Inert particles

Czech Republic which offers a dryer utilizing a swirling bed of inert particles (Kutsakova et al 1990 Kutsakova et al., 1991). 

Another condition for stable operation of the dryer with inert particles stems from the material properties—no elastic shell should be formed on the solid carrier at any stage of drying as impact due to particle collisions might not be sufficient to crack the shell. Here, the almond -shaped inert particles formed of bimetallic canopies, which change their shape when subject to tern- 

Assuming that drying the relatively thin layer of the wet material on inert carriers is externally controlled, Kutsakova and Utkin (1987) proposed the following equation for the moisture evaporation rate  

Integration of Equation 4.1 gives the following relationship for drying 

To calculate drying time, one should first identify the variation of the water vapor pressure at the material surface with the average temperature of inert particles and material moisture content. For drying in a vortex bed of inert particles, Kutsakova and Utkin (1987) developed the following experimental equation  

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Crystal Formation There are obviously two steps involved in the preparation of ciystal matter from a solution. The ciystals must first Form and then grow. The formation of a new sohd phase either on an inert particle in the solution or in the solution itself is called nucle-ation. The increase in size of this nucleus with a layer-by-layer addition of solute is called growth. Both nucleation and ciystal growth have supersaturation as a common driving force. Unless a solution is supersaturated, ciystals can neither form nor grow. Supersaturation refers to the quantity of solute present in solution compared with the quantity which would be present if the solution were kept for a veiy long period of time with solid phase in contac t with the solution. The latter value is the equilibrium solubility at the temperature and pressure under consideration. The supersaturation coefficient can be expressed... 

Grit Chambers Industries with sand or hard, inert particles in their wastewaters have found aerated grit chambers useful for the rapid separation of these inert particles. Aerated grit chambers are relatively small, with total volume based on 3-min retention at maximum flow. Diffused air is normally used to create the mixing pattern shown in Fig. 25-44, with the heavy, inert particles removed by centrifugal action and friction against the tank walls. The air flow rate is adjusted for the specific particles to be removed. Floatable solids are removed in the aerated grit chamber. It is important to provide for... 

Babcock, H. A. and D. A. Carnell, Transportation of Larger Inert Particles in Pipelines, presented AICHE, 83rd National Meeting, Paper No. 40 f, March 23, 1977, Houston, Texas. 

Fig. 13.15 Lateral corrosion in nickel dep>osit layer containing inert particles beneath microporous chromium...

Gas absorption in packed beds may be described as a gas-liquid-particle process involving reacting gas and liquid phases and an inert particle phase, the latter functioning mainly as a momentum-transfer medium. 

Fixed-bed reactors are used for testing commercial catalysts of larger particle sizes and to collect data for scale-up (validation of mathematical models, studying the influence of transport processes on overall reactor performance, etc.). Catalyst particles with a size ranging from 1 to 10 mm are tested using reactors of 20 to 100 mm ID. The reactor diameter can be decreased if the catalyst is diluted by fine inert particles the ratio of the reactor diameter to the size of catalyst particles then can be decreased to 3 1 (instead of the 10 to 20 recommended for fixed-bed catalytic reactors). This leads to a lower consumption of reactants. Very important for proper operation of fixed-bed reactors, both in cocurrent and countercurrent mode, is a uniform distribution of both phases over the entire cross-section of the reactor. If this is not the case, reactor performance will be significantly falsified by flow maldistribution. 

FIGURE 9.6 Apparatus for time resolution kinetic in FT-measurements. Quick ampoule sampling, internal references, accurate control of flows and pressure, precise zero time, accurate mixing of flows, and catalyst powder on inert particles. 

Copeland A process for oxidizing organic wastes in a fluidized bed of inert particles. The wastes may be solid, liquid, or gaseous, and the oxidant is air. Inorganic residues are collected as granular solids and the heat generated is normally utilized. Developed and marketed by Copeland Systems, Oak Brook, IL, United States, and used in a wide variety of industries. 

This rule holds reasonably well when C or t varies within a narrow range for acute exposure to a gaseous compound (Rinehart and Hatch, 1964) and for chronic exposure to an inert particle (Henderson et al., 1991). Excursion of C or / beyond these limits will cause the assumption Ct = K to be incorrect (Adams et al., 1950, 1952 Sidorenko and Pinigin, 1976 Andersen et al., 1979 Uemitsu et al., 1985). For example, an animal may be exposed to 1000 ppm of diethyl ether for 420 min or 1400 ppm for 300 min without incurring any anesthesia. However, exposure to 420,000 ppm for lmin will surely cause anesthesia or even death of the animal. Furthermore, toxicokinetic study of fiver enzymes affected by inhalation of carbon tetrachloride (Uemitsu et al., 1985), which has a saturable metabolism in rats, showed that Ct = K does not correctly reflect the toxicity value of this compound. Therefore, the limitations of Haber s rule must be recognized when it is used in interpolation or extrapolation of inhalation toxicity data. 

From recent work, we do know that chemical signals from the seeds direct the ants selections. Although the story is still incomplete, an extraordinary finding has been that a chemical compound called MMS (methyl 6-methylsalicylate) is present in the seeds the ants choose. MMS is found in the seeds of the ten or twelve unconnected species from seven plant families that flourish in Peruvian ant gardens. The ants seem to find this compound irresistible. Offered inert particles coated with MMS, they become excited, pick up these decoy seeds, and occasionally carry them about. 

Move 1] Currently atmospheric particulate matter is regulated based on various size categories because of the apparent association between particle size and adverse health effects. [Move 2] However, the current size-based understanding of atmospheric particles is relatively crude because it does not account for differences in the chemical composition of these particles. Presumably a chemically reactive particle has a greater potential for damage than a chemically inert particle of comparable size. Of the metals potentially... 

The direct sterilisation of particulafe solid foods in a gas-solid fluidized bed was proposed as long ago as 1968 by Lawrence et al. (1968) who sterilised wheat flour in steam-air mixtures at the pilot scale. However, Jowitt (1977) described an atmospheric pressure process for fhe sferilisation of canned foods in which the cans are immersed in a fluidized bed of inert particles. This has a number of advantages compared to the conventional retorting process using pressurised steam or hot water ... 

Not living—-just an inert particle Living—smallest unit of life... 

For liquid-phase catalytic or enzymatic reactions, catalysts or enzymes are used as homogeneous solutes in the hquid, or as sohd particles suspended in the hquid phase. In the latter case, (i) the particles per se may be catalysts (ii) the catalysts or enzymes are uniformly distributed within inert particles or (hi) the catalysts or enzymes exist at the surface of pores, inside the particles. In such heterogeneous catalytic or enzymatic systems, a variety of factors that include the mass transfer of reactants and products, heat effects accompanying the reactions, and/or some surface phenomena, may affect the apparent reaction rates. For example, in situation (iii) above, the reactants must move to the catalytic reaction sites within catalyst particles by various mechanisms of diffusion through the pores. In general, the apparent rates of reactions with catalyst or enzymatic particles are lower than the intrinsic reaction rates this is due to the various mass transfer resistances, as is discussed below. 

This means that an aqueous salt solution should not be viewed as a homogeneous liquid with a modified inter-molecular interaction, but rather as a colloidal suspension of inert particles in pure liquid water, with the particles formed by the ions and their first solvation shells. Following this view of an aqueous salt solution, the viscosity at low concentration can be described by the Einstein equation [19] ... 

The operation of a gel filtration column is illustrated in Figure 3.9. The stationary phase consists of inert particles that contain small pores of a controlled size. Microscopic examination of a particle reveals an interior resembling a sponge. A solution containing solutes of various molecular sizes is allowed to pass through the column under the influence of continuous solvent flow. Solute molecules larger than the pores cannot enter the interior... 

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