Phosphorrecycling durch Mitverwertung von Klärschlammaschen bei der Phosphorsäureherstellung

The approach of recycling phosphorus from sewage sludge ash by co-processing in conventional phosphoric acid production was investigated. Lab-scale experiments with real ashes and simulated industrial conditions showed that mixing of ash and phosphate rock prior to processing resulted in several disadvantages. As a solution the novel concept of return acid extraction is presented, which overcomes some of the identified shortcomings of direct mixing.     

Sauergasbasierte stoff- und energieautarke Trocknung von Klärschlamm und Gärresten

During the processing of biomass as well as during waste water treatment, residual materials with a high water content are produced. They must therefore be dried prior to thermal utilization. Classical drying processes often use fossil raw materials to generate the necessary energy. With sour gas-based drying based on carbon dioxide-air mixtures, an alternative is presented that considers CO₂ as a valuable raw material (second life) and uses it in the process for drying sewage sludge and fermentation residues. Especially in the drying of fermentation residues, significant differences in dry substance content (DS) were measured, which in individual cases amounted to up to 35 % DS with the same drying time. This is expressed, among other things, in a higher carbon content of 0.42 wt % (wf) in the dry material, accompanied by a heating and calorific value that is more than 1 MJ kg⁻¹ higher.     

Vorteile von Open-Source-Ansätzen bei der Etablierung einer automatisierten wirkungsbezogenen Analytik

The determination of toxic compounds in wastewater is perfomed using thin layer chromatography. For automation of effect-directed analytics, an existing technical solution was adapted as an open-source hardware approach in combination with additive manufacturing. The system is flexibly applicable to specific issues of automated determination of environmentally relevant compounds and makes a valuable contribution to the digitalization and automation of high-performance thin-layer chromatography systems.     

Untersuchung von Polymerablagerungen während der Synthese in einem Wärmeübertrager

To investigate the unwanted deposition of polymers on heat transfer surfaces (polymerization fouling) the deposition of a vinyl acetate/vinyl ester copolymer during emulsion polymerization is investigated. The aim is to identify fundamental differences to the fouling behavior of an already reacted vinyl acetate/ethylene copolymer. For a qualitative comparison the surface coverage is observed using a digital microscope. For the quantitative examination the fouling resistance is calculated from the mass and the layer height of the deposited material. The degree of polymerization has a significant influence on the deposition behavior. The already reacted material system shows a larger fouling mass and a more pronounced, crater-shaped surface coverage, whereas during polymerization fouling a clearly optically different drop-shaped surface coverage was formed.     

Klärschlammverbrennung in einer stationären Wirbelschicht mit integrierter Phosphor-Rückgewinnung

Currently, wet-chemical and thermochemical processes in particular are being discussed for the future obligatory recovery of phosphorus from sewage sludge. The coupling of phosphorus recovery with incineration in stationary fluidized bed incinerators, the dominant mono-incineration technology, offers potential advantages in terms of aftertreatment costs and economic efficiency. Tests have shown that by adjusting the incineration conditions and adding additives, an ash could be produced that corresponds to the fertilizer ordinance (DüMV) and can, therefore, potentially be used as phosphorus recyclate.     

Umsatz- und Selektivitätsverhalten von Dicobaltoctacarbonyl und Cyclopentadienylcobaltdicarbonyl auf Silicagel-, Alumosilicagel- und Aluminiumoxid-Trägern bei der Hydroformylierung von Hex-1-en

Conversion and Selectivity in Hydroformylation of Hex-1-en with Silica-Gel-, Silica-Alumina-Gel and Alumina-Oxide- Supported Dicobalt Octacarbonyl and Cyclopentadienylcobalt Dicarbonyl The catalytic influence of silica-gel-, silica-alumina-gel- and alumina-oxide-supported Co₂(CO)₈ and CpCo(CO)₂ on the conversion and selectivity in hydroformylation of hex-1-en has been studied at 353 K under 120 bar syngas pressure in acetonitrile. The support systems were prepared by impregnation of SiO₂ (Grace), SiO₂/4% Al₂O₃ (Kali Chemie), SiO₂/11% Al₂O₃ (Kali Chemie) and Al₂O₃ (Kali Chemie) using Co₂(CO)₈ and CpCo(CO)₂ solutions in pentane, dichlormethane and 2-chlorpropane. The results are discussed with regard to some measured relevant support characteristics. The turn over numbers especially those of silica-gel- and silica-alumina-gel supported Co₂(CO)₈ and CpCo(CO)₂ show positive effects in relation to a heterogeneous catalytic process within these reactions.     

Modellierung der Oberflächenstruktur von Nadelfilz-Filtermedien zur Simulation der kuchenbildenden Staubfiltration

The surface structure of different needled felts can be characterized quantitatively by a few key parameters, which are used to build model structures in a simple way. These model structures are then used to simulate the cake-forming dust filtration via CFD simulation and calculation of particle trajectories. By systematic variation of the key parameters for simulation calculations, the changes in the dust cake structure and in the operating behavior of surface filters from differently structured needled felts can be evaluated for a systematic theoretical study.     

Feinstzerkleinerung von CFK-Abfällen und Charakterisierung der Zerkleinerungsprodukte

The comminution of carbon fiber reinforced plastics (CFRP) is a central process step for almost all recycling processes. Size reduction creates a specific surface that serves as a measure in particular of the size reduction success of fines. The article shows the comminution from 1 m edge length in the feed material down to a target product size of less than 100 µm by means of three-stage comminution. The challenges of granulometric characterization of the comminution products and the associated evaluation of the comminution success are specifically addressed.     

Grundsätzliche Ansätze zur Verbesserung der Ressourceneffizienz in der Metallindustrie

Without the intensive use of metals, the implementation of current strategies such as the realisation of renewable energy production or electromobility in Germany would be unthinkable. A secure supply of all primary metals to industry cannot be considered guaranteed due to de facto monopoly structures and the trend towards decreasing ore contents. Improved recycling can increase resource efficiency and reduce dependence on imports. The challenges associated with this and possible solutions are discussed.     

Modularisierung in der Prozessindustrie – Bericht von der ACHEMA 2022

A wide range of solutions for modularization in the process industry were presented at ACHEMA 2022. In this report, new areas of modularization are presented in particular, as well as results of expert interviews regarding the current and future challenges of modular production are highlighted. Although extensive progress has been made in recent years, many companies are facing major challenges that can only be mastered in close cooperation between module and component suppliers, plant operators and system integrators, as well as automation solution providers.     

Notwendigkeit und Vermarktung von Flexibilitätsoptionen im Energiesystem der Zukunft

Demands on production, distribution and consumption of electrical energy change fundamentally with the energy revolution. Energy purchasing costs for inflexible consumers are rising and proceeds of inflexible producers are sinking. Companies are able to reduce costs by marketing operational flexibility options. This article sets out the need of flexibility in the energy system and the new marketing options. Flexibility potentials within infrastructure plants of a chemical park are analyzed, evaluated regarding marketing and activated in the presented research project FlexChemistry.     

Homogene oder heterogene Katalyse? Simultane Verwendung von basischen und sauren Zeolithen in der flüssigen Phase bei der Umesterung und Veresterung

Base catalyzed transesterification of triglycerides with methanol was studied in liquid phase on a K-LSX zeolite. The presence of free fatty acid results in its deactivation. Their esterification was catalyzed by an acidic H-Y zeolite. Surprisingly, in case of mixing of both catalysts, no catalytic activity was observed. Consequently, both reactions should proceed homogeneously because the formation of the intermediate methylat ion is suppressed. This could be explained in term of a fast ion exchange between the K⁺ ions of K-LSX and the H⁺ ions of Y-zeolite. On the other hand, the observed transport limitation indicates on a heterogeneously catalyzed reaction. Therefore, in case of even non-aqueous liquid phase reactions, a contribution of a homogeneous reaction path must be considered.     

Vorstellung eines Leitfadens zum Evaluieren der hygienegerechten konstruktiven Ausführung von Süßwarenmaschinen

Consumer protection is one of the most important criteria within industrial food production. The Machinery Directive and DIN EN 1672-2:2021-05 contain general requirements for hygienic design and cleanability of food processing machinery. Nevertheless, it happens that machines or equipment parts are used that are not suitable for the products to be processed. The consequences of this go as far as a public recall of products with a corresponding damage to the image of the food manufacturer. The working group of machine manufacturers and confectionery companies in the IVLV has dealt with the problem at the level of the association within the framework of a pre-competitive exchange and has developed a guideline for action as well as supporting forms for the procurement process of confectionery machines from the point of view of hygiene.     

Alkalische Aktivierung und Reaktivierung von Sekundärrohstoffen der Bau- und Abbruchindustrie

The present work deals with the production of geopolymers from brick flour and mixed rubble using an alkaline activator solution. The study aims to investigate whether these geopolymers can be reactivated several times without having to add new starting material, and how the number of reactivations affects the structure and material properties. The results show that geopolymers can be made from a mixture of brick flour and mixed rubble and can be ground up and reactivated up to three times.