SBLOX OPTIMISATION FOR INCREASED STEAM GENERATION

Caine Davies
Graduate Process Engineer, Oji Fibre Solutions, New Zealand

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Keywords: Pulp, Oxidation, Recovery Boiler, SBLOX

Kraft pulp mills rely on the firing of black liquor in the recovery boiler to supply the bulk of the energy to the mill. An opportunity was identified to increase the steam generation of the recovery boiler by manipulating the properties of the black liquor.

Sulphidity, suspected to be a driving factor of black liquor calorific value, was directly corelated to the level of oxidation in the strong black liquor oxidation plant (SBLOX).

Multiple trials took place investigating how liquor sulphur content changed with varying degrees of oxidisation in the SBLOX plant. It was established that total reduced sulphur (TRS) at the boiler could be used to indicate the level of sulphidity in the liquor, which affected the steam generation capacity of the black liquor.

Trials identified that in current operations, airflow to the SBLOX plant was higher than what was needed to achieve the appropraite levels of oxidation. A control strategy was developed to control the amount of airflow to the SBLOX plant based on the TRS at the boiler and increased steam generation at the boiler.

Caine Davies grew up in New Plymouth before heading down south to study process engineering in Christchurch. From there he moved to the Mount to start work as process engineer for Oji Tasman mill, where he’s been for the last 2 years.