Saturated type reactors

Gapped iron core or saturated type reactors 27/849... 

When it is required to limit the inrush current a fixed reactance (linear) reactor is more suitable. A variable type reactor will be necessary when it is to be used for voltage regulation or load sharing. In circuits where harmonics may be present, saturated type reactors may be preferred. 

The hydrogenation method is promising [194] as alkoxy groups are spUt off in a flow-type reactor which reduces considerably the duration of the analysis. The saturated hydrocarbons formed on hydrogenation are suitable for both gas chromatographic separation and detection. 

Thus, using small-scale tubular turbulent divergent-convergent-type reactors at the stage of uniform gas-liquid mixture formation, prior to feeding this mixture into a stirred tank polymerisation reactor, results in a notable (virtually hy one order of magnitude) increase in the phase contact surface. A developed phase interface facilitates the uniform saturation of liquid products with monomers and hydrogen. In this case, it allows improved performance characteristics of the EPR in contrast to stirred tank reactors. 

The reactions were performed in a plug-flow type reactor operating at one atomospheric pressure. Saturated 2-butanol vapor (293 K) was fed with a nitrogen-gas carrier to the catalyst bed. About 0.3 g of hydrotalcite-like materials were heated under a nitrogen stream at a given temperature for ca. 2h before starting the reactions. The products from the outlet of the reactor were analyzed by a HP 5890 gas chromatography with FID detector. 

Operation of a reactor in steady state or under transient conditions is governed by the mode of heat transfer, which varies with the coolant type and behavior within fuel assembHes (30). QuaHtative understanding of the different regimes using water cooling can be gained by examining heat flux, q, as a function of the difference in temperature between a heated surface and the saturation temperature of water (Eig. 1). 

Another special application of adsorption in space is presented by Grover et al. (1998). The University of Washington has designed an in situ resource utilization system to provide water to the life-support system in the laboratory module of the NASA Mars Reference Mission, a piloted mission to Mars. In this system, the Water Vapor Adsorption Reactor (WAVAR) extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular1 sieve. Using ambient winds and fan power to move atmosphere, the WAVAR adsorbs the water vapor until the zeolite 3A bed is nearly saturated, and then heats the bed within a sealed chamber by microwave radiation to drive off water for collection. Tire water vapor flows to a condenser where it freezes and is later liquefied for use in tire life-support system. 

In semicontinuous-flow reactors (Figure 9.2-2) [25] the dense gas is saturated with substrates in an autoclave and then fed continuously through the enzyme bed. The advantage of this type of reactor is that the pure gas should be compressed. The disadvantage of semicontinuous flow reactors is that the concentration of substrates in dense gases cannot be varied, and that with changes of pressure and temperature, precipitation of substrates or products in the reactor can occur. 

The fluidized bed reactor has been used by several researchers to study the kinetics of chemical weathering (Holdren and Speyer, 1985, 1987 Chou and Wollast, 1985). One of the advantages in using the fluidized bed reactors for studies of this type is that there are no strong concentration gradients in the aqueous and solid phases. Additionally, the concentration of the dissolved species can be maintained at levels well below saturation with respect to possible precipitates. This means, for example, that one could study mineral dissolution exclusively without secondary precipita-... 

Catalytic Experiment. The alkylation of meta-diisopropylbenzene with propylene was performed at 463 K in a flow-type fixed-bed reactor. The carrier gas nitrogen was first saturated with the vapor of meta-diisopropylbenzene (97 %, Aldrich) and then admixed with propylene (99 %, Matheson). The partial pressure of propylene and meta-diisopropylbenzene was 42.6 and 6.0 Torr, respectively. (The molar ratio of propylene and meta-diisopropylbenzene at the reactor inlet was 7.1 1). The modified residence time of propylene and meta-diisopropylbenzene W/Fpr0pyiene and W/Fm DiPB ranged from 4 to 20 and from 25 to 150 gh/mol, respectively, where W indicates the weight of dehydrated catalyst at 623 K and Fi indicates the molar flow rate of reactant i at the reactor inlet. The reaction conditions, viz. the reaction temperature, amount of catalyst, partial pressure and modified residence time of reactants, were chosen in order to obtain conversions of meta-diisopropylbenzene around 25 %. 

Several reactor types have been described [5, 7, 11, 12, 24-26]. They depend mainly on the type of reaction system that is investigated gas-solid (GS), liquid-solid (LS), gas-liquid-solid (GLS), liquid (L) and gas-liquid (GL) systems. The first three arc intended for solid or immobilized catalysts, whereas the last two refer to homogeneously catalyzed reactions. Unless unavoidable, the presence of two reaction phases (gas and liquid) should be avoided as far as possible for the case of data interpretation and experimentation. Premixing and saturation of the liquid phase with gas can be an alternative in this case. In homogenously catalyzed reactions continuous flow systems arc rarely encountered, since the catalyst also leaves the reactor with the product flow. So, fresh catalyst has to be fed in continuously, unless it has been immobilized somehow. One must be sure that in the analysis samples taken from the reactor contents or product stream that the catalyst docs not further affect the composition. Solid catalysts arc also to be fed continuously in rapidly deactivating systems, as in fluid catalytic cracking (FCC). 

On its way downwards, the liquid phase is of course depleted with respect to its more volatile component(s) and enriched in its heavier component(s). At the decisive locus, however, where both phases have their final contact (i.e., the top of the column), the composition of the liquid is obviously stationary. For a desired composition of the gas mixture, the appropriate values for the liquid phase composition and the saturator temperature must be found. This is best done in two successive steps, viz. by phase equilibrium calculations followed by experimental refinement of the calculated values. The multicomponent saturator showed an excellent performance, both in a unit for atmospheric pressure [18] and in a high-pressure apparatus [19, 20] So far, the discussion of methods for generating well defined feed mixtures in flow-type units has been restricted to gaseous streams. As a rule, liquid feed streams are much easier to prepare, simply by premixing the reactants in a reservoir and conveying this mixture to the reactor by means of a pump with a pulsation-free characteristic. 

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