Accumulator volume, mixing

B Some accumulation of energy 1 s to 10 min kinetic influence Some benefits (selectivity and process volume) from improved temperature control and better mixing/transport... 

This equation can be used directly for any well-mixed, batch, semi-batch or continuous volume element. The term on the left-hand side represents the rate of energy accumulation. The first term on the right-hand side depicts the energy needed to raise the temperature of the incoming reactants, including inert material, to the reactor temperature. The second term describes the heat... 

Ethylene is to be converted by catalytic air oxidation to ethylene oxide. The air and ethylene are mixed in the ratio 10 1 by volume. This mixture is combined with a recycle stream and the two streams are fed to the reactor. Of the ethylene entering the reactor, 40% is converted to ethylene oxide, 20% is converted to carbon dioxide and water, and the rest does not react. The exit gases from the reactor are treated to remove substantially all of the ethylene oxide and water, and the residue recycled. Purging of the recycle is required to avoid accumulation of carbon dioxide and hence maintain a constant feed to the reactor. Calculate the ratio of purge to recycle if not more than 8% of the ethylene fed is lost in the purge. What will be the composition of the corresponding reactor feed gas ... 

A simple method of effectively preventing accumulation of dangerously high concentrations of peroxidic species in distillation residues is that detailed in an outstanding practical textbook of preparative acetylene chemistry [2], The material to be distilled is mixed with an equal volume of non-volatile mineral oil. This remains after distillation as an inert diluent for polymeric peroxidic materials. 

Adsorption is a physical phenomenon in which some components adsorbates) in a fluid (liquid or gas) move to, and accumulate on, the surface of an appropriate solid adsorbent) that is in contact with the fluid. With the use of suitable adsorbents, desired components or contaminants in fluids can be separated. In bioprocesses, the adsorption of a component in a liquid is widely performed by using a variety of adsorbents, including porous charcoal, silica, polysaccharides, and synthetic resins. Such adsorbents of high adsorption capacities usually have very large surface areas per unit volume. The adsorbates in the fluids are adsorbed at the adsorbent surfaces due to van der Waals, electrostatic, biospecific, or other interactions, and thus become separated from the bulk of the fluid. In practice, adsorption can be performed either batchwise in mixing tanks, or continuously in fixed-bed or fluidized-bed adsorbers. In adsorption calculations, both equilibrium relationships and adsorption rates must be considered. 

The high rate of explosive reactions is the result of long accumulation in the system of active products or heat therefore, realization of the reaction under conditions of complete mixing, which can also replace a long period of accumulation, is for these reactions the best means of carrying out the reaction with maximum intensity over a minimum time in a minimum volume, which in a number of cases is of practical interest. 

Fig. 8.12 shows the setup of a laser beam and microphone for ethylene quantification with a PAS detector [24]. In the array, the eight reaction tubes are arranged linearly. A pulsed laser is passed through each effluent from the reactors to excite ethylene molecules. The pulsed laser used emitted at 943-950 cm-1 (where ethylene has a strong absorption) - a 10 or 100 Hz modulated 25 W laser with a pulse length of 35 or 25 ps. A microphone with a fast response time and decay was used. The ethylene concentration of each effluent was determined by the volume and response time. The signal from the most distant tube is weak so that the signals were accumulated for 2.5 s. Data presented in the reference are shown in Fig. 8.13. Ethylene concentrations were determined for the effluent from the mixed-oxide catalyst consisting of La, Ba, Pb, Th, Mn, Ni and Cu.

Batch Mixers In a batch mixer the shear rates throughout the volume are not uniform, and neither are the residence times of various fluid particles in the various shear-rate regions. Consequently, after a given time of mixing, different fluid particles experience different strain histories and accumulate different shear strains y. The SDF, g(y) dy, is defined as the fraction of the fluid in the mixer that has experienced a shear strain from y to y + dy. Alternatively, it is the probability of a fluid particle fed to the mixer to accumulating a shear strain of y in time t. By integrating g(y) dy, we get ... 

Carefully swirl to mix. Be certain to cover the bottom evenly, but do not swirl the solution up onto the container walls. The total initial volume is 5.0 mL. Screw the lid on the container and carefully place in position in the germanium gamma-ray detector counting chamber it should be centered and level. Count twice for a sufficient time period to accumulate 2000 counts (typically 100 s). Check to confirm that at least 2,000 counts have been accumulated at each of the peaks used for calibration. Collect the gross gamma-ray count rates for the full-energy peaks in Data Table 2B.1. 

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