Within the Institute of Chemical Engineering and Environmental Technology (CEET), the Working Group for Chemical Reaction Engineering deals with all aspects of homogeneous and heterogeneous (catalytic) reactions; from the investigation of reaction kinetics to the development of novel apparatuses and processes. The main focus is on intensification of processes through the introduction of chemical conversions for effluent free manufacture.

Two main research strategies are currently being pursued: One of them is in inorganic mineral processing and the other is in extraction of organic compounds from biomass-derived sources. Both projects are aimed at reducing environmental impacts of existing industrial chemical processes. One involves using the same starting material as the conventional process but switches to a radically new chemistry to avoid CO₂ emissions. The other uses a different raw material base than the existing processes, and involves the search for feasible separation/concentration methods to recover a particular family of chemicals from a dilute aqueous source, derived from biomass. The application examples represent the two main research fields; hydrogen utilization and storage, and reactive separation processes.

• Hydrogen utilization and storage, CO₂ emission mitigation

The state-of-the-art procedure for beneficiation of inorganic metal carbonates is based on thermal treatment at elevated temperatures to release the carbon dioxide from the carbonaceous ore. In order to mitigate CO₂ emissions, an alternative, environmental benign reaction path was developed. Hydrogenation of iron carbonate ores gives access to direct reduction of siderite to pig iron which allows for circumventing the sintering/blast furnace route. This so-called ‘reductive calcination’ process can also be applied to other metal carbonates.

For further upgrading of the product gas from reductive calcination or any CO₂ rich exhaust gas in general, CO₂ methanation or synthesis of methanol are promising approaches. Synthesis of methane and methanol present potential means for hydrogen storage. Bifunctional catalysts were successfully developed. They show high efficiency and selectivity while being robust and easy to handle. This research field is supported by the design of novel reactor concepts.

• Reactive separations

The current focus is on the separation of low-molecular weight carboxylic acids from aqueous effluents. This is an important task; not only from an environmental perspective regarding wastewater treatment. It also opens up an important source of yet unused resources from byproduct streams and effluents and, thus, gives access to complete exploitation of (biobased) raw materials.

Two esterification-enhanced separation strategies are currently investigated; reactive distillation and reactive extraction. Reactive distillation may be applied for the regeneration of the solvent from reactive extraction. Consequently, these two separation strategies are closely linked with each other. Emulsion-enhanced biphasic reactions represent another promising solver strategy. In this context, a novel metallosurfactant catalyst was developed that combines surfactant properties with the catalytic effect of transition metals. Both concepts are capable of processing highly dilute aqueous process streams. To provide complete technology routes, the reactive separation concepts can be complemented by pervaporative product purification.

The development of the Taylor-Couette Disc Contactor (TCDC) is a breakthrough in apparatus design. Its use is predestined for reactive extraction. The present research focuses on multiphase flow which enables continuous processing of up to four different phases in one single apparatus.