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Title: Experimental, numerical and analytical study for the improvement of biomass fluidized bed gasifiers
Author: Al-Akaishi, Ahmed
ISNI:       0000 0004 7652 2219
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2018
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The gasification of biomass is considered one of the most important sources of renewable energy due to the sustainability of agriculture waste around the world. There are many types of gasification systems depending on the mechanism of gasification. BFBG is one of the powerful gasifiers due to the mixing mechanism between the solid materials (biomass and the inert material) and the gas phase (air). Gasification process in the BFBG involves three main interactive factors: hydrodynamics, heat transfer and chemical reaction. The present work focuses on improving the hydrodynamic performance and the product gas quality of a new BFBG developed at Cardiff University. Hydrodynamics has been analysed experimentally and numerically using four different distributors designed to improve the fluidized bed fluidic patterns. The tests have been performed experimentally using a representative perspex prototype, while an isothermal 3D unsteady-state CFD simulation by using OpenFOAM software based on multiphase resolution was employed in order to select the optimal design that can improve the system performance. The post improving of the BFBG product gas with catalyst has been analysed numerically by using ASPEN PLUS software. The hydrodynamic behaviour of the BFBG with four different air distributors was studied experimentally in terms of pressure drop and bubble formation. Two design factors were observed as the major contributors towards the impact on the BFBG performance, i.e. the orifice size and the distribution of orifices. Small orifices with triangular arrangement have demonstrated superior performance than large orifice size with square arrangement. Similar findings were obtained from the CFD simulation of the BFBG with the four distributors with an accepted comparison with the experimental results and literature. Regarding the post -gasification improvement, ASPEN PLUS analysis showed the using of BFBG product gas with suitable amount of N2 and Ar can increase the H2 and CO selectivity, H2/CO ratio and decrease the heat duty. The analysis results were compared with literature.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available