Digester Scale Control Program Provides Superior Performance

<h6>Improvement Opportunity</h6> <p>A Northern Bleached Softwood Kraft (NBSK) mill in Western Canada wanted to optimize its digester scale control program to help them maintain an 18-month outage schedule, minimize heater acid washes, and control scale build-up in the digester and separator screen. The mill operates two identical digesters both fed by the same chip supply and liquor production cycle. They chose to run one digester using a product supplied by their long standing incumbent supplier versus Solenis&rsquo; Infinity SL4335 on the other digester for a complete 18-month cycle.</p> <h6>Recommended Solution</h6> <p>Solenis recommended Infinity SL4335 copolymer, crystal modification technology due to both its price position and it superior performance in similar applications. We also monitored the process for key variables that would increase or decrease scaling potential and made feed rate adjustments based on data driven decisions.</p> <h6>Results Achieved</h6> <p>Both digesters ran for a full 18-month cycle from outage to outage with typical operational issues. The incumbent program dosage was increased during the second half of the trial period to make it through the outage cycle. The Infinity SL4335 treated digester ran at an average application rate of 0.5 lb./ton (25%) lower than the competitive product. Even at that lower feed rate, the heater life on the Infinity SL4335 treated digester was 200+ days (54%) longer than the competitively treated digester which averaged ~130 days. Additionally, as the pictures below demonstrate, the scale build-up between the two digesters was significantly different.</p> <p><img style="max-width: 100%; width: auto; height: auto;" src="/link/5feb31a594594b639da6fbf80448e275.aspx" alt="" width="1280" height="1000" /></p>