Single phase reactors

Single-or three-phase Single-phase reactors are used in the neutral circuit either to limit the ground fault currents or as arc-suppression coils (Section 20.5). Similarly, three-phase reactors are used for three-pha.se applications. 

S/ze of a three phase reactor Size of a single-phase reactor... 

Computational fluid dynamics (CFD) is rapidly becoming a standard tool for the analysis of chemically reacting flows. For single-phase reactors, such as stirred tanks and empty tubes, it is already well-established. For multiphase reactors such as fixed beds, bubble columns, trickle beds and fluidized beds, its use is relatively new, and methods are still under development. The aim of this chapter is to present the application of CFD to the simulation of three-dimensional interstitial flow in packed tubes, with and without catalytic reaction. Although the use of... 

In a single-phase reactor we have to solve a mass-balance equation for each reaction. In a multiphase reactor we have to solve one mass balance equation for each reaction in each phase so for R reactions in P phases we would have to solve R x P simultaneous mass-balance equations. 

This seems Hke a formidable problem, but we note immediately that we can describe these situations simply as two or three of our old single-phase reactors coupled together (Figure 12-1). Here the superscripts a, P, and y are the designation of the phase, and is the interfacial area between phases. We use superscripts to designate phases in this chapter... 

Neither of these processes is yet practiced commercially, mainly because of materials durability problems. However, they indicate the types of processes in which use of a membrane could improve reactor performance compared to a single-phase reactor. 

Generalized Mass-Balance and Design Equations for a Single-Phase Reactor... 

Section 7 of this Handbook presents the theory of reaction kinetics that deals with homogeneous reactions in batch and continuous equipment. Single-phase reactors typically contain a liquid or a gas with (or without) a homogeneous catalyst that is processed in a reactor at conditions required to complete the desired chemical transformation. 

Reaction engineering may be experiencing the same thing. If we continue to work on fixed-bed single-phase reactors with multiple steady states in... 

Bioreactors In biotechnology, although single-phase reactors are used (e.g., see the enzyme reactor described above), multiphase reactors are predominant. There are characteristics of bioreactors that set them apart from the t) ical chemical reactors, such as, for example, the presence of biomass that can remain in suspension but can also form biofilms on any surface. Formation of biofilms can either be a desired or an unwanted side reaction, depending on the objective of the application. 

You are to simulate a single-phase reactor in which a single reaction takes place. The reaction has... 

In order to understand these aspects, it may be useful to consider the operation of a single-phase reactor of arbitrary type. The microscopic mass balance of a reactant over an element of reactor volume (Fig. 1.3) can be written in the following general form applicable to any reactor type ... 

The theory of single phase materials is not only of principal importance analyzing single phase reactor systems, it also serves as basis for the description of multiphase flows. 

In chemical reaction engineering single phase reactors are often modeled by a set of simplified ID heat and species mass balances. In these cases the axial velocity profile can be prescribed or calculate from the continuity equation. The reactor pressure is frequently assumed constant or calculated from simple relations deduced from the area averaged momentum equation. For gases the density is normally calculated from the ideal gas law. Moreover, in situations where the velocity profile is neither flat nor ideal the effects of radial convective... 

Turbulence closure models for the unknown terms in the flux- and variance equations for single phase reactor systems are discussed extensively by Baldyga and Bourne [5] and Fox [49] [50]. However, the application of these model closures should be treated with care as most of these parameterizations are expressed in terms of the turbulent eddy and other scalar dissipation rates (and dissipation energy spectra) which are about the weakest links in turbulence modeling. The predictive capabilities of the Re3molds averaged models... 

Single phase fluid flows (single phase reactors, i.e., laminar and turbulent flows). 

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