Eucalyptus globulus is the most profitable specie in Europe for pulping. However, in recent years... more Eucalyptus globulus is the most profitable specie in Europe for pulping. However, in recent years some diseases and pests have caused its defoliation, affecting the available quantity of wood. In this sense, the mills are studying how to avoid the loss of pulp yield as well as the optimization of byproducts in order to take advantage of every component present in the wood using biorefinery processes. One of the possible options is to complete the consumption of E. globulus with other species such as Eucalyptus nitens. The objective of this paper is to study the behavior of both species related to the dissolving pulp manufacturing process as well as the characteristics of the resulting products. Parameters that can be very useful for the evaluation of the raw material, such as the growing data or density of both species, have been compared. Major attention has been focused on the composition of both species and how it affects the characteristics of the possible final products. E. nitens presents good results of forestry characteristics, being better than E. globulus in terms of growing and resistance to frosts. The cellulose content of both species is similar, however the digestion process in the case of E. nitens needs to be improved in order to optimize the involved energy and the obtained products.
Journal of Chemical Technology & Biotechnology, 2014
BACKGROUND: Spent sulfite liquor is a by-product obtained in the process of manufacturing dissolv... more BACKGROUND: Spent sulfite liquor is a by-product obtained in the process of manufacturing dissolving pulp by the acid sulfite method. A full physico-chemical characterization of this waste has been developed in order to determine if it is susceptible to valorization by means of biorefinery processes. RESULTS: The main components present in this spent liquor are sugars from hemicelluloses (25.9%), mainly xylose (18.2%) because hardwood is used as a raw material, and lignosulfonates (50.6%). Taking into account the results obtained, a literature search has been done in order to establish the biorefinery options for this lignocellulosic waste, giving lignosulfonates, xylitol, ethanol, polyhydroxybutyrate or polybutylene-succinate, hydrogen and furfural as the best options. However, other compounds present in the liquor such as furans, acids and inorganic pollutants can complicate the valorization options. CONCLUSIONS: Spent sulfite liquor can be a good feedstock for biomass based processes. This paper will be useful for future work regarding the potential biorefinery opportunities of the sulfite mill.
Spent sulphite liquor is a lignocellulosic residue obtained in the acid sulphite pulping process ... more Spent sulphite liquor is a lignocellulosic residue obtained in the acid sulphite pulping process after the digestion of hardwood chips, and composed mainly by lignosulphonates and hemicelluloses. The aim of this work is to study the main process variables at different digestion conditions: maximum temperature, heating rate, and total SO 2 content, which affect the delignification process of hardwood chips to obtain dissolving pulp and to increase the total amount of fermentable sugars and lignosulphonates presented in this lignocellulosic waste. The best results are 210.5 g/L of lignosulphonates and 47.26 g/L of total monosaccharides obtained at higher temperatures of 1.058T and 1.072T, low heating rates of 0.334R and 0.285R, and total SO 2 content of 6.20%. Furthermore, concentrate-acid hydrolysis of the liquor with sulphuric acid was performed in order to study the evolution of the sugar content and the release of the inhibitors. Temperature, acid concentration, acid/liquor ratio and time were modified, showing that acid/liquid ratio is the most influential variable. Although increase in the content of sugars in neither case, a notable furfural and acetic acid concentration decrease is registered, 97.88% and 36.57% respectively, at 20 • C, 60% (w/w) sulphuric acid and acid/sample ratio of 1/0.1 (v/v).
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Papers by Cristina Rueda