Acetosolv pulping for the fractionation of empty fruit bunches from palm oil industry.

Influence of operational variables in the EFB pulping [acetic acid (60-95%), hydrochloric acid (0.10-0.25%) and time (60-180 min)], on the yield, drainability or beating grade, Kappa number, lignin and viscosity of pulps was studied. By using a factorial design, equations were obtained that reproduced the experimental results for the dependent variables with errors less than 9-18%. These equations can be used to find the suitable conditions, so that operating with not too high values of operating variables (with minor costs of operation and capital) pulps with acceptable properties could be obtained: operating with 86.25% acetic acid, 0.25% hydrochloric acid and 120 min time, produced pulps with 46.56% yield, 15.9 °SR drainability, 36.3 Kappa number, 10.3% lignin and 303 mL/g viscosity, values all of them close to the optimal predicted.