Static reactor analysis

Static reactors are most useful for comparatively slow reactions, or for characterizing explosion behavior (Fig. 13.4). Typical reaction times are seconds to minutes. However, due to a high sensitivity to surface effects, static reactor experiments are generally not as useful for quantitative analysis as alternative techniques. 

The static reactor method used for absolute rate determinations, and almost always for ortho -para deuterium studies, is generally that based on the micro-Pirani gauge analysis chamber as adapted by Ashmead et al. (3). The time necessary for a single determination of the extrinsic field effect by this method is unfortunately likely to be measured in hours or days rather than in seconds as for the flow reactor. To date the only application of this method to the extrinsic field effect appears to be that of Eley et al. (4). Van Cauwelaert and Hall (5) have described a recirculating adaptation of the static reactor that would seem to be useful for studying the field effect. 

All the catalytic hydrogenations (2-pentyl-2-nonenal or cinnamaldehyde) were carried out in a 200-ml static reactor under atmospheric pressure with a continuous flow of hydrogen and at temperatures ranging from 50°C to 120°C (23). Activity and selectivity values were obtained by gas phase chromatography analysis of the liquid mbdure on a Cp SIL5 capillary column. 

Safety and control calculations represent "side" calculations that are performed at each burnup step, once the proper neutron cross sections are determined, to calculate reactor behavior under accident and normal reactor control conditions. From the point of view of reactor analysis, both of these build on Steps 1-6 of analysis of the reactor static conditions to determine the reactor kinetic conditions. 

Kinetic experiments were carried out isothermaUy in autoclave reactors of sizes 300 and 600 ml. The stirring rate was typically 1800 rpm. In most cases, the reactors were operated as slurry reactors with small catalyst particles (45-90 tm), but comparative experiments were carried out with a static basket using large catalyst pellets. HPLC analysis was appHed for product analysis [22, 23]. 

If, for example, the reactor temperature is disturbed from 2/3, the high temperature steady state, to y4 that is not a steady-state temperature, then the static diagram helps us to determine the direction of temperature change towards a steady state of the system as follows. At y4 the heat generation exceeds the heat removal since G(y4) > R(y4) from the graph. Therefore, the temperature will increase. A quantitative analysis of the temperature-time trajectory can of course only be determined from a dynamic model of the system. 

When the reaction rate is slow, the main component should be absorbed not in a flow but rather under quasi-static conditions in the reactor upstream of the chromatographic column. For example, Janak and Novak [42], in the analysis of trace components in butadiene-1,3, provided for absorption of the main component by maleic anhydride... 

For a reactor to fulfil its intended task, its design must be cognizant of the inevitable deactivation of the catalyst and the significant changes in temperature and species profiles. In this study, the inputs to the bed are assumed static (fixed feed flows and wall temperature) to ease analysis of the evolution of the bed. A more comprehensive model is required where inputs to the bed are varied according to the changes in the reactor with the objective of maximizing the life of the catalyst. 

Sodium release to RGB under CD A has been estimated at about 1.5 t, based on the approach followed for FFTF reactor. The important input to this analysis are the transient and quasi-static pressure of the sodium after slug impact beneath the top shield and the fraction of the sodium mass in the reactor assembly which has potential to get ejected. These parameters are obtained from the detailed fast transient fluid-structure interaction analysis using an in-house computer code called FUSTIN. A preliminary estimate is also made on the transient pressure and temperature rise in the RGB for the 1.5 t of sodium release and the values are 30 kPa and 80 K respectively. 

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