Defoamer Program Unlocks Washer Bottleneck and Reduces Bleach Costs

GoalUnlock washer bottleneck and reduce bleach costs.

<h6>Customer Challenge</h6> <p>A southern U.S. pulp mill running DD washers in the brown stock area designed to run 1,800 TPD was limited to 1,675 TPD due to poor washer runnability. High defoamer carryover was resulting in dirt outbreaks on the pulp dryer. Due to issues in the O2 delignification system, air was being entrained in the stock going to the post O2 washer. Screen room temperatures would typically drop to 115-120 &deg;F due to fluctuations in stripped condensate temperature and availability to the screen room DD washer. The main production bottlenecks were the O2 delignification and screen room DD washers.</p> <h6>Recommended Solution</h6> <p>Solenis recommended replacing the existing two-product program, which consisted of an emulsion product and a concentrate product, with a single emulsion product consisting of Advantage&trade; CS9625 defoaming agent at the same feed points. Elimination of the concentrate product was believed to be key in reducing the silicone carryover and subsequent dirt outbreaks due to the enhanced dispersion of emulsions versus concentrates.</p> <h6>Results Achieved</h6> <p>This trial started as a &ldquo;demonstration trial,&rdquo; but the results were positive enough that the mill never went back to the incumbent program. Dirt outbreaks were virtually eliminated, resulting in an additional 54 min/day of uptime on the pulp dryer; conductivities to the bleach plant were reduced by 22%, resulting in a reduction in ClO2 usage of 3.5 lb/ton; as received defoamer usage was reduced by 0.44 lb/ton; and overall pulp production increased by 10 to 15% due to better control of entrained air, which debottlenecked the two troublesome DD washers.</p> <p><img style="max-width: 100%; width: auto; height: auto; display: block; margin-left: auto; margin-right: auto;" src="/link/5f98d29a1b84498782711e7a939a91d3.aspx" alt="" width="550" height="439" /></p> <p><img style="max-width: 80%; width: auto; height: auto; display: block; margin-left: auto; margin-right: auto;" src="/link/9e48bc0e737b4438a6015b7d549d15e7.aspx" alt="" width="550" height="466" /></p>