Brownstock Washer Challenges
Brownstock washing is an integral part of the chemical recovery process. A high efficiency brownstock washing operation maximizes washing efficiency and the recovery of sodium and dissolved organics with optimal dilution factor. However, it is inevitable that some of the macro-molecules, such as lignin, become entrained within the pulp causing the filtrate to interfere with the bleaching process. This increases bleaching costs by consuming more bleaching chemicals.
The ability of FITNIR’s analyzers to measure brownstock filtrate plays a critical role in optimizing the bleaching chemical charge, particularly for the first bleaching stage. Knowing the carryover allows for optimal compensation of ClO2 charge, while minimizing occurrences of over-charging of the first bleaching stage.
FITNIR’s Brownstock Washer analyzer application measures:
As a requested by the Process Engineer, FITNIR collaborated with Canfor Northwood pulp mill to develop the measurements. The trial is ongoing and data analysis is being carried out to correlate process variability with measurement signals. A control strategy is also being considered.
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