Sewage sludge combustion

Numerical simulation of the gas-solid flow in a fluidized bed by combining discrete particle method with computational fluid dynamics

Modeling of biomass gasification in fluidized bed

Pyoclastic density currents are awesome volcanic phenomena that can wreak destruction on a regional scale and can impact global climate. They deposit ignimbrites, which include vast impact lansdscape-modifying sheets with volumes exceeding 1000 km3.This book takes stock of our understanding of pyroclastic density currents and presents a new conceptual framework for investigating how ignimbrites are deposited. It integrates the results of field-based studies, laboratory experiments and numerical modelling, including work on clastic sedimentologym and industrial particle transport. Topics covered include the behaviour or particulate currents, mechanisms of clast support and segregation, interpreting ignimbrite lithofacies and architectures, and future research directions. The new approach focuses on processes and conditions within the lower flow-boundary zone of currents. Superb diagrams explain many new concepts, while the 95 photographs make an explanatiry atlas of deposit types. This is essential reading for workers investigating volcanic hazards, and for anyone wishing to interpret modern or ancient ignimbrites, as well as other catastrophically emplaced sediments.

“Given the depth of scholarship that they have brought to the subject, the power of their arguments, and the degree of synthesis with other fields, this would seemto qualify as a seminal work… I think that this will be the paper on the topic that others will have to contend with for many years to come.” Marcus Bursik, State University of New York

Pyroclastic density currents and the sedimentation of ignimbrites

Heterogeneous Kinetics of Coal Char Gasification and Combustion

A generalized method for predicting the minimum fluidization velocity

Bubble size is one of the most important parameters in the design and simulation of a fluidized-bed reactor.

A correlation of the bubble size and growth in fluidized beds of various diameters is developed. A maximum bubble diameter determined from the bubble coalescence is incorporated in the correlation to relate the effect of the bed diameter on the bubble size.

Experimental data of bubble size reported are used to develop and test the validity of the correlation. The bubble diameters calculated using this correlation show good agreement with the observed bubble diameters.

Estimation of bubble diameter in gaseous fluidized beds

Longitudinal liquid mixing in fluidized and fixed beds was studied using sinusoidal and pulse response techniques. The tracer used was light emissive fluorescein dye. A systematical study of liquid phase dispersion by varying particle size, fluid velocity, fraction voids, and particle density was conducted. A generalized correlation applicable to both fixed bed and fluidized bed was obtained. The application of the correlation in predicting the effect of the dispersion on reactor performance was discussed.

Longitudinal dispersion of liquid flowing through fixed and fluidized beds

Kinetic and diffusion models for gas-solid reactions in spherical particle, comparing core shrinking mechanism and activation energies

Comparison of kinetic and diffusional models for solid-gas reactions.

A model describing the entrainment of solid particles in the freeboard region of a fluidized bed is proposed. Published experimental data have been used to correlate the entrainment rate near the bed surface and the elutriation rate above the bed. It has been shown that the column diameter can have an important influence on the amount of fines elutriated.

C. Y. Wen

Papers

A generalized method for predicting the minimum fluidization velocity

Estimation of bubble diameter in gaseous fluidized beds

Longitudinal dispersion of liquid flowing through fixed and fluidized beds

Comparison of kinetic and diffusional models for solid-gas reactions.

Fluidized bed freeboard phenomena: Entrainment and elutriation