To reduce carbon dioxide and hydrogen sulfide concentration in simulated biogas, experiments were performed on a laboratory scale. The main goal was to use calcium, lead and zinc from fly ash from waste combustion power plants to form carbonates and sulfides for biogas upgrading within a process water cycle. Thereby, the contact time between the simulated biogas and the ionized process water was limited to less than 1 s. The investigation focused on the influence of hydrogen sulfide partial pressure, reaction time, reaction temperature, and process water volume flows. The experiments were performed with two different ashes.The results show that the kinetics for hydrogen sulfide reactions were better than for carbon dioxide where the mass transfer into the liquid phase slows down the upgrading process. This led to fast reactions for H2S in the initial volume and therefore to a bottleneck for further sequestration. For carbon dioxide the kinetics limit the process in the beginning until all reactants for carbonates and the process water volume flow limit the process also. For the process temperature, slightly better separation efficiencies were realized for carbon dioxide at 40 °C while the effect for hydrogen sulfide separation was contradictory for the used ashes. With higher process water volume flow, best results were achieved and the bottleneck of reactants ratios was compensated. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13144, 2019

Chemie Ingenieur TechnikVolume 89, Issue 5 p. 698-698 VorschauFree Access Vorschau: Chem. Ing. Tech. 6/2017 First published: 24 April 2017 https://doi.org/10.1002/cite.201770056AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume89, Issue5Special Issue: ProzessoptimierungMay 2017Pages 698-698 RelatedInformation

Die CO2-Beladung eines Waschmittels (WM) ist bei der Beurteilung der Effizienz eines Absorptions-/Desorptionsprozesses von entscheidender Bedeutung. Die Bestimmung uber Inline-Messverfahren ist jedoch kaum moglich. Eine Korrelation zur Bestimmung der CO2-Beladung in Abhangigkeit von der WM-Viskositat und -Temperatur wurde experimentell ermittelt. Die Korrelation konnte durch Kontrollmessungen und den Vergleich mit Literaturwerten verifiziert werden. Es ergab sich eine relative Abweichung von unter 10%. Gleichzeitig wurde untersucht, ob der pH-Wert und die elektrische Leitfahigkeit des WM ebenfalls geeignete Gro ss en fur eine Korrelation sind.Abstract The solvents CO2 loading is an important factor when evaluating the efficiency of an absorption/desorption process. There is almost no possibility to measure the CO2 loading inline. Therefore experiments were made to determine a correlation between the CO2 loading and the solvents viscosity as well as the solvents temperature. The correlation was verified using control tests and values from the literature. An overall maximum relative error under 10% could be observed. Simultaneously investigations were made to understand if the solvents electrical conductivity and pH value are suitable for a similar correlation.

Modularization has been identified as one of the research fields of the "50% idea". A development methodology for modules must consider both the economies of scale for investment costs and costs of operation and maintenance. In this paper, the impact of an absorber module, which is offered as discretized diameter scaling, on the total process is investigated at the example of the CO2 separation from biogas. The simulation shows the effect of this approach to the stripper diameter and the energy demand of the process. The calculations form the basis for applying cost models.

2-(2-Aminoexthoxy)ethanol or diglycolamine (DGA) is a CO2 absorption solvent that is suitable to treat natural gas, flue gas, and biogas or landfill gas. Equilibrium CO2 solubility in concentrated aqueous DGA solvents with varying molality was measured under absorption and desorption conditions at different temperatures. Viscosity and surface tension of the solvent before absorption, after absorption, and after desorption were determined. With increasing DGA molality, CO2 loading remained constant until the number of moles of DGA exceeded the number of moles of water. For a given DGA molality, with higher CO2 loading, viscosity increased exponentially and surface tension rose with a power of two.

Starch is a granular, hygroscopic, capillary-porous material with an intricate structure. It is known that drying starch till 0% moisture is a physical treatment that modifies starch properties. However, depending upon the heat and mass transfer mechanisms prevalent in the drying system, starch properties are modified in a unique manner. Therefore, the drying operation itself needs to be thoroughly understood. Potato starch was treated in an oven at three high-temperature levels (110, 130 and 140°C) and for three sample thicknesses (2.8, 5.6 and 11.2mm). It was observed that drying of starch with moisture content in the hygroscopic range occurred only in the 2nd falling rate period. Two existing theoretical, drying models, one based upon the Krischer Theory and the other based upon the Percolation Approach, were considered apt for modelling the oven drying. Both models describe the experimentally measured moisture profiles well. During drying, transition from one water sub-population to another was smooth. The effective diffusion coefficient decreased with moisture content and increased with temperature, but did not follow Arrhenius’ Law above 130°C.

The study focuses on the vacuum microwave treatment of low-moisture potato starch. Typical temperature and drying profiles are presented and explained with the help of other process parameters such as sample weight, pressure, incident and absorbed microwave power. Subsequently water absorption capacity of vacuum microwave treated and conduction heated samples was investigated at 55 degrees C. During vacuum microwave treatment, 50 g samples were treated with incident powers of 460, 500 and 750W at 3800 Pa for durations between 30 and 300 s. Water absorption capacity increased exponentially with the net absorbed energy but could not be functionally correlated to end temperature and incident power. During conduction heating, starch samples were treated at temperature values of 120, 130, 140, 150 and 160 degrees C, till constant weight. The water absorption capacity was observed to increase with increase in treatment temperature.

It is known that the water binding capacity of starch increases after vacuum microwave treatment. Microwave radiation absorbed by the starch sample affects its sensible, latent internal and chemical (bond and conformational) energy levels. A phenomenological model was developed based on energy sinks in starch, practically described as increasing temperature, breaking bonds between water and amylopectin/amylose molecules, changing the phase of water from liquid to vapor and structural rearrangements at short (single/double helices) and long (crystalline/amorphous) order. The model was validated by experimental data for different vacuum microwave treatment parameters, viz. incident power (460, 500 and 750 W), duration (30 to 340 s) and sample mass (10 to 70 g) at 4000 Pa. The results provide an insight into the physical aspects of the process and would facilitate its development on an industrial scale.

The prospect of modifying starch properties while drying was investigated. Potato starch (18% moisture, dry basis) was vacuum microwave treated for different durations (60 to 600 s) with power ratings of 600, 1,000, and 1,500 W at a reduced pressure of 5,000 Pa (absolute). The drying rate was observed to be partially constant but was accompanied by a curious rise in sample temperature. Under a polarized light microscope, reduction in granule size was noticed, which was confirmed from the bulk density measurements, and this shrinkage may be explained by the loss of constituent water. Water absorption capacity of the treated starch samples was further studied at 55°C. The results showed a sudden increase in the capacity, indicating a reduction in gelatinization temperature of starch. This may be attributed to the change in nature of starch from crystalline to amorphous as shown by X-ray diffractograms and to the cracks developed on the granule surface during treatment seen in the scanning electron microscope images. This modified starch can serve well in the paper and food industry.

Absorptive gas purification is one good possibility to reduce the CO 2 output of a power station. This contribution presents the new absorbent GenosorbN, with the results of initial experimental series. The degree of elimination to be targeted for the future is discussed.

Deactivation of catalytic processes such as direct oxidation of hydrogen sulfide by coking through hydrocarbon combustion has always been a topic of concern. Using, n-hexane as a model compound, we develop a kinetic model that predicts its coking rate on the basis of data obtained from a thermobalance. Considering two different processes in the coke reaction, active Site coverage and coke growth, and applying a probabilistic model, we obtain an apparent, activation energy of 34 and 126 kJ/mol, respectively. Thus, we estimate pore-plugging effects using two network models: a bundle of parallel cylindrical pores using a probabilistic model and a microporous network distributed in a Bethe lattice. Both models describe experimental data. Moreover, they confirm that the TiO2 catalyst used first deactivates through active sites coverage and second through pore obstruction. As such. the model may be used for estimating deactivation of reactions taking place simultaneously on the catalyst.

Chemie Ingenieur TechnikVolume 64, Issue 11 p. 1006-1007 Wissenschaftliche Kurzmitteilungen Rauchgaswäsche mit Polyethylenglycolethern† Dr. Norbert Mollekopf, Dr. Norbert Mollekopf LINDE AG, Werksgruppe Verfahrenstechnik und Anlagenbau, 8023 Höllriegelskreuth bei MünchenSearch for more papers by this author Dr. Norbert Mollekopf, Dr. Norbert Mollekopf LINDE AG, Werksgruppe Verfahrenstechnik und Anlagenbau, 8023 Höllriegelskreuth bei MünchenSearch for more papers by this author First published: November 1992 https://doi.org/10.1002/cite.330641107Citations: 1 † Vortrag auf dem Jahrestreffen der Verfahrens-Ingenieure, 25. bis 27. Sept. 1991 in Köln. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Literatur 1 Genosorb 300, Produktbeschreibung AL 2354d, Hoechst AG, Frankfurt/M. 1991. Google Scholar 2 Genosorb 1753, Produktbeschreibung AL 2355d, Hoechst AG, Frankfurt/M. 1991. Google Scholar 3 Rordorf, G. F.: Chemosphere 15 (1986) S. 1325/1332. Google Scholar Citing Literature Volume64, Issue11November 1992Pages 1006-1007 ReferencesRelatedInformation