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Innovation in ink removal

Deinking orders dazzle industry suppliers

Suppliers may not have come up with many technological breakthroughs in deinking in the last few years, but they have refined their systems to provide customers with a more cost-effective and simple deinking process. As a result, buyers are queuing up at the beginning of the production line

by Caroline Jewitt

Suppliers may not have come up with many technological breakthroughs in deinking in the last few years, but they have refined their systems to provide customers with a more cost-effective and simple deinking process. As a result, buyers are queuing up at the beginning of the production line

Deinking suppliers are virtually rushed off their feet as orders for rebuilds and new plants continue to roll in from around the globe. There may not be so many breakthroughs in new technology in the deinking arena, but there is still a huge call for the equipment that has already been around for years. As more paper and board PMs running on recycled fiber are installed worldwide, there is a steady influx of orders for suppliers to fulfil.

Keräyskuitu of Finland
Keräyskuitu of Finland keeps up-to-date with flotation technology

In Asia, for example, Nanping Paper is currently undergoing a major operation to transform itself from China's second largest newsprint producer into the number one supplier in the region. Part of the company's project involves installing a new 500 tonne/day deinking line at its mill in the Fujian province. The Andritz unit will produce recycled pulp from mixed waste made up of 70 percent old newspapers (ONP) and 30 percent old magazines (OMG). Some of the plant's equipment will actually come from Voith Paper as Andritz is the licensee for the company's stock preparation technology in China. Finished pulp from the line will supply Nanping's 180,000 tonne/yr PM 5, a modern gap former newsprint machine which started up in December 1999. The scope of the order covers the complete process, as well as a sludge dewatering system with a gravity table and screw press to dewater the sludge to a dryness of up to 50 percent, depending on its composition. Installation of the new line is due to start this month and the equipment is scheduled to come on stream in June.

Deinking orders roll in from around the world

The Far East is experiencing an upswing in demand for recycled fiber due to a number of capacity expansions in the region. Japanís Oji Paper revealed plans recently to boost denking capacity at its mill in Tomakomai, Hokkaido. The project will raise the siteís DIP capacity by 26 percent from 1,350 tonnes/day to 1,700 tonnes/day. When the new line starts up in April 2002, it will be the largest DIP facility in the country, according to the Japan Paper Association.

In February, Aspex Paper, a member of the Korindo group in Indonesia, started up PM 3's deinking line at its Celeungsi (Bogor) mill, south of Jakarta, following the completion of a rebuild and expansion project at the site. PM 3 produces newsprint from 100 percent ONP. Voith Paper supplied a two-stage secondary flotation system, disc filtering and screw system for the existing dispersion process. Aspex also bought a Meri Deltapurge unit for water loop cleaning to further boost the line's finished stock and end product quality. Originally, the dispersion stage was located ahead of the primary flotation unit. To increase finished stock quality, the dispersion process has been moved to a new position between the existing primary and new secondary flotation stages.

Toward the end of last year, PanAsia Paper Korea placed an order for a complete deinking line to be installed at its Chonju mill in Seoul. The new unit's capacity will reach 600 tonnes/day of finished stock. The Voith Paper system, DIP #5, will feed the mill's PMs 4 and 5 to produce high quality newsprint. The order includes a Protector system for the removal of coarse and fine particles, three-stage coarse screening and EcoCell pre-flotation equipment. The Korean producer has also called on the German company to supply a three-stage fine screening system with C-bar slotted baskets, a dispersion system and EcoCell post-flotation equipment.

Under the same project, Andritz is delivering bleaching technology. Meri is contributing sludge and rejects handling processes to the installation. Lamort has also supplied two Gyroclean cleaners to remove the smallest light contaminants, such as stickies.

Other orders in the Asian markets include a 200 tonne/day DIP system at Shixian Pulp and Paper in the Jilin Province and a 400 tonne/day unit for Wuhan Chenming in Hubei Province. Both of these Thermo Black Clawson plants utilize pre and post-MAC cells from Lamort.

US DIP plants expand

In the US, Alliance Forest Products is forging ahead with an expansion of the deinking equipment at its Coosa Pines mill in Alabama. The Montreal-based producer says that the new deinked pulp plant will triple the site's DIP output to 1,500 tonnes/day in the second half of this year. The unit's actual capacity will be closer to 1,700 tonnes/day. Alliance Forest Products says it will eliminate the use of mechanical, thermomechanical and kraft pulp in the mill's newsprint production through the scheme. Voith Paper is supplying HDC Cleaners, several MSM MultiSorters and MSS MultiScreens, as well as two EcoCell flotation lines. Meri has also been signed up to deliver two Sedimators for dewatering small, heavy weight cleaner rejects.

Also in the US, SP Newsprint aims to start up a new 800-900 tonne/day deinking plant at its Newberg mill, Oregon, in the third quarter of this year. The company says that it took the decision to install the new plant due to significant improvements in achievable deinked pulp quality. Equipment for the project includes a drum pulper and two EcoCell flotation machines and filtrate flotation from Voith Paper.

Meanwhile across the border in Canada, Abitibi-Consolidated recently revealed that it will construct a new deinking plant at its Thorold mill in Ontario. As a result of the project, the site is set to become the second and largest newsprint mill in Canada to produce the grade from 100 percent recycled fiber. The company aims to pick suppliers for the scheme in the middle of this month.

Orders keep on coming

Latin America is also claiming its fair share of deinking projects this year. Brazil's Central Brasileira Comercio e Industria de Papel (CBP) has just started up a 60 tonne/day deinking plant from Lamort at its site in Goiania. The unit will feed the company's new 70 tonne/day tissue machine which is due to come on stream in May or June.

Brazil's Santher has also placed two orders with Lamort to modify existing deinking lines. The first project was carried out toward the end of last year at the company's Governador Valladores mill. The supplier installed fine slots screening stage equipment to improve the unit's fiber cleaning process. The second contract covers a complete rebuild of the existing line at the BraganÁa plant.

In Argentina, Papelera Samseng, has ordered an 80 tonne/day deinking plant for its mill in the Pilar industrial estate, northwest of Buenos Aires. The Lamort unit will feed a tissue machine that the company plans to install.

Mexico's Pipsa-Mex has ordered a 250 tonne/day deinking plant for processing mixed office waste from Andritz-Ahlstrom. The unit will be installed at the company's Mexpape site and is due to start up in the first half of this year. Just a few of the components involved in the project include a FibreFlow drum pulper and feed system, high density cleaners, coarse screens, fine screens, flotation system and screw presses, as well as dispersers, washers and sludge presses. The producer is also upgrading the deinking plant at its Pronal newsprint mill. The unit's capacity is set to rise to 400 tonnes/day following the rebuild by Andritz-Ahlstrom. Startup of the improved system is penciled in for late-2001.

Europe improves DIP

Europe's list of installations includes Papeterie de Voiron of France. The company aims to build a new wastepaper treatment facility at its mill in Voreppe. Voith Paper is contributing an EcoCell deinking plant to the scheme. Metso Paper will supply complete screening and bleaching equipment for the 400 tonne/day DIP line. The main screening plant will include Metso Paper's DeltaC screens for coarse screening, Delta T screens for fine slots pre-screening and multistage MuST screens for fine low consistency screening. The complete three-stage bleaching plant will handle pulp in high and medium consistencies. Lamort's part of the contract covers the pulping equipment for the project including two Helico pulpers. Meri is handling the water cleaning side of the scheme and B+G Fördertechnik is supplying the pulper feed system. Construction of the plant is due to start in June for completion in October this year.

Meanwhile, Austria's Steyrerm¸hl is also investing in new deinking equipment. The unit will feed the company's rebuilt newsprint PM 4. Construction of the new 600 tonne/day line started at the end of last year and the equipment is scheduled to come on stream next month. Andritz will supply a FibreFlow drum and ModuScreens for the project. The rest of the equipment will be delivered by a consortium between Voith Paper and Andritz with the Austrian company supplying the complete dewatering package including two disc filters, two screw presses, one bleaching tower and four SF pumps. Voith Paper's remit includes EcoCell pre and post-flotation. Andritz is also rebuilding the site's existing DIP line, which is expected to improve the quality of the DIP and increase the unit's output to 150 tonnes/day with the option of further boosting production to 230 tonnes/day. The rebuilt line is due to start up in November this year.

The company's chief engineer, Lin Yiting, explains the reason behind the latest investment at Nanping. "China is short of fiber," he says. "Nanping had two options before the company made its final decision - to install a DIP (deinked pulp) or TMP (thermomechanical pulp) line," he continues. "It [the company] dropped the TMP plan as China also lacks a wood supply. The last and the best option is to install a DIP plant that allows the paper machine to use cheap wastepaper as its furnish. All the wastepaper that the company uses is from the US, which has proved to be of a better quality," Yiting says.

The company's general manager, Chen Shou Qin, adds, "At present, all countries are paying a lot of attention to protecting forest resources and reducing environmental pollution," he says. "The paper industry is also actively increasing recycling and its use of wastepaper. Now, secondary fiber has become one of the most important materials for papermaking," he continues.

But the recycled path is not necessarily the smoothest way for paper producers to proceed. "Due to the rising wastepaper recycling rate, the impurities and proportion of secondary fiber in wastepaper is increasing. But the quality of wastepaper is decreasing," Shou Qin says. "Higher and higher requirements are being put forward for the ability of wastepaper processing systems to separate impurities," he explains. Based on these requirements, Nanping is installing rotating drums, hole and slot screening, EcoCell pre and post-flotation, as well as a disk dispersion process to remove plastic coatings, ink spots and stickies as early and as much as possible. The company's effort to maximize its deinking expertise does not end there. "We are also studying the application of chemicals and biological enzymes in DIP," Shou Qin comments.

Nanping has set Andritz the challenge of supplying the company with a deinking line that produces fibers with 58 percent brightness. Brightness is a very important factor in this particular installation, according to Yiting. He also picks out other important deinking targets for Andritz to meet, such as reducing dirt speck count and fiber loss, improving glue removal and increasing recycled fiber strength.

Shandong Huatai is another Chinese player that is opting for deinking with the installation of a new deinked pulp line at its mill in Shandong province. Shandong Huatai is building a 460 tonne/day Andritz DIP line that is due to leap into action on May 1. The unit will have a maximum capacity of 500 tonnes/day.

Shandong Huatai says that costs and environmental concerns were the two major reasons for the company choosing to install the new deinking line. "Using wastepaper is much cheaper and more environmentally friendly than using nonwood fiber, which leads to discharging polluted effluent into the rivers," the company explains.

Both producers clearly believe in deinking as the profitable way forward. Nanping and Shandong Huatai say that local newsprint mills have been keen to expand on the back of growing demand in the region. "Publishers are increasing newspaper pagination and issuing new titles particularly in coastal cities, in line with improving literacy and living standards," Yiting says.

In fact, the increase in demand is so great, that it prompted Shandong Huatai to ship in a 160,000 tonne/yr newsprint PM that Haindl of Germany no longer required. The machine is due to start up next month.

Finns float onto the scene

Meanwhile, in Europe, deinking plans are also at the top of several companies' agendas. Stora Enso, Myllykoski and Metsä-Serla moved quickly to grab the first MuSTCell flotation cell off the production line at Metso Paper (formerly Valmet), for their jointly owned company, Keräyskuitu. Metso Paper deserves a pat on the back for the successful launch of this unit, as the company is something of a newcomer to the deinking sector. The supplier has been a rising star to watch in deinking since the merger of Sunds Defibrator and Valmet in the middle of 1999. Together, the companies are working toward providing complete systems for the pulp and paper industry, instead of just concentrating on individual areas of expertise.

At Keräyskuitu, the production manager, Seppo Pekkola, says that the mill's old cell capacity was not enough to keep up with the Finnish pulp plant's output and produced poor quality fiber, particularly in terms of brightness. "There has not been any revolutionary development in flotation cells in years," Pekkola says. "But Valmet's [Metso Paper] cell gives us the possibility to control the size and quantity of the bubbles during the process. You don't have to change the injection cocks if you want to change the bubble size," Pekkola explains.

The new system which started up in January this year replaces equipment that dated back to the 1970s. On top of the upgrade, Pekkola says there is room for even further improvement at the deinking plant in Sunila. "Our cell's theoretical capacity is now 340 tonnes/day. We are running at 230 tonnes/day. So we have the possibility of increasing our production in the future," he explains.

Metso Paper's new MuSTCell flotation cell is at the heart of the Finnish project. "The air dispersion operation principle represents a new solution differing from the other systems existing in the market," according to Metso Paper. Pulp aeration is carried out using a rotor system that has been specially developed for fiber suspensions. Pulp flows from the aeration stage to another stage based on the density difference between the aeration (inner) and separation (outer) sectors that are connected to each other with upper and lower flow channels. As a result, there is no need for pumps between the aeration stages. The supplier says the benefits of the new system include maximum brightness gain and flotation performance through the optimization of flotation sub-processes. Such optimization is a result of controlled aeration (air to pulp ratio, average bubble size), internal flows and reject removal (foam retention time). In addition, the unit runs on low energy consumption and in the absence of pumps, only needs power for the air supply and mixing stages, according to Metso Paper. The operational volume of the cells varies from 5-120 m3. The unit's maximum diameter can vary up to 8.95 m with a maximum height of 5 m.

Pekkola hails consistency as one of the main benefits of the newly installed system. "Raw materials and chemicals cause variations in the [deinking] process," he explains. "We believe that after optimizing the unit, we can reduce the inconsistencies, which gives a better pulp quality," he says. "If the raw material quality changes, we can alter many process parameters in the flotation cell while it is running. We no longer have to accept a situation where the raw materials change and we can't do anything about it. This is quite normal in many deinking plants," he continues.

Old news makes good news

Another major European installation that took place in the last 12 months was the new deinking unit at Haindl's Augsburg mill in Germany. The mill started up a 380 tonne/day deinking line in the middle of last year.

The plant was supplied by Voith Paper and went into action a week before the company's new 400,000 tonne/yr lightweight coated (LWC) PM 3 came on stream in June. The order covered pre and post-flotation, low consistency slotted fine screening incorporating new patented stickies flotation in the final stage, as well as two dispersion systems. Meri was responsible for the water cleaning systems and rejects treatment.

Augsburg's deinking plant manager, Wolfgang Krodel, says that the unit is running well and living up to the company's expectations. "Haindl already has a lot of experience in deinking, particularly at the Schongau mill that was founded in 1887," Krodel comments. The Schongau mill has a recycling capacity for recovered paper from household collections of 700,000 tonnes/yr. The main reason behind the company's installation of the new deinking plant at Augsburg was to capitalize on the bountiful supply of raw material available in Germany, according to Krodel. "We have a cheap source of raw material, but it is good quality. That is important," he says. "Good quality starts in the raw material and continues through the entire process here at Haindl," he says. Krodel also cites brightness and fiber strength as two important requirements of the deinked pulp that the company uses.

Keräyskuitu of Finland
The MuSTCell rolls off the production line

Andritz delivered all of the dewatering equipment, medium consistency SF-pumps and the discharge system for the high consistency peroxide bleaching tower for the project. Haindl commissioned a total of three dewatering stages, including a disc filter, medium consistency SF-pump and a screw press for the separation of filtrate loops and de-ashing after flotation I, flotation II and after the secondary disperging stage. "Each disc filter has a diameter of 5.2 m and thickens the deinked stock from 0.6-1.0 percent consistency up to approximately 12 percent," says Peter Braeuer, research and development (R&D) and technology manager for the pulp division at Andritz. "By using so-called 'low volume sectors' and also a center shaft with low filtrate volume, excellent filtrate qualities are achieved even at highest throughput," he says. The wire sectors used in this application are much easier to clean compared to other sector types, according to the company. "This offers clear advantages in maintenance, especially with deinked pulps at high ash contents," Braeuer comments.

Refining the process

Despite the plethora of orders keeping suppliers occupied, they are still finding the time to look into other ways of improving their existing equipment. Kvaerner Pulping, for example, has been busy trying to pull together the strings of the deinking process in order to simplify the entire system for its customers. The company's former R&D general manger, Pål Bendiksen, picks out dispersion as one area for particular attention with the development of Kvaerner Pulpingís Compact Disperger System. "A system consisting of a screw press equipped with consistency control, a Speed Heater and a disperser with disc gap control provides full and independent control of all important dispersion parameters, ie consistency, temperature and specific energy," according to Bendiksen. On top of that, the heater provides short retention time for lower fiber degradation, an even pulp flow and good mixing capabilities for bleaching purposes. He says that the system requires less floor space, as well as lower installation and operating costs than traditional systems.

Kvaerner Pulping's compact system may not push back the boundaries of deinking technology, but it goes a long way toward keeping customers happy with simple, cost-effective methods. Metso Paper is another company that holds dispersion in high esteem. The company's dispersion solutions include the DIVA disperser that is equipped with large conical fillings. The high-intensity HI-preheater is said to provide uniform and quick heating of all the pulp, while the DPL-plug screw ensures the uniform feed of the pulp to the pre-heater and eliminates steam losses.

Taking a look at Voith Paper, its current High Temperature Dispersion (HTD) system also continues to satisfy the public, with over 50 examples sold since the unit was introduced in 1995. "The machine features reliable and accurate control of the specific dispersion energy throughout the lifetime of the fillings," says Volker Niggl, Voith Paper's fiber treatment product manager.

Similarly, the company's EcoCell is still thriving four years after it was first introduced. Voith Paper says that by the end of last year, 78 plants had started up and in February this year, a further 15 plants were on order. The EcoCell removes a wide particle size spectrum for maximum brightness and cleanliness, the company says. The cell's modular design means that, theoretically, there should be no capacity limit for production in one line. The modular cell design in combination with the series arrangement provides the possibility of increasing the production capacity of an existing plant by up to 30 percent for the same technological results just by simply adding on additional cells, according to the company.

Thermo Black Clawson
Thermo Black Clawson develops the Ultra-TEK Screen Line with ID2 screening technology

Meanwhile, Thermo Black Clawson's customers are still keen to buy its systems that date back to the 1980s. The company says that the DNT High Speed Washers have been selling like hotcakes since their introduction in the late 1980s. "Tissue applications are the most popular," according to Mark Gilkey, the company's market manager for deinking. "But units have also been sold for ONP washing for newsprint and LWC (lightweight coated) grades, as well as for fine paper and top liner applications," he continues. In addition, Gilkey says that the company has installed several lines for washing OCC (old corrugated containers) pulp to upgrade fiber strength for liner board and to increase porosity for grades such as sack paper.

Equally, the company's latest, or rather improved, product to take off is the new Ultra-TEK Screen Line with ID2 Screening Technology. The equipment is aimed at enhancing the removal of both light and heavy debris streams. The ID-2 cylinder and rotor technology increases the active area of the screening surface. "By using the entire surface, capacity and runnability are improved," according to Gilkey. "The actual passing velocity through the slot is reduced, resulting in better sticky removal efficiency," he explains. Thermo Black Clawson's sister company, Lamort, is also celebrating strong sales of the relatively young MAC cell unit, with over 70 orders placed in the last five years.

Taking a laid back view

By all accounts, deinking suppliers have had a busy 12 months with a constant turnover of orders and a stream of refined equipment coming onto the market. But in terms of new technology, deinking has led a fairly static life over the past five to 10 years. There have been few major advances in technology and new systems are still based on the original components. Current deinking systems are more advanced due to suppliers improving the way in which the process works. Luckily for the suppliers, customers seem happy to accept the tried and tested methods and the orders keep coming in. But maybe innovators will put the cat among the pigeons in the near future. It just takes one bright spark to come up with a novel idea before everyone else jumps back on the development bandwagon.

Pulp&Paper International April 2001
Stories Columns Paperloop.com
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