Optimization of reactor operation

In fact, enzyme inactivation by exposure to the reaction temperature is unavoidable, since temperature exerts opposite effects o enzyme aetivity and stability so that operation temperature is always a compromise between the two. Enzyme inactivation during reaction operation occurs no matter how stable the enzyme is, since in any case operation is prolonged to the point in which a significant fraction of the initial activity is lost. Actually, the residual activity at which the biocatalyst should be disposed off is a quite relevant criterion for the optimization of reactor operation. 

Optimization of reactor operation policy is of paramount importance if improvement of product quality and increase of business profits are sought. In very specific terms, optimization of the reactor operation conditions is equivalent to producing the maximum amount of polymer product, presenting the best possible set of end-use properties, with minimum cost under safe and environmentally friendly conditions. This optimum solution is almost always a compromise. Increase of polymer productivity is usually obtained with the increase of the operational costs (increase of reactor volumes, reaction temperatures and reaction times, for instance). Besides, the simultaneous improvement of different end-use properties is often not possible (the improvement of mechanical performance is usually obtained through increase of molecular-weight averages, which causes the simultaneous increase of the melt viscosity and decrease of product processibihty). Therefore, the optimization can only be performed in terms of a relative balance among the many objectives that are pursued. 

Undoubtedly, much can be gained from the optimization of reactor operating conditions. Often neglected, however, is the fact that much more can be gained by optimizing the reactor size at the same time. This fact will be pointed out and illustrated whenever appropriate to emphasize the importance of optimizing with respect to both reactor size and operating conditions. 

The comparison of the results obtained from model particle systems with experience of biological systems shows a similar tendency on many points. Therefore it proved to be very advantageous for the basic investigations, especially for the comparison of different reactor types, to use suitable model particle systems with similar properties to those of biological material systems. This permitted the performance of test series under technically relevant operating conditions, similar to those prevailing in bioreactors, in a relatively short time. The results are more reproducible than in biological systems and therefore permit faster and more exact optimization of reactors. 

Ambulgekar et al. [30] investigated the oxidation of toluene using aqueous KMn04 as an oxidizing agent in the hydrodynamic cavitation reactor with an objective of optimization of the operating parameters. The reaction scheme can be depicted as follows ... 

Most of the work on ethanol reforming to date focused mainly on catalyst development, optimization of reaction operations and thermodynamic analyses. However, detailed kinetic studies, which are very useful to understand the activity at the molecular level and to build a suitable catalytic reactor on an industrial scale for the reforming of ethanol need to be pursued. 

Optimisation may be used, for example, to minimise the cost of reactor operation or to maximise conversion. Having set up a mathematical model of a reactor system, it is only necessary to define a cost or profit function and then to minimise or maximise this by variation of the operational parameters, such as temperature, feed flow rate or coolant flow rate. The extremum can then be found either manually by trial and error or by the use of numerical optimisation algorithms. The first method is easily applied with MADONNA, or with any other simulation software, if only one operational parameter is allowed to vary at any one time. If two or more parameters are to be optimised this method becomes extremely cumbersome. To handle such problems, MADONNA has a built-in optimisation algorithm for the minimisation of a user-defined objective function. This can be activated by the OPTIMIZE command from the Parameter menu. In MADONNA the use of parametric plots for a single variable optimisation is easy and straight-forward. It often suffices to identify optimal conditions, as shown in Case A below. 

In the current work, we present a comprehensive approach to the problem dynamic mathematical models for simultaneous reactions media, numerical methodology as well as model verification with experimental data. Design and optimization of industrially operating reactors can be based on this approach. 

As a batch reactor is utilized for the production of a wide variety of high value products, an optimization of batch operating conditions, e.g. temperature, operating time, etc. is... 

J. Bilbao, M. Olazar, A. Romero, J.M. Arandes, Optimization of the operation in a reactor with continuous catalyst circulation in the gaseous benzyl alcohol polymerization, Chem. Eng. Commun. 75 (1989) 121-134. 

The use of the HEA Column plus the DCN Reactor in series (see Figure 9.8) allows the optimization of the operating conditions and the operating cost. The HEA Column removes the majority of the NOx and stabilizes the NOx content in the tail gas. The DCN reactor destroys the remaining NOx as required to meet the emission limits. A comparison of the operating conditions for the Monsanto technology is given in Table 9.7". 

This section presents the oxidation of a poorly soluble compound, the tricyclic PAH anthracene, by the enzyme VP in a biphasic reactor. The optimization of the operation of the TPPB will be focused in four critical aspects ... 

The activation energy for the side reaction is 84.1 kJ/mol, making it nearly 3 times more responsive to temperature than the main reaction. At 453 K, where the side reaction starts playing an important role, this translates to a 5 percent increase in the side reaction per kelvin compared to less than 2 percent for the main reaction. At very high temperatures the side reaction completely dominates the picture. Control and optimization of reactor temperature is essential for economic operation. 

This section is focused on the catalyst selection for optimal Prox reactor operation. During the discussion, catalyst formulation will generally cover the active metal (Pt, Rh, Cu, etc.) and support (A1203, ZnO, etc.) with promoters (La, Ce, etc.) however, there are instances in which studies done are more focused on the active metal regardless of the support used and is indicated where appropriate. It should be kept in mind that catalyst formulation selection must be done in the context of the desired performance outcome, or avoidance of certain characteristics and reformate mix. 

In the present paper, the Pd-La/spinel catalyst for this reaction was developed. On this catalyst, the activity and selectivity were high, especially the stability was increased greatly, and it was up to 480 hours under the conditions of 220°C and LHSV=0.3h . But the high initial activity decreases along with time, which impairs the catalyst practice in industrial applications. For this reason, it is important to understand the deactivation mechanism. This work concerns an investigation into the coke formation on the Pd-La/spinel catalyst in the gas-phase amination of 2,6-DIPP. Furthermore, the correlation between coke deposition and combustion was analyzed. The results provide fundamentals not only to develop new catalysts but also to optimize the reactor operation parameters. 

Can you meet these design constraints with all three of the catalysts Once you have met the constraints, you can optimize the reactor operation over the remaining design decision variables. What is your final choice of catalyst size, and at what nominal Inlet pressure will you run the reactor Indude a plot of the pressure, conversion, and Thiele modulus versus reactor length for your final design. 

Illanes A, Wilson L, Raiman L (1999) Design of immobilized enzyme reactors for the continuous production of fructose syrup from whey permeate. Bioproc Eng 21 509-515 Illanes A, Wilson L, TomaseUo G (2000) Temperature optimization for reactor operation with chitin-immobiUzed lactase under modulated inactivation. Enzyme Microb Technol 27 270-278 Illanes A, Anjari S, Altamirano C et al. (2004) Optimization of cephalexin synthesis with immobilized penicillin acylase in ethylene glycol medium at low temperatures. J Mol Catal B Enzym 30 95-103... 

Temperature is a variable of paramount importance in any bioprocess. Temperature optimization of bioreactor operation is a complicated task since many variables and parameters are involved that are strongly dependent on temperature. Besides, temperature exerts opposite effects on enzyme activity and stability. Then, thermal optimization of enzyme reactor operation requires that temperature explicit functions for all parameters involved be determined and validated. Optimization wifi... 

Fig. 5.22 Surface of response for temperature optimization of continuous staggered CPBR with chitin-immobilised P-galactosidase, based on data in Table 5.3, considering the annual cost of reactor operation as the objective function...

Optimization of the Operational Parameters of the Enzymatic Membrane Reactor... 

A different reactor can change the regime. A good aim is to look for a reactor which operates in Regime I, i.e. high kio where the chemistry is not restrained by mass transfer. The final choice must obviously take account of requirements for heat transfer, particle suspension, foam control, materials of construction and a feasible size for the full scale equipment. Only in the simplest cases are there sufficient degrees of freedom to allow economic optimization of reactor type. 

Due to systematic activity on improvement of equipment and systems, optimizations of their operating modes the reactor plant main equipment specified lifetime has been increased from (25-30)x lO hrs for the first NSSSs up to (100-120)x lO hrs for the modem ones. 

The primary consequence of burnup is a drop in /c-effective as the fuel bums out and fission products are built up. This drop is compensated by the build-up of new fissile isotopes (notably Pu-239 from U-238 neutron absorption in uranium-fueled reactors). Generally, boiling water reactors and pressurized water reactors replace the fuel in stages, with fresh fuel assemblies replacing the most burned-out assemblies at scheduled shutdowns with nonreplaced assemblies often moved (shuffled) to new positions to optimize the reactor operating characteristics. 

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