Reactants liquid

Gas-phase reactant Liquid-phase reactant kcfl Special conditions... 

J4. Reactant liquid is pumped into a batch reactor at a variable rate. The reactor pressure also varies during the batch cycle. Specify the control valve size and the centrifugal pump head required. Assume a flat pump curve. 

The initial flow rate into the reactor is 20 gpm (sp gr = 1). It is decreased linearly with time down to 5 gpm at 5 hours into the batch cycle. The initial reactor pressure is 50 psig. It increases linearly with time up to 350 psig at 5 hours. The reactant liquid comes from a tank at atmospheric pressure. 

The major function of a bipolar plate, or simply called "plate," is to connect each cell electrically and to regulate the reactant gas (typically, hydrogen and air in a hydrogen fuel cell) or reactant liquid (typically, methanol in a DMFC) and liquid or gas coolant supply as well as reaction product removal in desired patterns. This plate must be at least electrically conductive and gas and/or liquid tightened. Considering these important functions and the larger fraction of volume, weight, and cost of the plate in a fuel cell, it is worthwhile to construct this chapter with emphasis on the current status and future trend in bipolar plate research and development, mainly for the plate materials and fabrication process. 

The reactor was tested using a range of methanol and water concentrations, and researchers found the best results using a water and methanol mixture with a steam-to-carbon ratio (S C) of 1.1 1. They were able to achieve 90% conversion at 260 °C with a reactant liquid flow rate of 12 cmYh. Assuming a fuel cell efficiency of 60% and 80% hydrogen utilization, they estimated the output power to be 15 W. Eventually the complete system will include a cata-... 

Fig. 1.5.1 Schematic diagram of the falling film aerosol generator. (A) Constant-temperature oil bath (B) and (C) reservoirs containing the reactant liquid (D) and (J) glass joints controlling the flow of the moving film (E) and (F) tubes to the variable-speed pump (G) exit tube (I) boiler lube (K) carrier gas (laden with nuclei) entrance. (From Ref. 31.)...

Fig. 1.5.3 Aerosol generator assembly for the production of composite or coated particles (a) carrier gas (e.g., helium) tank, (b) drying column containing silica gel and molecular sieve, (c) Millipore membrane of 0.1 p.m pore size, (d) flow meters, (e) nuclei (e.g., NaCI, AgCI) generator, (f) and (m) boilers containing different reactant liquids, (g) and (n) condensation chambers, (h) heater, (i) chamber for recondensation of droplets, (q) and (e) coreactant containers, (k) and (p) vapor injection ports, (I) and (g) reaction chambers, (r) powder collector. (From Ref. 39.)...

Reactants Liquid phase (in dioxan, 52°C) Vapour phase (120°C) ... 

The peroxo species can oxidize other reactants, liquids, catalyst, or final product in the subsequent coupling reaction. One example of such oxidation is observed in the preparation of triphenylphosphine (13—15). If this reaction is hydrolyzed in air instead of an inert N2 atmosphere, then the amount of triphenylphosphine oxide increases from less than 1 wt % to greater than 15 wt °/o. 

The electrodes are porous, favorable for gas diffusion in the reaction zone, i.e., at the contact between gaseous reactants, liquid electrolyte and electrode [340]. 

In Weibel etal. (2005a, b) Harvard University has announced that it is developing a new, incompressible reactants, liquid-based fuel cell for the isothermal oxidation of a coal/water/sulphuric acid slurry, and producing compressible carbon dioxide. Eurther detail is given at the end of Appendix A. 

To keep the reactants liquid, the reactor must operate at a pressure above their vapor pressure, which is given by... 

FIGURE 16.5 (a) Quasi-conical pore for an electrocatalyst in a three-phase system gaseous reactant, liquid... 

Phases Gas-solid, gas-solid reactant, liquid-solid, gas-liquid-solid. Good for very fast reactions and for consecutive reactions. Large transfer area temperature can be controlled by injection little backmixing that gives a well-defined residence time. 

The semibatch reactor (tank or tubular) contains a large amount of liquid reactant that continuously reacts on the addition of a second reactant (liquid or gas), which is instantly consumed. The kinetics is the same, but consumption increases over reaction time as the second component is added (Figure 15.1). 

Multiphase reactions may involve gas-liquid, gas-liquid-solid (solid as catalyst or reactant), liquid-liquid, liquid-liquid-solid reactions, etc. The reactions may vary from very slow to very fast, endothermic to highly exothermic. Based on the reaction characteristics, different types of multiphase reactors are used in industrial practice. A number of texts deaUng with design of multiphase reactors are available (Satterfield 1970 Shah 1979 Ramachandran and Chaudhari 1983 Westerterp et al. 1988 Deckwer 1992). Considerable information on theoretical, hydrodynamics, and mass transfer aspects of different multiphase reactors has become available since the publication of the above texts. This recent information is likely to allow rational, simple and yet reliable designs of many industrially important multiphase reactors. In this book, different types of multiphase reactors falUng under two categories—(1) gas-liquid and (2) gas-liquid-solid— are considered. The basic aim is to provide user-friendly, simple, and reasonably accurate design procedure for each multiphase reactor. 

For example, consider the complete combustion of a solid or liquid compound of carbon, hydrogen, and oxygen in which the combustion products are CO2 and H2O and there are no side reactions or auxiliary reactions. In the initial state of the isothermal bomb process, the bomb vessel contains the pure reactant, liquid water with O2 dissolved in it, and a gaseous mixture of O2 and H2O, all at a high pressure pi. In the final state, the bomb vessel contains liquid water with O2 and CO2 dissolved in it and a gaseous mixture of O2, H2O, and CO2, all at pressure p2- In addition, the bomb vessel contains internal parts of constant mass such as the sample holder and ignition wires. 

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