Applications to Reactor Engineering

In general, it may be concluded that the computational snapshot approach or other equivalent, state of the art CFD models can capture the key features of flow in stirred tank reactors and can be used to make either quantitative (for single-phase or pseudo-homogeneous applications) or semi-quantitative (for complex, multiphase applications) predictions. Possible applications to reactor engineering are discussed below. 

Rigby et al. (1997) also applied a CFD-based model to understand bubble break-up from ventilated cavities in gas-liquid reactors. Ranade etal. (2001d) used a volume of fluid (VOF) approach to understand cavity formation behind blades. Observations and insight gained through such studies may be used to develop appropriate sub-models, which can then be incorporated in a detailed reactor-engineering model. 

Ranade (1993) considered the case of a semi-batch stirred reactor to carry out diazotization reactions. The underlying chemistry can be represented by classical series-parallel reactions  

FIGURE 10.31 Comparison of predictions of CFD model with experimental data (from Ranade, 1993). Influence of (a) feed locations (denoted by A, B, C and D), (b) impeller speed, (c) reactant concentration. 

Feed pipes are located at impeller center plane 

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The development of oxychlorination technology in the late 1950s encouraged new growth in the vinyl chloride industry. Here, we will be considering an oxychlorination (OXY) reactor to illustrate the application of computational flow modeling to reactor engineering. 

Ranade and Tayalia (2000) validated the snapshot approach by considering a two-dimensional case of rotating flows. Application of this approach to simulating complex, three-dimensional flows in stirred tank reactors is discussed below. The next section will discuss application of this approach to cases relevant to reactor engineering. 

At this juncture, it would be useful to re-examine the lessons learnt from our experience of the application of computational flow modeling to reactor engineering. From our experience, it is extremely important to correctly ... 

Yamano, H., Fujita, S., Tobita, Y., Sato, I., Niwa, H., 2008. Development of a three dimensional CDA analysis code SIMMER-IV and its first application to reactor case. Nuclear Engineering and Design 238 (1), 66—73. 

In the past decade, Savannah River Site (SRS) processes to implement a quality assurance (QA) program achieved less than satisfactory results. In December 1981, the U.S. Department of Energy (DOE) provided a better focus for their QA requirements by invoking American Nuclear Standard Institue/American Society for Mechanical Engineers (ANSI/ASME) Standard NQA-1 as their desired standard (SR Order 5700.6A, Reference 1). However, the Savannah River Plant (SRP) QA Manual, DPW 83-111-3 (Reference 2), applicable to reactors, was not fully responsive to the DOE order and was never fully implemented. On April 1,... 

The two main principles involved in establishing conditions for performing a reaction are chemical kinetics and thermodynamics. Chemical kinetics is the study of rate and mechanism by which one chemical species is converted to another. The rate is the mass in moles of a product produced or reactant consumed per unit time. The mechanism is the sequence of individual chemical reaction whose overall result yields the observed reaction. Thermodynamics is a fundamental of engineering having many applications to chemical reactor design. 

Thermod5mamics is a fundamental engineering science that has many applications to chemical reactor design. Here we give a summary of two important topics determination of heat capacities and heats of reaction for inclusion in energy balances, and determination of free energies of reaction to calculate equihbrium compositions and to aid in the determination of reverse reaction... 

Whitaker, S, Local Thermal Equilibrium An Application to Packed Bed Catalytic Reactor Design, Chemical Engineering Science 41, 2029, 1986. 

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