Feed rate of reactant

The initial concentration of styrene is 0.8 kmol-m-3 and of butadiene is 3.6 kmol-m-3. The feed rate of reactants is 20 t-h-1. Estimate the total number of reactors required for polymerization of 85% of the limiting reactant. Assume the density of reaction mixture to be 870 kg-m-3 and the molar mass of styrene is 104 kg-kmol-1 and that of butadiene 54 kg-kmol-1. 

The phenomena shown in Figures 5 7 are considered as follows with the increase of the residence time 0, the feed rates of reactants decrease so that both G and B decrease. The decrease of Im with the increase of 0 is caused by the decrease of G rather than the increase of 0. ... 

For crosscurrent flow, shown in Fig. 26.96, there will be a definite reaction plane in the solids whose angle depends solely on the stoichiometry and the relative feed rate of reactants. In practice, heat transfer characteristics may somewhat modify the angle of this plane. 

Therefore, the most efficient preparation of monodispersed particles can be achieved by regulating the feed rate of reactants (= — dC/dt) as proportional to tm in the case of diffusion-controlled growth and to t1 in the case of reaction-controlled growth, as illustrated in Fig. 4.1.10. 

H J Sevot, G F Versteeg, W P M van Swaaij, A non-permselective membrane reactor for chemical processes normally requiring stnet stoichiometric feed rates of reactants, Chem Eng Set 1990,45,2415 2421... 

In a CNMR/ORG as shown in Figure 10.15 [Sloot et al.. 1990], the reactants A and B introduced to a catalytic membrane from its opposite sides react inside a small reaction zone in the membrane. If the reaction is instantaneous and irreversible, the reaction zone shrinks to a reaction plane theoretically. At the reaction zone or plane, the molar fractions of both reactants will be very low. In principle, it is possible to control the location of the reaction zonc/plane so that slip or penetration of one reactant to the opposing side of the membrane is avoided. The molar fluxes of the two reactants are then always in stoichiometric ratio. Thus, the CNMR s are particularly attractive to those chemical processes which normally require strict stoichiometric feed rates of reactants. An example is the Gaus reaction which involves hydrogen sulfide and sulfur dioxide. 

Membranes have also been used in reactors where their permselective properties are not important. Instead their well-engineered porous matrix provides a well-controlled catalytic zone for those reactions requiring strict stoichiomeuic feed rates of reactants or a clear interface for multiphase reactions (e.g., a gas and a liquid reactant fed from opposing sides of the membrane). Functional models for these types of membrane reactors have also been developed. The conditions under which these reactors provide performance advantages have been identified. 

Mass Balance Equations (3-1) and (3-2) can be written for a volume element A V extending over the entire cross section of the tube, as shown in Fig. 3-2. This is because there is no variation in properties or velocity in the radial direction. Suppose the mass feed rate of reactant to the reactor is F and the conversion of this reactant at the entrance to the volume element is x. In the absence of axial mixing, reactant can enter the element only by bulk flow of the stream. Hence the first term in Eq. (3-1) is (1 — x)At. If the conversion leaving the element is x -f- Ax, the second term is T(1 — x — Ax) Af. Since the operation is at steady state, the fourth term is zero. The third... 

Fig. 4.18. Catalytic behavior and structural changes of glassy Cu7oZr30 alloy during exposure to CO2 hydrogenation conditions [4.23], A) Change of C02 hydrogenation activity and product distribution as a function of time-on-stream. Dashed line indicates the calculated equilibrium conversion. Symbols C02 conversion selectivities to methanol O, carbon monoxide V, and ethanol A. Hydrogenation conditions 1.2 g of sample, feed rates of reactants C02,2.3 mmol/s H2, 7.6 mmol/s total pressure 15 bar. B) X-ray diffraction patterns of active sample after steady-state conversion was reached (Cu K,)...

The method, as suggested by Westerterp et al. [1] and by Van Gelder et al. [12], to obtain the maximal yield of an intermediate product without hydrogen recycle has been experimentally evaluated. The packed bubble column reactor can be run with a correct amount of hydrogen supplied to achieve the maximum yield of intermediate product at a certain feed rate of reactant in the liquid phase. A small amount of the inert gas - in our case nitrogen - must be added to the reactor to assure a stable performance of the reactor in case almost all supplied hydrogen is consumed. The reactor pressure... 

Examination of Figures 12.7 and 12.8 shows that the 1-bar curve on Figure 12.8 corresponds exactly to the 0.1 bar curve in Figure 12.7 except that in Figure 12.8 productivity is about one tenth that in Figure 12.7. This is due to the fact that the amount that can be converted, defined on the total feed rate of reactants, is reduced by a factor of ten by the introduction of the diluent. Curves at pressures other than 1 bar show the effects of decreasing rates of reaction due to dilution. Similarly intertwined curves would be observed at zero dilution on Figure 12.7 at pressures one tenth of those in... 

Feed rates of reactants (mmol/h) MA AA AcOH HCHO MeOH MA+AA (MA+AA)... 

Feed rate of reactant in moles/oc. of gross reactor volume per second. Dimensionless parameter which determines fraction of surface available. For order reaction in a single pore of length L, h is defined by eq. (28). For practical catalyst granules, a rigorous definition of h is given by eq. 64a (for first order reaction). In eq. 66 and the accompanying discussion it is shown that these two definitions are essentially equivalent. 

Automatic control and warning of abnormal feed rates of reactants and high temperatures in process units, excessive flow rates which can disturb catalyst beds and conversion efiiciency, affected production rates, or waste reactants due to incomplete conversion. 

Reaction temp.= 300 "C, W/F= 33 g-cat. h/mol (W= weight of catalyst, F= feed rate of reactant), flow rate of carrier gas= 600 ml/h, averaged initial activity for 1 h after feeding of reactant. 

One reactant feed (A) is on flow control,/a = 1, relying on self-regulation. The main advantage of this configuration is that the production rate can be easily set. The flow rate of reactant B at reactor inlet/r,b is fixed. The feed rate of reactant B,f, is used to control the inventory of reactant at some location, for example an intermediate storage tank. 

The size of a continuous reactor Vr and the residence time r, respectively, needed for a given duty are found as follows (assuming steady state and conversion of reactant A). The ratio of the reaction volume to the feed rate of reactant A is deduced from ... 

Now we can compare the volumes (or weights of catalyst) required to achieve a specified conversion in each of the two ideal, continuous reactors. Suppose we have an ideal CSTR and an ideal PFR. The same reaction is being carried out in both reactors. The PFR is isothermal and operates at the same temperature as the CSTR. The molar feed rate of Reactant A to both reactors is Fao- If the kinetics are normal, which reactor will require the smaller volume to produce a specified conversion, xa,c, in the effluent stream ... 

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