Wet End pH Control & Adjustment

Carbon Dioxide for pH Control in Pulp and Paper Chemical Processes

Cost effective pH control with CO2

Because of the many interacting chemical and physical systems required in the papermaking process, papermakers are continuously faced with decisions about how to optimize their processes.

To minimize wet end chemical changes and to identify discrete physical process system changes for adjustment or correction in a controlled manner, papermakers turn to wet end pH control of whitewater, incoming pulp and headbox. Carbon dioxide (CO2) provides a safe and cost effective method of paper machine pH control by minimizing pH swings and increasing productivity. It allows papermaking additives to be optimized in performance, enables improved refining performance and provides more consistent sheet drainage on the paper machine wire. CO2 for wet end pH control also speeds up boilout solution neutralizations after machine boilouts.


  • Increased paper machine productivity
  • Improved fines and additives retention and control
  • Reduced acid handling and cost of storage
  • Lowered maintenance requirements

Using Praxair CO2 in place of acids reduces on-site acid storage and handling and helps avoid corrosion and associated system maintenance cost. Doing so is a commercially proven, safe and simple application for the stock preparation and paper machine wet end stages in mills that make most grades of alkaline, neutral and tissue paper.

Stock Preparation & Paper Machine Wet End pH Control with CO2 (132KB)