Continuous reaction gas

Continuous reaction gas chromatography The dehydrogenation of cyclohexane over Pt/g-A1203 (with A.W. Wardwell and R.W. Carr, Jr.). American Chemical Society Symposium Series no. 196. Washington, D.C. American Chemical Society (1982). 

Continuous Reaction Gas Chromatography The Dehydrogenation of Cyclohexane over Pt/y-Al203... 

In bubble-column slurry reactors, momentum is transferred to the liquid phase by the movement of gas bubbles. The liquid medium is stationary in most cases. Finely divided solids with particle diameters of the order of 0.01 mm are used. The operation is usually carried out in columns with high height-to-diameter ratios. The operation may be employed for batchwise conversion of a liquid reactant, or for continuous reaction between gaseous reactants. 

Continuous reaction of organic 290-420 ppm S03/inert gas passed in at 26-54°C. Reaction 170... 

Water in its supercritical state has fascinating properties as a reaction medium and behaves very differently from water under standard conditions [771]. The density of SC-H2O as well as its viscosity, dielectric constant and the solubility of various materials can be changed continuously between gas-like and liquid-like values by varying the pressure over a range of a few bars. At ordinary temperatures this is not possible. For instance, the dielectric constant of water at the critical temperature has a value similar to that of toluene. Under these conditions, apolar compounds such as alkanes may be completely miscible with sc-H2O which behaves almost like a non-aqueous fluid. 

Mode of operation (Semi)batch or continuous concurrent upward motion of phases Continuous concurrent upward motion of phases Continuous concurrent upwani or downward in different parts of the reaction zone Continuous concurrent upward motion of phases Continuous concurrent (1) or countercurrent (2) upward (a) or downw-ard (b) irickle-bcd (1 +b) Continuous countwcurrcni gas upward liquid downward Cominumis concurrent downward... 

Three gas chromatographes, each kept under different conditions, were simultaneously used to analyse all reaction gas components as continuously as possible. In the special case of a very rapid response with the period shorter than a few minutes, the same response was repeated a few times and the results obtained were superimposed in order to draw a response curve as continuously as possible. 

Since oxygen is a substrate, Vmax and Km are functions of the oxygen concentration co2> which is fixed by Po2 in the continuously flowing gas phase. At low values of CG, the reaction is pseudo-first-order with respect to glucose, and (A) simplifies to... 

There are, however, two broad classes of exceptions to this conclusion. The first comes with the slow reaction of a gas with a very porous solid. Here reaction can occur throughout the solid, in which situation the continuous reaction model may be expected to better fit reality. An example of this is the slow poisoning of a catalyst pellet, a situation treated in Chapter 21. 

The primary influences on reaction rates, selectivities, and mechanisms are the bulk physical properties of the fluid, which can be varied continuously from gas-like to liquid-hke. 

The steam production section comprising the steam superheater and waste-heat boiler is designed to lower the reaction-gas temperature from 645°C to 280°C (further oxidation in these vessels will also continue to produce reaction heat). Steam of sufficient quality is to be produced for export to the adjacent ammonia and ammonium nitrate plants. Medium-pressure steam (at 380°C and 4000 kPa) is preferred. 

The equilibrium continues to shift as the temperature of the reaction-gas mixture falls. Eventually a further 15% of the nitrogen oxide has reacted to form nitrogen dioxide, and 3% of this nitrogen dioxide reacts to form nitrogen tetroxide. 

Agitated Stirred Tanks Stirred tanks are common gas-liquid reactors. Reaction requirements dictate whether the gas and liquid are in a batch or continuous mode. For a liquid-phase reaction with a long time constant, a batch mode may be used. The reactor is filled with liquid, and gas is continuously fed into the reactor to maintain pressure. If by-product gases form, these gases may need to be purged continuously, if gas solubility is limiting, a higher-purity gas may be continuously fed (and, if required, recycled). As the liquid residence time decreases, product may be continuously removed as well. A... 

Several other examples for potential application of reverse-flow operated catalytic reactors are described in Ref. 9. Also, other potential techniques of forced unsteady-state operation which allow for combining chemical reaction and heat exchange in a fixed catalyst bed are discussed. One such technique is sequential switching between inlet and outlet ports of the reaction gas between two or more packed beds (Fig. 2(c)). In this case, the thermal wave travels continuously through a series of packed beds in one direction, as if along a closed ring. However, this operation is more complex and requires more catalyst than the reverse-flow operation. 

TFE is obtained by the thermal decomposition of this monochlorodifluoromethane (known as Freon) in a continuous noncatalytic gas-phase reaction, carried out at or below atmospheric pressure at temperatures from 600 to 900°C ... 

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