Changes in the physical properties (such as particle density, bulk density of the bed, shrinkage and bed porosity of fresh green peas particulates were compared at 50 o C, during fluidized bed drying and fixed bed drying. Empirical relationships of the following nature were developed for the changes in shrinkage [VR = A + B MR], particle density [ρ p = A + B MR + C exp (-DMR)], and bulk density...

One significant factor in the operation of a fluidized bed combustor is the manner in which coal particles disperse and mix with the bed material upon entering the bed. A thermal tracing technique was used to study the mixing characteristics in a 1/4 scale model of a pressurized bubbling fluidized bed combustor. Particles cooled by liquid nitrogen are injected into the bed in the same way that ...

conclusions results indicated that annular fluidized bed reactor’s adsorbers are useful techniques for vocs adsorption. comparison of two particle ranges indicates that in all concentrations and all flow rates of the experiments, smaller particle size adsorption are better. in superficial velocity above the minimum fluidization velocity, pressure drop of fluidized beds are less than the pressur...

In order to operate a process which uses immobilized enzymes at constant conversion and constant capacity, the refreshment of the enzyme must be continuous. In this paper, two reactor types with continuous refreshment of the biocatalyst are discussed: the stirred tank and the multistage fluidized bed. A method is presented for dimensioning a reactor in such a way that the costs for the conversi...

Natural substrates like sand, soil, leaf litter and snow vary widely in penetration resistance. To search for principles of appendage design in robots and animals that permit high performance on such flowable ground, we developed a ground control technique by which the penetration resistance of a dry granular substrate could be widely and rapidly varied. The approach was embodied in a device co...

A process for lignin removal from alkaline pulping liquors (black liquors) has been developed within the FRAM2 R&D Program (Future Resource Adapted Pulp Mill, part 2). The lignin product (Fig. 1) from a demonstration plant, owned and operated by Innventia (formerly STFI-Packforsk), was characterized and used in different combustion trials with good results – co-firing of lignin and bark in a fl...

The efficiency of fluidized bed reactors depends on bubble distribution, bubble size and bubble velocity within the reactor. The sizes and size distributions of particles used in the bed may lead to different bubble behaviour. The objective of this work is to study the influence of particle size distribution on bubble behaviour. The results from the experiments will be used for validation of CF...

Knowledge about ignition processes of coal in fluidized beds is of importance for the start-up and dynamic control of these combustors. Initial experiments in a transparent fluidized bed scale model showed the existence of a considerable induction period for the ignition of char, especially at low bed temperatures (e.g., 800-950K for bituminous coal). This paper focuses on char-ignition delay a...

In this work we have tested the fluidized bed desulfurization performance of lime particles obtained by means of a proprietary limestone slow calcination pre-treatment technique. This performance was compared to that of the parent untreated limestone particles. The occurrence of particle fragmentation and attrition during the fluidized bed operation was also investigated with a specific test pr...

In this paper computational analysis of circulating fluidized bed combustion using the fluent software is analysed. This work is concerned about gas–solid two-phase mixtures flowing upwards through the fast beds. The procedures studied are applicable to all types of fluidized-bed boilers. The type of information resulting from various ways of analyzing the pressure and temperature in fluidized ...