Optimum reaction temperature curve

Figure 14. Equilibrium limitation of exothermic reactions. A) Equilibrium conversion as a function of temperature B) Optimum reaction rate curve C) Improvement of conversion by multiple beds with interstage cooling.

In order to conduct the reactions along the optimum reactive temperature curve, the heat of reaction must be removed from the catalyst bed, and to reduce the reaction temperature (to recover the extracted heat). 

In addition the temperature dependency of enzyme activity must be measured, also yielding an optimum curve. This temperature optimum depends on the assay conditions, especially the incubation time, and is not, on its own, useful to identify a reasonable reaction temperature. Instead of this, the temperature stability of the enzyme has to be determined. To that end the enzyme is incubated with all relevant reaction components in test tubes, changing the temperature while keeping all other parameters constant. The assay conditions have to be as close as possible to the conditions relevant in the final process. In particular, stability measurements have to be performed in the presence of a relevant concentration of all substrates and coenzymes which have a stabilizing influence on the enzyme. 

In addition, when electric current flows through the electrolyte. Joule heat is released. Heat exchange occurs between the formation tank (or battery) and the surrounding atmosphere. The reactions during the different formation stages all provide individual contributions to the overall thermal balance of the system. Consequently, the temperature curves feature a maximum, and with attenuation of the exothermic chemical reactions of sulfation, the temperature of the tank (battery) decreases slowly. Battery manufacturing practice has shown that the optimum temperature range for the formation process is between 25 and 55°C. 

ATP formation on creatine and MgCl2 concentrations was also examined and the results are summarized in Fig. 6 and Fig. 7. Without creatine, ATP formation occurred later and more slowly but at the same high conversion level. The addition of excess creatine caused acceleration of ATP formation. Without creatine, the induction period took two times longer. As shown in the time conversion curve with heptakis-(2,6-dimethyl)-g-CD (DM-g-CD) without creatine, ATP formation occurred later and more slowly at the same conversion level. Besides these examinations, the effect of O2, buffer solution and temperature were observed. Without O2, the reaction did not proceed. Ionic strength and pH of the phosphate buffer and reaction temperature were optimum under the present conditions. The results obtained here showed the same kind of catalytic activity of the CD in the equilibrium between ADP and ATP in this scheme 1. This new type of transphosphorylation seems to be a... 

An isothermal DSC curve shows at a glance whether a reaction proceeds normally in other words, the rate of reaction and thus the heat flow reaches a maximum upon the reaction mixture s attainment of the reaction temperature. To locate a suitable isothermal reaction temperature, a dynamic experiment is carried out at 10 "C/min. The optimum isothermal temperature will lie between the start of reaction (at 20% of the peak height) and the peak maximum temperature. For example, an epoxy resin used for powder coating gives values of 180 °C to 220 °C. Conversely, an autocatalytic reaction shows an increasing reaction rate after an induction period. 

When the reaction is controlled by process dynamics, the optimum temperature curve of the reversible exothermic reaction (without any side reaction) can be obtained according to the kinetic equation using the common method that for finding the extremum. 

Fig. 8.5 Optimum temperature curve of ammonia synthesis reaction...

The cocurrent flow makes it possible to obtain a temperature profile which is close to the optimum the gas is heated adiabatically to a temperature close to the maximum reaction rate curve, and the temperature/conversion profile then follows closely the maximum rate curve for the test of the catalyst bed length. 

The experimental data of distillation curves of hydrocracked products obtained at the lowest LHSV (0.33 h ) at three reaction temperatures were used to determine the optimum set of parameters (5, a, Aq, a, and of the continuous kinetic model. Figure 11.6 shows the comparison between experimental and predicted distillation curves of the feedstock and the product hydrocracked at LHSV of 0.33 h" and 420°C. This plot is an example of the way the data are fed and reported by the MATLAB computer program as dimensionless curves. At 420°C, the optimum set of parameter values is a = 0.246, = 1.487, = 22.83, 8 = 1.67 x 10" , and... 

Influence of Salt Concentration. A series of experiments were performed to determine the influence of the salt concentration on the S02 reaction rate. The salts used were NaCl and NaN03 in concentrations ranging from 1 to 15 mole%. The experiments were carried out at a relative humidity of 54%, and a reactor temperature of 66°C. As can be seen from Figure 9, the conversion increases with increasing concentration of additive until about 10 mole%. After this the curve levels off. The optimum concentration of additive is then about 10 mole% for 1 1 electrolytes like NaCl and NaN03. 

For highly exothermic reactions, it is necessary to maintain the temperature at a desired level. In general, the heat-transfer coefficient is proportional to (Pg/F)0 25-033, and the actual power cost varies linearly with (Pt/V) these dependencies lead to an optimum value of the reactor volume. For these reactions, when the demand for mass transfer is not important, the radial-flow turbine (curved blades) can be used for an efficient heat transfer. Optimum stirring conditions in the laminar flow regime have been evaluated by Zlokarnik and Judat (1988) and Pawlowski and Zlokarnik (1972). 

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