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Title: In-line continuous measurement of the size distribution of pneumatically conveyed particles using piezoelectric sensing and digital imaging techniques
Author: Gao , Lingjun
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2013
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Gas-solid two-phase flows are widely seen in many industrial processes. A good example of these is the pneumatically conveyed pulverised fuel (coal/biomass) flow in the power generation industry. In order to achieve efficient operation of a power plant it is desirable to monitor the physical characteristics of fuel particles. As one of the most important characteristics, particle size distribution should be monitored to increase combustion efficiency, to minimise pollutant emissions, and to reduce milling cost. This thesis describes the design, implementation and experimental evaluation of two prototype instrumentation systems for in-line, continuous size measurement of pneumatically conveyed particles. A review of methodologies and techno logies for the in-line measurement of particle size distribution is given, together with the discussions of existing problems and technical requirements in their applications. Based on this review, a particle impact sensing system using a piezoelectric film sensor incorporating particle impact modelling and signal processing algorithms is proposed. Experimental results obtained on a laboratory test rig demonstrate that the system is capable of measuring particle size distribution and can be used to provide an assessment of flow characteristics wider various flow conditions. The system also demonstrates that this technology is practical and operational on a full-scale power plant. Additionally, the thesis also reports the latest development in particle imaging technology. A novel particle imaging system using multi-wavelength illumination sources is designed and implemented. Experimental results on a laboratory-scale rig show that the multi-wavelength design has increased the coverage of flow field and improved the system repeatability compared to the single-wavelength system. Finally, the particle impact sensing system and particle imaging system have their own advantages and limitations and both require further research. The work reported in this thesis offers a foundation for future in-line measurement of particle size distribution and demonstrates the potential of the proposed techniques.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available