Justin Toland, Editor, PPI magazine, RISI
Dec. 1, 2004
Pulp and papermakers often talk about expanding the business 'step by step': a sensible approach. But sometimes, the next step cannot be a small one it must be a 'giant leap'. Taking that step requires the "courage to change", points out Jimmy Lee, CEO of Mercer International. Mercer has just taken the courageous step of starting up a new 552,000 tonne/yr market pulp mill, Zellstoff Stendal (Stendal), located in Arneburg, Sachsen-Anhalt, eastern Germany. In the process, the US-owned pulp and papermaker has more than doubled its NBSK capacity (Mercer's Rosenthal mill, Blankenstein, Thuringia, Germany produces approximately 300,000 tonnes/yr market pulp).
The new mill, which started up at the end of July, was first announced in January 2000. As is often the case with projects of this size, it took some time for financing for the Euro 1 billion ($1.3 billion) scheme to be put in place. The bulk of the funding comprised a loan of Euro 819 million arranged by Bayerische Hypovereinbank of Munich and partly underwritten by Nord-LB, Hannover and Halifax-Bank of Scotland. However, Mercer had to wait until June 2002 for EU approval for support and subsidies of around Euro 250 million offered by the German government. Mercer owns 64% of Stendal, German electricity giant, RWE, holds a 29% stake, while the remaining 7% belongs to Fahr Beteiligungen AG, owner of the industrial park where the mill is located.
With the money in place, the project moved quickly. RWE, which was awarded the Euro 716 million turnkey construction and erection contract, broke ground on August 26, 2002. The project required 130,000 m³ of concrete, 14,200 tonnes of reinforced concrete and 48,000 pre-assembled parts. At the height of construction, there were 2,500 people working on what was the biggest building site in Sachsen-Anhalt. The machine house was completed in August 2003, an occasion marked by a visit from German Chancellor, Gerhard Schröder.
Metso supplied the complete fiberline, from wood handling to finished bales, as well as a millwide automation system, an order worth Euro 135 million in total. Mercer awarded the contract for the black liquor evaporation plant (670 tonnes/hr), recovery boiler (3,250 tonnes dry solids/day) and recausticizing plant (8000 m³/day) to Andritz. Other key suppliers included Purac (biological water treatment), Sulzer Pumps (pumps and agitators) and Wiessner (air engineering). All the major suppliers were well established and performed in line with their reputations, notes Lee. "We had no major issues with the suppliers," he says.
As process engineer, Eberhard Dobschall, explains, the startup of the mill was a very special moment for all involved: "At the weekend we filled the first digester with chips , added the first liquor on Monday and when the first pulp came out the following Wednesday our hairs stood on end. We felt very proud."
Stendal's pulp is made from 70-80% pine, 20-30% spruce. Wood procurement is the responsibility of subsidiary company, ZS Holz, while a second daughter company, ZS Transport, is responsible for both internal logistics and wood chip transport and product shipments to all markets. Stendal is PEFC-certified and will source wood exclusively from sustainable forests within a 300 km radius of the mill, as well as using chips from sawmills.
According to Dobschall, the mill aims to use 70% own-produced chips and 30% from outside.
Daily consumption when the mill reaches full output will be 9,000 m³ solid wood. There is three weeks roundwood storage space on site.
The logs are processed using Metso ChipWay technology, consisting of two debarking and chipping lines. Each line can handle up to 300 m³ solid wood/hr. The wood infeed system GentleFeed conveys the logs into the debarking drum on top of moving lamellas, rather than using chains or sprockets, the aim being to eliminate wood breakages and improve yield and chip quality, thereby decreasing the need for bleaching chemicals.
Together with the infeed system, the Easy Tyre debarking drums and Camura GS chippers are designed to minimize wood losses and maximize the uniformity of chips destined for the digester. The mill also has a bark press that will be used in winter when the bark is less dry. Unused bark is stored and then burnt in the bark boiler to generate energy. Stendal's bark and recovery boilers between them generate 90 MW energy. Since the mill needs only 55 MW, the remainder can be sold to electricity suppliers. Mercer believes the mill will be an "industry leader" in terms of efficient production and good environmental performance.
Only chips of the right size and quality are made into pulp; those that are too large are rechipped, while fines go to the bark storage area prior to being burnt in the bark boiler. Chips produced on-site and those brought in from sawmills are stored in separate 60,000 m³ chip piles for quality control reasons.
Making the pulp
Stendal employs Metso's SuperBatch pulp digesting process, including eight 400 m³ digesters, together with pressurized accumulators and tanks for black, white and displacement liquor. After cooking, knots and shives are separated using four-stage DeltaCombi screening. The pulp is then further delignified in a two-stage OxyTrac oxygen delignification process. Bleaching is in four stages with washing by Twin Roll wash presses after each stage: the sequence for ECF pulp is Q-OP-D-PO; for TCF it is Q-OP-PAA-PO. Stendal was initially conceived as a TCF-only mill, but the plans were redrawn to allow it to produce both ECF and TCF pulp, with more of a focus on ECF. According to the Mercer CEO, TCF production will really depend on the market, but, "The distinction between the two grades is minuscule today," believes Lee. Stendal expects to start producing TCF pulp end-2004/early 2005.
The pulp is stored in a 10,000 m³ tank and screened again in four stages before dewatering. The Metso DryWay pulp drying line is 7.2 m wide with a web speed of 250 m/min. Maximum output is 1,800 tonnes/day dry solids. Fiber content is 1% at the headbox, increasing to 20-22% after the wire section. The press section features one Combi-Press and one Valmet SymZL shoe press making it possible to achieve 52% dryness prior to the airborne dryer. There, the pulp is dried at 120°C and when the sheet emerges it has a 90% dryness content. There is a measurement point after the airborne dryer that tests parameters such as water content and brightness. Dobschall explains that brightness is 88-90 ISO ("90 for A-prime quality pulp").
The sheet is then cut (first in machine direction, then cross-machine direction), stacked in 250 kg bales, pressed to minimize volume, packaged, printed and stacked in eight-tonne 'units' (8 x 4 bales). As each truck can hold 24 tonnes, this means one truckload requires three forklift journeys.
Information management and process automation is via a MetsoDNA system the same solution that is in use at Mercer's Rosenthal mill. The technology is used to operate and control the entire pulp mill from wood handling to bale storage and from water intake to wastewater treatment. The automation network comprises 42 process control nodes processing in excess of 30,000 signals distributed to more than 40 rack and electrical rooms. The system also covers integrated sectional drives and machine controls, quality control and millwide information management and bale line quality management. There are 23 operator control nodes in total, divided between the central control room and two auxiliary control areas (in wood handling and pulp drying). "It's a very good system," says Dobschall.
Ready for the market
The storage area at Stendal can hold around 20,000 tonnes at any one time, or approximately 12 days' storage once the mill hits its target output of 1,700 tonnes/day. According to Dobschall, "In principle, all the pulp we are producing is basically the same, but we divide it into three qualities: A-prime, B-prime and C-prime." This latter, the lowest quality, was only produced immediately after startup. Now the mill produces mostly B-prime pulp with some A-prime as well. End-uses for Stendal's NBSK include printing papers, tissue papers and white packaging grades.
Lee explains that Stendal's sales focus will be similar to that of Rosenthal: approximately 40% of output to Germany, 30% to Italy, and the remainder mainly to the rest of Europe. "We could sell some pulp further afield in time," he notes. The mill's location close to the River Elbe is good for the backhaul of containers, meaning that, "We can ship to China relatively cost effectively, for instance," says Lee. However, he believes China is too much of a spot market for now, but that it could be a favorable market for Mercer longer-term as more new paper and board making capacity comes on stream.
The mill is aiming to reach a minimum 80% of rated capacity before end-2004 and expects to hit full capacity toward the end of 2005. "So far it has been better than most startup curves," says Lee. "It has not matched that of Rosenthal, but that was exceptional. It has been pretty good."
According to Lee, "The start up of Stendal is a milestone in terms of [Mercer's] development. We now have the most modern, competitive softwood kraft pulp mill in Europe, and we have the quantity and quality to serve our larger and more demanding customers," he explains.
A positive change
The Mercer CEO also believes that Stendal benefits the forest industries in Germany as a whole, helping to provide a lot of indirect employment in addition to the 580 jobs directly associated with the mill (350 employees and 30 contractors, as well as the 200 people employed by ZS Holz and ZS Transport). "We are now the largest wood consumer in Germany. The German sawmill industry is expanding, without Stendal these companies would find it difficult to find a market for their chips."
Lee adds that, since forest resources in Germany have recently been found to be three times higher than previous forecasts, there is sufficient fiber available to allow more wood processing projects to be set-up without affecting the environmental balance. However, Lee also expects that Stendal will be "one of the last" new market pulp mills in Europe. For Mercer, "To be absolute low cost is critical to survival" as a pulp producer, he believes.
The Mercer CEO also views the startup of Stendal as good for the business climate as a whole in Germany, as he explained in his address to the 800-plus guests and dignitaries (including Chancellor Schröder) gathered to celebrate the inauguration of the mill: "The completion of this technically demanding project in less than three years shows that Germany offers noticeably better opportunities for investment than some people may have assumed. The success may indeed give other international companies the courage to undertake challenging industrial projects in Germany and also foster in German entrepreneurs the need for courage to change... Change is not only possible, but positive."