Kinetics of the reaction between the solid sodium carbonate and the gaseous sulphur dioxide. IV. Effect of the gas phase composition and of temperature in an integral fixed-bed reactor

Mareček, J.; Mocek, K.; Erdös, E.

doi:10.1135/cccc19700154

Cited by 13 publications

(8 citation statements)

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“…With Na,CO, the reaction occurs at a relatively low temperature. Marecek et al (1970) and Hartman (1 978) found optimal values at 393 to 423 K. In spite of the low temperature, the rate is greater by one to two orders of magnitude than that of the limestone-SO, reaction at temperatures around 1,100 K (Hartman, 1978). Also, sodium carbonate reacts completely, while with some limestones the reaction ceases due to pore closure before most of the solid reacts (Hartman and Coughlin, 1974;Dogu, 1981).…”

Section: Introductionmentioning

confidence: 99%

“…The overall kinetics of the reaction of SO, with Na2C0, has also been investigated. However, a first-order rate equation (Dogu, 1986;Marecek et al, 1970) or a Langmuir-Hinshelwood type expression (Erdos, 1969) has been employed for the overall reaction to produce sodium sulfite and CO,. Although adsorption equilibrium for SO, is assumed, the mechanisms of the adsorption step and the effect of temperature and gas composition on the reaction are not well understood (Dogu, 1986;Marecek et al, 1969).…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of the sodium carbonate–sulfur dioxide reaction

Kimura

Smith

1987

AIChE Journal

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The kinetics of the SO,-Na,CO, reaction were studied at 353 to 413 K and atmospheric pressure with thermal gravimetric analysis data. Since the reaction is very fast, special precautions were taken to operate at conditions such that transport effects did not influence results. The data indicated that Na,SO, was formed by two paths: direct reaction, and adsorption of SO, followed by conversion of adsorbed SO, to adsorbed CO, and finally desorption to final product. Rate constants were evaluated for each step in the proposed mechanism. Product distribution predicted from the rate constants agreed well with the distribution calculated from the experimental data at temperatures from 353 to 413 K. At 4 13 K the results suggested a change in mechanism.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetics of the sodium carbonate–sulfur dioxide reaction

Kimura

Smith

1987

AIChE Journal

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“…Part of the line where the desulfurization of the flue gases was performed is shown in Figure 1. Sections (1) to (14) relate to the original line of the basic technology, sections (15) to (22) represent the additional installation for the desulfurization process. The description of the scheme is evident from the legend in Figure 1.…”

Section: Experimental Partmentioning

confidence: 99%

Application of the Active Soda Process for Removing Sulphur Dioxide from Flue Gases

Erdös¹,

Mocek²,

Lippert³

et al. 1989

JAPCA

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“…Solid carbonates are frequently used for removal of SO2 from flue gases (Hartman, 1978). Activated soda has been reported to react rapidly with sulfur dioxide, even at temperatures as low as 423 K (Marecek et al, 1970T. Dogu, 1984.…”

Section: Introductionmentioning

confidence: 99%

“…Moments of these response peaks are then equated with model equations for the moments in order to evaluate the rate and equilibrium parameters.A gas-solid reaction that also has some potential for removal of SO, from flue gases is the SO,-sodium carbonate system. When sodium bicarbonate is heated to about 473 K, a porous activated soda is produced that reacts rapidly with SO, (Marecek et al, 1970;T. Dogu, 1984).…”

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confidence: 99%

Single‐Pellet, moment method for analysis of gas‐solid reactions

et al. 1986

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A single-pellet, moment technique is presented for evaluating reaction rate constants, effective diffusivities, and adsorption equilibrium constants for gas-solid noncatalytic reactions. Experimental pulseresponse data for the reaction of SO, with activated soda at 473 K were obtained to illustrate the method. The results show that intraparticle diffusion is the controlling mechanism for this reaction. The value of the Thiele modulus for axial transport was found to be 8.6 for a cylindrical pellet of porosity 0.56, tortuosity 2.3, and length 3 x lo-' m. SCOPEEffective diffusivities of reactant and products, adsorption equilibrium and reaction rate constants are essential for the design of fluid-solid, noncatalytic reactors. The single-pellet, moment technique has been shown to be a valuable tool for evaluating effective diffusivities and adsorption parameters in porous solids Smith, 1975, 1976). One of the objectives of this work was to extend the application of the technique to reaction systems. The experimental procedure consists of introducing a pulse of reactive gas to one end face of a porous, cylindrical pellet of solid reactant and measuring the concentration vs. time re-sponse peak leaving the other end face. Moments of these response peaks are then equated with model equations for the moments in order to evaluate the rate and equilibrium parameters.A gas-solid reaction that also has some potential for removal of SO, from flue gases is the SO,-sodium carbonate system. When sodium bicarbonate is heated to about 473 K, a porous activated soda is produced that reacts rapidly with SO, (Marecek et al., 1970;T. Dogu, 1984). Pulse-response data were measured for this system to illustrate the method and to obtain values for reaction rate and diffusion parameters. CONCLUSIONS AND SIGNIFICANCEThis work has demonstrated that gas-solid reaction rate constants together with effective diffusivities and adsorption equilibrium constants of reactant and products can be determined by the single-pellet, moment technique. Such results were obtained for the gas-solid reaction of SO, with activated soda at 473 K. The value of the Thiele modulus, determined from the first moment of the response curve of the product gas (CO,), was 8.6 for a pellet of porosity 0.56 and length 3 x lo-' m. The tortuosity factor of the pellet evaluated from inert tracer runs was 2.3. The adsorption equilibrium constant and effective diffusivity of CO, (in helium) were p,K, = 0.14 and D, = 0.22 x The effective diffusivity of the reactant gas (SO,) rn'ls.was evaluated from the ratio of zeroth moment of the product (CO,) response, in the reaction runs and the CO, response for the adsorption runs. The result, D," = 0.23 x m2/s, is larger than expected for pore-volume diffusion. Assuming that the discrepancy is due to surface diffusion of SO,, this mechanism could contribute about 20% to the total diffusive flux in the pellet.By carrying out the pulse-response experiments for two pellets of different lengths but with the same porosity, dead volume effect...

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Kinetics of the reaction between the solid sodium carbonate and the gaseous sulphur dioxide. IV. Effect of the gas phase composition and of temperature in an integral fixed-bed reactor

Cited by 13 publications

References 0 publications

Kinetics of the sodium carbonate–sulfur dioxide reaction

Kinetics of the sodium carbonate–sulfur dioxide reaction

Application of the Active Soda Process for Removing Sulphur Dioxide from Flue Gases

Single‐Pellet, moment method for analysis of gas‐solid reactions

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