Reactors solid catalysis

Data of chemical composition 106 Pressure changes 145 Variables related to composition 164 Half iife and initial rate data 177 Temperature variation. Activation energy Homogeneous catalysis 202 Enzyme and solid catalysis 210 Flow reactor data 222 CSTR data 231 Complex reactions 238... 

Triphase liquid/liquid/solid catalysis has been carried out with a continuous flow reactor 120). A mixture of 1-bromooctane in o-dichlorobenzene and aqueous potas-... 

As a consequence of the line broadening effects of internal magnetic interactions on solid-state NMR spectra (Section ILA), experiments that characterize working solid catalysis require the application of the MAS technique. Because of the salient feature of MAS NMR spectroscopy (rapid sample spinning during the measurement), specific techniques had to be developed to allow characterization of solids in sealed vessels under batch reaction conditions and in fixed-bed reactors under flow conditions. 

Fittings, pipe, resistances, 95, 98-100 Fixed bed solid catalysis, 596 name reactor, 573 Flash conditions, 375-377 example, 378... 

While all pyrolysis oil production reactor systems produce similar materials, each reactor produces a unique compound slate. The first decision, especially for a potential chemical or fuel producer, rather than a reactor developer, is to determine what products to make and which reactor system to use. The operating parameters of any reactor system designed to produce pyrolysis oil, especially temperature, can be altered to change the pyrolysis oil product composition and yield. Different feedstocks will produce different pyrolysis oil compositions and by-products, e.g. amorphous silica from rice hulls or rice straw, fatty acids from pine. Finally, feedstock pretreatment and/or catalysis, or reactor-bed catalysis can be used to improve specific product yields (7). Reactor system developers need to examine what they can produce and make this information available to chemical manufacturers and suppliers/owners of biomass feedstocks. This assumes that analysis of die entire liquid product from thermal conversion can be made, including quantitative analysis for any compounds that are being considered for recoveiy. Physical characterization - pH, viscosity, solids content, etc.is also needed. However, what can be produced is of no value, if it cannot be recovered or used economically. This involves examining the trade-offs between yield and current commercial value, recovery costs, and potential commercial value,... 

Part III Beyond the Fundamentals presents material not commonly covered in textbooks, addressing aspects of reactors involving more than one phase. It discusses solid catalyzed fluid-phase reactions in fixed-bed and fluidized-bed reactors, gas-solid noncatalytic reactions, reactions involving at least one liquid phase (gas-liquid and liquid-liquid), and multiphase reactions. This section also describes membrane-assisted reactor engineering, combo reactors, homogeneous catalysis, and phase-transfer catalysis. The final chapter provides a perspective on future trends in reaction engineering. 

Iliuta, I. and Larachi, F. (2001). Wet Air Oxidation Solid Catalysis Analysis of Fixed And Sparged Three-Phase Reactors, Chem. Eng. Process., 40, pp. 175-185. 

Catalysis in a single fluid phase (liquid, gas or supercritical fluid) is called homogeneous catalysis because the phase in which it occurs is relatively unifonn or homogeneous. The catalyst may be molecular or ionic. Catalysis at an interface (usually a solid surface) is called heterogeneous catalysis, an implication of this tenn is that more than one phase is present in the reactor, and the reactants are usually concentrated in a fluid phase in contact with the catalyst, e.g., a gas in contact with a solid. Most catalysts used in the largest teclmological processes are solids. The tenn catalytic site (or active site) describes the groups on the surface to which reactants bond for catalysis to occur the identities of the catalytic sites are often unknown because most solid surfaces are nonunifonn in stmcture and composition and difficult to characterize well, and the active sites often constitute a small minority of the surface sites. 

M. Stoukides, Solid-Electrolyte Membrane reactors Current experience and future outlook, Catalysis Reviews - Science and Engineering 42(1 2), 1 -70 (2000). 

Mathpati, C.S. and Joshi, J.B. (2007) Insight into theories of heat and mass transfer at the solid/fluid interface using direct numerical simulation and large eddy simulation. Joint 6th International Symposium on Catalysis in Multiphase Reactors/5th International Symposium on Multifunctional Reactors (CAMURE-6/ISMR-5-), 2007, Pune. 

In any catalyst selection procedure the first step will be the search for an active phase, be it a. solid or complexes in a. solution. For heterogeneous catalysis the. second step is also deeisive for the success of process development the choice of the optimal particle morphology. The choice of catalyst morphology (size, shape, porous texture, activity distribution, etc.) depends on intrinsic reaction kinetics as well as on diffusion rates of reactants and products. The catalyst cannot be cho.sen independently of the reactor type, because different reactor types place different demands on the catalyst. For instance, fixed-bed reactors require relatively large particles to minimize the pressure drop, while in fluidized-bed reactors relatively small particles must be used. However, an optimal choice is possible within the limits set by the reactor type. 

It is envisioned that this new LAB technology would be most readily applicable industrially as a retrofit to existing LAB commercial units, possibly as a slip-stream reactor.19,20 The manufacturer would then have the flexibility to tailor the 2-phenyl content of their LAB and LAS products according to the customer s specific needs. Alternative solid acid reactor configurations have been presented at an earlier Organic Reactions Catalysis Meeting.21... 

This chapter is devoted to fixed-bed catalytic reactors (FBCR), and is the first of four chapters on reactors for multiphase reactions. The importance of catalytic reactors in general stems from the fact that, in the chemical industry, catalysis is the rule rather than the exception. Subsequent chapters deal with reactors for noncatalytic fluid-solid reactions, fluidized- and other moving-particle reactors (both catalytic and noncatalytic), and reactors for fluid-fluid reactions. 

Abdallah, R. and Fumey, B. and Meille, V. and de Bellefon, C. (2007). Micro-structured reactors as a tool for chiral modifier screening in gas-liquid-solid asymmetric hydrogenation. Catalysis Today, 125, 34-39. 

For practical purposes it is often beneficial to use a heterogeneous system with the enzyme as a solid preparation which easily can be separated from the product in the liquid phase. Solid enzyme preparatiorrs can conveniently be used in packed bed and stirred tank reactors. As in other cases with heterogeneous catalysis, mass trarrsfer limitations can reduce the overall reaction rate, but usually this is no major problem. 

The use of another supported base catalyst was disclosed in a recent patent. A Zn0/Al203 catalyst was used in the production of alkyl esters from the alcoholysis of oils. Reactions were carried out at high temperatures (above 200°C) and pressures in batch and continuous flow packed-bed reactors. High conversions were observed (over 80% total oil conversion) after 2h of reaction. Unfortunately, it is not clear up to what degree the Zn0/Al203 solid was responsible for the actual catalysis since the metallic surface of the reactor used was most probably contributing as well. For instance, in one case an ester yield of 91% was obtained in the presence of catalyst, while in the absence of catalysts under the same reaction conditions the yield was 60%. 

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