Reactor shape

Figure 5. Effect of reactor shapes on Isotherms, flow streamlines and relative deposition rates of GaAs. The absolute growth rates scale as 0.88 (a) 0.91 (b) 0.94 (c) 1.0 (d) 1.08 (e).

Transitions in reactor shape from 3D to 2D projections or functional surfaces are interesting not the least from a technological point of view. It has to be mentioned that the reduction to two-dimensional structures or surfaces is easily possible due to the unique material properties of the basic building blocks, namely self-assembly and self-organization in a fluid-crystalline matrix. 

Figure 23.2 depicts four models of reactor shape changes in order to study and evaluate the chemical and physical peculiarities of volume- and shape-change modulated kinetics as well as thermod3mamics of bio-related... 

It is expected that ki is influenced by reactor shape, type of agitator, method of introducing the gas, and similar quantities which are a function of the... 

Other contributions have involved system modelling for specific situations such as a flow-based viscosimeter [43] and the development of novel strategies for system calibration [44]. The influence of tubular reactor shapes (coiled, 3-D, twisted and wave-shaped) has also been investigated [45—49] and comprehensively reviewed [50]. In this regard, contributions by Kolev and Pungor [51—54] are also relevant. 

Let us assume that a reaction is carried out in a reactor shaped as a thin, long pipe. 

The dAc dz term is usually zero since most tubular reactors have a constant diameter. For the exceptional case, we suppose that Adz) is known, say from the design drawings of the reactor. It must be a smooth (meaning differentiable) and slowly varying function of z or else the assumption of piston flow will run into hydrodynamic as well as mathematical difficulties. Abrupt changes in Ac will create secondary flows that invalidate the assumptions of piston flow. Thus reactors shaped like a megaphone are acceptable those with an abrupt change in diameter are not. 

The basic differential equations, as well as the integral equations for both longitudinal and backmixing reactors, are shown in Table 3-3. The corresponding product-distribution equations are shown in Table 3-4. From these equations it can be seen that backmixing, and thus reactor shape, has a considerable effect on product distribution as well as on required holding time. 

We made a TAP-like reactor as an attachment for TM+ (Fig.29) to analyze the NSR reaction. A quartz tube with a 4.5mm internal diameter and a length of 3Hmm is inserted into the TAP-like reactor with TM+. The time resolution of a transient reaction analysis with TAP is lower than that with TM-t-, because the time profile of reactants and products with TAP is obtained as the result of multistcp reaction and diffusion, which arc caused by the tube reactor shape instead of the planar catalyst. The most important advantages of TAP arc to evaluate the amount of decrease of reactant gas and product quantitatively. 

Furthermore, the reactor shape in the present instance is not spherical and therefore not of minimum size. The reactor is cylindrical and elongated. As the neutron density in a neutronic reactor is highest in the center, the effect of elongation is to reduce the neutron density at the ends of the long dimension of the reactor where the inlet and outlet are located. In this manner, the neutron escape is greatest in line along the short dimension of the reactor midway between the ends thereof and... 

The flow also depends on the reactor shape. The cylindrical tubular reactor is the most used but there are other shapes as conical and cylindrical trunk with transversal flow, which change the velocity profile affecting the flow as shown in Figure 14.1. The choice of the type of reactor depends on the flow and other factors ... 

In the 4S design, the reactor building is isolated horizontally by seismic isolators. The design standard already exists for such isolators for nuclear power plants (NPPs) in Japan [XIV-8]. The thin reactor shape results in a higher characteristic frequency therefore, the 4S reactor could be rigid against vertical shock. 

Specimen Reactor Shape Polymer (g) Water content Aeration rate... 

Most actual reactors deviate from these idealized systems primarily because of nonuniform velocity profiles, channeling and bypassing of fluids, and the presence of stagnant regions caused by reactor shape and internal components such as baffles, heat-transfer coils, and measurement probes. Disruptions to the flow path are common when dealing with heterogeneous systems, particularly when solids are present. To model these actual reactors, various regions are compartmentalized and... 

Compound parabolic collectors (CPCs) belong to the most promising photocatalytic solar reactors which combine the advantages of parabolic trough concentrator and non-concentrating system [178]. CPCs are low-concentration static collectors with reflective surface and can be designed for any given reactor shape (see Fig. 7.3a) [182]. The CPC reflectors are usually made from polished aluminum... 

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