Chemical engineering reactor volume measurement

It is worth describing other operations where differences between the chemist s laboratory and the chemical engineer s pilot plant and plant create the need for different approaches. Pumping, flow measurement, and reactor volume measurement are a few of the more common operations deserving the chemist s attention. 

Particle diameter is a primary variable important to many chemical engineering calculations, including settling, slurry flow, fluidized beds, packed reactors, and packed distillation towers. Unfortunately, this dimension is usually difficult or impossible to measure, because the particles are small or irregular. Consequently, chemical engineers have become familiar with the notion of equivalent diameter of a partiele, which is the diameter of a sphere that has a volume equal to that of the particle. 

Some of this theoretical thinking may be utilized in reactor analysis and design. Illustrations of gas-liquid reactors are shown in Fig. 19-26. Unfortunately, some of the parameter values required to undertake a rigorous analysis often are not available. As discussed in Sec. 7, the intrinsic rate constant kc for a liquid-phase reaction without the complications of diffusional resistances may be estimated from properly designed laboratory experiments. Gas- and liquid-phase holdups may be estimated from correlations or measured. The interfacial area per unit reactor volume a may be estimated from correlations or measurements that utilize techniques of transmission or reflection of light, though these are limited to small diameters. The combined volumetric mass-transfer coefficient kLa, can be also directly measured in reactive or nonreactive systems (see, e.g., Char-pentier, Advances in Chemical Engineering, vol. 11, Academic Press, 1981, pp. 2-135). Mass-transfer coefficients, interfacial areas, and liquid holdup typical for various gas-liquid reactors are provided in Tables 19-10 and 19-11. 

Calculation of the volume of reactor required under real conditions is a centred problem of chemical reaction engineering. But in these applications the rate function r remains the most important information required. This book will be devoted largely to the rate function r, its form and its meaning. Alternatively, the formulae collected in Table 1.8.1 are those that may be used to obtain the rate function from kinetic measurements in ideal reactors. 

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