This PhD project focuses on the thermo-chemical conversion of CO₂ to syngas, which is a mixture of CO, CO₂, H₂,  small  amounts  of  higher  hydrocarbons  and  H₂O. The CO₂ is  fed together with steam or in pure form into a fluidized bed gasifier, where biomass is converted to a high-value syngas. In this process, the end product CO₂ is converted to CO which is the carbon source for further synthesis routes. This syngas is further used for the production of biofuels, synthetic natural gas, fine chemicals, proteins or nutrients in the  other  PhDs  theses  of  this  doctoral  college.  Therefore,  it  is  import  to  have  knowledge  about  the  downstream processes of syngas utilization and its optimal composition as well.

In close interaction with PIs and PhD students within this doctoral college, suitable syngas compositions will be evaluated, and the CO₂ biomass gasification process integrated in the CO₂Refinery. The aim of this PhD project is to optimize the  operation  parameters  during  CO₂  gasification  to  increase  the  CO₂  conversion  and  carbon  utilization  efficiency.

PhD student: Florian Müller

Supervisor: Franz Winter
Co-Supervisors: Stefan Müller

The project concerns thermochemical energy storage in combination with sCO₂-power cycles. In a first step thermochemical energy  storage  concepts,  based  on  decarbonization  /  carbonization  of  metal  oxides  shall  be  analyzed.  Additionally, even other thermochemical storage materials for Power2Heat2Power(P2H2P)-concepts will be taken into consideration. An important measure is their applicability for the combination with sCO₂-cycles.  After  selecting  the  most  interesting  cycles  they  will  be  modelled  and  simulated  by  using  a  stationary process simulation software, e.g.  IpsePro or Ebsilon.  The different cycles will be evaluated according to technical and economic aspects.

PhD student: Leisan Mukhametshina

Supervisor: Andreas Werner
Co-Supervisors: Franz Winter, Michael Harasek

Upgrading of CO₂ into fuels, chemicals, and feed products is of key interest in a CO₂Refinery. Platform chemicals can be synthesized using chemical or biological catalysts directly from crude gas streams. Using this integrated chemo-biological refining approach, bulk and fine chemicals, fuels, energy carriers and feed will be generated as end-products. The main topic of this PhD project is the development of catalytically active polymeric hollow-fibre membrane reactor, with direct applicability for low-temperature CO₂ conversion.

PhD student: Julia Kalarus

Supervisor: Katharina Schröder
Co-Supervisors: Franz Winter, Michael Harasek, Karin Föttinger

A variety of microorganisms can utilize CO₂ as source for biomass growth and metabolite formation. This project  will  use  CO₂,  CO  and  H₂  from  gasification  of  plant  biomass  and  industrial  sources  as  alternative  carbon and energy sources to produce value-added chemicals and fuels. In addition, CO₂-derived methanol obtained via chemical synthesis will be used as a co-substrate in microbial fermentations. Finally, wildtype and genetically engineered acetogenic hosts will be used to develop continuous bioprocessing strategies for efficient autotrophic and mixotrophic production of chemicals.

PhD student: Ivo van den Hurk

Supervisor: Stefan Pflügl
Co-Supervisors: Matthias Steiger

The conversion of CO₂ to value-added platform chemicals such as methanol provides a route to address global climate change but also to reduce the dependency on fossil fuels. In this respect, catalysis plays a key  role.  This  PhD  thesis  is  dedicated  to  catalyst  development  for  CO₂  conversion,  preferentially  to  methanol,   by   combining   synthesis,   materials   characterization,   reaction   kinetics,   and   operando   spectroscopy. Fundamental insights into the elementary reaction steps occurring at the catalyst surface will be the basis for a rational design and improvement of the catalytic materials.

PhD student: Gustavo Alves

Supervisor: Karin Föttinger
Co-Supervisors: Thomas Konegger, Franz Winter, Christoph Rameshan

Microorganisms have the ability to assimilate different C1 molecules including methanol, formate or CO₂ into  their  biomass.  Methanol  is  a  promising  intermediate  chemical  as  it  can  be  produced  from  CO₂  and hydrogen streams or by direct electrolysis of CO₂. It can serve as base chemical, fuel or as a substrate for microbial fermentation. Methylotrophic yeasts like Hansenula polymorphacan grow on methanol as sole carbon  source  and  using  metabolic  engineering  approached  various  chemical  compounds  can  be  produced.

PhD student: Roghayeh Shirvani

Supervisor: Matthias Steiger
Co-Supervisors: Stefan Pflügl, Thomas Konegger

The aim of this PhD project is to optimize the production of synthetic natural gas (SNG) suitable for gas grid feed-in with variable gas mixtures derived from CO₂ gasification with focus on high CO₂ contents in syngas.  Thereby,  the  fluidized  bed  catalysts  shall  be  developed  with  increased  attrition  resistance  and  enhanced  CO₂  conversion,  maximized  carbon  conversion  by  variable  syngas  compositions  and  limited  carbon  deposition  on  the  catalyst  surface.  Basic  research  for  parameter  variation  of  e.g.  reactor  design, gas hourly space velocity, process temperature, process pressure and testing of different catalysts shall be conducted.

PhD student: Alexander Bartik

Supervisor: Stefan Müller
Co-Supervisors: Michael Harasek, Florian Benedikt

Chemical conversion processes, in particular with regard to CO₂ utilization, typically take place at elevated temperatures and/or under chemically demanding conditions. Ceramics are ideal framework materials – e.g.  as  substrates  or  carriers  –  for  catalytic  reactions  and  biosynthetic  processes  due  to  their  excellent  thermal  stability,  chemical  and  biological  inertness,  and  corrosion  resistance.  This  project  involves  the  development  of  porous  ceramics  with  tailored  pore  structures  suitable  for  a  variety  of  CO₂  utilization processes, employing new methodological approaches.

PhD student: Katharina Rauchenwald

Supervisor: Thomas Konegger
Co-Supervisors: Karin Föttinger, Matthias Steiger

Process  simulation  allows  the  steady  state  or  dynamic  representation  of  complex  multistage  process  routes at unit operation level. Considering thermodynamics of separation and reaction processes, material and  energy  balances  are  calculated  to  find  optimal  combinations  of  process  units.  In  the  context  of  CO₂refinery,  upstream  processes  to  produce  CO₂,  reaction  processes  to  convert  CO₂  to  valuables,  and  downstream processes to separate the valuables including recycles and by-product treatment have to be implemented into the process simulator. Due to frequent temperature changes along the process routes, energy integration is a key success factor for the selection of favourable process routes reducing energy consumption  and/or  energy  storage  needs.  With  key  process  parameters,  the  material  and  energy  balances at hand, the environmental impact of process routes from cradle to gate or even from cradle to grave  can  be  calculated.  Usually,  life  cycle  analysis  fed  with  balancing  data  from  process  simulation  or  experiments is the common approach in this context.

For technologies in stages of early development (low technology readiness level, TRL) as targeted in the proposed  PhD  works  #1  to  #7  of  CO₂Refinery,   special  care  must  be  taken  in  LCA  studies,  since  most  reference technologies are mature and have been optimized over decades. In contrast, low TRL processes usually  have  higher  energy  demand  or  solvent  consumption  because  of  not  yet  established  heat  integration and/or process optimization.

PhD student: Diana Dimande

Supervisor: Michael Harasek
Co-Supervisors: Bettina Mihalyi, Walter Wukovits

Carbon  dioxide  utilization  for  the  production  of  fuels,  chemicals  and  materials  has  the  potential  to  decrease CO₂ emissions and reduce fossil fuel consumption. It is likely that CO₂ utilization can be used as a CO₂ mitigation tool helping us to reach European emission reduction goals. However, for the broader implementation of this strategy, it is important to reach economic competitiveness of carbon utilization processes, as well as to ensure clear environmental benefits in the whole supply chain.

PhD student: Frank Radosits

Supervisor: Amela Ajanovic
Co-Supervisors: Reinhard Haas