The Need for Dynamic Process Simulation: A Review of Offshore Power‐to‐X Systems

The integration of offshore wind energy into Power-to-X (PtX) process chains offers opportunities for the efficient use of renewable energy. This article analyzes different PtX process chain configurations and their adaptation to the offshore environment. However, direct coupling of PtX platforms with fluctuating electrical energy poses major challenges. Dynamic process simulation is presented for analysis of different plant configurations and operating strategies. The article emphasizes the need for interdisciplinary research to consider technological as well as economic and environmental aspects

Towards a novel computer-aided optimization of microreactors: Techno-economic evaluation of an immobilized enzyme system

Immobilized multi-enzyme cascades are increasingly used in microfluidic devices. In particular, their application in continuous flow reactors shows great potential, utilizing the benefits of reusability and control of the reaction conditions. However, capitalizing on this potential is challenging and requires detailed knowledge of the investigated system. Here, we show the application of computational methods for optimization with multi-level reactor design (MLRD) methodology based on the underlying physical and chemical processes. We optimize a stereoselective reduction of a diketone catalyzed by ketoreductase (Gre2) and Nicotinamidadenindinukleotidphosphat (NADPH) cofactor regeneration with glucose dehydrogenase (GDH). Both enzymes are separately immobilized on magnetic beads forming a packed bed within the microreactor. We derive optimal reactor feed concentrations and enzyme ratios for enhanced performance and a basic economic model in order to maximize the techno-economic performance (TEP) for the first reduction of 5-nitrononane-2,8-dione

Downsizing Sustainable Aviation Fuel Production with Additive Manufacturing-An Experimental Study on a 3D printed Reactor for Fischer-Tropsch Synthesis

Sustainable aviation fuels (SAF) are needed in large quantities to reduce the negative impact of flying on the climate. So-called power-to-liquid (PtL) plants can produce SAF from renewable electricity, water, and carbon dioxide. Reactors for these processes that are suitable for flexible operation are difficult to manufacture. Metal 3D printing, also known as additive manufacturing (AM), enables the fabrication of process equipment, such as chemical reactors, with highly optimized functions. In this publication, we present an AM reactor design and conduct experiments for Fischer-Tropsch synthesis (FTS) under challenging conditions. The design includes heating, cooling, and sensing, among others, and can be easily fabricated without welding. We confirm that our reactor has excellent temperature control and high productivity of FTS products up to 800 kgC5+ mcat−3 h−1 (mass flow rate of hydrocarbons, liquid or solid at ambient conditions, per catalyst volume). The typical space-time yield for conventional multi-tubular Fischer-Tropsch reactors is ~100 kgC5+ mcat−3 h−1. The increased productivity is achieved by designing reactor structures in which the channels for catalyst and cooling/heating fluid are in the millimeter range. With the effective control of heat release, we observe neither the formation of hot spots nor catalyst deactivation

A Microstructured Cover Flow Mixer for Hydrothermal Synthesis of ZnO Nanoparticles in Supercritical Water

A microstructured cover flow mixer equipped with two cyclone structures was used for stable continuous hydrothermal synthesis of ZnO nanoparticles from Zn(NO$_3$)$_2$ and NaOH aqueous solutions in supercritical water. The effects of the NaOH/Zn(NO$_3$)$_2$ ratio, Zn(NO$_3$)$_2$ molality, and flow rate on Zn conversion, crystal structure, particle size, particle morphology, and mixer clogging were examined. The advantages of this mixer were identified by comparing with the results obtained using the same chemical conditions with tee-type, cross-type, and central collision-type mixers

Fabrication of Sectionally Permeable Components with Curved Surface by Laser‐Beam Powder‐Bed Fusion

Devices in process engineering often include permeable components. As shown in our recent work for planar components, laser-beam powder bed fusion offers the opportunity to integrate permeable sections into complex monolithic metal parts in one go. This paper extends the approach to components with curved surfaces. Different scan strategies were investigated for their effects on surface morphology and permeability of tubular samples. It was found that in order to ensure consistent properties of a permeable tube, different starting points or rotation of the scan vectors have to be used

Tap Reactor for Temporally and Spatially Resolved Analysis of the CO2_{2} Methanation Reaction

Chemical energy carriers produced according to power-to-X concepts will play a crucial role in the future energy system. Here, CO$_{2}$ methanation is described as one promising route. However, transient operating conditions and the resulting effects on catalyst stability are to be considered. In this contribution, a tap reactor for spatially and temporally resolved analysis of the methanation reaction is presented. The Ni catalyst investigated was implemented as coating. Reaction data as a function of time and reactor coordinate under various operating conditions are presented and discussed. A comparison with simulation data validates the presented tap reactor concept

Experimental Investigation of the Gas/Liquid Phase Separation Using a Membrane-Based Micro Contactor

The gas/liquid phase separation of CO2 from a water-methanol solution at the anode side of a µDirect-Methanol-Fuel-Cell (µDMFC) plays a key role in the overall performance of fuel cells. This point is of particular importance if the µDMFC is based on a “Lab-on-a-Chip” design with transient working behaviour, as well as with a recycling and a recovery system for unused fuel. By integrating a membrane-based micro contactor downstream into the µDMFC, the efficient removal of CO2 from a water-methanol solution is possible. In this work, a systematic study of the separation process regarding gas permeability with and without two-phase flow is presented. By considering the µDMFC working behaviour, an improvement of the overall separation performance is pursued. In general, the gas/liquid phase separation is achieved by (1) using a combination of the pressure gradient as a driving force, and (2) capillary forces in the pores of the membrane acting as a transport barrier depending on the nature of it (hydrophilic/hydrophobic). Additionally, the separation efficiency, pressure gradient, orientation, liquid loss, and active membrane area for different feed inlet temperatures and methanol concentrations are investigated to obtain an insight into the separation process at transient working conditions of the µDMFC