The use of cooking and dispersing additives in the sulfate delignification of the composition of hardwood

The purpose of the work is to assess the effect of cooking and dispersing additives on the yield, degree of delignification, quantitative and qualitative resin content during sulfate cooking of the hardwood composition. Birch and aspen wood chips were used for cooking (50:50); temperature rise to 175 °C – 40 min, cooking at 175 °C – 180 min; consumption of active alkali – 15% units of Na₂O from a.s.d.; sulfidity of white liquor – 25%; hydromodule – 4.0; consumption of cooking a dispersing additive of 0.8 kg per ton a.s.d. It was found that all additives reduce the content of extractive substances in cellulose by 1.25...2 times compared with the control cooking and cellulose does not contain encapsulated resin. It was found that the use of samples Sinalab 72151, Sinalab 74415 and (SINALAB® 8683) leads to an increase in yield (without non-testing) and a decrease in stiffness. The cellulose mass contains mainly coagulated and, in small quantities, dispersed resin. The samples are recommended for delignification of the hardwood composition as the most promising. It has been shown that the use of samples Sinalab 74415BX, Sinalab 72101, Sinalab 74418SR and Sinalab 74418 leads to an increase in yield, absence of non-steam, while increasing the hardness of cellulose with the exception of sample Sinalab PP10-3152. When using the Sinalab 74418 additive, cellulose contains only dispersed resin, and when using other additives, there is coagulated and dispersed resin in different ratios. To improve the results, it is necessary to select the conditions of impregnation, cooking and washing. The use of Sinalab 63602 and Sinalab 74393 samples during cooking leads to a decrease in lignin selectivity, but a high proportion of extractive substances removal is achieved. These additives are more effective to use when rinsing.

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