Evaporator Flushing Creates Significant Water Savings and Energy Efficiency at Cloquet Mill

Minnesota Facility Saves 2 Million Gallons of Water and 3.2 Million Pounds of Steam
Feb 14, 2023 8:00 AM ET
Energy efficiency at Cloquet Mill

Focused on a Thrive25 sustainability goal to reduce energy use, Sappi North America has also successfully reduced water and steam use at the Cloquet Mill.

Sappi’s Thrive25 sustainability goal seeks to reduce total specific energy use by 1% annually for five years. The Cloquet project resulted in saving over 2 million gallons of water and 3.2 million pounds of steam; it also increased production through increased black liquor firing, all of which exceeded the 1%-a-year energy reduction goal.

The Cloquet Mill initiated a Rapid Lean Six Sigma energy project to target TUBEL super-concentrator evaporator flush reduction.

The goal of the TUBEL flushing project was to reduce the flush water volume by 25%, ultimately reducing the amount of energy needed to reprocess the flush water by 25%. The team reevaluated flushing techniques, triggers, durations, and sources of water. Ultimately, the project established new flushing operational parameters, implemented best practices for flushing duration, and achieved over double the initially planned savings.

These types of energy reductions can be achieved in several ways, including capital investment, operational efficiency improvements, and targeted continuous improvement projects, such as Cloquet’s successful Rapid Lean Six Sigma project.