Experiments on a confined fluidized bed system with various shapes of particles have been presented in the paper. Its influence on hydrodynamic properties in the whole range of gas velocity has been analysed. Relations allowing calculation of the Richardson-Zaki-type equation coefficients, including description of inter-particle void and gas pressure drop in such systems have been determined. Necessary condition for confined fluidization of non-spherical coarse particles has also been determined.

In this study the authors minimise the total process cost for the heating of solid particles in a horizontal fluidised bed by an optimal choice of the inlet heating gas temperature profile and the total gas flow. Solid particles flowed along the apparatus and were heated by a hot gas entering from the bottom of the fluidised apparatus. The hydrodynamics of the fluidised bed is described by a two-phase Kunii - Levenspiel model. We assumed that the gas was flowing only vertically, whereas solid particles were flowing horizontally and because of dispersion they could be additionally mixed up in the same direction. The mixing rate was described by the axial dispersion coefficient. As any economic values of variables describing analysing process are subject to local and time fluctuations, the accepted objective function describes the total cost of the process expressed in exergy units. The continuous optimisation algorithm of the Maximum Principle was used for calculations. A mathematical model of the process, including boundary conditions in a form convenient for optimisation, was derived and presented. The optimization results are presented as an optimal profile of inlet gas temperature. The influence of heat transfer kinetics and dispersion coefficients on optimal runs of the heating process is discussed. Results of this discussion constitute a novelty in comparison to information presented in current literature.

The article presents the investigations of fluidized combustion of oily wastes derived from cold rollingmill process on a zeolite bed. Oily wastes generated in the rolling-mill process arc one of the most hazardous residues from metallurgical works because the toxic additives content. The experiments were carried out using a small laboratory combustor with full measurement equipment. The measurement apparatus associated with the combustion chamber made it possible to measure the basic parameters of the process including the composition of exhaust gasses. It has been shown that the combustion of oily wastes from cold rolling-mill process can be conducted efficiently and friendly for the environment.

The paper presents modeling and simulation results of the operation of a three-phase fluidized bed bioreactorwith partial recirculation of biomass. The proposed quantitative description of the bioreactor takes into account biomass growth on inert carriers, microorganisms decay and interphase biomass transfer. Stationary characteristics of the bioreactor and local stability of steady-stateswere determined. The influence of microbiological growth kinetics on the multiplicity of steady-states was discussed. The relationship between biofilm growth and boundaries of fluidized bed existence was shown.

The application of fluidized fly ash in underground mining excavations is limited due to its significant content of free calcium and calcium sulfate. In order to increase the amount of utilized fly ash from fluidized beds, it should be converted to a product with properties that meet the requirements for mining applications. This research presents the results of an attempt to adapt fluidized fly ashes for use in underground mining techniques, by means of carbonation and granulation. Carbonation was performed with the use of technical carbon dioxide and resulted in the reduction of free calcium content to a value below 1%. Granulation on the other hand, resulted in obtaining a product with good physical and mechanical parameters. The performed mineralogical and chemical studies indicate that trace amounts of “binding” phases, such as basanite and/or gypsum are present in the carbonized ash. The addition of water, during the granulation of carbonized fluidized fly ash, resulted in changes in the mineral phases leading to the formation of ettringite and gypsum as well as the recrystallization of the amorphous substance. It was confirmed that the carbonization and granulation of flying fluidized ashes positively affects the possibility of using these ashes in underground mining excavations.

The article presents investigation results of the effect of sand fluidization on the structure and mechanical properties of AlSi9 aluminum alloy. Castings were made by lost foam casting process with sand fluidization in mold at the stages of their solidification and cooling. Sand fluidization was achieved by blowing sand bed with compressed air in a foundry container. The metallographic study was carrying out on samples cut from different sections of the castings. Mechanical properties were determined on specimens made from cast samples. Microstructural analysis showed that sand fluidization increases the cooling rate, as a result, the main microstructural components of the alloy – SDAS, eutectic silicon and needles of the rich-iron phase – decrease. Moreover, in different sections of the casting structure is more uniform. With an increasing the air flow rate, a greater refinement of the structure is observed. Through the use of sand fluidization, the mechanical properties of LFC aluminum alloys increase to the level of gravity die castings.

The industrial grinding devices, which work in the high-energetic fluidized bed conditions make it possible to obtain guaranteed particle size distribution of product and decrease of consumption energy. The matrix model for transformation of particle size distribution in the fluidized bed opposed jet mill is presented in the part IV of article. The proposed model contains the mass population balance of particle equation, in which are block matrices: the matrix of circuit M, the matrix of inputs F and the matrix of feed F0. The matrix M contains blocks with the transition matrix P, the classification matrix C, the identity matrix I and the zero matrix 0. The matrix was marked using with discrete forms of the selection and breakage functions, mean while the matrices of classification - using the equation, describing classification of grains in the grinding chamber of mill. In paper was discussed this model in details (part 2.1). The correctness of received form of the selection and breakage functions was confirmed. The method determination of the transition matrix for fluidized-jet grinding of grains (part 2.2) and the classification matrix for gravitational and centrifugal zones of grains (part 2.3) are presented. The verification of model obtained on basis results with experimental investigations, which were performed on a laboratory fluidized bed opposed jet mill. The experiment contained grinding of selected narrow size fractions of limestone in turbulent fluidized layer conditions, what in part I and part II of article (Zbroński, Górecka-Zbrońska 2007a, b) are presented. The parameters of parametric identification were: factor of proportionality - contained in the equation on the discrete form of selection function and sizes of limiting grains - contained in equation on the diagonal elements of classification matrix for stage of gravitational and centrifugal (part 3). The classic Fisher-Snedecor test was applied for estimation of prediction particle size distribution of grinding product (part 4). The significant divergences between numerical and experimental results of particle size distribution weren't affirmed. The experimental verification, parametric identification and statistical estimation of the proposed model showed that this model make it possible to forecasting particle size distribution of grinding product.

The article deals with studying the hydrodynamic characteristics of the fluidized bed in gravitation shelf dryers. The algorithm to calculate hydrodynamic characteristics of the fluidized bed in the dryer’s workspace is described. Every block of the algorithm has a primary hydrodynamic characteristics theoretical model of calculation. Principles of disperse phase motion in various areas in the gravitation shelf dryer are established. The software realization of the author’s mathematic model to calculate disperse phase motion trajectory in a free and constrained regime, disperse phase residence time in the dryers’ workspace, polydisperse systems classification is proposed in the study. Calculations of disperse phase motion hydrodynamic characteristics using the software product ANSYS CFX, based on the author’s mathematic model, are presented in the article. The software product enables automating calculation simultaneously by several optimization criteria and visualizing calculation results in the form of 3D images. The disperse phase flow velocity fields are obtained; principles of a wide fraction of the disperse phase distribution in the workspace of the shelf dryer are fixed. The way to define disperse phase residence time91 in the workspace of the shelf dryer in free (without consideration of cooperation with other particles and dryer’s elements) and con-strained motion regimes is proposed in the research. The calculation results make a base for the optimal choice of the gravitation shelf dryer working chamber sizes.

The subject matter of the article comprises cement-bentonite-water hardening slurries with an addition of fluidized-bed fly-ash resulting from the combustion of hard and brown coal. The main objective of the study was to determine the filtration resistance of hardening slurries in the context of long-term exposure to the filtration of an aggressive substance in relation to a cement binder. A nitric acid aqueous solution with a concentration of 0.5 M was used, which modelled acid aggressiveness. The authors studied the hydraulic conductivity of the slurries as a function of time (18 months) for the exposure to a 0.5 M solution of nitric acid. Changes in the phase composition and hardening slurry surface structures were analysed in terms of their filtration resistance to the action of acid aggressiveness. The comparative base were samples subjected to filtration in tap water (neutral environment). The article reviews a methodology for studying hydraulic conductivity (k10) of hardening slurries. It also presents a study involving the phase composition using the X-ray diffraction analysis (XRD) method, infrared (IR) spectroscopy and showing an image of the hardening slurry surface structure. The findings of other researchers that the application of fluidized-bed fly-ash additives positively impacted improving the resistance of the cement matrix to acid aggressiveness were confirmed. The hydrated colloidal compounds, identified within the subsurface zone of the slurry, which has been in contact with an acidic environment, provide extra sealing of the material structure, thus significantly limiting the access of aggressive substance to the interior of the slurry.