Reactor concentration feed ratio

The product distribution is insensitive to the concentration of reactant B. If B is cheap and does not offer a potential pollution problem downstream, its concentration may be kept at any convenient level. If B is costly or must be removed for other reasons, one has the options of operating with low B concentrations at high conversions in a relatively large reactor to produce a product containing very little B, or of operating at higher B concentrations in a smaller reactor with separation and recycle of unused B. The specified product distribution requires that the mole ratio of V to W be 3 1. To produce 1 mole of W and three of F, one must consume 4 moles of A and 5 moles of B. The feed ratio employed in an actual situation may differ appreciably from 1.25 to enhance the reaction rate or to allow for discarding some A and B. 

The first step is relevant to the start-up phase, which in this particular case we chose to extend for up to 1 h in order to verify the reactor stability also in these conditions, where water is not present and while there is a higher oxygen concentration in the feed gas with respect to the ATR conditions. By lowering the 02 CH4 ratio, the H2 concentration at the reactor outlet increases, approaching the value expected by thermodynamic evaluation and CH4 conversion is still complete. A further decrease in the 02 CH4 feed ratio to values lower than 1.16 corresponds to an abrupt decrease in temperature in the lower section and a simultaneous temperature increase in the catalytic reforming section. 

This equation is appropriate in the case of typical stationary SCR applications where a sub-stoichiometric XHyXO feed ratio is employed to minimize the slip of unconverted ammonia. However, considering that water does not affect the Nremoval in the concentration range of industrial interest (>5% v/v), the term /kinetic constant k c, so that the following simplified rate equation has been successfully applied for the modeling of industrial reactors [38, 39, 27] ... 

It has been demonstrated that kg can be estimated by analogy with the Graetz-Nusselt problem governing heat transfer to a fiuid in a duct with constant wall temperature (SH= Nut) [30] and that the axial concentration profiles of NO and of N H 3 provided by the 1D model are equivalent and almost superimposed with those of a rigorous multidimensional model of the SCR monolith reactor in the case of square channels and of ER kinetics, which must be introduced to comply with industrial conditions for steady-state applications characterized by substoichiometric NH3 NO feed ratio, that is, a[Pg.401]

Catalytic hydrogenation in supercritical carbou dioxide has been studied. The effects of temperature, pressure, and CO2 concentration on the rate of reaction are important. Hydrogenation rates of the two double bonds of an unsaturated ketone on a commercial alumina-supported palladium catalyst were measured in a continuous gra-dient-less internal-recycle reactor at different temperatures, pressures, and C02-to-feed ratios. The accurate control of the organic, carbon dioxide, and hydrogen feed flow rates and of the temperature and pressure inside the reactor provided reproducible values of the product stream compositions, which were measured on-line after separation of the gaseous components (Bertucco et al., 1997). 

Figure 2.89 CO conversion vs. reaction temperature in (a) micro channel and (b) monolith reactors. CO feed concentration 5000 ppm 02/C0 ratio 1.0. GHSV (micro channels) ...

In the first set of runs In Table I, the H2/CO feed ratio exceeds the consumption ratio, 7/12 m 0.58 In the second It Is less than the consumption ratio. In each case, the H2 partial pressure In the reactor Increased with decreased agitation, as conversion dropped. In the absence of mass transfer resistance this would be expected to Increase the P/0 ratio. The fact that the P/0 ratio In both cases Instead decreased is consistent with the postulate that the H- concentration In the liquid has decreased. The corresponding mass transfer resistance K, back-calculated from equation (8), is given at each stirring speed together with the hydrogen and carbon monoxide liquid-phase concentrations that are estimated by equations (6) and (7). 

At the same time, the absolute maximum rate is the same as it was before, regard-less of total pressure. This is clear from the fundamental expression given in equation 12.3, where we see that k, is a function of temperature and site concentration but independent of reactor total pressure. At the same time, the maximum product of the two 6 fractions describing surface coverage, whose sum cannot exceed 1, is A Thus for each temperature there is an absolute maximum rate available at a specific feed ratio and pressure. 

We have developed a one-dimensional non-isothermal model for the countercurrent WGS membrane reactor with a C02-selective membrane in the hollow-fiber configuration using air as the sweep gas. With this model, we have elucidated the effects of system parameters, including feed CO concentration, feed temperature, and sweep-to-feed molar ratio, on the reactor for synthesis gases from steam reforming and autothermal reforming. The... 

Fortunately the combination of above variables required to produce 900-f Btu gas is easy to achieve in practical reactor systems. For example, the reactor can operate at gas transmission-line pressures, both the gas coal feed ratio and the methane concentration in the feed gas allow operation at carbon conversion levels resulting in balanced plant opera-... 

Polymerizations. Polymerizations were performed in solution with a 0.5-L continuous stirred tank reactor this apparatus provided polymers of constant composition. After steady-state operation was obtained (approximately three residence times, see Figure 1), 10-mL samples were periodically taken from the effluent, added to 200 xL of a hydroquinone solution, and stored at 10 °C. These samples were subsequently analyzed by HPLC to estimate the mean and variance of the residual monomer concentration and copolymer composition. The polymerization temperatures were 45 and 60 °C for the dimethylamines and 50 °C for DADMAC. The initial monomer concentration was 0.5 mol L" and the monomer feed ratio was varied between 0.3 and 0.7. Azocyanovaleric acid (ACV, Wako Chemical Co.) and potassium persulfate (KPS, BDH Chemicals) were used to initiate the reaction. The solution was agitated at 300 1 rpm for the duration of the polymerization. 

A kinetic model for the deactivation by coke deposition of a catalyst (based on a HZSM-5 zeolite) used in the transformation of aqueous ethanol into hydrocarbons has been proposed. The experiments have been carried out in an isothermal fixed bed reactor by feeding the reactor with ethene, ethanol/water with different mass ratios and diethyl ether. The kinetic model quantifies the effect on coke deposition of the concentration of the organic components in the reaction medium, and takes into account the attenuating effect of water on coke deposition. 

Since U is recovered as UNH crystal for a blanket fuel fabrication in the U crystallization process, the crystal ratio of U should be evaluated with a dissolver solution of irradiated fast neutron reactor. The crystal ratio of UNH affects HNO3 concentration in the feed... 

Figure 13-30 Normalized concentration downstream of the feed jet array in the Toor tubular reactor for L = 12 400 L/mol s reactant feed ratio of 1.26 and an average velocity of 0.75 m/s. The experimental values of Vassilatos and Toor (1965) are compared to simulation values using paired-interaction closure. The reaction was a single second-order...

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