Challenges in pulp mill recovery cycles

摘要

Tightening emission limits and closed-loop water systems in a chemical pulp mills call for a greater understanding of the process flows in the chemical recovery cycle. Knowledge of both chemical and physical characteristics and behaviour is vital for controlling and developing the process and equipment. In preventing problems such as scaling and ensuring trouble free operations of the evaporation plant and recovery boiler information on the composition of the black liquor has become essential, specifically with the trend of raising the black liquor dry solids. Attention also has to be paid to the presence and removal of non-process elements, conveyed by the raw material, in the chemical recovery process.