Reducing cost and improving quality of demineralization with high-performance resins.
Demand for eucalyptus wood pulp has experienced increasing in demand from 2006 until today. Due to its tropical climate, favorable soil and investment in silviculture technologies (growing and cultivation of trees) since the 1950s, Brazil is now the world’s largest producer of short-fiber hardwood pulp from eucalyptus, which enables the production of opaque, bright and smooth paper. Water availability and quality, however, are issues in Brazil and technologies allowing efficient and cost-effective reuse / recycling of water are in demand.
One of the largest pulp & paper producers in Brazil originally contacted us in 2013 about the possibility of switching from a competitor’s brand to Purolite’s standard resins for their demineralization line for their pulp processes. Because water treatment processes can be costly, we wanted to ensure the system was running as efficiently as possible.
During the operational audit, the customer noted that their primary concerns were with the high cost to produce demineralized water and poor water quality. The customer’s system included counterflow cation and anion vessels followed by a mixed bed for polishing the water for increased purity. The water quality suffered from high silica and conductivity which if not managed properly would cause deposition causing corrosion, overheating and significant and costly system downtime. Because even the post-treatment water was not achieving acceptable quality and they were needing to purge the boiler more and more frequently.
After doing a complete audit of the system including the plant specifications, set up, water chemistry and regeneration sequence, we checked all parts of the system including laterals inside the tank and water flow during the regeneration. We suggested that they switch from standard resins to Purolite’s Shallow Shell™ Technology (SST®) resins to achieve the greatest improvement for water quality and reducing operational costs. The resins are specifically designed to increase regeneration efficiency, reduce leakage and fouling and conserve rinse water and regeneration chemicals.
We used our proprietary modelling software to demonstrate different performance scenarios and return on investment for the resin solution. A performance improvement of at least 15% could be guaranteed.
The customer purchased and installed SST® resins (Purolite Shallow Shell™ SSTPPC60H and Purolite Shallow Shell™ SSTPFA63) for both their cation and anion counterflow equipment and monitored the results.
Over the course of 6 months, the SST resins helped the system achieve a 27% increase in in-service use before regeneration was necessary. Plus, the system experienced a 39% reduction in acid consumption and a 23% reduction in caustic soda (NaOH) consumption during regeneration. Additionally, there was a 41% savings in total water volume used for regeneration and in waste water for the demineralization system.
The results were far better than expected. Due to the significant increase in the demineralization water quality, the mixed bed polisher system increased cycle time by 300% before experiencing leakage and requiring a regeneration.
Purolite also assisted the team with instructions on how to keep the demineralization and mixed bed polishing systems operating most efficiently.
The customer continues to purchase SST resins for their systems and are happy with the consistent results.