Washing of pulp using evaporator condensate

Artikel i vetenskaplig tidskrift, 2009

One way to effectively reduce the water consumption and obtain a wash liquid with low concentration of metal ions at the pulp mill IS to use recycled condensate as wash liquid. The condensate originates froth the evaporator system where. recycled liquor is evaporated before it is burnt ill the recovery boiler The main problem with recycling of condensate is the fact that these always contain Impurities of varying concentration These Impurities plainly cause odour problems in the process or in the final product To investigate the field of application, one unbleached pulp and ogle blenched pulp were washed with four different condensates with different COD concentrations the washing results were consistently good for condensates with low concentration of COD, but sonic Unexpected results were obtained for the case where the condensate with the highest concentration of COD was used To investigate the characteristics of the pulp, an adsorption study including manganese, calcium and magnesium was performed. The adsorbed amounts of ions were all fouled to be within the normal range.