Performance enhancement reactor

Fig ure 10-12a. The configuration of this radial fixed-flow reactor provides scope for investigating proposed performance-enhancing modifications. 

Application of CFD to reactors and other process vessels is sure to grow. It not only permits innovation and performance enhancement for new processes and equipment, but also allows substantial improvement in the operation of mature technologies. 

Another example of performance enhancement using a zeolite/TUD-1 catalyst is shown in n-hexane cracking using a series of zeolite-Beta-embedded TUD-1 catalysts (29) 20, 40 and 60 wt% zeolite Beta in Al-Si-TUD-1 (Si/Al = 150). These are compared to pure zeolite Beta, and to a physical mixture of 40% zeolite Beta and 60% Al-Si-TUD-1. These catalysts were tested in a fixed bed reactor, at atmospheric pressure, with constant residence time at 538°C. The pseudo-first-order rate constants are shown in Figure 41.8. Note that the zeohte-loaded catalysts were clearly superior to both the pure zeolite Beta catalyst and the zeohte-TUD-1 physical mixture. Again, this is evidence that catalyst performance benefits from a hierarchical pore stracture such as zeolite embedded in TUD-1. 

Reactor Company Type of cathode Frequency and method of product removal Performance enhancement mainly via ... 

The viability of one particular use of a membrane reactor for partial oxidation reactions has been studied through mathematical modeling. The partial oxidation of methane has been used as a model selective oxidation reaction, where the intermediate product is much more reactive than the reactant. Kinetic data for V205/Si02 catalysts for methane partial oxidation are available in the literature and have been used in the modeling. Values have been selected for the other key parameters which appear in the dimensionless form of the reactor design equations based upon the physical properties of commercially available membrane materials. This parametric study has identified which parameters are most important, and what the values of these parameters must be to realize a performance enhancement over a plug-flow reactor. 

The suspension process is practiced by only a few companies because it offers a higher degree of production control and product engineering during polymerization step. This process suspends the water-based reactant in a hydrocarbon-based solvent. The net result is that the suspension polymerization creates the primary polymer particle in the reactor rather than mechanically in postreactions stages. Performance enhancements can also be during or just after the reaction stage. 

C. O. Jeon, D. S. Lee and J. M. Park (2003). Rhodocyclus and Proteobacteria microbial communities in activated sludge performing enhanced biological phosphorus removal in a sequencing batch reactor. Water Res., 37, 2195-21205. 

The Competitive edge of any reactor technology rests on how well the underlying flow processes are designed and operated. If the underlying flow processes are adequately studied and controlled, there is always scope for performance enhancement and for... 

Performance enhancement of existing or new reactors may be realized in a variety of ways, such as ... 

These models require information about mean velocity and the turbulence field within the stirred vessels. Computational flow models can be developed to provide such fluid dynamic information required by the reactor models. Although in principle, it is possible to solve the population balance model equations within the CFM framework, a simplified compartment-mixing model may be adequate to simulate an industrial reactor. In this approach, a CFD model is developed to establish the relationship between reactor hardware and the resulting fluid dynamics. This information is used by a relatively simple, compartment-mixing model coupled with a population balance model (Vivaldo-Lima et al., 1998). The approach is shown schematically in Fig. 9.2. Detailed polymerization kinetics can be included. Vivaldo-Lima et a/. (1998) have successfully used such an approach to predict particle size distribution (PSD) of the product polymer. Their two-compartment model was able to capture the bi-modal behavior observed in the experimental PSD data. After adequate validation, such a computational model can be used to optimize reactor configuration and operation to enhance reactor performance. 

FIGURE 9.4 Two alternatives to enhance reactor performance, (a) Four pitched blade turbine, (b) two pitched blade turbine with cage. 

A. Rouge, A. Renken, Performance enhancement of a microchannel reactor under periodic operation, in G.F. Froment, K.C. Waugh (Eds.), Reaction kinetics and the development and operation of catalytic processes, Studies in Surface Science and Catalysis, Vol. 133Elsevier Science B. V., Amsterdam, 2001, p. 239. 

Table 5 summarises the design concepts and means of performance enhancement for selected reactors, a subdivision being made according to the nature of the metal product and its frequency of removal. 

The presence of the membrane at the initial reaction stage (reactor entrance) increases cost without giving a significant performance enhancement. The membrane operates only in the second part of the catalytic bed where the hydrogen partial pressure is high enough to promote the permeation in the desired direction, from the reaction to permeate side. 

Rouge, A. and Renken, A. (2001) Performance enhancement of a microchannel reactor under periodic operation. Stud. 

This chapter is organised as follows firstly, enhanced processes concepts are presented (Section 6.2), then the sorbent properties and performances (Section 6.3), thirdly enhanced reactor configurations (Section 6.4) are discussed and finally, examples of performances and economic benefits of sorption-enhanced processes for CO2 capture are shown (Section 6.5). 

As briefly introduced in the previous sections, the sorbent is the most important component in an enhanced reactor since it determines the reactor design and the performance of the process. The sorbent material must have the following characteristics ... 

In the past decade, a wide variety of aromatic substitution reactions has been intensively investigated by applying microreaction technology in conjunction with appropiate process settings to identify routes towards optimized process performance. Enhanced heat and mass transport characteristics achievable in microstruc-tured reactors have been dehberately used to obtain higer product yields, selectivities and purities. Moreover, microreactors have been suceessfuly used to identity synthesis routes towards new products and process conditions which are not attainable in macroscopic bacth processes. 

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