Boilouts are used to remove deposits of pitch, fibres, minerals and biological slime from the wetted surfaces of a paper machine during a shutdown. Some mill operators alternate between alkaline boilouts and acidic boilouts. After an alkaline boilout, carbon dioxide (CO2) can be used to neutralise the alkaline washwater on the paper machine and/or on its way to the wastewater treatment plant.
Mineral acids are often used for this process, but they present a number of downsides. CO2 overcomes many of these issues as it is more economical and non-corrosive. In addition, it is safer to handle and dose, and has a smaller environmental footprint.
Here at Linde, we have vast experience in the use of CO2 for wastewater neutralisation applications, supporting customers with a wide range of supply schemes and tailored dosing equipment.