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The chemical and biotechnology industries are facing new challenges in the use of renewable resources. The complex nature of these materials requires the use of advanced techniques to understand the kinetics of reactions in this context. This study presents an interdisciplinary approach to analyze cofactor coupled enzymatic two-substrate kinetics and competitive two-substrate kinetics in a fast and efficient manner. By studying the adsorption energy distribution (AED), it is possible to determine the individual parameters of the reaction kinetics. In the case of a single alcohol reaction, the AED is able to identify parameters in agreement with the literature with few experimental data points compared to classical methods. In the case of a competitive reaction, AED analysis can automatically determine the number of competing substrates, whereas traditional nonlinear regression requires prior knowledge of this information for parameter identification. [ABSTRACT FROM AUTHOR]

Membrane processes are considered as comparably mild separation processes offering the potential for significant energy savings compared with azeotropic distillation processes. Despite higher investment and material costs, they are of particular interest for improving the energy efficiency in the chemical industry. However, energy savings of more than 20%–30% are rarely reported and even a general superiority can be disputed. To further elucidate this controversial, the current study pursues a quantitative assessment of the thermodynamic efficiency of pervaporation and vapor permeation processes with stand‐alone distillation and hybrid membrane‐assisted distillation processes for the separation of azeotropic mixtures. The results confirm the case‐dependent potential of distillation processes to outperform membrane‐assisted separations in terms of energy efficiency, considering proper heat integration. Although energy efficiency is becoming significantly important, it should be considered in the context of economic performance to determine an optimal trade‐off and to select the best process alternative during conceptual process design. [ABSTRACT FROM AUTHOR]

In the context of process intensification, milli-structured plate reactors provide significant advantages over conventional reactors in terms of heat and mass transfer as well as process safety. The ART® plate reactor PR37 of Ehrfeld Mikrotechnik GmbH offers excellent heat transfer, narrow residence time distributions and high mixing efficiency, while simultaneously allowing an effective scale-up to industrial applications due to its modular set up. This does not only enable the realization of novel process windows exceeding the limits of conventional reactors, but also provides optimal prerequisites for kinetic modelling due to the well-defined process conditions, providing key information regarding process design and optimization. The integration of the ART PR37 with Model-based Design of Experiments (MBDoE) allows for an intensification of kinetic studies, combining the well-defined operating conditions with a rapid and targeted identification of kinetic models. In the current study this combination is applied to successfully identify the kinetics of a multistep aromatic nucleophilic substitution reaction with low experimental effort, saving time and resources compared to conventional factorial Design of Experiments. [ABSTRACT FROM AUTHOR]

Distillation-based separation processes, such as extractive or heteroazeotropic distillation, present important processes for separating azeotropic mixtures in the chemical and biochemical industry. However, heteroazeotropic distillation has received much less attention than extractive distillation, which can be attributed to multiple reasons. The phase equilibrium calculations require a correct evaluation of phase stability, while the topology of the heterogeneous mixtures is generally more complex, comprising multiple azeotropes and distillation regions, resulting in an increased modeling complexity. Due to the integration of distillation columns and a decanter, even the simulation of these processes is considered more challenging, while an optimal process design should include the selection of a suitable solvent, considering the performance of the integrated hybrid process. Yet, the intricate mixture topologies largely impede the use of simplified criteria for solvent selection. To overcome these limitations and allow for a process-based screening of potential solvents, the current work presents a topology-based initialization and optimization approach for designing heteroazeotropic distillation processes. The systematic initialization enables an efficient evaluation of different solvents with different mixture topologies, which is further exploited for optimization-based sensitivity analysis and multi-objective optimization. Three case studies are analyzed with about 170 individually optimized process designs, including stage numbers, feed locations, phase ratios, and heat duties. [ABSTRACT FROM AUTHOR]

While rate‐based models are available in commercial flowsheet simulation tools, packed distillation columns are still mostly designed based on the equilibrium stage model in combination with HETP values. In order to discriminate between both types of models in a simple way, this article proposes an algorithmic test, based on a geometric criterion for total reflux operation. Substantial differences are illustrated especially for wide‐boiling mixtures, while component‐specific mass transfer rates either increase or reduce the deviation. The derived results are validated by dedicated experiments. [ABSTRACT FROM AUTHOR]

The growing demand for flexible and compact separation technologies has promoted the application of high‐gravity technology, like rotating packed beds (RPBs). Mass transfer characterization and packing design play an important role in the development of this technology. This article provides a systematic approach towards the evaluation of packing and the development of advanced packing design for distillation in RPBs. For the latter, an additive manufacturing approach is used to develop a new Zickzack packing for RPBs. The new packing provides better mass transfer at reduced pressure drop compared to available conventional packings, while being competitive in terms of mass transfer with the industrially applied rotating zigzag bed at significantly reduced pressure drop. [ABSTRACT FROM AUTHOR]

The capacity of today's gas‐liquid contacting equipment such as tray or packed columns is limited by the gravitational‐driven liquid flow. Intensified equipment applying centrifugal force offers great potential for enhancing the mass transfer and for reducing equipment size. Yet, detailed knowledge about the liquid flow inside rotating packings is scarce due to limited accessibility with conventional measurement systems. In this study, a gamma‐ray computed tomography is employed to quantify the liquid hold‐up and its distribution in the moving packing. [ABSTRACT FROM AUTHOR]

Carbon dioxide is considered the most important contributor to the global warming effect. To reduce greenhouse gas emissions, CO2 should be separated from the exhaust gas stream in a selective way. The most often applied technology to capture CO2 from exhaust gases is the reactive absorption in aqueous amine solutions, which is currently widely used in different industrial applications. The efficiency of this technology could be improved by applying high-gravity technologies that intensify mass transfer and can enable substantial equipment size reduction compared to the traditionally used packed columns. Rotating packed bed (RPB) technology meets these requirements very well. Applying innovative materials such as the highly efficient enzyme carbonic anhydrase can further improve the efficiency of the CO2 absorption process. This combination of intensified technology together with new solvents is expected to improve the total efficiency of CO2 absorption. In this study, we present our experimental results of CO2 absorption using 30 wt% N-methyldiethanolamine (MDEA) solution in water in an RPB unit with and without carbonic anhydrase for different gas and liquid flow rates. The results indicate significantly improved performance of CO2 absorption, up to 18 times compared to the solvent without enzyme. [ABSTRACT FROM AUTHOR]

The current article presents the extension of a recently developed optimization‐based approach to process synthesis for process intensification. It generates phenomena‐based flowsheet options using superstructure optimization and provides a dedicated translation into equipment‐based flowsheets. The considered case‐study illustrates the application of the method for the analysis of ethyl tert‐butyl ether production, based on the conversion of tert‐butyl alcohol, under consideration of variable configurations of a rector network and a newly introduced pervaporation‐based membrane‐reactor block. To overcome restrictions of the classical unit operations concept, process synthesis needs to be performed on a lower level of aggregation, through combination of single phenomena, or aggregated building blocks. This paper extends a recently presented optimization‐based approach building on this concept and illustrates its use in process analysis. [ABSTRACT FROM AUTHOR]

Our contribution adds important new insight to the recent finding that polyoxometalate catalysts, such as H8PV5Mo7O40 (HPA‐5), are very effective catalysts in the extractive oxidative desulfurization of fuels using molecular oxygen. Our contribution focuses on aspects of catalyst stability and deactivation caused by the accumulation of acidic products and intermediates, i. e. sulfuric acid, formic acid, acetic acid, sulfoacetic acid or 2‐sulfobenzoic acid. These compounds reduce the pH value of the aqueous catalyst phase during the course of the desulfurization reaction. At lower pH values, the higher V‐substituted species rearrange to lower V‐substituted species and VO2+. This rearrangement is responsible for a decreasing activity in extractive oxidative desulfurization. We show that formic acid, acetic acid, sulfoacetic acid and 2‐sulfobenzoic acid block active sites of the catalyst. Oxalic acid, in contrast, has been found to exert a remarkable positive effect on catalyst activity. The feasibility of catalyst recycling and efficient isolation of the decomposition products is demonstrated using four commercially available organic solvent nanofiltration membranes. The catalyst stability and deactivation behavior of P−V−Mo substituted Keggin polyoxometalates in the extractive oxidative desulfurization (ECODS) reaction using molecular oxygen is described. The products and intermediates of the ECODS reaction formic acid, acetic acid, sulfoacetic acid and 2‐sulfobenzoic acid block the active sites of the catalyst. Oxalic acid, in contrast, is oxidized to carbon dioxide and promotes the desulfurization reaction. The feasibility of catalyst recycling and efficient isolation of the decomposition products is demonstrated using four commercially available organic solvent nanofiltration membranes. [ABSTRACT FROM AUTHOR]

Abstract: The chemical industry has witnessed many important developments during past decades largely enabled by process intensification techniques. Some of them are already proven at commercial scale (e.g. reactive distillation) while others (e.g. ultrasound‐assisted extraction/crystallization/reaction) are on their way to becoming the next‐generation technologies. This article focuses on the advances of ultrasound (US)‐assisted technologies that could lead in the near future to significant improvements in commercial activities. The aim is to provide an authoritative discussion on US‐assisted technologies that are currently emerging from the research environment into the chemical industry, as well as give an overview of the current state‐of‐the‐art applications of US in chemical processing (e.g. enzymatic reactive distillation, crystallization of API). Sufficient information is included to allow the assessment of US‐assisted technologies and the challenges for implementation, as well as their potential for commercial applications. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Enzymatic reactive distillation (ERD) is a biocatalyzed process, in which enzymes are immobilized in catalytic packing. The combination of enzymatic reaction and thermal separation helps to overcome chemical reaction and phase equilibrium limitations. Processing of chiral molecules, in particular, can benefit from ERD application, which might lead to more eco-efficient processing of these valuable chemicals. Therefore an integrated approach to evaluate this technology is followed. RESULTS To evaluate ERD the transesterification of racemic (R/S)-1-phenylethanol (RPE/SPE) to (R)-phenylethyl acetate (PEA) catalyzed by Candida antarctica lipase B (EC: 3.1.1.3) is investigated with regard to kinetics and physical property data, which provide a basis for the modeling of an ERD process. Furthermore, ERD experiments show a selective conversion of RPE to PEA, which is predicted by the established ERD model with high accuracy. CONCLUSION The ERD experiments demonstrate the feasibility of chiral processing for the transesterification by means of ERD and a validated ERD model is developed, allowing for a conceptual evaluation of ERD. This provides the basis for a future comparison of ERD with benchmark processes that will reveal the economic potential of ERD processes. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

While membrane processes like pervaporation are considered as key technology towards more sustainable separation processes, they are rarely considered in conceptual design. In order to enable an identification of promising applications, the current article proposes a systematic approach that covers the synthesis of pervaporation-assisted process variants and promotes the use of optimization-based methods for process analysis. It seeks to minimize and guide necessary experiments and includes competitive reference processes as well as further means for process intensification in the evaluation. [ABSTRACT FROM AUTHOR]

Process intensification provides a whole toolbox of innovative solutions for improved energy efficiency of chemical processes. However, evaluation of this potential is hampered by the unavailability of suitable models and design tools. Integrated processes like dividing wall columns either have to be mapped by available unit operation models or tailored equation-based models have to be developed. The current article reviews available methods for conceptual design and optimization of dividing wall columns and provides a detailed comparison of two representative optimization approaches. [ABSTRACT FROM AUTHOR]

Organic solvent nanofiltration is a convenient method for the recovery of homogeneous transition metal catalysts. The long chain olefin 1-dodecene is hydroformylated continuously, and the commercially available catalyst complex is separated efficiently using a commercially available nanofiltration membrane. An advantage of this method is that both reaction and separation take place in a single liquid phase. Only continuous operation shows interactions of reaction and separation in the long run. Low energy demand, high scalability as well as transferability to other reactions make this method promising for new industrial applications. [ABSTRACT FROM AUTHOR]

With growing interest in the biomass value chain, a multitude of reactions are proposed in literature for the conversion of biomass into a variety of biofuels. In the early design stage, data for a detailed design is scarce rendering an in-depth analysis of all possibilities challenging. In this contribution, the screening methodology process network flux analysis (PNFA) is introduced assessing systematically the cost and energy performance of processing pathways. Based on the limited data available, a ranking of biorefinery pathways and a detection of bottlenecks is achieved by considering the reaction performance as well as the feasibility and energy demand of various separation strategies using thermodynamic sound shortcut models. PNFA is applied to a network of six gasoline biofuels from lignocellulosic biomass. While 2-butanol is ruled out due to a lack in yield and selectivity, iso-butanol and 2-butanone are identified as economically promising fuels beyond ethanol. [ABSTRACT FROM AUTHOR]