Reactor utilization

Unlike radioisotope generators, nuclear reactors utilize the much more intense process of nuclear chain reaction. Since this process is controlled in the reactor, the energy output could be regulated depending on the system s requirements. It actually could produce twice its nominal power, if necessai"y. Nuclear reactors can pro dde greater electrical output than radioisotope generators using the same types of thermal converters. This output is comparable to that of fuel cells and solar arrays, while nuclear reactors are more durable and compact. 

There is a steady flow of publication which contributes theories and information to help in the choice of catalysts, the improvement of their selectivity, or the improvement in reactor utilization through increase in... 

Moderate Reactor Productivity. The rhodium catalyst is continuously recycled, but the catalyst is inherently unstable at low CO partial pressures, for example in the post-reactor flash tank. Under these conditions the catalyst may lose CO and eventually form insoluble Rhl3 resulting in an unacceptable loss of expensive catalyst. This reaction is also more likely to occur at low water concentrations, hence in order to run the process satisfactorily catalyst concentrations are kept low and water concentrations relatively high. Hence through a combination of lower than optimum reaction rate (because of low catalyst concentrations) and water taking up valuable reactor volume the overall reactor utilization is less than optimum. 

Distillation required - energy intensive Low reactor utilization Energy-intensive diluent recovery... 

Trickle Bed Reactors (2). A trickle bed reactor utilizes a fixed bed over which liquid flows without filling the void spaces between particles. The liquid usually flows downward under the influence of gravity, while the gas flows upward or downward through the void spaces amid the catalyst pellets and the liquid holdup. Generally cocurrent downward flow of liquid and gas is preferred because it facilitates... 

Existing uses of proteases in foods have been discussed in the foregoing section. Expanding such applications in the future depends upon our ability to control both the processes themselves and their costs. The development of continuous reactors utilizing free or immobilized enzymes will address each of these constraints. Furthermore, our understanding of the chemical basis for the various functional properties of proteins must be expanded... 

The ebullated, expanded, and slurry-bed reactors utilize a fluent catalyst zone unlike the stationary catalyst design of fixed-bed reactors. This design overcomes several of the problems encountered when processing residua in fixed-bed catalytic reactors. The commercial H-Oil process (Eccles et al., 1982 Nongbri and Tasker, 1985) employs the ebullated-bed, whereas the... 

A typical nuclear reactor utilizes uranium oxide, whose uranium content is approximately 3 percent uranium-235, and 97 percent uranium-238, by mass. During the fission reaction, the uranium-235 is consumed and fission products form. As the amount of uranium-235 decreases and the amounts of fission products increase, the fission process becomes less efficient. At some point, the spent nuclear fuel is removed and stored. Some of the radioactive fission products, because of their radioactivity and long half-lives, must be stored securely for thousands of years. Thus, nuclear waste management poses a tremendous challenge. 

Laurell T, Drott J, Rosengren L, Lindstrom K. Enhanced enzyme activity in silicon integrated enzyme reactors utilizing porous silicon as the coupling matrix. Sensors Actuators, B 1996 31 161-166. 

Polystyrene can be easily prepared by emulsion or suspension techniques. Harkins (1 ), Smith and Ewart(2) and Garden ( ) have described the mechanisms of emulsTon polymerization in batch reactors, and the results have been extended to a series of continuous stirred tank reactors (CSTR)( o Much information on continuous emulsion reactors Ts documented in the patent literature, with such innovations as use of a seed latex (5), use of pulsatile flow to reduce plugging of the tube ( ), and turbulent flow to reduce plugging (7 ). Feldon (8) discusses the tubular polymerization of SBR rubber wTth laminar flow (at Reynolds numbers of 660). There have been recent studies on continuous stirred tank reactors utilizing Smith-Ewart kinetics in a single CSTR ( ) as well as predictions of particle size distribution (10). Continuous tubular reactors have been examined for non-polymeric reactions (1 1 ) and polymeric reactions (12.1 31 The objective of this study was to develop a model for the continuous emulsion polymerization of styrene in a tubular reactor, and to verify the model with experimental data. 

The entrained flow reactor utilized in this study is virtually the same unit described by Scaroni et al. ( ). In order to improve knowledge about, and control of, the time-temperature history of the coal particles, modifications have been made to the reactor and to the predictions of the time-temperature history of particles in the reactor (9,10). 

The treatment by secondary plasma reactor utilizes chemically reactive species created in glow discharge without influences of electron and ion bombardments and luminous gas phase. In-glow LPCAT treatment, on the other hand, utilizes luminous gas phase without the influence of ion and electron bombardment, and chemically reactive species are created on PTFE by energy transfer from the luminous gas phase. Thus, surface treatment by secondary plasma works only with gases that produce relatively long-lived chemically reactive species. Most secondary plasma treatments appear to be surface modifications by air or oxygen. 

V. P. Gupta and W. J. M. Douglas [AIChE J., 13 (1967) 883] carried out the isobutylene hydration reaction with excess water in a stirred tank reactor utilizing a cationic exchange resin as the catalyst. Use the following data to determine the effectiveness factor for the ion exchange resin at 85°C and 3.9 percent conversion. 

Heavy-water reactors utilize heavy water (D2O) as a moderator. They can be operated with natural uranium, since the capture cross-section for the thermal neutrons, necessary for controlling nuclear chain reactions, is very low for D2O compared with H2O. Enrichment of U is therefore not necessary. The high price of heavy water (only present as 0.015% in natural water) is, however, a disadvantage. The resulting higher investment costs... 

Plastic material is pyrolyzed in a fluidized bed reactor utilizing quartz sand heated to about 800°C. The fluidizing medium is preheated pyrolysis gas. 

In addition to the studies of Becker et al. [116], Tayakout et al. [117,118] and Tsai et al. [119], a number of other groups have presented models which take into account the possibility of external mass transport limitations [124-126], Such effects could become of concern in industrial membrane reactors utilizing larger size membranes. 

Bulk—polymerization in the absence of a dispersing or diluting medium High reactor utilization, low separation cost, high product purity, no transfer reactions High viscosity during the course of polymerization Low-density polyethylene, PVC, methyl methacrylate... 

Figure 13.3 shows a plant layout. Recycled benzene along with makeup benzene and nitrous oxide are preheated and continuously fed to a moving bed reactor utilizing the zeolite catalyst. The latter flows vertically down the reactor by gravity, while the reaction gas flows across the annular catalyst beds. The predominant reactions are exothermic about 250 kj are released per mole of phenol produced. In addition, significantly more heat can be generated by the deep oxidation of benzene to... 

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