Hegely L.,H+ Technology |
Lang P.,H+ Technology |
Kovacs G.,Richter Gedeon Plc
Chemical Engineering Transactions | Year: 2013
The recovery of methanol from a multicomponent aqueous waste solvent mixture was studied. The components form several minimum azeotropes, of which the methanol-THF and methanol-toluene azeotropes limit the recovery of methanol by traditional batch distillation (BD). THF and toluene are removed in the fore-cut, causing a significant loss of methanol. The addition of water decreases both methanol-THF and methanol-toluene relative volatility, and therefore by feeding water as entrainer, methanol loss can be decreased. A new BED operational policy is suggested, where water feeding is applied only during the heating-up of the column (BED1). Compared to BD, at the end of the heating-up, the concentration of organic pollutants is increased, and that of methanol is significantly decreased in the top of the column. Water feeding can continue during the fore-cut (BED2), but this increases the amount of fore-cut and dilutes the mixture from which methanol is recovered. Laboratory experiments were performed in a packed column to compare the BD and the two BED operational policies. The highest recovery was obtained by BED1, the lowest one by BD. The preliminary and posterior rigorous dynamic simulation of the experiments was made with a professional dynamic flowsheet simulator. Industrial-size pilot productions of BD and BED1 in a 50 bubble cap tray column also showed a 5% increase in methanol recovery. Copyright © 2013, AIDIC Servizi S.r.l.
Pap K.,Semmelweis University |
Berta A.,Semmelweis University |
Szoke G.,Semmelweis University |
Dunay M.,Szent Istvan University |
And 6 more authors.
Physiological Research | Year: 2015
We used a model of tibial lengthening in rabbits to study the postoperative pain pattern during limb-lengthening and morphological changes in the dorsal root ganglia (DRG), including alteration of substance P (SP) expression. Four groups of animals (naïve; OG: osteotomized only group; SDG/FDG: slow/fast distraction groups, with 1 mm/3 mm lengthening a day, respectively) were used. Signs of increasing postoperative pain were detected until the 10th postoperative day in OG/SDG/FDG, then they decreased in OG but remained higher in SDG/FDG until the distraction finished, suggesting that the pain response is based mainly on surgical trauma until the 10th day, while the lengthening extended its duration and increased its intensity. The only morphological change observed in the DRGs was the presence of large vacuoles in some large neurons of OG/SDG/FDG. Cell size analysis of the S1 DRGs showed no cell loss in any of the three groups; a significant increase in the number of SP-positive large DRG cells in the OG; and a significant decrease in the number of SP-immunoreactive small DRG neurons in the SDG/FDG. Faster and larger distraction resulted in more severe signs of pain sensation, and further reduced the number of SP-positive small cells, compared to slow distraction. © 2015 Institute of Physiology.