INVESTIGADORES
AREA Maria cristina
artículos
Título:
NSSC Process Optimization: Pulping, Pulps and Spent Liquors
Autor/es:
AREA, M.C., FELISSIA, F.E.; VENICA A.D.; VALADE, J.L.
Revista:
TAPPI JOURNAL
Editorial:
TECH ASSOC PULP PAPER IND INC
Referencias:
Año: 2001 vol. 84 p. 1 - 13
ISSN:
0734-1415
Resumen:
The objective of this work was to obtain the best physical properties of NSSC pulps using low charges of chemical products and to determine the operating conditions at which spent liquors containing the lowest ratio of inorganic/organic solids can be obtained (improving or maintaining the pulp quality). Hybrid poplar (Populus deltoides) was used as raw material. The experimental design did examine four variables at five levels (Central Composite Design CCD= 29 runs, five central points). Minimum and maximum limits of the independent variables were established using mill conditions as set point values. Variables studied were: cooking time (10 to 30 min), cooking temperature (154 to 186ºC), sodium sulfite (4 to 12% o.d.) and sodium carbonate charges on wood (0 to 3% o.d.). Each property was evaluated by comparison with the mill reference data (yield: 80%, 260 CSF, tensile index: 38 N.m/g). Cooking conditions for highest mechanical properties were: temperature of 186ºC, cooking time of 30 min, 11.6% of Na2SO4 and 3.05% of Na2CO3 on o.d. wood. These conditions implied important pulp brightness and yield reductions. Optimum conditions minimizing the inorganic/organic solids ratio were: 26 min, 177ºC, 6.0% Na2SO3, 2.54% Na2CO3. Spent liquors organic solids compositions were also determined. Time, temperature, and sulfite charge showed the greatest effects on organic material dissolution. Carbonate charge acts through interactions. Pilot plant trials were done to verify the laboratory results and the found equations. Four pulps were manufactured, using Spanish poplar as raw material. On these pulps, physical testing on 60 g/m 2 handsheets and typical corrugated board tests on 120 g/m 2 handsheets (CMT, RCT, STFI) were completed.