Volume of reactor

In the design of a fine chemicals plant equally important to the choice and positioning of the equipment is the selection of its size, especially the volume of the reaction vessels. Volumes of reactors vary quite widely, namely between 1,000 and 10,000 L, or ia rare cases 16,000 L. The cost of a production train ready for operation iacreases as a function of the 0.7 power. The personnel requirement iacreases at an even lower rate. Thus a large plant usiag large equipment would be expected to be more economical to mn than a small one. 

Reduction to Liquid Metal. Reduction to Hquid metal is the most common metal reduction process. It is preferred for metals of moderate melting point and low vapor pressure. Because most metallic compounds are fairly insoluble in molten metals, the separation of the Hquified metal from a sohd residue or from another Hquid phase of different density is usually complete and relatively simple. Because the product is in condensed form, the throughput per unit volume of reactor is high, and the number and si2e of the units is rninimi2ed. The common furnaces for production of Hquid metals are the blast furnace, the reverberatory furnace, the converter, the flash smelting furnace, and the electric-arc furnace (see Furnaces, electric). 

Fluidized Bed. This reactor consists of a sand bed on which the biomass is grown. Siace the sand particles are small, a very large biomass can be developed ia a small volume of reactor. Ia order to fluidize the bed, a high recycle is required. 

The space velocity is defined as the standard volume of the reactant stream fed per unit time divided by the volume of reactor space filled with catalyst. 

Gas hold-up is defined as Ha = Bubble volume/Reactor volume, which is the volume of gas per unit volume of reactor. Assume the system is an agitated vessel. Let us use Richard s data to define gas hold-up 3... 

Dilution rate is defined as the number of tank volume pass through per unit time, D = F/V. The residence time is defined as the tune required for one unit volume of reactor to be replaced by the flow rate, t = VIv. When feed is sterile, there is no cell entering the bioreactor, which means x0 = 0, the rate may be simplified and reduced to ... 

Neai the wash out, the reactor is very sensitive to variations of dilution rate D. A small change in D gives a relatively large shift in X and S. The rate of cell production per unit volume of reactor is DX. These quantities are shown in Figure 6.5, where there is a sharp maximum in the curve of DX. We can compute maximal cell rate by taking the derivative of DX with respect to D, then solving the equation. The derivative of DX with respect to D is defined as ... 

Volumetric flow rate of gas per unit volume of reactor. 

The volume of reactor without beads was 1.4 1. The column was loaded with the solidified uniform beads of S. cerevisiae. The void volume of the reactor was 660 ml when it was packed with immobilised beads. The growth of beads with different proportions of column packing is shown in Figure 8.9. A fresh feed of 10 g l 1 glucose solution was pumped from the bottom of the reactor. The optimum amount of packing obtained was 65-70% of the reactor volume. The trend of the collected data resembles the growth curve of yeast in... 

The other important factor is a, the geometric surface area exposed to gas per volume of reactor, which depends on the void fraction and the dimension of the packing. The product of the transfer coefficient and the surface-to-volume ratio governs the rate of heat and mass transfer per... 

The case of = 1 is a reasonable approximation for a great variety of cases, while = 0 covers another common situation where the reaction rate is limited by the disengagement of molecules from the surface. SIa has its usual interpretation as moles formed per unit volume of reactor per unit time when Ai is the... 

A definite correlation of the results of the measurements can be achieved by using the adiabatic compressor power per unit volume of reactor according to Eq. (10) which is shown in Fig. 15 [27]. The experimentally determined loss factor is required in Eq. (10). The measured data for spargers with holes dL= 0.2 - 2 mm can be correlated with Eq. (24). 

Dividing the balance equation by the volume of reactor, V, leads to the equation in the form... 

On the other hand, the enhanced heat dissipation from the small volume of reagent into the relatively large volume of reactor body can be disadvantageous where the sample within micro-channels has to be heated up. In a conventional heating method, for example using a thermal bath or oven, the reactor body needs to be heated up first and then the heat is transferred by thermal conduction into the sample in the micro-channels. In this case, only a very small portion of heat is ef-... 

The most obvious disadvantage in principle stems from the fact that the outlet stream is the same as the contents of the vessel. This implies that all reaction takes place at the lowest concentration (of reactant A, say, cA) between inlet and outlet. For normal kinetics, in which rate of reaction (-rA) decreases as cA decreases, this means that a greater volume of reactor is needed to obtain a desired conversion. (For abnormal kinetics, the opposite would be true, but this is unusual-what is an example of one such situation )... 

Material Balance Volume of Reactor Rate of Production... 

The material balance for a PFR is developed in a manner similar to that for a CSTR, except that the control volume is a differential volume (Figure 2.4), since properties change continuously in the axial direction. The material balance for a PFR developed in Section 2.4.2 is from the point of view of interpreting rate of reaction. Here, we turn the situation around to examine it from the point of view of the volume of reactor, V. Thus equation 2.4-4, for steady-state operation involving reaction represented by A+. ..- vcC +. . ., may be written as a differential equation for reactant A as follows ... 

We assume that the reactor is a cylinder of radius R. The volume of reactor from the inlet to positionx is V(x) = ttR1x, or dV = irR dx. Substitution of this for dV in equation 15.2-1 and rearrangement lead to... 

If the pressure of hydrogen in the reactor is 1 bar, calculate 3%, the rate of reaction per unit volume of reactor, and comment on the relative values of the transfer/reaction resistances involved in the process. 

At steady-state, the rates of all these are the same and equal to the overall rate of reaction, 3%. On the basis of unit volume of reactor space that is the volume of gas, liquid and solid, each of these steps is considered in turn. 

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