摘要:

AbstractFixed‐bed, catalytic reactors in which gas and liquid phases flow concurrently downward, termed trickle beds, are becoming more widely used in chemical processing, particularly in the petrochemical industry. Shah (1979) has summarized the advantages of trickle‐bed reactors and mentioned some of the processes in which the reactors are used. Shah's monograph and earlier reviews (Satterfield, 1975; Goto et al., 1977; Hofmann, 1978; Gianetto et al., 1978) have discussed factors affecting reactor performance.In the last few years additional experimental and theoretical studies that contribute to improved design and scaleup of trickle‐bed reactors have been published. The scope of this paper is to review critically these improvements. Progress in understanding local rates of reaction is considered first. Then recent developments in reactor design are ana

ISSN:0001-1541    

DOI:10.1002/aic.690290102

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractA solution is obtained for convective diffusion with axial diffusion and homogeneous and heterogeous reactions in a tube. The results have been used successfully to examine the validity of a model with simplified inlet boundary condition and to establish the conditions for a one‐dimensional dispersion mode

ISSN:0001-1541    

DOI:10.1002/aic.690290103

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractNitrogen oxide removal efficiencies of up to 97% were obtained in tests using columns packed with Intalox saddles. These studies were conducted at atmospheric pressure with water as the scrub solution and nitrogen oxide feed concentrations of up to 10%. A mathematical model based on mass‐transfer, kinetic, and equilibrium data is presented; calculated removal efficiencies using this model agree very well with the experimental dat

ISSN:0001-1541    

DOI:10.1002/aic.690290104

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractThe rise velocities of bubbles, slugs and pressure waves in a fluidized bed have been measured on‐line through the use of pressure transducers coupled with the cross‐correlation technique. Sand and glass beads with different particle sizes were tested. Effects of the gas flow rate and column diameter on the rise velocities of bubbles and slugs were investigated. The results were correlated with two models developed in this work and were compared with the data obtained by other investigat

ISSN:0001-1541    

DOI:10.1002/aic.690290105

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractThe generation of carbon fines by attrition during the fluidized combustion of a bituminous coal has been studied by means of a 140mm ID fluidized‐bed combustor under variable excess air factor, bed temperature, fluidizing velocity and size of bed sand and coal. Results indicate that rates of attrited fines are roughly proportional to excess of gas velocity above the minimum for fluidization and bed carbon exposed surface. Attrition rate constant is affected by size of sand and, to a less extent, and particularly with finer coal, by bed temperatur

ISSN:0001-1541    

DOI:10.1002/aic.690290106

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractFeasible operating conditions are obtained for an azeotropic distillation tower using a nonlinear programming algorithm. The boil‐up rate, fractional recovery of product, and bottoms purities of entrainer and by‐product are adjusted to locate an overhead vapor stream that condenses into two liquid phases, but is in equilibrium with a single liquid phase on the top tray. A new objective function is introduced and minimized, subject to inequality constraints, using Powell's algorithm (1977). Results are obtained for dehydration of alcohol with benz

ISSN:0001-1541    

DOI:10.1002/aic.690290107

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractThe absorption of dilute SO2into aqueous double slurries containing CaCO3and Mg(OH)2was carried out using a stirred tank with a plane gas‐liquid interface. The absorption rate increased and finally reached that under the completely gas‐film controlled conditions as the absorption process proceeded. The desulfurization process using the double slurry was formulated by a two‐reaction‐plane model in which there are no particles suspended in‐between the interface and the primary reaction plane. It was suggested from comparison of the experimental absorption rates with the theoretical predictions that 40 to 60% of the absorbed sulfur dioxide may be present as an effective magnesium sulfite

ISSN:0001-1541    

DOI:10.1002/aic.690290108

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractHighly selective transfer of hydrogen sulfide (H2S) from much larger quantities of carbon dioxide (CO2) has been accomplished by absorption and reaction into fine sprays of buffered carbonate solution. Selectivity after the intensely agitated atomization zone is dramatically improved once the droplets have formed and stagnate internally. H2S transfer in this latter zone is virtually independent of the presence of CO2, even at CO2:H2S ratios of 100; CO2transfer, however, is adversely affected by the presence of H2S. The gas film resistance for mass transfer is effectively eliminated with the 50 μm mean droplet diameter. The data indicate approximately constant hydrodynamics throughout the formed droplet zone and allow good theoretical prediction of enhancement factors for this complex system. Thus the design of more efficient equipment is possible if the gas‐liquid contacting method is tailored to take advantage of differences in the transfer and reaction rate properties of gases to be separat

ISSN:0001-1541    

DOI:10.1002/aic.690290109

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractPerturbation chromatography previously has been used experimentally as an efficient method for obtaining sorption equilibria for systems with up to two vapor phase components at finite concentration. The objective of this work was to obtain a theoretical result that could be used for experimental determinations of sorption of multiple interfering species at finite concentration. Results obtained are applicable for both non‐stoichiometric and stoichiometric situations for systems that may have flowing phase velocity and volume changes associated with interphase transport and also may have interactions among the sorbed components. The dependence of each effluent peak characteristic velocity upon all of the component equilibrium isotherms requires that the equilibria be considered as a whole by simultaneously fitting a set of composition grid perturbation response data to appropriate isotherm surface equation

ISSN:0001-1541    

DOI:10.1002/aic.690290110

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY

摘要:

AbstractThe kinetics of reaction between CO2and lime is investigated in the range of 673 to 998 K with a view to examining the effects of product layer deposition and variations in the limestone calcination atmosphere. The reaction is initially rapid and chemically controlled and goes through a sudden transition to a much slower regime controlled by diffusion in the product CaCO3layer. The magnitude of the estimated product layer diffusivity is in the range of 10−18to 10−21m2/s, the corresponding activation energy is 88.9 ± 3.7 kJ/mol below 688 K and 179.2 ± 7.0 kJ/mol above that temperature, suggestive of solid state diffusion. Plausible mechanisms are disc

ISSN:0001-1541    

DOI:10.1002/aic.690290111

出版商:American Institute of Chemical Engineers    

年代:1983

数据来源: WILEY