Repacking slashes water consumption and maintenance costs

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Repacking slashes water consumption and maintenance costs

August 22, 2010 - 16:00

BRUSSELS, Aug. 23, 2010 (RISI) -Many pulp and paper mills have been consolidating sources of supply for gasketing and packing, among them the Tembec Spruce Falls mill in Kapuskasing, ON. An integrated forest products company, Tembec operates 40 pulp, paper and wood mills in North America and Europe.

Garlock Sealing Technologies supplies all of the company's Canadian mills, converting and simplifying its sealing requirements through a program that has yielded significant benefits for Tembec. Initially Garlock of Canada replaced other manufacturers' gasketing and packing for the company's paperboard mill in Temiscaming, QC, where Tembec was established in 1973.

After similar conversions at many of the company's other mills, Garlock was consulted by the Spruce Falls mill, which had invested in a new thermomechanical pulping (TMP) process. TMP technologist Ken Belanger looked to Garlock for a solution to the too-frequent replacement of failed packing the revamped mill required. Belanger and Garlock conducted a complete survey to determine the water consumption of each pump in the mill, an extremely time-consuming undertaking. But Belanger indicated it was worth the investment in time to arrive at a successful resolution of the problem for the plant's future.

Figure 1 - The standardized packing could not withstand the conditions encountered in the TMP process
Figure 2 - Packing specified for each individual pulp reduced packing consumption threefold and water consumption by more than 70%

Root cause of the problem

The original goal was to extend the life of the mill's compression packing from about six weeks to three months. Unfortunately, the new TMP plant had been standardized on one style of packing throughout the mill, which turned out to be the root cause of the problems it was experiencing. The compression packing the mill was using was a good general-service seal for standard- and medium-service requirements, but it was not capable of withstanding the harsher environment of the TMP process.

At Spruce Falls, the performance and longevity of the packing were based primarily on the speed of the pump and the media being pumped through the stuffing box.

Many other factors were taken into account as well, including the percentage of solids in the media, the pump manufacturer's flush water requirement, and most importantly, access for quick installation of the packing.

The first step was to determine the correct packing for each of the 96 pumps in the Tembec facility.

It was found that many of the pumps required different configurations of two styles of packing, based on each individual piece of equipment. In addition to supplying the packing, Garlock educated the Tembec staff on the repacking program and conducted on-site training for the trades.

Since its implementation, the program has resulted in a threefold reduction in the mill's packing consumption, a significant reduction in maintenance costs, and a more than 70% reduction in the combined water consumption of the mill's 96 pumps. The latter was an unanticipated benefit for the mill and the company, as was the reduction in the associated cost of treating the water to operate the pumps.

"I'm extremely pleased with the results thus far," says Belanger. "Further minor improvements are being looked at to enhance the ongoing cost saving program, with Garlock of Canada as a main contributor."