Modelling and experimental investigation of gas-solid flows in circulating fluidized beds
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Modelling and experimental investigation of gas-solid flows in circulating fluidized beds
Mon, 09/06/2014 - 13:15 to 14:00
Location:
Speaker:
Prof. Haigang Wang
Affiliation:
Institute of Engineering Thermophysics, Chinese Academy of Sciences
Synopsis:
Circulating fluidized bed (CFB) is one kind of clean coal combustion technologies which plays an important role in the power generation and coal gasification industry. Large thermal capacity and high steam pressure is a tendency for the development of CFB boilers. To meet the demands for high steam parameter and large thermal capacity, high efficiency of gas-solid separation is a key to achieving high combustion efficiency, reducing limestone consumption and NOx emission. Over the past two decades computational fluid dynamics (CFD) and electrical capacitance tomographic (ECT) techniques have been developed to see inside particle processes, and the knowledge gained from such studies has improved energy efficiency and product quality. Examples from industrial research with different scale of CFB system are presented to illustrate the use of CFD and ECT in challenging particle process measurements. Further, a new approach based on computational particle fluid dynamic (CPFD) method combined with electrical capacitance tomography (ECT) is presented to investigate the hydrodynamic behavior of gas-solid flow in a CFB with six cyclone separators in order to improve the design and performance of a large scale CFB boiler.
Biography:
Prof. Haigang Wang received his Ph.D from the Institute of Engineering Thermo-physics, Chinese Academy of Sciences (CAS) in 2003 and a CAS President Award. He is member of AIChE and IEEE. His specialty is in the areas of CFD simulation, mathematical modelling, and 2D and 3D ECT for multi-phase flows measurement, e.g. gas-solids circulating fluidised beds in the power industry, and fluidised bed dryers in the pharmaceutical industry. During the past few years, he participated in several key projects, e.g. “Numerical study of air flow and heat transfer in gravel embankments in the permafrost areas by FEM”, and “Gas-solids flows in circulating fluidised bed by ECT”. For these projects, he developed a novel approach to multi-phase flow measurement based on ECT and numerical models, aiming to investigate the complex gas-solids behaviour and to measure solids concentration and solids mass flow rate. He used a conical ECT sensor to measure the gas-solids flows in cyclone separators, and reconstructed 3D images. He also measured the solids flow rate in diplegs of circulating fluidised beds, based on ECT and cross-correlation. Since 2005, he has been working on two projects supported by EPSRC in UK. He is a key investigator in the above projects, aiming to achieve product quality control of particles by combining modelling, imaging and distributed control. He has published more than 80 peer reviewed journal and international conference papers and granted an international patent. Some recent results on wet granular flow behaviour, fluidised bed drying, mathematical modelling and online measurement of moisture by tomography imaging have been published in high-impact Journals (like AIChE, Chemical Engineering Science, Measurement Science and Technology, IEEE Sensor Journal), which have received strong interests from industry, e.g. AstraZeneca, GEA pharmaceutical Company.