University of Twente Student Theses


Impedimetric analysis of the activity of single fluid cracking catalyst particles

Hendrix, J.M. (2018) Impedimetric analysis of the activity of single fluid cracking catalyst particles.

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Abstract:Fluid catalyst cracking (FCC) particles are crucial for the transformation of crude oil into usable products. The particle acts as catalyst to convert large hydrocarbon chains into, for instance, gasoline. During the cracking process, FCC particles become deactivated due to the accumulation of material. This causes a reduced efficiency of the cracking process. In the current cracking process, it is not possible to selectively remove the deactivated particles. The possibility to detect FCC particle activity, by using the electrical impedance, was investigated in this thesis. Literature indicates a relation between the activity of FCC particles and the amount of metal that has been accumulated on the particle. Several models were made to relate this change in metal accumulation to a measurable impedance of a microfluidic sensor. These models show that it is most favourable to measure the high frequency capacitance of the particles, while using anisole as medium. The expected change in capacitance of this system was modelled to be between 7 and 12aF. To measure this change in capacitance, a lock-in architecture was designed with a noise level of 6.3aF. The system was tested, while using anisole as medium, by measuring both air bubbles and polystyrene particles. This resulted in expected system behaviour. During the final experiments, two categories of particles where measured: fresh and deactivated FCC particles. During these measurements, around 40 particles of each group where measured and video analysis was used to estimate the size of the particles. The experimental results were fitted into a cube function with respect to the particle radius. The experiments showed that impedance variations of FCC particles of the same category are more significant than impedance changes due to metal accumulation. Nevertheless, a correlation exists between the activity of a particle and the average impedance. For a particle with a radius of 40 micron, the experimental results showed an average difference in impedance between fresh and deactivated particles of 20.5F, which closely resembles the model results. Although more particles should be measured to verify this difference, the average impedance of Fluid cracking catalyst (FCC) could potentially be used to identify groups of reduced activity.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:35 chemistry, 53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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