Reactors general

BWRf 6 General Description of a Boiling Water Reactor, General Electric Co., Nuclear Energy Group, San Jose, California, 1980. 

Reactors may be operated batchwise or continuously, e.g. in tubular, tubes in shell (with or without internal catalyst beds), continuous stirred tank or fluidized bed reactors. Continuous reactors generally offer the advantage of low materials inventory and reduced variation of operating parameters. Recycle of reactants, products or of diluent is often used with continuous reactors, possibly in conjunction with an external heat exchanger. 

I., Mikkola, J.-P., and Salmi, T. (2004) The development of monolith reactors general strategy with a case study. Chem. Eng. Sci., 59, 5629-5635. 

Janssen, E., and S. Levy, 1962, Burnout Limit Curves for Boiling Water Reactors, General Electric Co. Rep. APED-3892. (5)... 

Typically, reactors are made of stainless steel, which is resistant to most materials although the reactors have been known to catalyse reactions themselves [20], As mentioned above, scH20 corrodes steel, and mixtures of scC02 and water give an acid which is capable of corroding steel relatively quickly under supercritical conditions. Batch reactors generally consist of cylinders of steel with an... 

Pressure drop Fixed-, moving-bed, and BFB G/S reactors Liquid-phase reactors Generally all deep beds Entrained-bed reactors... 

Fig. ]. Contemporary direct-cycle reactor system used in boiling water reactor. (General Electric.1...

Fig 32. Loop arrangement in the liquid-metal fast breeder reactor. General Electric)... 

These are actions of the computer which are initiated by events, e.g. switching off a pump when a tank has been filled to a certain level. They form the basis of the response of computer-controlled plant to alarm conditions, e.g. if the temperature in the reactor described in Fig. 7.102 exceeds a specified value then action must be taken by the computer, such as rapidly increasing the flow of coolant or reducing the feed to the reactor. Generally, sensor-initiated operations must be performed within a specified maximum time interval and are often in the form of alarm interrupts (Section 7.18.3). Smaller systems will regularly scan a set of specific process variables via a multiplexer to see if any action is necessary. The latter arrangement is called polling. 

Another factor to be considered is the time required to fabricate additional liners if the initial supply is depleted. Recently, General Atomics claimed it was able to fabricate 20-mil thick liners of the required diameter for the reactor. General Atomics plans to float a precious-metal liner in a cylindrical Hastelloy pressure vessel and use cooled elastomeric O-rings that have performed satisfactorily on other SCWO systems to form the SCWO reactor. The annular space between the liner and the vessel wall will be monitored for leaks to indicate when change-out of the liner is required. No decision has been made yet on whether to use platinum or Pt-20%Ir. Because they have markedly different mechanical properties, these two liner materials may require significantly different fabrication methods. Platinum is relatively weak and very ductile Pt-20%Ir is less ductile but 10 times stronger. Final selection of the liner material for use at the NECDF was scheduled for early 2000. Fabrication... 

HEX reactors generally fall into three basic types (18). 

A modular micro structured chemical reaction system (ICS) similar to [R 14] is claimed by Bard [84]. The system can use various replaceable and interchangeable cylindrical or rectangular reactors. Generally, the ICS system can include fluid flow handling and control components, mixers, reaction chip-type units, separator devices, process variable detectors and controllers and a computer interface for communicating with the master control center (see Figure 4.31) [84],... 

Today s laboratory-scale batch microwave reactors generally offer a maximum batch size of 1 L reaction volume, in most cases divided into several smaller reaction vessels (multivessel rotor systems). According to the definition given at the beginning, this would not exactly match the one vessel ... 

Another important issue evolves if the dendritic catalyst will be used in a continuous-flow membrane reactor. Generally, two forms of leaching have to be considered when dendritic transition metal catalysts are used in such reactors depletion of the dendritic catalyst through the membrane and metal dissociation (possibly after decomposition) from the dendrimer resulting... 

Industrial reactors generally operate adiabatically. Cholette and Blanchet [8] compared adiabatic plug flow reactor to the CSTRmm. For exothermic reactions, they inferred that the performance of a CSTRmm is better than that of a plug flow reactor at low values of conversion, and vice-versa at high values of conversion. They further showed that the design considerations for endothermic reactions are similar to those for isothermal reactions. 

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