Chemie Ingenieur Technik最新文献

Chemical membrane reactors combine a chemical reaction with an in-situ removal/import of products/educts through a permselective membrane. The corresponding reactors are named extractor-type or distributor-type membrane reactors. Three recent examples for boosting a chemical reaction in an extractor-type membrane reactor with water-selective zeolite membranes and three examples for distributor-type membrane reactors with oxygen-selective ceramic membranes will be discussed.

Spent coffee grounds (SCG) contain coffee oil with a significant amount of unsaturated fatty acids. In a publicly funded research project, SCG from the industrial production of instant coffee was investigated regarding their applications in the material processing industry. The isolation, functionalization, and application of the unsaturated fatty acids was a central objective. Fatty acids enclosed in the SCG were released in the form of fatty acid methyl esters by means of an in situ process of esterification and transesterification.

The removal of unwanted droplets in thermal separation units is often accomplished using knitted wire meshes. Alongside the separation efficiency, the pressure drop plays a crucial role for the design of these demisters. Wire meshes have been subject to limited investigations, and correlations for predicting the pressure drop, both with or without loading (referred to as dry pressure drop), have not yet been validated. To address this gap, experimental analyses of porosity and dry pressure drop were conducted over a wide range of wire mesh parameters and intake gas velocities. An empirical correlation was developed from these experimental results and further data from the literature. This correlation enables prediction of the pressure drop with a mean deviation of ±20 %.

Harnessing basic oxygen furnace gas (BOFG) from steel mills as an alternative carbon source is a promising option to reduce greenhouse gas (GHG) emissions. This study explores two process concepts to purify CO from BOFG for subsequent phosgene synthesis: (i) vacuum pressure swing adsorption (VPSA) yielding pure CO, and (ii) CO₂ separation via monoethanolamine (MEA) absorption producing CO-enriched gas. By combining process optimization with life cycle assessment (LCA), process parameters are identified that minimize GHG emissions. The MEA concept can reduce emissions by up to 60 %, whereas the VPSA concept achieves a reduction of 47 %. Utilizing renewable energy enables further reductions, indicating additional environmental benefits in the future. Overall, both processes effectively produce low-carbon CO for phosgene synthesis, with increasing environmental benefits in future energy systems.

The dynamic carbon footprint profile of methanol production from steel mill gases is affected by fluctuations of steel mill gas flow rates and compositions, as well as the composition of electricity mix. The cross-industrial network of steel mill, gas conditioning, hydrogen production, chemical synthesis, and power generation was simulated under dynamic conditions. Dynamic life cycle assessment (LCA) was carried out for computing the dynamic carbon footprint profile in 15-min resolution for the integrated system of steel and methanol production. The dynamic LCA indicated that the CO₂ emissions in a power plant, electrolytic hydrogen demand, and variations in electricity mix were the major drivers of the fluctuations in the total carbon footprint. Dynamic LCA is useful for quantifying temporal uncertainty in environmental impacts. This insight can be used to analyze uncertainty in impacts for downstream products, processes, and use cases.

Pillow plate heat exchangers show promising performance in extending the operating range of thermosiphon reboilers. Here, the evaporation of binary mixtures during natural circulation evaporation in a pillow plate apparatus was investigated. The experimental results show that the thermal performance is dominated by mixture effects and a component system-dependent minimum is found. The model approach according to Bennett and Chen has proven to reliably estimate the product-side heat transfer coefficient for pure substances and mixtures with a low boiling point distance. For wide-boiling mixtures and low pressures the approach must be adjusted.

The production of renewable and sustainable fuels must comply with the EU regulatory framework (Renewable Energy Directive (EU) 2023/2413, Commission Delegated Regulations (EU) 2023/1184, and (EU) 2023/1185) for the use of renewable energy in the transport sector. The utilization of steel mill gases (SMGs) and alternative CO₂ sources (waste incineration plants (WIPs), lime industry) to produce renewable fuels of non-biological origin (RFNBOs) and recycled carbon fuels (RCFs) are attractive options as a high share of RFNBOs can be achieved with a significant reduction in greenhouse gas (GHG) emissions compared to fossil fuel use.

The carbon footprint of methanol from cradle-to-grave is evaluated using three process concepts to capture CO₂, i.e., one using CO₂ from direct air capture (DAC) and the other two utilizing CO₂ from a steel mill's blast furnace gas (BFG). Hydrogen is supplied by onsite electrolysis, or from a German offshore wind park, or an Australian solar park with ammonia as hydrogen carrier. The study is of interest to life cycle assessment (LCA) practitioners, policymakers, and industries’ management who are involved in regulating, planning, implementing, and operating projects which aim to produce fuels using hydrogen from electrolysis (so-called ‘e-fuels’). The influence of assumptions in the RED-II delegated act regarding recycled carbon fuels and renewable liquid and gaseous fuels of non-biological origin on the carbon footprint results is examined. The RED-II assumption regarding the credits for captured CO₂ after 2041 indicate that DAC-based concepts are advantageous with respect to BFG, although the LCA results indicate the opposite. Using green hydrogen from nearby locations reduces carbon footprints more than faraway locations due to transport-related emissions.

Adhesive forces of micrometer-sized alumina (Al₂O₃) and polystyrene (PS) particles are investigated under elevated temperatures using a high-temperature atomic force microscope, where the smooth contact partner is heated. In the case of Al₂O₃ particles, only van der Waals interactions occur. The adhesive forces between PS particles and heated contact surface increase strongly starting from the glass transition temperature. An initial flattening of the particles up to melting at the contact point was detected. The adhesion forces can be described by means of a semi-empirical equation.

When utilizing industrial exhaust gases for methanol synthesis, catalyst poisoning is an important issue. Long-term in-situ poisoning under industrially relevant conditions with sulfur-containing molecules co-fed into the feed gas flow and supplemented by extensive post-mortem characterization of the catalyst bed is an efficient way to deepen the understanding of the poisoning mechanism and the different poisoning strengths of H₂S, thiophene, and COS reported in literature. Unfortunately, such studies are rare due to the corrosive effects of sulfur compounds on typical lab-scale flow setups. Therefore, this communication provides a detailed description of a setup built for poisoning studies using sulfur-containing molecules under industrially relevant methanol synthesis conditions.