Documents disponibles écrits par cet auteur

Applicability of short totally chlorine free bleaching sequences to miscanthus x giganteus organosolv pulps / Juan Jose Villaverde in Industrial & engineering chemistry research, Vol. 50 N° 17 (Septembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 9847-9851 Titre : Applicability of short totally chlorine free bleaching sequences to miscanthus x giganteus organosolv pulps Type de document : texte imprimé Auteurs : Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur Année de publication : 2011 Article en page(s) : pp. 9847-9851 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bleaching Résumé : The applicability of short totally chlorine free (TCF) treatments, including ozone (Z), peroxide (P), and peroxyacetic acid (Pa) processes, to Acetosolv, formic acid, and Milox pulps from Miscanthus x giganteus was checked. In some cases, a previous step using a Formacell treatment (Fll step) was used. The evolution of pulp yield, brightness, kappa number, and pulp viscosity was monitored after each stage. The best results were obtained from sequences ZPP, ZPaP, and PaZP for Acetosolv, formic acid, and Milox pulps, respectively. Final viscosities of these sequences were 708, 782, and 576 mL/g, respectively, and brightness values were between 84.7 and 912%. These results, together with kappa numbers below 1.0, demonstrated the ability of the three acidic organosolv processes to produce pulps of high purity with good properties by dean, short TCF sequences (three stages). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483626 [article] Applicability of short totally chlorine free bleaching sequences to miscanthus x giganteus organosolv pulps [texte imprimé] / Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur . - 2011 . - pp. 9847-9851. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 9847-9851 Mots-clés : Bleaching Résumé : The applicability of short totally chlorine free (TCF) treatments, including ozone (Z), peroxide (P), and peroxyacetic acid (Pa) processes, to Acetosolv, formic acid, and Milox pulps from Miscanthus x giganteus was checked. In some cases, a previous step using a Formacell treatment (Fll step) was used. The evolution of pulp yield, brightness, kappa number, and pulp viscosity was monitored after each stage. The best results were obtained from sequences ZPP, ZPaP, and PaZP for Acetosolv, formic acid, and Milox pulps, respectively. Final viscosities of these sequences were 708, 782, and 576 mL/g, respectively, and brightness values were between 84.7 and 912%. These results, together with kappa numbers below 1.0, demonstrated the ability of the three acidic organosolv processes to produce pulps of high purity with good properties by dean, short TCF sequences (three stages). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483626

Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors / Juan Jose Villaverde in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9830–9836 Titre : Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors Type de document : texte imprimé Auteurs : Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur Année de publication : 2010 Article en page(s) : pp. 9830–9836 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Semibleached  Miscanthus  x  giganteus  Acetosolv  pulp  Alkaline  treatmentPeroxyacetate  treatment Résumé : The bleaching of semibleached Miscanthus x giganteus Acetosolv pulp, after alkaline and peroxyacetate treatments, was investigated by a novel totally chlorine-free (TCF) sequence. Oxygen delignification (O-stage), peroxide (P-stage), and oxygen-pressurized hydrogen peroxide stage (PO-stage) were assayed in order to reach the target values for dissolving pulps. Using factorial experimental designs, we investigated the effects of the bleaching variables on the parameters defining the process and checked the effects after adding chelating agents. Regression equations satisfactorily fitted the experimental results, and under the optimum conditions, a fully bleached pulp (86.9% ISO brightness) with a viscosity of 786 cm3/g and a very favorable kappa number (1.3) was obtained. Carbohydrate protectors substantially improved the characteristics of dissolving pulps, but pulps with kappa values above 6 did not improve with carbohydrate protectors as expected. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008277 [article] Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors [texte imprimé] / Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur . - 2010 . - pp. 9830–9836. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9830–9836 Mots-clés : Semibleached  Miscanthus  x  giganteus  Acetosolv  pulp  Alkaline  treatmentPeroxyacetate  treatment Résumé : The bleaching of semibleached Miscanthus x giganteus Acetosolv pulp, after alkaline and peroxyacetate treatments, was investigated by a novel totally chlorine-free (TCF) sequence. Oxygen delignification (O-stage), peroxide (P-stage), and oxygen-pressurized hydrogen peroxide stage (PO-stage) were assayed in order to reach the target values for dissolving pulps. Using factorial experimental designs, we investigated the effects of the bleaching variables on the parameters defining the process and checked the effects after adding chelating agents. Regression equations satisfactorily fitted the experimental results, and under the optimum conditions, a fully bleached pulp (86.9% ISO brightness) with a viscosity of 786 cm3/g and a very favorable kappa number (1.3) was obtained. Carbohydrate protectors substantially improved the characteristics of dissolving pulps, but pulps with kappa values above 6 did not improve with carbohydrate protectors as expected. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008277