Application of CO2 for paper mill production optimisation
We can find different paper production line phases at which the application of CO2 for pH secure acidification leads to a relevant improvement by upgrading the drainage or recovering chemicals.
Reduce the pH of the pulp to have a better draining
La CO2 può essere utilizzata per il controllo del pH della cellulosa in due punti diversi
Replace part of the compressed air with CO2 as a carrier gas during the flotation
CO2 is used to produce Precipitated Calcium Carbonate for print paper production
pulp to have better
CO2 is used for the pH control of the pulp near the head box of the paper machine. This pH control provides a better draining performance at the wire in the paper machine.
CO2 is used in effluent treatment in flotation system to replace part of the compressed air used as a carrier gas during flotation (primary treatment of fiber recovery).
As CO2 has more affinity with the liquid phase than the air, so along the process it creates small bubbles, and improves flotation during the process, improving the flotation. Efficiency can be increased by around 15%. Usually, CO2 replaces from 40 to 60% of the total compressed air used.
CO2 is used for PCC (Precipitated
Calcium Carbonate); production,
PCC is used as a filler in the alkaline sizing papers production (print paper).
Kraft pulp pH control tower.
CO2 is used to replace strong acids (HCO2 SO4 ), and aluminium sulphate providing a smoother control, it avoids great variation at the CO2 .
It's used before or after the refining process, aiming a thin adjustment of the pH level, and consequently, a reduction of the consumption of aluminium sulphate or sulfuric acid dosed for pH control, which is, total or parcial to neutral / alkaline sizing of paper.
Slide to learn about Nippon Gases over time