Kraft (Sulfate) Pulp: Brown Stock Washing

Brown stock washing (BSW) can be considered the key operation influencing the economics of the pulping process, as well as the environmental load of the mill. Through optimization of the brown stock washing process and raising the black liquor solids content, mills gain immediate profits, cleaner and higher quality pulp for bleaching and optimized consumption of water, chemicals and energy.

Conventional methods such as Chemical Oxygen Demand (COD) tests (that only indicate organic compounds) or standard dry solids or COD lab analysis fail to measure the wash loss satisfactorily. Total Dissolved Solids (TDS) has proven to be a reliable parameter for measuring washing efficiency, because it takes account of both the inorganic and organic fractions, thus all washable solids (real wash loss) are quantified.

Real-time control of Total Dissolved Solids in brown stock washing

Download our application note to learn how Vaisala Polaris SAFE-DRIVE Process Refractometer PR53SD measurement technology addresses the critical factors required for measuring TDS in all types of brown stock washers and washing processes. This technology provides:

• Indication of TDS in solution
• Precise concentration measurement of washable liquid substances
• Detection of organic materials with a large molecular size, such as lignin
• Measurement that is unaffected by COD caused by methanol

Download the application note in PDF by filling out the form.

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