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BTG’s bright idea delivers fast less than 1 year payback for European DIP mill

BTG’s BT-5400 UV brightness transmitter proves the best and brightest solution to reducing costs and boosting performance at French recycled paper specialist ArjoWiggins.

Achieving consistent product quality when using a mix of widely varying furnish types represents a major challenge for any mill.

Until now, most manufacturers have simply resorted to liberal dosing of chemical additives to remedy pulp variations that threaten the quality of finished products. But under pressure to slash unnecessary overheads, innovative mills are turning to advanced technology to help them deliver quality output at optimum cost.

By dosing properly the various types of furnish and eliminating the need for excessive chemical dosing, the BT-5400 UV paid for itself in less than 1 year.

BTG’s BT-5400 UV is specially designed for monitoring and optimizing pulp bleaching. Featuring a unique method of measuring brightness and a user-programmable algorithm, this easy-to-use transmitter delivers exceptionally accurate results through calculating compensated brightness signals that take into account variables and inputs from a variety of process measurements.

Trials of the BT-5400 UV at ArjoWiggins’ Le Bourray de-inked pulp (DIP) mill at Saint-Mars-la-Brière, just outside Le Mans, demonstrated full ROI in less than one year by allowing the mill to optimize the introduction of various recycled fiber furnish – eliminating the need for bleaching agent dosing and allowing the mill to use lower-brightness recycled fiber whenever possible.

Access to accurate data on brightness levels has enabled the mill to maintain its stringent quality control standards while simplifying its process and optimizing the use of chemical agents.

BTG BT-5400 UV benefits

• Easy handling and installation
• 100% safe insertion and removal of probe
• Maximum installation flexibility
• Easy access to sensor parameters, locally or remote via modem
• Flexible selection of output signals: Brightness, Color, ERIC, Fluorescence

RESULTS AND IMPROVEMENTS

Figure 1:
Installation points of BT-5400 UV in DIP mill

Figure 2:
BT-5400 UV measures OBA content

The Le Bourray DIP mill, which produces 110,000 T/y of recycled tissue and coated recycled printing and writing paper, regularly draws on eight principal recycled fiber sources. It is configured with two DIP loops with flotation (Fig. 1).

The UV LED of the BT-5400 UV is used to measure OBA content (Fig 2).

The transmitter was calibrated for (Fig.3):
- Brightness, R457
- Brightness, R457 + UV
- ERIC
- L a b
The brightness is measured at the blue wavelength of 457 nm, according to ISO 2470-2 standard.

In the first trial position, the mill used the R457 + UV brightness settings to establish a brightness set point. Operators actively monitor this brightness level, and can manually adjust the recycled fiber furnish in line with brightness increases or decreases. If brightness rises above set point, operators now take the opportunity of feeding a lower-brightness recycled fiber to the DIP plant. Thanks to better furnish dosages, the mill could improve overall quality by reducing brightness variations.

Figure 3:
BT R457 + UV calibration, R² = 0.92

Figure 4:
Measurements showing the correlation between ERIC and brightness values

Trials in the second position revealed additional cost benefits linked to the ERIC number (residual ink count). The mill’s operators found that during periods of high ERIC, brightness levels dropped (Fig.4). By readjusting the de-inking line parameters they were able to decrease ERIC, therefore keeping the right pulp brightness without the need to add costly bleaching chemicals.

By providing accurate information on pulp quality, the BT-5400 UV will continue to generate substantial savings for ArjoWiggins for many years to come – just one more way BTG is helping its customers boost their productivity and market competitiveness.