This paper reports on the influence of independent variables
in the ethylene glycol/soda pulping of olive wood
trimmings (165–1958C, 30–90 min, ethylene glycol concentration
5–15%, soda concentration 2.5–7.5% and liquid/
solid ratio 4–6), on the yield and Kappa index of the
pulps and the strength properties (breaking length, burst
index and tear index) of paper sheets. By using a central
composite factorial design, equations that relate each
dependent variable to the different independent variables
were obtained which reproduced the experimental results
for the dependent variables with errors less than 12%.
Using a temperature of 1848C, ethylene glycol and soda
concentrations of 15% and 7%, respectively, a liquid/solid
ratio of 5:1 and a cooking time of 30 min results in
yield, Kappa index, breaking length, burst index and tear
index values that depart by 14.3%, 8.2%, 17.1%, 17.0%
and 2.3%, respectively, from their optimum levels. These
conditions result in substantial savings in power consumption
and immobilised capital investments as they
involve a lower temperature, a lower liquid/solid ratio,
and a shorter time than the maximum values tested.