Chemie Ingenieur Technik最新文献

Reactive silica materials like vitreous silica or cristobalite were dissolved at temperatures between 100 and 220 °C for up to 7 days in NaOH lyes. The liquid and solid reaction products were analyzed chemically. Sodium water glasses with silica concentrations of up to 27 wt % and molar SiO₂/Na₂O ratios of up to 3.7 were obtained. The experimental data were evaluated by an approximation algorithm. The initial size reduction rates ranged between 0.1 and 7 µm h⁻¹, depending on the temperature and the choice of starting materials. Correlations between thermodynamics and kinetics were discussed.

As part of the joint research project Carbon2Chem^®, mathematical models are used to simulate operating scenarios of cross-industry networks, in particular chemical plants in industrial environments with high CO₂ emissions. In this context, a cloud-based distributed co-simulation is used to enable the parallelized simulation of a large number of different variants. This enables optimal design of the plant networks and the efficient determination of optimal operating conditions. The architecture of this approach is described, and its performance is examined and evaluated.

Heat transfer in evaporation units play a vital role in the design and optimization of heat pumps and refrigeration systems. Existing correlations are often limited to the respective heat transfer surface. Furthermore, the majority of correlations reported have a lack of reliable validation beyond the test of their ability to describe the data they have been fitted to. In the present study, the heat transfer in case of flooded evaporation on an enhanced tube was examined for two refrigerants and propane. The experimentally measured data were used to develop a new correlation for the shell-side heat transfer. The correlation was assessed on a separate test set, not utilized in the process of model development. The correlation and procedure are reliable and transferable tools for estimation of heat transfer in enhanced tube evaporators for refrigerants.

Carbon is a key element in industrial production, but CO₂ is also a greenhouse gas whose release into the atmosphere must be avoided. If its generation cannot be avoided for process-related reasons, then a comprehensive carbon management is required to enable climate-neutral production in industry. In the Carbon2Chem^® project, partners from industry and science are successfully researching technical components that enable the implementation of concepts for CO₂ capture and utilization (CCU) as part of carbon management.

A fluid mechanics course in process engineering designed according to the students’ wishes mixes lecture and exercise in co-teaching and flipped-classroom elements with gamification. The effectiveness increases as the number of points achieved in the exam increases by 31.9 % compared to the average of the four previous years. The withdrawal rate drops from 54.8 % to 17.4 % and the failure rate from 38.7 % to 23.7 %, which enhances efficiency. The students’ self-report shows a better preparation to the course sessions, but they do not feel stressed much additionally. About 80 % of the initially attending students participate at the end of the course.

In the processing of construction waste, the sorting of the delivered mixtures is one of the decisive process steps in order to produce recyclates that can be reused. In the fine-grain range, there is a lack of suitable processes for this. A procedure that has not been investigated so far is to separate concrete-mortar-brick mixtures on the basis of the magnetic susceptibility. Based on measurements of the susceptibility, sorting experiments were carried out using a rare earth roll magnetic separator. The positive results of the experiments described here call for further investigation of the performance of the sorting method.

Fouling on column internals leads to many malfunctions in chemical processes every year. Despite the importance for the industry, only a few systematic studies exist on the fouling of column internals. Here, a new screening test rig is presented for the rapid and easy characterization of a wide range of internals with respect to their fouling tolerance. A countercurrent of saturated NaCl/water solution and air is used to force crystallization fouling. Photographs help to identify the initial points of fouling on two random packings and provide insights into the growth of deposits. In addition, the fouling tolerance of five different trays is investigated, demonstrating that trays with larger curtain area show greater fouling tolerance.

The energy transition in Germany requires a high amount of new wind turbines and photovoltaic power for supply of new electricity consumers for heat and traffic. In addition, high electricity demand for production of hydrogen has to be supplied. The corresponding planning for transmission system extension does not take into account economic and environmental burden. As an alternative to the planned oversized transmission grid extension, a second bidding zone for Germany is suggested.

Micro heat exchangers improve heat and mass transfer compared to conventional heat exchangers, enabling more energy-efficient applications. However, their sensitivity to fouling limits broader industrial application. This approach presents a combined investigation of fouling and cleaning in microscale heat exchangers using two test rigs. Individual sets of analysis methods are developed to improve the understanding of heat and mass transfer on the microscale. In addition to known methods, such as pressure loss analysis, newly developed and established image analysis techniques are used to monitor fouling and cleaning. Based on the presented methods, it is possible to predict the initial position of thermally induced fouling and to demonstrate the applicability of automated cleaning on the microscale.

Based on the scenario framework 2023‒2037/2045 [1] approved by the German Bundesnetzagentur für Elektrizität, Gas, Telekommunikation, Post und Eisenbahnen, a possible picture of the energy landscape for the case of a completely defossilized energy supply was drawn up with the help of hourly resolved producer and consumer profiles. On this basis, the question was addressed as to whether the hydrogen required for this should be produced domestically and how much decentralized, household-based seasonal storage would relieve the low-voltage grids. An estimate provides reference values for the financial expenditure and the area required to achieve this goal.