Reactor unit design

8 - core catcher, 9 - upper stationary shield slab, 10 - hot inner, tank, 

13 - containment, 14 - refuelling mechanism, 15 - elevator, 16 - refuelling cell, 17 - FAs transfer siechaniem 

8 -refuelling machine, 9 - elevator, 10 - protective dome containment), 

11 - fuel transfer cell, 12 - washing cell, 13 - fuel transfer mechanism. 

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Reactor unit design characteristics are a significant component of the PRIS database. Significantly, they represent a comprehensive source of information on all reactor units worldwide, whether in operation, under construction or permanently shutdown. In combination with other PRIS data and outputs, such as production data, outage data and performance indicators, design characteristics offer an important tool for various performance analyses. The classification system enables the appropriate characteristics to be used as convenient selection or filtration criteria for choosing reactor units suitable for a particular analysis, thereby improving the relevancy of such analyses. 

Sasol uses both fixed-bed reactors and transported fluidized-bed reactors to convert synthesis gas to hydrocarbons. The multitubular, water-cooled fixed-bed reactors were designed by Lurgi and Ruhrchemie, whereas the newer fluidized-bed reactors scaled up from a pilot unit by Kellogg are now known as Sasol Synthol reactors. The two reactor types use different iron-based catalysts and give different product distributions. 

In the modern unit design, the main vessel elevations and catalyst transfer lines are typically set to achieve optimum pressure differentials because the process favors high regenerator pressure, to enhance power recovery from the flue gas and coke-burning kinetics, and low reactor pressure to enhance product yields and selectivities. 

The ROTOBERTY internal recycle laboratory reactor was designed to produce experimental results that can be used for developing reaction kinetics and to test catalysts. These results are valid at the conditions of large-scale plant operations. Since internal flow rates contacting the catalyst are known, heat and mass transfer rates can be calculated between the catalyst and the recycling fluid. With these known, their influence on catalyst performance can be evaluated in the experiments as well as in production units. Operating conditions, some construction features, and performance characteristics are given next. 

The large physical size of the later Magnox stations, such as Wylfa, led to the development of the more compact advanced gas-cooled reactor (AGR) design [31] that could utilize the standard turbine generator units available in the UK, Stainless-steel clad, enriched uranium oxide fuel can tolerate higher temperatures... 

The One-Dimensional Pseudo Homogeneous Model of Fixed Bed Reactors. The design of tubular fixed bed catalytic reactors has generally been based on a one-dimensional model that assumes that species concentrations and fluid temperature vary only in the axial direction. Heat transfer between the reacting fluid and the reactor walls is considered by presuming that all of the resistance is contained within a very thin boundary layer next to the wall and by using a heat transfer coefficient based on the temperature difference between the fluid and the wall. Per unit area of the tube... 

When we can predict the response of the reacting system to changes in operating conditions (how rates and equilibrium conversion change with temperature and pressure), when we are able to compare yields for alternative designs (adiabatic versus isothermal operations, single versus multiple reactor units, flow versus batch system), and when we can estimate the economics of these various alternatives, then and only then will we feel sure that we can arrive at the design well fitted for the purpose at hand. Unfortunately, real situations are rarely simple. 

After the CFD analysis and scale model studies are complete, the SCR unit design is done. Scale up and fabrication of the unit follows. The SCR catalyst modules and other equipment are produced. SCR catalyst for an FCCU is delivered as modules to reduce the number of crane lifts to load the reactor. The individual catalyst cubes... 

In complex systems such as three-phase reactors, the methods of mathematical modeling cannot provide the required information for process design and scale-up since it is practically impossible to take into account all existing phenomena and safely predict the influence of hydrodynamics, heat and mass transfer, or kinetics on each other (Datsevich and Muhkortov, 2004). Thus, models are almost always approximate in nature. They are based on a number of assumptions that cannot be met during scale-up. So, it is not surprising that industrial unit designers do not completely trust the results obtained from mathematical modeling. Thus, several systems cannot be fully modeled mathematically and other methods for scale-up are followed. 

These reactants A and B are thus brought together in a reactor with the required temperature, pressure and catalysts to speed up the reaction. It is important that the reactor is designed with a suitable material of construction in such a manner that chemicals A and B spend the required reaction time. The final step might be to send the product to a continuous distillation unit or to a settling tank or to any other device which may be called as a separator which would separate C away from other chemicals in the stream. The additional... 

Impurities such as diolefins and mercaptans in the feed to the reactor affect adversely the quality of the alkylate produced. This is considered to be more critical in sulfuric acid than in HF catalyst units. Also, certain sulfuric unit designs seem to tolerate more normal butane than others. Whereas the isobutane content of the recycle to a hydrofluoric acid unit can operate at purities of around 75% without affecting product qualities appreciably, the isobutane content of the recycle stream to most sulfuric acid units should be 90 % or better. 

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