Treating build-up with CO2

Carbon dioxide (CO2) can be the key to treating build-up in a mill’s screen rooms. CO2 is a naturally occurring, weakly acidic gas that is easier to use and safer to handle than mineral acids. And unlike mineral acids, it does not cause corrosion of mill equipment. This means less repair costs, less maintenance and increased productivity.

The accumulation of non-dispersed alkali soaps and resins combined with calcium ions can lead to the build-up of pitch on screening equipment — reducing productivity and increasing maintenance costs. In the past, mills have used sulfuric acid or other process acid streams to solve this problem. But mineral acid can cause severe corrosion problems in and around the acid injection point on washers, screens, pipes and holding tanks. Using CO2 instead of mineral acid is a proven, reliable and effective way to treat build-up. By using CO2 to acidify the brown-white water loop, the pitch is rendered soluble with no effect on liquor sulfidity. In addition, the use of dispersants and talc can often be eliminated for an overall reduction of production, maintenance and capital costs. Let Praxair help you reduce your reliance on mineral acid treatments and find a cleaner, more cost effective way to treat pulp-screening build-up.