Conventional catalytic hydrogenation of oils is essentially constrained by mass-transfer resistance because of the poor solubility of hydrogen in liquid-phase substrates. Supercritical fluids (SCFs) offer a solution by creating a single, homogeneous reaction medium that dissolves both hydrogen and high-molecular-weight oils, thus overcoming the interfacial transport limitations. This review synthesizes several research to establish a unified framework for the supercritical hydrogenation of different feedstocks, including heavy oils, vegetable oils, and emerging streams like bio- and plastic-derived pyrolysis oils. The central goal of this work is to provide a deep understanding of phase behavior which is a critical aspect of the process design, directly influencing reaction rates, selectivity, and overall efficiency. By integrating principles of thermodynamics, heat and mass transfer, catalysis selection, and reactor design, this review provides applicable design metrics for developing a more suitable upgrading technology with higher space yield times for a wide spectrum of complex oils.

The electrochemical carbon dioxide reduction reaction (CO2RR) is of increasing importance for the development of a closed carbon cycle. Ethanol is an attractive target product due to its high energy density and large market size. Therefore, publications describing the CO2RR to ethanol are first compared. Both flow cells and zero-gap cells show the most promising results. However, this work has shown that accumulation of liquid organic products in the catholyte of a flow cell would lead to a significant increase in the overpotential. The resulting low concentration of products in the catholyte (<3.5 mol %), which should not be exceeded, leads to high separation costs. Consequently, a downstream process is developed based on the product stream of the most promising CO2RR in a zero-gap cell. Afterward, a techno-economic assessment (TEA) of the entire process from CO2 capture to CO2RR to product purification was performed. The electricity for the CO2RR is still the main cost driver, followed by the CO2 recovery, whose costs are caused by the low single-pass CO2 conversion. Strategies for improving the entire process are outlined, and an Excel calculation tool for adapting the TEA is provided.

The electrochemical carbon dioxide reduction reaction (CO2RR) is of increasing importance for the development of a closed carbon cycle. Here, electrolytes are often used to increase the electrical conductivity and thus the current density. In addition, the use of compressed CO 2 and electrolyte -containing organic solvents suppresses hydrogen evolution. However, the electrical conductivity of CO 2 -saturated electrolyte solutions is mostly unknown. Therefore, their electrical conductivity was investigated in this work at different electrolyte concentrations, pressures (up to 150 bar) and temperatures (298.15 K and 343.15 K). In addition, the simplified Mean Spherical Approximation (MSA-simple) model, supported by ePC-SAFT for density modeling, was used to successfully model the conductivity. The results show that CO 2 -saturated electrolyte solutions generally exhibit lower conductivities than CO 2 -free electrolyte solutions. However, at very low electrolyte and CO 2 concentrations, the conductivities were higher in CO 2 -saturated electrolyte solutions than in CO 2 -free electrolyte solutions, which is a new finding in the literature.

CO2 can be electrochemically converted to commodity chemicals with the support of aqueous or organic electrolytes. However, aqueous electrolytes mainly lead to H-2 production due to the low solubility of CO2 in water whereas organic electrolytes favor the formation of organic products. In addition to selectivity, fast CO2 conversion is also important, which is significantly influenced by the conductivity of the electrolyte. However, the most studied electrolytes are aqueous and at low salt concentrations. Therefore, in this work, the electrical conductivity of 164 electrolytes was investigated in a wide concentration range and a temperature range T = (288.15 to 333.15 K) using automated conductometry. After the measurements, the results were correlated using the Casteel-Amis equation. This choice was made because many factors affecting conductivity are well documented in the literature but not universally quantifiable for all electrolytes due to isolated consideration. The wide variety of different electrolytes investigated in this study highlights the importance of considering these factors holistically rather than in isolation. Nevertheless, NaI and KSCN in methanol and (C2H5)(4)NBF4 in acetonitrile were identified as the three organic electrolytes with the highest conductivity. These solutions have the potential to be used as electrolytes for CO2 reduction.

The electrochemical CO2 reduction reaction (CO2RR) to organic products is becoming increasingly important. Here, organic electrolytes play a crucial role, since adding salt to organic solvent allows an increase in the current density, and together with supercritical CO2 organic electrolytes suppress hydrogen evolution during the CO2RR. Since the selectivity to organic products depends on the CO2 content, CO2 solubility was investigated in organic electrolytes at different salt concentrations, pressures (up to 150 bar), and temperatures (25 °C and 70 °C). These organic electrolytes included the mixtures NaI-methanol, KSCN-methanol, (C2H5)4NBF4-acetonitrile, and (C4H9)4NBF4-acetonitrile. Afterwards, electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT) was applied to predict the CO2 solubility in these organic electrolytes. The results showed that i) CO2 solubility decreased with increasing temperature and salt concentration, ii) dissolving CO2 may cause a precipitation of salts, and that iii) ePC-SAFT allowed to qualitatively model the CO2 solubility in organic electrolytes

Particles from Gas Saturated Solutions-Drying was employed to pulverize black carrot extract at mild and non oxidative conditions. Potato proteins were chosen as carrier as they are health promoting ingredient just as black carrot extract, which increases the potential nutraceutical use of the final powder. The effect of pressure, temperature and nozzle size were investigated. The mean particle size values of PGSS-dried particles were ranged between 8.04 and 11.56 mu m. Encapsulation efficiency of particles were between 69.49 % and 81.78 %, while it was 78.58 % and 84.80 % for freeze-dried and spray-dried particles, respectively. Anthocyanin retention (84.02-87.27 %) in PGSS-dried particles was similar to that of freeze-dried particles and lower than that of spray dried particles. Higher protection was observed based on in vitro bioaccessability results in PGSS-dried particles and they had more spherical shape than spray-dried particles. The moisture of particles was highly affected by the spray tower temperature and gas-to-liquid ratio.

Conventional leather dyeing consumes high amounts of dyes and increases pollution of tannery wastewater. We have focused on the reduction of dyestuff and the avoidance of water and additional chemicals for the colorization of leather. Waterless leather dyeing with supercritical CO2 as solvent for the dye 1-(methylamino) anthraquinone was performed in a technical scale autoclave. The intensity and uniformity of the dyed leathers was assessed using spectroscopic color measurements. The rub fastness was assessed according to DIN EN ISO 11640. In the result, waterless dyeing at 100 bar and 40 degrees C leads to uniform, intensive colorizations of the leather surface at a usage of 0.1 g of dye per square foot of leather. The dyed leathers achieve the highest rub fastness grades. The exhaustion of dyestuff is almost 100%. The waterless dyeing process offers potential to save significant amounts of dyestuff and reduce wastewater emissions by 100%.

The wastewater pollution of tanneries is of high concern. The investigation of technologies to minimize the consumption of chemicals in the leather production process can reduce the environmental burden. We focus on the reduction of ammonium salts in the leather production process. Salt-free deliming of animal hides with compressed carbon dioxide as deliming agent is performed for the first time in a technical scale 20-L drum. As a result, CO2-deliming at 30 bar and 30 °C is two times faster than conventional deliming. In addition, the deliming efficiency is slightly improved. The initial calcium (Ca) content of the hides of 8 g/kg reaches the lowest value of 2 g/kg after a process time of 3 h. However, a process time of 60 min is sufficient to reach an elimination of 50 wt% of the initial lime. The resulting Ca-content of 4 g/kg after 60 min CO2-deliming at 30 bar is comparable with the Ca-content of conventional delimed hide. We clarify that the ampholytic character of the collagen itself enables a buffering of the pH-value at pH-7. The stable pH-value supports the selection of specific bating enzymes that decompose non-collagen proteins. No buffering salts contaminate the wastewater. The high-pressure CO2-deliming process has high potential to reduce wastewater emissions, save costs for chemicals, and process time in industrial beamhouse applications.

A simple schlieren technique is used to visualize strong gradients of refractive index in liquids under atmospheric conditions and elevated pressure. The gradients are mainly caused by concentration differences within a thin liquid sheet. A simple system using Matlab and open source applications is designed and applied to demonstrate the challenges and limitations of a quantitative approach for strong gradients in liquids. Possibilities for the optimization regarding the detection of strong gradients are shown, but rather qualitative than quantitative results are obtained.

A methodology for identifying suitable locations for the CO2-based production of olefins in Germany is presented. Based on electricity and CO2 requirements, locations are identified that can provide sufficient CO2 and renewable energy for the conversion of CO2 to olefins. In addition, the use of existing infrastructures is taken into account. The regional, technical renewable energy potential in Germany is sufficient to produce similar to 800 kt of olefins from CO2-based methanol per year in one plant. But the currently available CO2 point sources with high CO2 concentrations of around 100 % are not sufficient to meet the CO2 requirement of an 800 kt a(-1) methanol-to-olefins plant. If existing refineries are preferred due to existing infrastructure services, locations in the north of Cologne, in Lower Saxony, and in Brandenburg are particularly suitable. A full substitution of fossil olefins by CO2-based olefins is possible in Germany. The challenge is to provide sufficient renewable electricity for the production of H-2 with a low CO2 intensity.

The electrocatalytic reduction of carbon dioxide (CO2) by means of renewable energies is widely recognized as a promising approach to establish a sustainable closed carbon cycle economy. However, widespread application is hampered by the inherent difficulty in suppressing the hydrogen evolution reaction and controlling the overall process selectivity. Further critical parameters are the limited solubility of CO2 in many electrolytes and its hindered mass transport to the electrodes. Herein we report on a series of nanoparticle Cu electrocatalysts on different carbon supports and their potential to perform the electrochemical CO2 reduction under supercritical conditions (scCO(2)). Herein, CO2 serves as the reaction medium and reactant alike. By a detailed comparison to ambient conditions we show that scCO(2) conditions largely suppress the undesirable hydrogen evolution and favor the production of formic acid by the Cu electrodes. Furthermore, we show that scCO(2) conditions significantly prevent Cu nanoparticle agglomeration during electrocatalysis.

Chemie Ingenieur TechnikVolume 92, Issue 9 p. 1283-1284 Poster CO2 – ein geeigneter Elektrolyt für seine eigene Reduktion unter Hochdruck? M. Dorn, M. Dorn Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorK. Junge Puring, K. Junge Puring Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorO. Evers, O. Evers Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorM. Prokein, M. Prokein Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorU.-P. Apfel, U.-P. Apfel Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorS. Kareth, Corresponding Author S. Kareth kareth@vtp.rub.de Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandCorrespondence: S. Kareth (kareth@vtp.rub.de), Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorM. Petermann, M. Petermann Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorE. Weidner, E. Weidner Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorN. Mölders, N. Mölders Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this author M. Dorn, M. Dorn Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorK. Junge Puring, K. Junge Puring Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorO. Evers, O. Evers Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorM. Prokein, M. Prokein Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this authorU.-P. Apfel, U.-P. Apfel Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorS. Kareth, Corresponding Author S. Kareth kareth@vtp.rub.de Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandCorrespondence: S. Kareth (kareth@vtp.rub.de), Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorM. Petermann, M. Petermann Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorE. Weidner, E. Weidner Ruhr-Universität Bochum, Fakultät für Maschinenbau, Universitätsstr. 150, 44801 Bochum, DeutschlandSearch for more papers by this authorN. Mölders, N. Mölders Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, DeutschlandSearch for more papers by this author First published: 28 August 2020 https://doi.org/10.1002/cite.202055178AboutPDF 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. Volume92, Issue9Special Issue: 10. ProcessNet-Jahrestagung und 34. DECHEMA-Jahrestagung der Biotechnologen 2020: Processes for FutureSeptember 2020Pages 1283-1284 RelatedInformation

Due to the brittle nature of poly(lactic acid) many attempts have been made to flexibilize this polyester for applications such as thin films and foils. However, due to complex phase behavior, many drawbacks for plasticizer and blend components are described. To overcome miscibility, post crystallization and migration issues a principle of click-chemistry was employed to change the molecular characteristics from external to internal plasticization by fixation of a plastisizing unit with help of a stereocomplex crystallization. Hydroxyl terminated polycaprolactone oligomers were used as a macroinitiator for the ring opening polymerization of d-lactide, resulting in blockcopolymers with plasticizing unit polycaprolactone and compatibilizing poly(d-lactic acid)-blocks. The generated block copolymers were blended with a poly(l-lactic acid)-matrix and formed so called stereocomplex crystals. In comparison to unbound polycaprolactone the polycaprolactone blocks show a lower migration tendency regarding a solution test in toluene. Besides that, trapping the plasticizing units via stereocomplex also improves the efficiency of the plasticizer. In comparison to polymer blends with the same amount of non-bonded polycaprolactone oligomers of the same molecular weight, block copolymers with poly(d-lactic acid) and polycaprolactone can shift the glass transition temperature to lower values. This effect can be explained by the modulated crystallization of the polycaprolactone-blocks trapped into the matrix, so that a higher effective amount can interact with the poly(l-lactic acid)-matrix.

In this work, a simple optical measurement method for two-phase bubbly flow investigations was developed using backlight imaging and particle image velocimetry techniques. Besides information about bubble sizes, surface area and volumes, the mean dispersed phase mass flow rate and the mean dissolution of the dispersed phase in the continuous phase at the end of a static mixer were accurately estimated. The method was validated with air-in-glycerol and water-in-oil systems, and then proven with CO2-glycerol and CO2-PEG6000 dispersions under high pressure. A 30-element SMX4 plus static mixer with a nominal outer diameter of 4.8 mm was used for all mass transfer investigations. Measurements of the dispersed phase mass flow and the dissolution of the dispersed phase at the end of the mixer are reported with combined uncertainties of 8.1 % and 1.0 wt-%. The first experiments with CO2-glycerol and CO2-PEG6000 prove the applicability of this method for systems under high pressure. (C) 2020 Published by Elsevier B.V.

In the conventional leather production process, basic chromium sulphate (BCS) penetrates fully inside the collagen matrix during tanning and forms oligo-nuclear complexes that stabilize the skin structure during basification. Accelerated chromium sulphate complexation by basifying the BCS before full penetration leads to surface tanning and low leather qualities. Therefore, long processing times of 16 h for tanning and basification are common in modern tanneries. We used sodium hydrogen carbonate to basify BCS before penetration. However, instead of conventional tanning we performed CO 2 tanning at 30 bar. The influence of accelerated chromium sulphate complexation on the leather quality was investigated. To estimate the structures of the formed chromium complexes, we considered the pH trend of the tanning solution during basification depending on the amount of basifying agent. The distribution of chromium oxide (Cr 2 O 3 ) and the shrinkage temperature ( T s ) in three different layers of the cross section were analysed. The analytics allowed the assessment whether the tanning agent penetrates through the whole cross section or adheres to the surface during CO 2 tanning. We show that CO 2 -intensified tanning allows accelerated chromium sulphate complexation and a reduction in the tanning time from 16 to 4 h. The Cr 2 O 3 is equally distributed, and T s above 100 °C meets the standards of high-quality wet blue. However, the pH value of the tanning solution must not rise above 4.5 during basification. Otherwise, the T s decrease dramatically. The feasibility of the process is demonstrated in a 1700-L drum, with a batch size of about 500 kg. The CO 2 -intensified tanning process has high potential to save time and chemicals and reduce emissions in industrial applications and is commercially competitive. Graphic abstract

Chemie Ingenieur TechnikVolume 92, Issue 7 p. 994-994 VorschauFree Access Vorschau: Chem. Ing. Tech. 8/2020 First published: 24 June 2020 https://doi.org/10.1002/cite.202070706AboutPDF 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 onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume92, Issue7Special Issue: Separation Units 4.0July 2020Pages 994-994 RelatedInformation

The use of CO2 as raw material is increasingly gaining in importance as an option for climate protection and as an alternative raw material feedstock. Both direct electrochemical syntheses and thermochemical processes are associated with a high demand for electrical energy. A contribution to climate protection is only possible in the case of low-carbon power generation, as can be realized, e.g., by wind power or solar energy. This article presents a methodology for identifying suitable sites for the CO2-based production of olefins in Germany.

Methane production at biocathodes is an innovative approach of storing renewable electrical energy in chemical energy via the biological conversion of carbon dioxide. Methane producing microorganisms use electricity to catalyze the conversion of carbon dioxide into methane; a form of carbon-neutral natural gas. However, the rates of methane production remain too low for practical application. To improve performance, high area-to-volume ratio with good mass transfer is required. In this study, we used the design of redox flow-batteries with a high area-to-volume ratio of 2.0 cm(2)/cm(3) and an external capillary manifold for flow distribution. Current densities up to 35 A/m(2) were applied, resulting in volumetric methane production rates of up to 12.5 L CH4/L/d, three times higher than rates reported so far. The highest energy efficiency of 30% was obtained at 25 A/m(2). Even with a low relative abundance of methanogens in the microbial community (20%), dense biofilm growth was observed on the outer surface of the biocathode. Flow-battery cell design shows promising performance for application of methane-producing biocathodes. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Plasma catalysis, the combination of non-thermal plasma and catalyst, is a promising approach for optimizing chemical conversions as the removal of gas trace components. The various technological opportunities for the generation of atmospheric non-thermal plasma combined with the variety of usable catalysts result in a huge amount of different experimental approaches. The aim of the presented review is to give an overview of plasma catalytic reactor designs currently discussed in literature as well as to point out technological differences and potential for up-scaling.