Pulp Paper & Logistics
CRISTINI 9
(Z-direction tensile, etc). This paper describes a
case study from the world’s fastest corrugating medium machine, the Propapier PM2 at Eisenhüttenstadt, demonstrating a control strategy that allows this mill to reduce considerably the energy consumption in the forming section, thanks to a consistency control operated by four sensors, placed in strategic positions of the former, as shown in Figure 3. Propapier’s innovative PM2
produces corrugated board base paper and has an annual capacity of 650.000 t/y. Optimum dewatering in the
former is a key-factor for energy saving in drives and blowers. Development of specific setting in the forming section allows an important potential saving in different grades production. Tests carried out have shown
reliable results in terms of accuracy. FiberScanFIX readings, at different
dryness percentages (achieved by decreasing vacuum levels), were absolutely comparable to the lab result, even more linear being not effected by the human error, as shown in Figure 4. Various tests, conducted by applying different combination of
The optimisation of the energy
consumption in the paper machine consists of spending the necessary energy only where it is needed, and avoiding wasted energy that might lead to excessive wear of the machine elements (forming fabrics, ceramics, motors and pumps).
The FiberScanFIX sensors placed Figure 3: FiberScanFix layout
vacuum levels in different suction boxes (low and medium vacuum) has shown an average energy saving (electricity) of 10 per cent in drives and 4 per cent in blowers. The high vacuum suction boxes had the biggest effect in electricity saving due to the fabric friction. The friction in fact depends on
to the level of water carried by the forming fabric. Also, the dryer the sheet, the highest is the fabric wear.
In particular, it has been possible
to reduce by 16 per cent the vacuum level on the high vacuum boxes and 10 per cent in the medium vacuum boxes, without effecting the press efficiency, machine run ability and steam consumption, as shown in Figure 5. The graph shows how the
vacuum reduction influences the consistency level after the wire suction roll.
A dryness decrease of 0.75 per
cent in the forming section, with a production of 90 gr/m2 at a machine speed of 1,540 m/min has absolutely no negative impact on the press dewatering. The press section, with this specific setting is able to compensate the dryness loss. Furthermore it was found that an high consistency level output in the forming brings no benefit in press dryness output. Based on Figure 5, low vacuum
reduction has less impact than medium vacuum, but at the same time it offers a great potential in energy saving. This is the basis for asserting that
regardless of the paper production (machine speed, basis weight) there’s always a margin of saving with regard to the low vacuum.
in strategic positions better distribute the dewatering, defining the best operative condition for each vacuum element. A potential energy saving, thanks
to specific setting, is calculated at more than 400 KWh, which is equal on PM2 to more than €250,000 a year in savings, assuming an average electricity cost of 0.08 €/KWh. In a fast evolving paper world,
this technology is a new firm point, for better papermaking, at lower production costs. * Peter Resvanis and Phillipos
Vrizas, Propapier PM1/2 GmbH, Burg/Eisenhüttenstadt, and Luca Canali, S.A. Giuseppe Cristini S.p.A. More information from SA Giuseppe Cristini SpA, via Bombardieri 5, 24020 Fiorano al Serio (BG) Italy. Tel: 39 035 715111. Web:
http://www.cristini. com/
Figure 4: Comparison results
Figure 5: Vacuum reduction May 2013
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