PAPERmaking! Vol11 Nr3 2025

1906

Journal of Material Cycles and Waste Management (2025) 27:1901–1913

Table 2 Comparison of specific energy consumption between industrial and laboratory processes

Reference

Equipment

Specific energy con- sumption (kWh/ metric ton)

Pulper

392

Recycled—Bajpai [23]

Recycled/virgin, Disc refiner—Smook [24] Recycled/virgin, Claflin refiner—Smook [24] Recycled/virgin, Jordan refiner—Smook [24] Linerboard – Base, Disc refiner – J&L [25] Linerboard – Top, Disc refiner – J&L [25] Medium – Waste, Disc refiner – J&L [25] Grades with OCC, Disc refiner – J&L [25]

Stock Preparation Refiner

70/230 90/250

116/280 99–138 197–237 39–59 50–100

Dispersion

60–80

Roux [26]

Kneading

60–80

Roux [26]

Fan pump

13

Calculated value based on data from Biermann [27]

PFI (1-rev)

0.18

UBKP referred from Kerekes [21]

0.15

SCHW and WS referred from Kerekes [21]

PFI (4,500-rev)

810

Calculated value based on Kerekes [21]

675

Calculated value based on Kerekes [21]

PFI (1,500-rev)

270

Calculated value based on Kerekes [21]

225

Calculated value based on Kerekes [21]

PFI (500-rev)

75

Calculated value based on Kerekes [21]

PFI (200-rev)

30

Calculated value based on Kerekes [21]

TAPPI Disintegration (15,000 rev, 5 min) 224

Measured by power meter

TAPPI Disintegration (1-rev)

0.015

Measured by power meter

TAPPI Disintegration (repulpability, 15,000 rev, 5 min)

171

Measured by power meter according to the standard of Fibre Box Association (FBA)

TAPPI Disintegration (repulpability, 1-rev)

0.011

Measured by power meter according to the standard of Fibre Box Association (FBA)

Blender (repulpability)

1,615

Measured by power meter according to the standard of Fibre Box Association (FBA)

were used to explore how the energy levels chosen can affect the results. The lab scale recycling shows yield losses from the handsheet-making process in which the pulp stock initially starts at 0.3% consistency and ends up around 10% when couched off the wire. The paper machine wire had 0.3 by 0.3 mm openings allowing small fibers and fines to be lost. No retention aid or recirculation of the water was used. The experimental lab methods used herein for yield loss cannot mimic all the different actual conditions and environments of industrial pulp and paper processing but are a reasonable way to provide yield losses that can be used to track relative differences in yields amongst different pulp fibers. As expected, the UBKP showed very high yields with yields per cycle around 97% in Fig. 3. This is because UBKP is a long and coarse fiber, and most of the fibers can be retained in the paper web over the paper machine wire during handsheet formation. It is interesting to note that even though SCHW is a short fiber, it still produced a yield of 82% for cycle 0, and it also demonstrated quite

Fig. 3 The Yield (for the individual cycle) and Yield’ (cumulative yield up to that cycle) of multiple recycle loops of UBKP, SCHW, and wheat straw with a heavily refined condition

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