Solid pellets

Place 5 ml. of benzaldehyde in a wide-necked stout-walled bottle of about 100 ml. capacity (a conical flask is too fragile for this purpose) and add 50 ml. of concentrated dy 0 880) ammonia solution. Cork the bottle securely, shake vigorously, and then allow to stand for 24 hours, by which time the layer of benzaldehyde at the bottom of the bottle will have been converted into a hard mass of hydrobenzamide. (If after 24 hours the crude hydrobenzamide is still syrupy, shake the mixture vigorously and allow to stand for another hour, when the conversion will be complete.) Break up the solid pellet with a strong spatula, filter at the pump, wash with water and drain thoroughly. Recrystallise from ethanol methylated spirit should not be used, as it contains sufficient water to cause partial hydrolysis back to benzaldehyde and ammonia. Hydrobenzamide is obtained as colourless crystals, m.p. 101° (and not 110° as frequently quoted) yield, 4 g. 

A shell of radii r and r + Sr within the solid pellet particle of radius R may be considered. Making a material balance for the reactant, then ... 

The Augusta facility produced plastics, including Amodel, a hard but moldable high-performance nylon. Amodel is manufactured by passing a solution of diamines and dicarboxylic acids through a series of reactors. The reaction is completed in an extruder, and the material is then formed and cooled into solid pellets. 

There are several resistances which may hinder the movement of a molecule of adsorbate from the bulk fluid outside a pellet to an adsorption site on its internal surface, as shown in Figure 17.15. Some of these are sequential and have to be traversed in series, whilst others derive from possible parallel paths. In broad terms, a molecule, under the influence of concentration gradients, diffuses from the turbulent bulk fluid through a laminar boundary layer around a solid pellet to its external surface. It then diffuses, by various possible mechanisms, through the pores or the lattice vacancies in the pellet until it is held by an adsorption site. During desorption the process is reversed. 

Figure 5.8 Solid pellet discharge control device. The device is shown schematically in Fig. 5.6...

Free subcellular particles or virus from Percoll by centrifuging the respective fraction of cell fractionation in a fixed-angle rotor at 100 000 X g for 90 min. Percoll forms a solid pellet whidi contains practically no material of interest. 

One proposed technique is to aim an array of laser beams at a common point and drop solid pellets of hydrogen isotopes through the synchronous crossfire, as Figure 4.32 shows. The energy of the multiple beams should crush the pellets to... 

The polymer-gas solution to be tested is prepared separately, and is loaded into the rheometer barrel as a well-mixed, equilibrated sample. The loading method depends on whether the polymer itself is a liquid or a solid at room temperature. For liquid polymers such as PDMS, Gerhard (1994) developed a sealed module that attached to the top of the rheometer barrel, with a side valve though which an equilibrated liquid polymer-gas sample is injected. For solid polymers such as polystyrene, Kwag (1998) found that the diffusion of gas from solid pellets at room temperature was sufficiently slow to allow direct loading of the sample as solid pellets pre-... 

Transport the solid pellets or powder from the hopper to the screw channel... 

Sample Transparent, bubble and particulate-free liquids Powder samples require diffuse reflectance probe Transparent liquid, thin solid pellets and ideal for gases Special ATR probes needed Same probe is used for all samples liquids, slurries, emulsions, powders, solids, samples with particulates, and bubbles... 

Uniform motion of the solid pellets with constant voidage. Pellets are spherical in shape and a shrinking core,sharp interface model is assumed for the pellet reduction(8 9 ). For the gas species, the dimensionless continuity eqtns are ... 

A parametric study of moving bed behaviour has been undertaken. The solid pellets are assumed to be preheated to the appropriate reduction temperatures before entering the reaction zone of the reactor. Although this neglects the solids preheat zone, this can easily be included in the model if required. The present study therefore is focussed on the reaction zone itself where the important parameters of gas and solid flow rates, gas inlet temperature and gas mixture composition are considered. Reactor length is also of major importance but in the present paper this has been fixed at lm in order to obtain comparative data. 

Solids conveying is carried out in two steps the feed hopper and the back (entrance) portion of the screw. The feed hopper is an inverted cone or pyramid, in which solid pellets or powder flow downward from the force of gravity. If they flow poorly ( arcing or bridging ), the problem may be solved by installing a vibrator or a stirrer ( crammer/feeder ) in the hopper, or by coating the particles with a small amount of a chemical that acts as an external lubricant. ... 

Gather these materials A kitchen scale delicate enough to record the weight of 3 teaspoonfuls of a chemical salt crystalline sodium carbonate (Na2C03) solid pellets of sodium hydroxide (NaOH) filter paper and paper and pencil. 

Sodium borohydride Solid pellets or preferably an aqueous solution, stabilised with NaOH, of concentration geared to the hydride generator. 

A typical experimental arrangement used for diffusion measurements consists of a cylindrical solid pellet (or multiple pellets in parallel) placed between two gas chambers with the flat surfaces exposed to the gases. Two gas streams of known flow rates and dif-... 

All other samples were prepared by pressing solid pellets which were then wet with the calibrated Nujol to obtain complete combustion. 

Dry reagent-grade cyclohexane (50 mL) glass wool naphthalene or other solid pellet press acetone for rinsing ice (3 lb) ice grinder or shaver coarse rock salt (2 lb). 

The conversion of the solid pellet expressed in terms of core radius is given by... 

I m only using this as an example, not asking you to actually mess around with sodium hydroxide, but for safety s sake I should go ahead and mention that this chemical can be pretty caustic, especially in the solid pellet form. Take all necessary precautions (gloves, goggles) when handling this stuff... 

Step 9. The solution of sodium chloride and sodium carbonate leaving the waste liquor neutralizer is combined with the waste liquor from the product centrifuge (Step 12). The combined solution is split into two streams. One goes to a waste treatment facility, and the other goes to the NaOH makeup tank, an agitated jacketed batch vessel. Solid pellets of sodium hydroxide are added to this tank to bring the NaOH concentration... 

In Section 7.2.2 we saw the role that nitric oxide plays in smog formation and the incentive we would have for reducing its concentration in the atmosphere. It is proposed to reduce the concentration of NO in an effluent stream from a plant by passing it through a packed bed of spherical porous carbonaceous solid pellets. A 2% NO-98% air mixture flows at a rate of 1 X 10" mVs (0.001 dm /s) through a 2-in,-ID tube packed with porous solid at a temperature of 1173 K and a pressure of 101.3 kPa. The reaction... 

---