
Macpherson points out that low density bales are more likely to fall apart. They also tend to fill loads inefficiently and result in disputes.
When it comes to stackability, Macpherson notes there are some advocates who believe bales should be stacked overlapping, like a brick wall, rather than directly on top of each other, as the former arrangement may be less likely to fall.
“However within a container or trailer this compromises space and therefore tonnage potential,” Macpherson says. The latter is more important from the perspective of most contracts, and it’s safely achievable.
The author is managing editor of Recycling Today Global Edition and can be reached at email@example.com.