Characterization of Gas-Solid Injection into Fluidized Bed Reactors for Biomass Residues Valorization

The use of biomass/biomass residues as feedstocks for bioenergy and biofuel processes is of rising interest for climate change mitigation. Thermochemical conversion of biomass in fluidized bed reactors, through pyrolysis, gasification, and combustion, requires efficient feedstock penetration and mixing through reliable feed injection systems. Pneumatic biomass injection produces a gas-solid jet in the reactor that requires proper momentum to disperse the feedstock. Nevertheless, assessing multiphase jet penetration in fluidized beds is challenging because of the complex and opaque systems with rapid interactions of the jet and the bed bubbles, and because of the many experimental challenges to characterize gas/particles flows. 
In this PhD project, biomass residues will be used as feedstocks to investigate the jet penetration and mixing in fluidized beds at ambient and reaction conditions. The PhD student will perform experiments at ambient conditions with different pneumatic injectors coupled to a fluidized bed of 20 cm. The gas-solid flow can be evaluated with a high-speed camera and the jet penetration in fluidized beds of Geldart A and B powders will have to be measured with different techniques, such as optical, pitot, capacitance, and fluorescent probes. From this, the injector design and testing conditions can be proposed for biomass penetration experiments in reaction environments, such as gasification and combustion. A hot fluidization unit can be used by the PhD student at the Hamburg University of Technology (Germany), which can achieve 950°C and has a similar diameter than IFPEN’s cold-flow unit.
From this experimental campaign, empirical models and operation maps should be developed for pneumatic biomass injection and jet penetration for a wide range of operating conditions. Furthermore, the experimental data can be used for CFD model validation at IFPEN and, subsequently, for developing scale up rules for proper biomass injection and mixing at industrial scale.

Keywords: Fluidization, Biofuel, Bioenergy, Pneumatic Conveying, Combustion, Gasification, CFD

• Academic supervisor    Prof Frederic AUGIER, IFPEN, ORCID: 0000-0003-1640-4360 and Prof Stefan HEINRICH, TUHH, ORCID: 0000-0002-7901-1698
• Doctoral School    ED162 MEGA, University Lyon 1, Claude Bernard
• IFPEN supervisor    Dr Lucas MASSARO SOUSA, ORCID: 0000-0002-4182-9347, and Dr Benjamin AMBLARD
• PhD location    IFPEN (Solaize, France) with 6 months in TUHH (Hamburg, Germany)
• Duration and start date    3 years, starting in fourth quarter 2024 (4 November)
• Employer    IFPEN
• Academic requirements    University Master degree in chemical engineering or fluid mechanics
• Language requirements    English level B2 (CEFR)
• Other requirements    Interest for experimentation and modelling would be appreciated  (background on fluidization, CFD tools and/or biomass valorization).

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.