Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Geometries, basic reactor

Throughout the remainder of this section we will be concerned with the solution of Eqs. (8.3), using the conditions (8.4) for three basic reactor geometries. For convenience in notation we write the differential equations in the form... [Pg.423]

To restore the homogeneity of the control parameters in the plane of observation, another geometry of reactor has been developed The system is a thin flat disc of gel fed from the opposite faces [50, 51]. The direction of observation is orthogonal to the faces. Although this design has become the most popular, the basic problems raised by the presence of gradients still remain. The structure is localized in a more or less thick stratum parallel to the faces although the patterns often appear as bidimensional, they are actually distributed over a certain depth and are the projection of a three-dimensional... [Pg.234]

The basic requirements of a reactor are 1) fissionable material in a geometry that inhibits the escape of neutrons, 2) a high likelihood that neutron capture causes fission, 3) control of the neutron production to prevent a runaway reaction, and 4) removal of the heat generated in operation and after shutdown. The inability to completely turnoff the heat evolution when the chain reaction stops is a safety problem that distinguishes a nuclear reactor from a fossil-fuel burning power plant. [Pg.205]

In the CRE literature, the residence time distribution (RTD) has been shown to be a powerful tool for handling isothermal first-order reactions in arbitrary reactor geometries. (See Nauman and Buffham (1983) for a detailed introduction to RTD theory.) The basic ideas behind RTD theory can be most easily understood in a Lagrangian framework. The residence time of a fluid element is defined to be its age a as it leaves the reactor. Thus, in a PFR, the RTD function E(a) has the simple form of a delta function ... [Pg.27]

The basic problem is that the rate is a function of position X within the peUef while we need an average concentration to insert into our reactor mass balances. We first have to solve for the concentration profile Ca (x) and then we eliminate it in terms of the concentration at the surface of the pellet C/4s and geometry of the pellet. We wiU find that we can represent the reaction as... [Pg.284]

The reaction system is one of the most important parts of choosing a basic module for the design of a photochemical reactor. This might be explained by enumerating some of the corresponding parameters and describing their impact on reactor geometry and operational conditions ... [Pg.239]

The basic developments reported herein can be used to predict multicomponent adsorption rates in different types of contacting units, such as slurry adsorbers, moving bed units and columnar operation. The adsorption rate and equilibrium equations would remain the same, but the reactor material balance equation would be different depending on the reactor type and geometry. Thus, the multicomponent adsorption model can be utilized in practical processing applications in the chemical industry, air pollution control, and water and wastewater treatment. [Pg.51]

S //Asa mediator between CFD calculations and macro-scale process simulations, the reactor geometry is represented by a relatively small number of cells which are assumed to be ideally mixed. The basic equations for mass, impulse and energy balance are calculated for these cells. Mass transport between the cells is considered in a network-of-cells model by coupling equations which account for convection and dispersion. The software is capable of optimizing a process in iterative simulation cycles in a short time on a standard PC, but it also requires experimentally-based data to calibrate the software modules to a specific micro reactor. [Pg.597]

For ease of fabrication and modular construction, tubular reactors are widely used in continuous processes in the chemical processing industry. Therefore, shell-and-tube membrane reactors will be adopted as the basic model geometry in this chapter. In real production situations, however, more complex geometries and flow configurations are encountered which may require three-dimensional numerical simulation of the complicated physicochemical hydrodynamics. With the advent of more powerful computers and more efficient computational fluid dynamics (CFD) codes, the solution to these complicated problems starts to become feasible. This is particularly true in view of the ongoing intensified interest in parallel computing as applied to CFD. [Pg.411]

In a simple membrane reactor, basically the membrane divides the reactor into two compartments the feed and the permeate sides. The geometries of the membrane and the reaction vessel can vary. The feed may be introduced at the entrance to the reactor or at intermediate locations and the exiting retentate stream, for process economics, may be recycled back to the reactor. Furthermore, the flow directions of the feed and the sweep (including permeate) streams can be co-current or counter-current or some combinations. It is obvious that there are numerous possible process and equipment configurations even for a geometrically simple membrane reactor. [Pg.411]

In this chapter, first, the existing correlations for three-phase monolith reactors will be reviewed. It should be emphasized that most of these correlations were derived from a limited number of experiments, and care must be taken in applying them outside the ranges studied. Furthermore, most of the theoretical work concerns Taylor flow in cylindrical channels (see Chapter 9). However, for other geometries and flow patterns we have to rely on empirical or semiempirical correlations. Next, the modeling of the monolith reactors will be presented. On this basis, comparisons will be made between three basic types of continuous three-phase reactor monolith reactor (MR), trickle-bed reactor (TBR), and slurry reactor (SR). Finally, for MRs, factors important in the reactor design will be discussed. [Pg.267]

The degree of conversion was computed using Eq. (3.55) by means of basic relations for a reactor with large N with the result that at constant flow rate the maximum achievable conversion is 71%. Remarkably, Shih and Carr [905] computed, for a FIA reactor of an unspecified geometry, the maximum conversion to be 71.5% using a different, very elegant mathematical approach. [Pg.129]


See other pages where Geometries, basic reactor is mentioned: [Pg.293]    [Pg.1]    [Pg.31]    [Pg.20]    [Pg.220]    [Pg.484]    [Pg.152]    [Pg.567]    [Pg.34]    [Pg.238]    [Pg.414]    [Pg.13]    [Pg.220]    [Pg.172]    [Pg.567]    [Pg.275]    [Pg.538]    [Pg.601]    [Pg.140]    [Pg.219]    [Pg.567]    [Pg.596]    [Pg.567]    [Pg.42]    [Pg.62]    [Pg.240]    [Pg.414]    [Pg.2103]    [Pg.445]    [Pg.493]    [Pg.494]    [Pg.177]    [Pg.381]    [Pg.2089]    [Pg.843]    [Pg.330]    [Pg.148]   
See also in sourсe #XX -- [ Pg.375 ]




SEARCH



Basic geometry

© 2024 chempedia.info