Bubble column reactors, review

An excellent reference is Deckwer (Bubble Column Reactors, Wiley, 1992). Two complementary reviews of this subject are by Shah et al. [AlChE J. 28 353-379 (1982)] and Deckwer [in de Lasa (ed.), Chemical Reactor Design and Technology, Martinus Nijhoff, 1985, pp. 411-461]. Useful comments are made by Doraiswamy and Sharma (Heterogeneous Reactions,Wiley 1984). 

FIG. 19-31 Some examples of bubble column reactor types, (a) Conventional bubble column with no internals. (6) Tray bubble column, (c) Packed bubble column with the packing being either an inert or a catalyst. [From Mills, Ramachandran, and Chaudhari, Multiphase Reaction Engineeringfor Fine Chemicals and Pharmaceuticals, Reviews in Chemical Engineering, 8(1-2), 1992, Figs. 2, 3, and 4.]... 

In the design of upflow, three phase bubble column reactors, it is important that the catalyst remains well distributed throughout the bed, or reactor space time yields will suffer. The solid concentration profiles of 2.5, 50 and 100 ym silica and iron oxide particles in water and organic solutions were measured in a 12.7 cm ID bubble column to determine what conditions gave satisfactory solids suspension. These results were compared against the theoretical mean solid settling velocity and the sedimentation diffusion models. Discrepancies between the data and models are discussed. The implications for the design of the reactors for the slurry phase Fischer-Tropsch synthesis are reviewed. 

Pavlica and Olson38 outlined a generalized axial dispersion model for the isothermal bubble-column reactor in which a pseudo-first-order reaction occurred in both the gas and liquid phases. The model considered axial mixing in both the gas and the liquid phases. Here, we review a model for the reactor in which a generalized (m, n)th-order reaction between a gaseous species A and a liquid species C is carried out in the liquid phase. There are many chlorination, nitration, sulfonation, alkylation, and hydrogenation reactions which can be... 

The symposium upon which this volume is based focused on three areas in reaction engineering fluidized bed reactors, bubble column reactors, and packed bed reactors. Each area comprises a section of this book. Professor J. R. Grace chaired and coordinated the fluidized bed sessions Professors Y. T. Shah and A. Bishop, the bubble column reactor session and Professor A. Varma, the packed bed reactor session. Each section in this book opens with a brief review chapter by the session chairman that includes an overview of the chapters in each session. 

The general difficulties in design and scale-up of bubble column reactors concern reaction specific data, such as solubilities and kinetic parameters as well as hydrodynamic properties. The paper critically reviews correlations and new results which are applicable in estimation of hydrodynamic parameters of two-phase and three-phase (slurry) bubble column reactors. 

Correlations for for a wide variety of situations can be found in the review article Design parameter estimations for bubble column reactors, by Y T. Shah et al., AIChE J., 28, 353 (1982). 

Shah, Y. T., B. G. Kelkar, S. P. Godbole, and W. D. Deckwer, Design Parameters Estimations for Bubble Column Reactors (journal review), AZChEJ., 28, 353 (1982). 

When carrying out a gas-liquid reaction, the gas may be dispersed in the liquid, as in bubble-column reactors or stirred tanks, or the gas phase may be continuous, as in spray contactors or trickle-bed reactors. The fundamental kinetics are independent of the reactor type, but the reaction rate per unit volume and the selectivity may differ because of differences in surface area, mass transfer coefficient, and extent of mixing. In the following sections, gas holdup and mass transfer correlations and other performance data for gas liquid reactors are reviewed and some problems of scaleup are discussed. 

The structured packing for column and ceramic monoliths has been in use for several decades. The latter is used in catalytic converters for automobile exhausts for the in-line conversion of CO and oxides of nitrogen into harmless oxides. It is also used for catalyst and adsorbent supports in process industries. They offer higher specific surface area and low pressure drop. A comprehensive review of monolith reactors as alternatives to trickle-bed, slurry, and slurry bubble column reactors is available in Roy et al. [65]. The monolith reactor... 

This review paper is concentrated on problems in scaling-up multiphase catalytic fixed bed reactors such as trickle-bed or packed bubble column reactors, in which two fluid phases (gas and liquid) pass concurrently through a bed of solid (usually porous) catalyst particles. These types of reactors are widely used in chemical and petrochemical industry as well as in biotechnology and waste water treatment. Typical processes are the hydrodesulphurization of petroleum fractions, the butinediol syntheses in the Reppe process for synthetic rubber, the anthrachinon/hydrochinon process for H202 production, biochemical processes with fixed enzymes or the oxidative treatment of waste water under pressure. 

Shaikh A, Al-Dahhan M. (2013b) Scale-up of bubble column reactors a review of current state-of-the-art. Ind. Eng. Chem. Res. DOI 10.1021/ie30208Qm, Publication Date (Web) 28 Mar 2013. 

In addition to the commercial reactors, the Germans tested at the lab or pilot scale many types of reactors. These reactors are included in the reviews mentioned later in the text and will not be described, except for work with the slurry bubble column reactor and the foam reactor. 

The slurry-phase methanol process has been developed and commercialized [62-64]. Deckwer has published a major treatise on bubble column reactors [65]. Saxena [66] reviewed the use of bubble column reactors for FTS. A review of more recent studies has been presented [67]. The reader is referred to these for the description of reactor details. In the following, only brief accounts will be given for some of the major topics. 

Roy, S., Vashishtha, M. and Saroha, A. (2010) Catalytic Wet Air Oxidation of Oxalic Acid Using Platinum Catalysts in Bubble Column Reactor A Review, J. Eng. Science and Technology Review, 3, pp. 95-107. 

Much more information is available on the product ky a than on kl and a separately. For low solids concentrations it may be assumed that the solids do not affect the value of A a, so that the existing relations for two-phase gas-liquid reactors can be applied. For reviews on these relationships, see Lee and Foster [76], for draft tube slurry reactors Goto et al. [77], for bubble columns Deckwer and Schumpe [78] and Deckwer [79], and for stirred tank reactors Mann [80] and Schluter and Deckwer [81]. Despite of much research published on the influence of solids on k a there is still no universally applicable relation describing the influence of all types of particles in any weight fraction in any liquid. 

A review on earlier studies of liquid-phase axial dispersion in unstirred bubble-columns with no solids is given by Ostergaard.97 Van de Vusse138 has discussed the liquid-phase RTD in stirred slurry reactors. 

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