Carsten Zetzl
University of Hamburg
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Publication
Featured researches published by Carsten Zetzl.
Separation Science and Technology | 2001
Jamal Benkhedda; Jean-Noël Jaubert; Danielle Barth; Carsten Zetzl; Gerd Brunner
The equilibrium loadings of m-xylene from supercritical carbon dioxide on activated carbon are reported. The experimental data were obtained by measuring the outlet concentration of m-xylene eluted from a column packed with activated carbon until the effluent reached the input concentration. The Freundlich isotherm expression was found to correlate the experimental data satisfactorily. In a second step, the regeneration by supercritical carbon dioxide of activated carbon loaded with m-xylene was investigated. The experimental data demonstrated that the adsorptive capacities of the regenerated activated carbon for m-xylene after many cycles were close to those of the virgin carbon and remained stable. The effects of temperature, pressure, and flow rate on regeneration efficiency were also studied.
Holzforschung | 2011
Christian Kirsch; Carsten Zetzl; Irina Smirnova
Abstract The limitations of the current biorefinery process utilizing stirred-tank reactors for the enzymatic step include poor mixing in the case of high biomass loadings, additional steps for the product separation, and a long reaction time. In this study the hydrothermal pretreatment and the enzymatic hydrolysis of the lignocellulosic biomass were combined in one fixed-bed reactor. The influence of the shear forces during recirculation and enzyme stability at elevated temperatures were investigated. It has been shown that the shear forces resulting from pumping have a negligible effect on enzyme activity. However, large pressure drops reduce the enzyme activity significantly. Furthermore, the enzyme stability was significantly increased at elevated temperatures (60°C) by applying static pressures up to 200 bar (56% residual activity at 60°C after 24 h). This is beneficial for the process as a higher temperature accelerates the reaction. Further improvement of the overall process efficiency was achieved by increasing the solid-to-water ratio and circulation of the enzyme solution. At a biomass content of 7%, a glucose concentration of 61 g l-1 and a yield of 85% was achieved. The integrated process was first done on a laboratory scale (50 ml). At 100 bar, 60°C and 10% biomass loading an increased initial reaction rate was observed. However, this effect was followed by the stagnation of the glucose yield as one of the enzymes, Novozyme 188, showed no remarkable stabilization with pressure. Nevertheless, an overall glucose yield of 40% was achieved after 5.5 h, compared to 14 h under normal pressure and 50°C.
euro mediterranean conference | 2017
Mouna Kehili; Ayachi Zammel; Carsten Zetzl; Irina Smirnova; Noureddine Allouche; Sami Sayadi
Nowadays, with the expanding awareness about environmental safety, energy security and potential biomass recycling, much effort has been extended towards adding value to biowastes of agri-food industries. In this context, Tunisia was ranked among the first 10 countries in the world for the industrial transformation of tomatoes which resulted in large quantities of by-products, ranging between 20,000 and 30,000 tons per year.
Journal of Supercritical Fluids | 2008
Christian Schacht; Carsten Zetzl; Gerd Brunner
Journal of Supercritical Fluids | 2012
C.A. García-González; M.C. Camino-Rey; M. Alnaief; Carsten Zetzl; Irina Smirnova
Journal of Agricultural and Food Chemistry | 2002
Marleny D. A. Saldaña; Carsten Zetzl; Rahoma S. Mohamed, ,† and; Gerd Brunner
Journal of Supercritical Fluids | 2005
Leandro Danielski; Carsten Zetzl; Haiko Hense; Gerd Brunner
Journal of Supercritical Fluids | 2005
Sócrates Quispe-Condori; Deny Sánchez; Mary Ann Foglio; Paulo de Tarso Vieira e Rosa; Carsten Zetzl; Gerd Brunner; M. Angela A. Meireles
Fluid Phase Equilibria | 2004
Susana Lucas; Mª José Cocero; Carsten Zetzl; Gerd Brunner
Food Research International | 2005
J.M. del Valle; Tim Rogalinski; Carsten Zetzl; Gerd Brunner