Gas mixture flow

The burners on cooking stoves are very much like Bunsen tubes. The fuel induces air and the two gases premix prior to reaching the burner ring with its flame holes. It is possible to idealize this situation as an ejector. For an ejector, the total gas mixture flow rate can be related to the rate of fuel admitted to the system through continuity of momentum... 

Fig. 3.21 A multicomponent gas mixture flows through the inner tube, which is selectively permeable for compound A.

The measurements with small grains characterize a reaction in the kinetic region. The composition of the gas mixture flowing out of the cycle, which is determined by analysis, is just the composition of the reaction medium. The reaction rate is easily calculated from the same results of analysis the extent of the reaction, during some time, t, is equal to the increment of the amount of any product or to the decrement of the amount of any reactant when the gas mixture has passed through the system divided by the respective stoichiometric coefficient. Since the reaction is steady state, f is proportional to t and since the reaction proceeds under nongradient conditions, , is proportional to the surface of the catalyst, s. As a result, the general Eq. (3) reduces to... 

Step 1 Feed gas mixture flows into column 2 while product flows out. A portion of this product is passed through column 1 at a lower pressure acting as a purge. 

Tube Reactor, Parallel Flow A sketch of this reactor configuration is shown in Figure 17. Here the reactant gas or gas mixture flows axially down a tube (circular or rectangular cross section) over a heated susceptor... 

In the Monsanto process (referred to as PRISM separators), the gas mixture flows around an array of hollow fibers, and only hydrogen and helium can diffuse into the fibers through the semi-permeable, polysulfone-coated walls. Separation from CH4, CO, O2 and N2 can be accomplished in this way46. The PRISM technology is now owned and marketed by Air Products. 

Experiments were conducted in which the gas mixture flowing to the culture flask contained MJ as well as ethylene [in the optimum combination with 17% (v/v) 02 and 1.5 % (v/v) C02]. The results given in Fig. 7 demonstrate clearly that ethylene and MJ co-mediate the induction of paclitaxel biosynthesis. When MJ was supplied by passing an air stream over concentrated MJ in a flask, no product formation was noted. When the optimal gas mixture was applied to the headspace of the culture without first passing over the pure MJ in a flask, the level of paclitaxel accumulation was about 20% of that found in the culture to which both MJ and C2H4 had been applied by means of the vapor phase. The 8-day period of time before induction may represent the time required for the critical concentration of MJ to dissolve in the culture medium under the flow (40 ml total gas mixture min-1) and temperature (21 °C) conditions of the experiment. 

Experimental Apparatus. Our experimental apparatus is shown in Fig. la. Constant composition gas streams of CO, N2 and O2 were obtained by three separate sonic orifice meters. The flow through the sonic orifice meters is affected only by the upstream pressure and is independent of the. fluctuations downstream as long as the ratio between the upstream and downstream pressures is greater than 2. Exposure of the reactant streams to stainless steel was minimized by using only Teflon tubing after the switching valve junction. The switching valve directed a desired gas mixture flow to the reactor while another gas mixture flow was... 

Let us now consider a catalytic packed bed reactor , i.e. a tubular reactor filled with a grained catalyst through which the gas mixture flows. With the particle diameter of the catalyst, dp, an additional dimensionless number dp/d is added to the pi-space the Reynolds number is now expediently formed with dp. The reaction rate is related to the unit of the bulk volume and characterized by an effective reaction rate constant ko,eff = k . The thermal conductivity (k) also has to be valid for the gas/bulk solids system and diffusion can be considered as being negligible (Sc is irrelevant). The complete pi-space is therefore ... 

References Catalyst weigh(mg) Gas mixture Flow rate (ml min-1) GHSV (h-1 mlg- ) Measurement... 

Advantages of this procedure are (a) rapidity (heat exchanges are favoured by the gas mixture flowing at atmospheric pressure) (b) sensitivity (surface areas as low as 0.5 m2 can be measured) and (c) simplicity (it does not require vacuum or dead volume calibration). The main interest of this procedure is to provide one experimental point for the application of the single point BET determination (cf. Chapter 6). Thus, one adsorptive-carrier gas mixture (for example 10% N2, 90% He) can be stored and used as required. Measurement of equilibrium pressure is not required, but the atmospheric pressure, p, should be known. In the above example, the equilibrium pressure is p/9. If possible, the mixture is chosen so that the determination is made within the expected linear range of the BET plot. 

Catalyst Monolith. The previous discussion in this chapter focused primarily on chemical reactions taking place in packed-bed reactors. However, when a gaseous feedstream contains significant amoimts of particulate matter, dust tends to clog the catalyst bed. To process feedstreams of this type, parallel-plate reactors (monoliths) are commonly used. Figure 11-11 shows a schematic diagram of a monolith reactor. The reacting gas mixture flows between the parallel plates, and the reaction takes place on the smface of the plates. 

As a typical example of an application we will look at an absorption column, Fig. 1.55, in which component A in a gas mixture flowing up the column is dissolved in a liquid flowing countercurrent to it. 

The gas mixture flow (molecules and atoms) within the porous oxide-SE (Pt RE), Gjj (0 J, can be represented by the following equation ... 

In previous studies, optimizations of chemiluminescence NOj analyzers were carried out. For example, the surface in the reaction chamber had been coated with gold to improve the optical collecting ratio. In this study, we examined the change in sensitivity (signal intensity) caused by altering the inlet of the reaction chamber and the form of the gas mixture flow in the reaction chamber. The model calculation of the flows has given that NO has not completely reacted with O3 within the reaction chamber. 

Most of the work cited above has dealt with treating the soot in some way before doing the combustion experiments. We wish to report experiments conducted on soot from a diesel vehicle which has been deposited onto catalytic monolithic substrates. This sooted substrate is then placed in a laboratory apparatus where a synthetic gas mixture flows over the sample, and the soot combustion is monitored as a function of temperature. The laboratory set up simulates regeneration conditions on a vehicle. Using this technique we have been able to obtain kinetic information about the oxidation of soot and gaseous products. Comparisons of base metal and noble metal catalysts were also conducted and are reported. It is intended that this work will help elucidate the mechanism involved in the catalytic combustion of soot which should help in developing improved catalytic materials. 

The output gas mixture flows through wash bottle filled with water, which absorbs the unreacted fluorine. The OFg is then condensed in two glass traps immersed in liquid nitrogen. 

Thus, the aforementioned analysis has shown that upon passage of gas mixture flows through devices of preliminary condensation, a temperature decrease may be expected, favorable for the condensation of water vapor or heavy hydrocarbon vapors. 

The results that were obtained when the isotopic composition of oxygen was switched from 02 to 02 in the gas mixture flowing over the LaMnOs, Lao.7SrojMn03, and LaosSrosMnOs at 900°C are shown as time variation of the fraction (f and Og,... 

Kuhn, S.Z., Schrock, V.E., and P.F. Peterson. 1997. An investigation of condensation from steam-gas mixtures flowing downward inside a vertical tube. Nucl. Eng. Des. 177 53-69. 

In this section, chemical kinetics in multi-component reacting gas mixture flows are studied under the conditions of strong vibrational and chemical non-equilibrium. Experimental results on the relaxation times of various processes demonstrate that, in a wide temperature range, the equilibration of translational and rotational degrees of freedom proceeds much faster compared to the vibrational relaxation and chemical reactions. The characteristic relaxation times satisfy the relation... 

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