Kraft (Sulfate) Pulp: Recovery Boiler

In the recovery boiler, dry solids liquor content required for firing is at least 60 %, but preferably more than 65 % to maximize the flue gas emissions, boiler efficiency and energy production.

Too low concentration of dry solids fed to the burners may result in a steam explosion with consequent destruction of the boiler. To ensure safe operation, it is essential to use process refractometers and digital divert system to monitor the black liquor feed to the recovery boiler.

Controlling black liquor dry solids in feed to recovery boiler

Download our application note to learn how Vaisala K-PATENTS® Digital Divert Control System DD-23 ensures that weak liquor is not fed into the boiler.

If the black liquor concentration falls below 58%, the system shall give an audible alarm signal, and go to a diversion function to direct the black liquor flow to by-pass the boiler. A concentration value of 60% shall give an audible alarm to notify the users about the low concentration. Further-more, the control unit shall check that the difference between the two individual refractometer signals does not exceed 2%.

Download the application note in PDF by filling the form.

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