Area of research:
Diploma & Master Thesis
The position is suitable for part-time employment.
The bioliq® concept developed at KIT is a three step conversion process for the production of 2nd generation drop-in biofuels from biomass waste, such as wheat straw. First, biomass is converted in decentralized fast pyrolysis units to yield energy dense biosyncrude, a mixture of bio-oil and char. This slurry is the feed for large scale pressurized entrained flow gasification operated at 8 MPa to yield producer gas free of tars. Finally, this gas is converted via DME synthesis to yield designer fuels.
The given task is set in the first step, fast pyrolysis. This initial conversion is performed in a twin-screw mixing reactor at 500 °C. The comminuted biomass feed is thermochemically converted to hot pyrolysis vapors, gas, and char fines within seconds. Solid char particles are separated by cyclones prior to a two-step condensation of the vapors yielding an organic and an aqueous condensate. The organic condensate represents the main product of this conversion step and the design of the product recovery is crucial for its quality. A major fraction of said organic condensate is present as aerosols after quenching.
The objective of this work is to investigate the influence of heat and mass transfer models/assumptions on the performance of a model that describes aerosol formation. This includes adapted heat and mass transfer models for the specific case (particles in a gas flow), consideration of intraparticle gradients and influence of aging effects. In order to create an efficient simulation environment, it is required to include existing Fortran subroutines that feature (among others) a thermodynamic model of pyrolysis oil phase equilibria into the latest version of AerCoDe 4.0, which is a simulation tool to describe aerosol formation. Currently, the number of components in the model is fixed and should be replaced by an adaptive version to increase model flexibility.