Plug flow, isothermal

Detailed Modeling Results. The results of a series of detailed calculations for an ideal isothermal plug-flow Langmuir system are summarized in Figure 15. The soHd lines show the form of the theoretical breakthrough curves for adsorption and desorption, calculated from the following set of model equations and expressed in terms of the dimensionless variables T, and P ... 

Another view is given in Figure 3.1.2 (Berty 1979), to understand the inner workings of recycle reactors. Here the recycle reactor is represented as an ideal, isothermal, plug-flow, tubular reactor with external recycle. This view justifies the frequently used name loop reactor. As is customary for the calculation of performance for tubular reactors, the rate equations are integrated from initial to final conditions within the inner balance limit. This calculation represents an implicit problem since the initial conditions depend on the result because of the recycle stream. Therefore, repeated trial and error calculations are needed for recycle... 

Continuous isothermal plug flow reaetor (the reaetor mixture is at thermal equilibrium with the surroundings). 

CONTINUOUS ISOTHERMAL PLUG FLOW TUBULAR REACTOR... 

A one-dimensional isothermal plug-flow model is used because the inner diameter of the reactor is 4 mm. Although the apparent gas flow rate is small, axial dispersion can be neglected because the catalj st is closely compacted and the concentration profile is placid. With the assumption of Langmuir adsorption, the reactor model can be formulated as. 

The results confirm that the adsorption of ammonia is very fast and that ammonia is strongly adsorbed on the catalyst surface. The data were analyzed by a dynamic isothermal plug flow reactor model and estimates of the relevant kinetic parameters were obtained by global nonlinear regression over the entire set of runs. The influences of both intra-particle and external mass transfer limitations were estimated to be negligible, on the basis of theoretical diagnostic criteria. 

At present conversion is 2/3 for our elementary second-order liquid reaction 2A 2R when operating in an isothermal plug flow reactor with a recycle ratio of unity. What will be the conversion if the recycle stream is shut off ... 

An isothermal, plug flow, fixed bed reforming pilot plant (shown in Fig. 14) was used to generate the kinetic data. The reactor was U shaped and contained roughly 70 ml of catalyst. Five sample taps were spaced along the reactor length to determine compositions over a wide range of catalyst contact times. The reactor assembly was immersed in a fluidized sand bath to maintain isothermal conditions. 

Most commonly, distributed parameter models are applied to describe the performance of diesel particulate traps, which are a part of the diesel engine exhaust system. Those models are one- or two-dimensional, non-isothermal plug-flow reactor models with constant convection terms, but without diffusion/dispersion terms. 

It is worthwhile to compare the conversion obtained in an isothermal plug flow reactor with that obtained in a CSTR for given reaction kinetics. A fair comparison is given in Fig. 7.3 for irreversible first-order kinetics by showing the conversion obtained in both reactors as a function of To- The conversion of A obtained in a plug flow reactor is higher than that obtained in a CSTR. This holds for every positive partial reaction order with respect to A. For multiple reactions selectivities and yield enter into the picture. 

CALCULATING THE SIZE OF AN ISOTHERMAL PLUG-FLOW REACTOR 5.9... 

In this section, we still restrict ourselves to the consideration of systems where only the overall behavior is of interest, but we extend the analysis to actual chemical reactors. Indeed, the discussion in the previous section was limited to the overall kinetics of multicomponent mixtures seen from the viewpoint of chemical reaction engineering, the discussion was in essence limited to the behavior in isothermal batch reactors, or, equivalently, in isothermal plug flow reactors. In this section, we present a discussion of reactors other than these two equivalent basic ones. The fundamental problem in this area is concisely discussed next for a very simple example. 

A non-isothermal plug-flow membrane reactor on both sides of the membrane has been developed and applied to the methane steam reforming reaction to produce synthesis gas at high temperatures according to [Oeitel et al., 1987]... 

Early attempts to approximate gas-solid contacting in fluid catalyst beds were based on the assumption either of isothermal plug flow of the fluidizing gas through the bed with the catalyst uniformly distributed or of isothermal complete mixing of the gas within the bed. The simple dispersion model, falling between the above two cases, was also used (G8, R4). Evidence from both large-scale and laboratory observations (G9a, L12),... 

Catalytic reactions were carried out in an isothermal plug flow reactor at 673K. Products were collected during the run and the average conversion measured. Reaction times varied between 1 and 30 minutes. 99.45% pure 2M obtained froia Aldrich was used without further purification. The principal impurity was 3-Methylpentane (0.55%). Experimental procedures and analytical techniques were outlined elsewhere (7 8). 

For an isothermal plug flow packed bed reactor the following system of differential equations can be obtained... 

In this section, you will solve the equations for an isothermal plug flow reactor. The first problem is very simple, and is patterned after a problem on the California Professional Engineers License Examination, according to Fogler (2005). Here it is modified. You take a reactor in which components A and C are fed in equimolar amounts, and the following reaction takes place ... 

Isothermal plug flow reactor. Chapter 8, p. 118 Nonisothermal plug flow reactor. Chapter 8, p. 121. 

Below, we analyze the operation of isothermal plug-flow reactors with single reactions for different types of chemical reactions. For convenience, we divide the analysis into two sections (i) design and (ii) determination of the rate expression. In the former, we determine the size of the reactor for a known reaction rate, specified feed rate, and specified extent (or conversion). In the second section, we determine the rate expression and its parameters from reactor operating data. 

---