Influence of the operational variables on the pulping and beating of the orange tree pruning

The influence of operational variables in the soda-anthraquinone pulping of orange tree wood and in the pulp beating (temperature, 155 to 185 °C; time, 40 to 90 min; soda concentration, 10 to 16%; and number of PFI beating revolutions, 0 to 3000), on the yield and beating grade of pulps, and the physical properties of resulting papersheets was studied, with a view to identifying the optimum operating conditions. Equations that reproduced the dependent variables with errors in most cases much less than 20% were obtained. An optimum compromise was found as regards operating conditions (170 °C, 40 min, 13% soda concentration and 2700 number of PFI beating revolutions), obtaining a pulp whose values of tensile index, burst index and tear index were 59.11 Nm/g, 4.10 kN/g and 2.79 mNm2/g, respectively; these values deviate 5.8%, 2.2% and 1.4%, respectively of their maximum values. The pulp yield obtained under these operating conditions was 43.9%, decreasing from the maximum value in a 15%; the beating grade retrieved was of 39.5 °SR, a 23% lower than the maximum, with the advantage of an increased drainability in paper manufacture. These conditions involve a lower temperature, time, soda concentration and beating than those required to maximize the studied paper properties; so it is possible to save energy, chemical and capital for industrial facilities.