Pulp and Paper Canada


May 1, 1999  By Pulp & Paper Canada

Today, chemical additives are an essential part of the business of making paper. In addition to the technical merits of their products, chemical suppliers are now being rated on their level of support…

Today, chemical additives are an essential part of the business of making paper. In addition to the technical merits of their products, chemical suppliers are now being rated on their level of support programs including in-mill services. As a result of these thorough business evaluations, “partnership” programs between suppliers and paper companies are becoming more common. Rather than consumable commodities, retention chemicals are being regarded as business investments that contribute to a mill’s product and process improvement programs.

The Alma, QC, division of Abitibi-Consolidated Inc. has applied this value-based approach to chemical supplier selection. The mill, which produces about 750 tonnes per day (t/d) of directory grades and newsprint, has seen many changes in its papermaking furnish over the past few years, first with the introduction of deinked (DIP) pulp in 1995 and then thermomechanical pulp (TMP) in 1996. These changes in the furnish introduced potential problems with machine deposits of pitch and stickies. Also, the retention of the TMP was naturally lower than the previous groundwood-based furnish. By the end of 1996, the mill decided to re-evaluate its retention and deposits control chemicals and the business relationships with chemical suppliers.


The introduction of the DIP and TMP was a technical challenge that made change a necessary ingredient in the mill’s culture. Gratien Girard, director of production, paper machines, explains that, “Our people are open and accepting of change. They now feel more comfortable with trials.”

With this culture of change established, he explains why they looked at new chemical suppliers: “Previously, we had two different suppliers in the mill and different chemical handling technology. Our goals were to have one supplier with good technical services and reliable chemical preparation equipment and to have the best retention program for our new furnish. We wanted only one business arrangement, which would be a contract for all paper machines with all equipment and technical services included.”

The supplier evaluation trials for PMs 9 and 10 were scheduled during the last three months of 1996. These identical 5.6-metre-trim machines run directory grades with basis weights between 28 and 51.8 g/m2 at an average speed of 655 m/m. The most common grammage is 36.6 g/m2. Filler clay is added to the sheet to manage the opacity level. Sheet ash levels are about 5 %.

The overall objectives of the trials were set and explained to three chemical suppliers. The main objectives were:

Obtain the best retention for fibre and ash without compromising formation;

Reduce the accumulation of pitch and stickies;

Improve the efficiency of both machines.

Of course, the cost per tonne must be consistent with guidelines set by the mill.

The planning, coordination and evaluation of these trials were not left to chance. The mill’s seven-person team prepared a detailed plan that would rate suppliers on numerous performance criteria that were specific to these machines. The evaluation criteria were divided into two groups: quality benefits and benefits which would provide a measurable return on investment. The team assigned weighting factors to each of the individual contributing benefits. The weighing factors were then normalized to provide an equal overall weighing for quality and direct monetary benefits. Table I shows how the matrix evaluation was constructed.


After installing new slotted screens, a baseline period was established in September 1996. Then, each supplier would have a one-month evaluation period. Each supplier would be responsible for the installation and maintenance of the chemical preparation and metering equipment. The suppliers were assigned a fixed total cost in dollars per tonne. To be impartial to all suppliers, an Abitibi-Consolidated tester would be assigned to do all laboratory testing work during the trial period. Holes and light spots were reported by on-line fault detection systems.

Bernard Lemay, efficiency and quality optimization engineer, explains why they chose a lengthy one-month trial for each supplier: “We don’t believe in a short one-week trial because there is too much variability. A longer period is more fair to the suppliers.” Girard adds that, “You need to have at least a one-month trial to see what has happened across the whole mill.”

After three consecutive one-month trials, the mill selected what they found to be the best overall supplier for the mill, Nalco Canada Inc., Burlington, ON. Its two-component system consists of a coagulant, which neutralizes the charge of “anionic trash” thus assisting the retention of fine colloidal particles, and a polyacrylamide flocculant, which provides the bridging mechanisms required to retain fibres, fines and fillers together in the sheet.

The decision was not an easy one, as the suppliers were close in many criteria. Louise Lepage, efficiency and optimization engineer, reports that Nalco, along with another supplier, provided low pitch accumulation and a lower frequency of light spots in the sheet.

She reports that the transition from one chemical supplier to another has been smooth. “The operators have a better understanding of retention chemicals and more confidence in their use.” The mill’s dedication to furnish management and papermaking chemistry is evident when visiting the wet end control room between PMs 9 and 10. There, operators can view recent consistency and freeness tests of TMP, kraft, DIP, broke and mixed stock. pH measurements are taken on the DIP and headbox white water. Retention tests are taken twice per shift. The test results are available on the video screen of a Pgase lab data system which is linked to the test lab.

The mill realized the benefits of good on-site technical service when Stephane Dube, the Nalco representative, together with the mill personnel found a troublesome contamination problem. In the original design for polymer addition, the dilution water for the flocculant was not filtered. Large brown deposits were coming through the machine, creating holes and breaks. This problem was evident during the trial because more dilution water was being used. By filtering the dilution water the problem has been reduced and the machine efficiency has improved.”

After the trials on PMs 9 and 10, the mill evaluated chemical suppliers for PM 14, a 150 000-t/y newsprint machine. Similarly, in mid-1997 Nalco was selected as the supplier for that machine. The mill is currently adding on-line retention control on PM 14.

Girard reports that the new chemical system for the three paper machines have produced “better quality and stable paper.” He says that; “The paper machine chemicals supplied by Nalco are part of the optimization across the entire mill.” During the same period, the mill has implemented optimization programs in the TMP plant and a program to improve the quality of the waste paper supply to the DIP plant. These changes in the furnish quality and paper machine chemistry contributed to efficiency increases of greater than 3% on PM 14 and greater than 2% on PMs 9 and 10

The partnership model between the Alma mill and Nalco has proven to be a good and profitable one. The mill highly regards the committed level of technical service provided by Nalco in the all-inclusive contract price. Girard notes that, as part of the merged Abitibi-Consolidated organization, the mill has access to a broader business arrangement and a stronger purchasing position with suppliers.

The model for supplier evaluation has been well proven at the Alma mill. Next, the mill intends to evaluate suppliers of felt cleaning chemicals. With planned increases in DIP pulping capacity and machine production levels, the cleanliness of machine clothing will be well tested.P&PC

Mark Williamson is a freelance writer based in Thornhill, ON.

TABLE I Matrix evaluation chart for retention chemical suppliers

Item Quality Monetary Supplier X Supplier Y Supplier Z
benefits benefits
weighting weighting
factor factor
Cationic demand 9.2
Fibre retention 10
Filler retention 10
Opacity 5.2
Light spots 13.1
Small holes 13.1
Formation (NUI) 9.2
Linting 5.2
Steam Consumption 10
Drainage 4
Cost per tonne 10
Service 4
Equipment 7
Total weighting 55 55 Sum Sum Sum

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