Brazilian Pulp Mill Enhances Bleaching Process with Cutting-Edge Ozone Solution

The Fibria Jacareí pulp mill in São Paulo, Brazil, upgraded its ozone bleaching treatment system in 2012 and has since been operating the largest ozone production facility in the world. Replacing part of the existing ozone equipment with a more reliable ozone solution has resulted in substantial cost savings annually, and a single ozone plant now allows for more than 99 percent availability. Using ozone, the mill bleaches 3,600 tons of eucalyptus pulp per day on two production lines.

The Challenge

The paper industry is known for its potential to pollute freshwater bodies around the world. As one of the world’s largest pulp producers, the Fibria Jacareí pulp mill is committed to reducing its environmental impact. The facility uses ozone technology as a sustainable alternative to chlorine and chlorine dioxide bleaching. Chlorine dioxide is known to generate hazardous byproducts such as absorbable organic halogens (AOX) found in wastewater and some end products such as paper and cardboard. In contrast, the only byproduct associated with ozone is oxygen. In addition, ozone bleaching technology halves the volume of freshwater needed for pulp bleaching and, as a result, halves the volume of wastewater produced. This significantly reduces the environmental impact and simultaneously lowers bleaching operating costs. Only 1 kilogram of ozone is required to achieve the same level of bleaching efficiency achieved by 2 kilograms of chlorine dioxide, providing further savings. The Fibria Jacareí pulp mill consists of two operating lines that use ozone to bleach pulp. One line, which is operated by Avercap and uses three parallel containerized ozone systems with a cumulative capacity of 500 kilograms per hour, consistently delivered its target reliability rate of 99.8 percent. The second line was operated by a different company and was less reliable. When the contract on the second line was due for renewal, the Fibria Jacareí team sought to improve the line’s reliability and increase the mill’s efficiency while continuing to honor the company’s commitment to sustainable practices. “... We saw it as an opportunity to increase our ozone delivery at Jacareí and, consequently, the overall efficiency of the mill,” said Miguel Elian, general manager of Avercap. “As is often the case with pulp and paper mills, space was a critical factor at Jacareí, so we were looking for a compact solution we could install in the dedicated area already owned by Avercap on-site.” Based on the reliability of the ozone equipment on the existing line over a 10-year period, the Fibria team approached the same ozone technology provider for a solution.

The Solution

Following detailed technical discussions, Fibria installed another containerized ozone system, similar to the three systems already in operation. The containerized ozone systems consist of specifically designed containers housing the generator and its subcomponents. The insulated container is equipped with an air-conditioning system suitable for the Brazilian climate, a heating system and an emergency ventilation system. The complete custom-made solution included ozone compression, complete off-gas management and oxygen valorization, which addressed the challenges the mill faced. The new containerized ozone system was tailored to produce 250 kilograms of ozone per hour, giving the upgraded ozone plant the largest installed ozone capacity on the market, with a design production of 750 kilograms per hour (1 ton per hour during peaks). Two key features distinguished the solution: the use of electrode/dielectric technology and variable frequency technology for the ozone generators. These features of the ozone equipment deliver superior reliability, production flexibility and low power consumption in a compact package that significantly minimizes space requirements and associated costs. The positioning of the ozone destruction unit on the roof of the three parallel ozone generators makes the solution ideal for use in the confined areas of the mill.

The Result

Since the installation, the ozone systems have kept both pulp bleach lines operating with more than 99 percent reliability. “The level of customization offered by the ozone solution provider, the reduced installation and startup time, and cost efficiency were all key factors in their selection for this project,” said Paulo Gaia, pulp mill manager at the Jacareí mill. In 2013, Fibria’s commitment to sustainable bleaching practices at the Jacareí mill was recognized by Global Water Intelligence through an award of distinction for industrial water sustainability.