10th GERG Young Researchers’ Awards

Every one or two years, the European Gas Research Group (GERG) organises a competition to highlight the current work by postgraduate students in the field of renewable or other low carbon gases.

One of the three winners of the 10th GERG Young Researcher's Award is Robin Beckmüller from the Chair of Thermodynamics. He was honored for the progress he made in his doctoral thesis entitled "New Fundamental Equations of State for an Improved Description of Hydrogen-Rich Mixtures with the Reference Model GERG-2008".

Eickhoff-Prize

Since 1989, the Eickhoff company has donated one prize each to the Faculty of Electrical Engineering and Information Technology and the Faculty of Mechanical Engineering for outstanding scientific achievements in the doctoral process.

This year, Johnny Chhor (left) and Tobias Neumann (right) have been awarded. Tobias Neumann completed his doctocal thesis entitled “Accurate Description of Mixtures with Minor Components Relevant for CSS Including a New Approach for Reactive Mixtures” at the chair of thermodynamics of RUB.

Model for Gas Solubilities in Seawater

A model was developed to calculate gas solubilities in seawater-like solutions:
The model presented is a combination of a mixture model in the form of the Helmholtz energy and an equation in the terms of the Gibbs energy. The combination allows the quantification of the effect of salt on the solubilities of combustion gases in water. This approach can be used to model the storage of CO2 in saline aquifers, which is captured from combustion gases in the course of CCS (Carbon Capture & Storage). This allows a consistent simulation of the CCS transport and storage processes with Helmholtz equations.

Equation of State for ​Vinyl Chloride

A fundamental equation in the form of the Helmholtz energy for vinyl chloride has been published in the literature for the first time. The article appeared in the International Journal of Thermophysics.

Accurate thermophysical property data are important for the optimal design of production processes. This publication includes an equation of state that can reproduce the underlying experimental data within its measurement uncertainty. This work, combined with other equations from the literature, provides industry with a complete set for modeling the vinyl chloride manufacturing process. ​

International Cooperation

To access the key role of sorption effects in pyrolysis and char conversion of solid biomass fuels in an oxyfuel atmosphere, a pore-structure dependent kinetic (PSK) adsorption model for the prediction of adsorption and diffusion of relevant oxyfuel agents was developed within the project oxyflame. On basis of already derived parameter sets for the adsorption of O2 and CO2, the model is validated with the measured adsorption kinetics of water vapor. The experimental investigations are performed by Dr. Horacio A. Duarte from the Texas A&M University in cooperation with Tim Eisenbach (RUB). Dr. Horacio A. Duarte is spending 5 months as a guest-researcher at the chair.​

Thermodynamic Properties of Methyl Dienthanolamine

In cooperation with the Paderborn University and the TU Berlin, density and speed of sound measurements for methyl diethanolamine were conducted in wide temperature and pressure ranges. Based on these data and all other thermodynamic property data available in the literature an equation of state in terms of the Helmholtz energy was developed.
The experimental data and the equation of state are published in the International Journal of Thermophysics and are available open-access thanks to Projekt DEAL: https://doi.org/10.1007/s10765-021-02933-7

Speed of Sound Measurements and a Fundamental Equation of State for Propylene Glycol

Highly accurate speed of sound data for liquid propylene glycol were measured using the pulse-echo technique. These data were subsequently used to develop a fundamental equation of state in terms of the Helmholtz energy. For the first time, it allows accurate and consistent calculation of all thermodynamic state variables of propylene glycol.
This equation was developed in cooperation with the NIST (Boulder, USA) and has been published in the Journal of Physical and Chemical Reference Data: https://doi.org/10.1063/5.0050021

Virtual Symposium 2021

Every three years the National Institute of Standards and Technology (NIST), the ASME and the AIChE organize the Symposium on Thermophysical Properties in Boulder, Colorado – the most important international conference for the property related research at the chair of thermodynamics. In normal times the chair has always been represented by several researchers presenting talks and posters in Boulder. However, times are not normal. This year, the thermodynamics team of RUB could only present its results virtually. But still one statement holds (once more): our team was among the most represented groups worldwide.

International Cooperation

The circular use of nitrogen as an important plant nutrient plays an essential role in the transition to a sustainable economy. The Adsorption of nitrogen at chars can distribute to this goal. A cooperation between the chair of thermodynamics and the Future Energy Center of Mäladalens Högskola (MDH) aimes to characterize pyrochar, hydrochar, and lignite towards their suitability as adsorbents as well as their influences on anaerobic digestion. The experiments are conducted by Sebastian Schwede (MDH) and Anna Leithäuser (RUB), who is spending a four-month research stay at the MDH in Sweden. The project is funded by the DS CCCE and a scholarship from “The foundation of dentist Gustav Dahls memory”.

Methods for micropore analysis by CO2 adsorption

Within the framework of the SFB/TRR 129 Oxyflame, we performed a systematic comparison of models for micropore analysis of biomasses using CO2 adsorption and published it in Energy & Fuels (https://doi.org/10.1021/acs.energyfuels.1c00280). The results of the Dubinin-Astakhov (DA) and Dubinin-Radushkevich (DR) models were compared with the non-local density functional theory (NLDFT). By using the following share link, the publication can be downloaded free of charge (limited to 50 accesses): https://pubs.acs.org/articlesonrequest/AOR-FEAR9YA2HNUZ2JH76VQC

Equations of State for hydrogen-rich Mixtures

As a partner of the Fraunhofer High-Performance Center DYNAFLEX and member of the ACT ELEGANCY project, we have developed new equations of state for hydrogen-rich mixtures in cooperation with the National Institute of Standards and Technology (Boulder, USA), which have been recently published in the Journal of Physical and Chemical Reference Data: https://doi.org/10.1063/5.0040533
The mixture models for the binary systems H2+CH4, H2+N2, H2+CO, and H2+CO2 are formulated in terms of the Helmholtz energy and allow for accurate calculations of the thermodynamic properties of hydrogen-rich natural gas mixtures.

Density Measurements of Amines

We measured densities of monoethanolamine and diethanolamine and published them open-access in the International Journal of Thermophysics, thanks to Projekt DEAL: https://doi.org/10.1007/s10765-021-02808-x 
In the scope of the present study, a vibrating-tube densimeter (VTD) was utilized to measure densities at temperatures up to 423 K and pressures up to 90 MPa. The familiar setup of the VTD was modified to enable measurements of liquid DEA, due to its melting point which is significantly above ambient temperature. The newly gained datasets provides the only densities for pressures above 0.7 MPa and cover wide ranges of temperature.

Speed of Sound Measurements in Methanol

Following the publication of densities of methanol, we additionally provide speeds of sound in methanol, now published in the International Journal of Thermophysics and available open-access thanks to Projekt DEAL: https://doi.org/10.1007/s10765-021-02811-2 
The utilized speed of sound apparatus employs the double-path length puls-echo technique. Here, the time difference between two captured echoes is determined after unequal path-lenghts are covered. The newly gained dataset complement the data situation available from literature and insists to advance the development of a new equation of state.

Density Measurements of Methanol

We provide density measurements of methanol and related correlation equations, developed in cooperation with the Chemnitz University of Technology, recently published in Industrial & Engineering Chemistry Research: https://doi.org/10.1021/acs.iecr.0c06248 
In the scope of the present study, a vibrating-tube densimeter was utilized to measure densities at temperatures up to 423 K and pressures up to 90 MPa. Additionally, equations of two different approaches were correlated to the newly gained dataset and allow the calculation of densities in methanol over wide ranges of temperature and pressure.

Speed of Sound Measurements in Alkanes

In cooperation with the Chemnitz University of Technology speed of sound measurements in n-hexane and n-heptane were published in the International Journal of Thermo-physics and are available open-access thanks to Projekt DEAL: https://doi.org/10.1007/s10765-020-02778-6
The utilized speed of sound apparatus employs the double-path length puls-echo technique. Here, the time difference between two captured echoes is determined after unequal path-lenghts are covered. The newly gained datasets complement the data situation available from literature and advance the development of new equations of state.

Heat transfer coefficients in highly viscous mixtures

In cooperation with the Chemnitz University of Technology and the Dutch Metrology Insitute VSL, a study on the application of different liquefaction techniques for natural gases was conducted as part of the EMPIR LNG III project. Now it was published open-access in the AIChE Journal (https://doi.org/10.1002/aic.17128).​
In this study, we present the design of a reference liquefier that prevents a compositional distortion of the liquefied sample via a supercritical liquefaction technique. Moreover, the applicability of condensation for liquefaction as an alternative method was assessed by experimental investigations and VLE calculations.​

Study on the laboratory-scale liquefaction of natural gases

In cooperation with the Chemnitz University of Technology and the Dutch Metrology Insitute VSL, a study on the application of different liquefaction techniques for natural gases was conducted  as part of the EMPIR LNG III projekt. Now it was published open-access in the AIChE Journal (https://doi.org/10.1002/aic.17128).
In this study, we present the design of a reference liquefier that prevents a compositional distortion of the liquefied sample via a supercritical liquefaction technique. Moreover, the applicability of condensation for liquefaction as an alternative method was assessed by experimental investigations and VLE calculations.

International Cooperation

Thermophysical properties play an important role in all industrial processes and are addressed in research projects both at RUB, SINTEF Energy Research and the Norwegian University of Science and Technology (NTNU). For accurate viscosity measurements of binary (H2 + CO2) and (H2 + CH4) mixtures, an international cooperation has been initiated between a current project carried out in the thermodynamic laboratory of RUB, funded by the Fraunhofer High Performance Center DYNAFLEX, and a project at SINTEF and NTNU, which is part of the framework of the Norwegian CCS Center (NCCS). As part of this cooperation, measurements are carried out by Benjamin Betken (RUB) and Bahareh Khosravi (NTNU), who is currently at RUB for a four months research stay.

New kinetic adsorption model published

Within the SFB/TRR 129 Oxyflame, a new adsorption model was published in the journal "Chemical Engineering Science" (https://doi.org/10.1016/j.ces.2020.116281). The pore-structure dependent kinetic adsorption (PSK) model allows the time-resolved determination of mass transport coefficients, effective diffusion coefficients, and adsorption flow rates.