Reactor thermodynamic analysis

This paper reviews data on certain thermodynamic aspects of the nonstoichiometric Pu-0 system, which may serve as a basis for use In reactor safety analysis. Emphasis Is placed on phase relationships, vaporization behavior, oxygen-potential measurements, and evaluation of pertinent thermodynamic quantities. Limited high temperature oxygen potential data obtained above the fluorite, diphasic, and sesquioxide phases In the Pu-0 system are presented. 

Reactor safety analysis, thermodynamics of Pu-oxygen system 109-21... 

As shown above, a thermodynamic analysis indicates what to expect from the reactants as they reach the deposition surface at a given temperature. The question now is, how do these reactants reach that deposition surface In other words, what is the mass-transport mechanism The answer to this question is important since the phenomena involved determines the reaction rate and the design and optimization of the CVD reactor. 

The general reaction of methane conversion for the thermodynamic analysis of the ATR reactor can be written as follows ... 

From the foregoing analysis 1t is clear that a process modification that helps eliminate or minimize the irreversibility associated with the reactor feed preparation will lead to a major reduction in the thermal mismatch, reduce the exergy dependence on the power plant, and increase the overall energy efficiency. In the author s opinion, this conclusion would not be evident as readily without the thermodynamic analysis of process irreversibilities, which attests to the value of such exergy analyses. 

G. Tsatsaronis, P. Schuster, H. R5rtgen "Thermodynamic Analysis of a Coal Hydrogasification Process for SNG Production by using Heat from a High-Temperature Nuclear Reactor, 2nd World Congress of Chemi-cal Engineering, Montreal, Canada, October 4-9, 1981, Vol. II, pp. 4o1-4o4. 

Many industrial reactions are not carried to equilibrium. In this circumstance the reactor design is based primarily on reaction rate. However, the choice of operating conditions may still be determined by equilibrium considerations as already illustrated with respect to the oxidation of sulfur dioxide. In addition, the equilibrium conversion of a reaction provides a goal by which to measure improvements in the process. Similarly, it may determine whether or not an experimental investigation of a new process is worthwhile. For example, if the thermodynamic analysis indicates that a yield of only 20 percent is possible at equilibrium and a 50 percent yield is necessary for the process to be economically attractive, there is no purpose to an experimental study. On the other hand, if the equilibrium yield is 80 percent, an experimental program to determine the reaction rate for various conditions of operation (catalyst, temperature, pressure, etc.) may be warranted. 

The work to drive the compressor Wc comes from the turbine, and the additional work of the t IV, is the net work output of the power plant. The compressor and turbine efficiencies are giv the figure. Assume air an ideal gas for which CP = (7/2)H Including the nuclear reactor as the system and treating it as a heat reservoir at 650°C, make a thermodynamic analysis of the j T0 = 293.15 K. 

Example 5.15 Retrofits of distillation columns by thermodynamic analysis The synthesis of methanol takes place in a tube reactor in section 3 in the methanol plant shown in Figure 5.7. The reactor outlet is flashed at 45°C and 75 bar, and the liquid product (stream 407) containing 73.45 mol% of methanol is fed into the separation section (see Figure 5.8), where the methanol is purified. Stream 407 and the makeup water are the feed streams to the section. Table 5.2 shows the properties and compositions of the streams in section 3. The converged simulations are obtained from the Redlich-Kwong-Soave method to estimate the vapor properties, while the activity coefficient... 

Shinnar, R., Thermodynamic analysis in chemical processes and reactor design. Chem. Eng. Sci. 43, 2303 (1988). 

Recently, Comas et al.219 performed the thermodynamic analysis of the SRE reaction in the presence of CaO as a C02 sorbent. The equilibrium calculations indicate that the presence of CaO in the ethanol steam reforming reactor enhances the H2 yield while reducing the CO concentrations in the outlet of the reformer. Furthermore, the temperature range at which maximum H2 yield could be obtained also shifts from above 700 °C for the conventional steam reforming reaction without CaO to below 700 °C, typically around 500 °C in the presence of CaO. It appears that the presence of CaO along with ethanol reforming catalyst shift the WGS equilibrium in the forward direction and converts more CO into C02 that will be simultaneously removed by CaO by adsorption. 

Silicon dioxide, one of the products of this interaction, is insoluble in pure alkali metal halides and separates from the molten medium owing to the difference in densities. Thermodynamic analysis of the processes of molten iodide purification with different halogenating agents shows that their effectiveness reduces in the sequence SH4 > HI >h [294], An obvious advantage of silicon halides for the purification of halide melts used for singlecrystal growth is the fact that their use does not result in the appearance of additional impurities in the purified melts, since these processes are usually performed in quartz (Si02) vessels-reactors. 

This example illustrates both the advantages and disadvantages of the black-box style of thermodynamic analysis. If we are interested in merely computing the total heat requirement for the reaction, the black-box or overall analysis is clearly the most expeditious and does not require any kinetic data. However, black-box thermodynamics gives us no information about the reactor size or the details of the heat program (that is, the heat flow as a function of time in the batch reactor or as a function of distance in the tubular reactor). The decision of whether to use the black-box or more detailed thermodynamic analysis will largely depend on the amount of kinetic information available and the degree of detail desired in the final solution. ... 

We now turn to processing situations in which heat effects are of primary importance examples include chemical reactors and separators that exploit phase partitioning. Thermodynamic analysis of these situations invoke the stuff equations in particular, steady-state heat effects are computed from (12.3.5). To obtain the partial molar enthalpies that appear in (12.3.5), we need enthalpies as functions of composition so in 12.4.1 we show how enthalpy-concentration diagrams can be constructed from volumetric equations of state applied to binary mixtures in phase equilibrium. Then we apply the energy balance (12.3.5) to multicomponent flash separators ( 12.4.2), binary absorbers ( 12.4.3), and chemical reactors ( 12.4.4). 

Al-Megren H. A., Barbieri G., Mirabelli L, Brunetti A., Drioli E., Al-Kinany M. C. 2013. Direct conversion of n-butane to isobutene in a membrane reactor A thermodynamic analysis. Industrial Engineering and Chemistry Research 52(31) 10380-10386. doi 10.1021/ie400006c. 

Medrano, J.A., Spallina, V, van Sint Annaland, M. and Gallucci, F. (2014) Thermodynamic analysis of a membrane-assisted chemical looping reforming reactor concept for combined H2 production and CO2 capture. International Journal of Hydrogen Energy, 39, 4725 738. 

Lopez, E., Divins, N.J. and Llorca, J. (2012) Hydrogen production from ethanol over Pd-Rh/Ce02 with a metallic membrane reactor. Catalysis Today, 193, 145-150. Montane, D., Bolshak, E. and Abello, S. (2011) Thermodynamic analysis of fuel processors based on catalytic-wall reactors and membrane systems for ethanol steam reforming. Chemical Engineering Journal, 175, 519-533. 

Minato, K. Thermodynamic analysis of cesium and iodine behavior in severe light water reactor accidents. J. Nucl. Materials 185, 154-158 (1991)... 

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