M-real Hallein's new CHP plant is helping the Austrian LWC mill cut energy costs
February 2007
By Justin Toland, Editor
Rising energy costs, recycling costs and more stringent environmental legislation have all made paper mills view solutions such as biomass-fired combined heat and power (CHP) plants as a necessity, rather than a nice option.
M-real Hallein mill, located next to the River Salzach, 15 km from Salzburg in picturesque western Austria, started up its new CHP plant in May 2006. The 30 MW plant, which provides some 20% of the mill's requirements, replaces four steam blocks that generate 30 tonnes/hr of steam from fossil fuels. The CHP facility, which has a capacity of 33 tonnes steam/hr, can supply 21 MW of process heat, as well as 4.84 MW of electricity. It is fed with a mixture of rejects, bark, wood, cores and sludge (15 tonnes/hr of raw material is needed).
Austrian Energy & Environment supplied the fluidized bed boiler and steam turbine island, FMW, the raw material handling equipment, and ABB the power grid connection. Alpine Mayreder provided the building works for the Euro 35.6 million ($46.8 million) project, which was carried out in partnership with Alternative Energy Salzburg Ltd (AESG).
The new plant provides the mill with residual heat and process steam and supplies district heat for 850 households and green electricty for 15,000 households via Salzburg's local grid. Under Austrian law, the 4.84 MW of electricity the mill produces must be exported to the grid and the mill must buy back the electricity it needs to meet its requirements. However, even with today's high energy prices, the subsidy for supplying the grid with 'green' electricity is higher than the cost of the electricity the mill has to buy back. Hallein also benefits from the EU emissions trading scheme (ETS). The ETS rewards industrial sites that reduce CO2 emissions, by giving them a CO2 allocation for a fixed period of time, and allowing them to sell any unused portion of the emissions allocation. According to the head of the customer service center, M-real Hallein, Gottfried Golser, the new CHP plant will reduce the mill's CO2 emissions by 33,000-45,000 tonnes/yr. The plant also enables the mill to cut its natural gas use by 23 million Nm³/yr.
The mill in detail
M-real Hallein employs some 700 people, including apprentices. Founded in 1890, the mill produces 300,000 tonnes/yr of coated fine paper on two machines (PM 3 and PM 4), plus 150,000 tonnes/yr of spruce sulfite pulp. Turnover in 2005 was Euro 225 million.
Three trains per day bring in raw materials and take out finished goods. The mill buys in roundwood, woodchips, pulp and chemicals including calcium carbonate (from Omya's factory in Gomen, Austria) and starch. Since 2005, the mill has been using mainly PEFC-certified wood (see sidebar).
The single pulp line was converted to a totally-chlorine free (TCF) acidic magnesium-bisulfite process in 1988. The bleaching sequence is OPMgO-A-PnaOH. There are seven digesters. These are fed with 95% sawmill chips (sourced from sawmills within a 150 km radius of the mill); 5% of the wood fiber input is debarked and chipped on site. Some 70% of output is sent as slush pulp to the two paper machines, with approximately 35,000 tonnes/yr half-dried and sold to tissue mills in Germany. The dewatering machine has a capacity of 45,000 tonnes/yr.
PM 3 and PM 4 are located in the same machine house. Built by Escher Wyss/Beloit and started up in 1964, PM 3 has been rebuilt four times, the last coming in 2001, when the dryer hood was replaced and the pre-coating section changed. The 3.8 m-wide unit has a running speed of 750 m/min and produces pre-coated base paper in a basis weight range of 135-295 g/m².
PM 4, supplied by Wärtsilä and Voith Paper, was born in 1970. It has been rebuilt five times, with the most recent overhaul a rebuild of the coating section, carried out by Voith in 2005. Also 3.8 m-wide, PM 4 has a running speed of 1,000 m/min and a grammage range of 80-170 g/m². PM 4 churns out single coated woodfree coated paper and precoated base paper.
"We have old machines but they have had a lot of rebuilds: we are really up-to-date with the equipment," says Golser.
CM 2, M-real Hallein's offline coater, started up in 1991. It was supplied by Voith Paper and has a running speed of 1,500 m/min. Two grades of paper, EuroArt Plus silk and EuroArt Plus gloss (both 150-350 g/m²) are coated on the unit. These two grades account for 260,000 tonnes/yr of the mill's output. The other 40,000 tonnes/yr is EuroBulk, a paper that is only produced at M-real Hallein. Launched in 2004, EuroBulk is a coated paper with the feel of an uncoated grade. It is mainly produced on PM 4. The basis weight range is 80-250 g/m².
M-real Hallein produces only sheets, no reels. This month, the mill is set to install its eighth sheeter, a 2.2 m-wide Bielomatik-Jagenberg machine with a capacity of 80,000 tonnes/yr. The seven existing sheeters have a combined capacity of some 900 tonnes/day. The finishing department also includes ream wrappers able to handle up to 120,000 tonnes/yr.
Reel storage is fully automated and features a Demag vaccum lifting system.
Some 94% of all output is exported, with 61% of all production heading elsewhere in Europe (17% goes to Germany), 10% to North America and 23% to the rest of the world. Deliveries to the US go by container from the port of Koper in Slovenia to New York.
The sales offices can book orders directly from the 15,000-tonne reel storage area, speeding up the time it takes to go through converting and dispatch. In fact, there are separate control systems for pulp and paper manufacturing and converting and dispatch.
"We need approximately 1,800 one-way pallets per day for delivering sheets," explains Golser. Regular pallet deliveries enable the mill to make external deliveries quickly. M-real Hallein mill is "small but flexible," says Golser. "We are faster to deliver than our competitors," he adds.
|
|
|
There are 3.3 million ha of PEFC-certified forest in Austria. The certification scheme was introduced in the country in 1999. Today, some 75% of all timber used by the pulp and paper industry in Austria is PEFC. Globally, M-real aims to increase the amount of PEFC-certified wood it uses (presently 63%). As of November 2006, M-real Hallein mill was using 81% PEFC-certified raw material. In 2005, the facility implemented a chain-of-custody certification system for all purchased wood.
|
Pulp & Paper International is FREE to qualified subscribers.
Click here to find out more.
