Browsing by Author "Chinnaraj, Haripriya"

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Open Access
Powering the future : Germany's Wasserstoffstrategie in the transition to climate neutrality : case study on green hydrogen for the chemical industry
(2024) Seithümmer, Valentin Benedikt; Lutz, Julia Valentina; Kaufmann, Samuel Jaro; Chinnaraj, Haripriya; Rößner, Paul; Birke, Kai Peter
This article provides a comprehensive insight into Germany's transition to climate neutrality, bringing together the political framework of Germany's Climate Protection Act (CPA), the funding strategy of its key pillar, namely the “Wasserstoffstrategie” and the technical dimensions for non-technical stakeholders through a case study of Germany's largest current hydrogen user, the chemical industry. Increasing complexity of our modern economy and society and a lack of clarity in reporting contribute to misleading conclusions and can facilitate polarised views. To overcome that gap, we aim to draw a clear picture of these complex scientific topics and make them also accessible to non-technical stakeholders. This paper reviews Germany's climate policy, emphasizing the federal constitutional court's pivotal role. By calculating prospective GHG-reduction paths for Germany, we illuminate the gap between aspirational targets and practical strategies, emphasizing the need to translate global targets into actionable national plans. Taking the crucial, often-overlooked CO2-budget into account, potential shortcomings are revealed, even when annual emission goals are met by Germany. Shifting focus of this paper to the German hydrogen strategy, a core part of the Climate Protection Program, we reveal a strong emphasis on international collaboration. This involves a global hydrogen ramp-up and facilitation of hydrogen imports, offering trade opportunities but also introducing dependencies and potential price increases. A scale estimation case study on green hydrogen production for the German chemical industry underscores the rationale behind prioritising imports over domestic production. Calculating a demand of 7840 windmills (78.37 TW h) that require 168 000 football pitches (7000 m2 per pitch) of space, it provides easy to grasp insights into the necessary actions for a climate neutral Germany. This perspective frames Germany's climate goals, the Wasserstoffstrategie, and the technical scale of implementing renewables by conducting a case study on green hydrogen. Hereby, it highlights the magnitude of the climate problem and the immense scale of solutions required for a sustainable technical transition in a clear and sound manner.
Open Access
Reaction-engineering approach for stable rotating glow-to-arc plasma : key principles of effective gas-conversion processes
(2024) Kaufmann, Samuel Jaro; Chinnaraj, Haripriya; Buschmann, Johanna; Rößner, Paul; Birke, Kai Peter
This work presents advancements in a rotating glow-to-arc plasma reactor, designed for stable gas conversion of robust molecules like CO2, N2, and CH4. Plasma-based systems play a critical role in Power-to-X research, offering electrified, sustainable pathways for industrial gas conversion. Here, we scaled the reactor’s power from 200 W to 1.2 kW in a CO2 plasma, which introduced instability due to uplift forces and arc behavior. These were mitigated by integrating silicon carbide (SiC) ceramic foam as a mechanical restriction, significantly enhancing stability by reducing arc movement, confining convection, and balancing volumetric flow within the arc. Using high-speed camera analysis and in situ electronic frequency measurements, we identified dominant frequencies tied to operational parameters, supporting potential in operando monitoring and control. Arc-rotation frequencies from 5 to 50 Hz and higher frequencies (500 to 2700 Hz) related to arc chattering reveal the system’s dynamic response to power and flow changes. Furthermore, refining the specific energy input (SEI) to account for plasma residence time allowed for a more precise calculation of effective SEI, optimizing energy delivery to target molecules. Our findings underscore the reactor’s promise for scalable, efficient gas conversion in sustainable energy applications.