Kinetic of the reaction between the solid sodium carbonate and the gaseous sulphur dioxide. III. Study in an integral fixed-bed reactor

Bareš, Jiří; Mareček, J.; Mocek, K.; Erdös, E.

doi:10.1135/cccc19701628

Cited by 18 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been well established that thermal decomposition of NaHCO, particles can produce a highly porous Na,CO, product that reacts rapidly with SO, in waste gases (Bares et at., 1970; Marecek et al, 1970). Also, rates of decomposition and of reaction with SO, have been measured separately on different samples (Subramanian et al, 1972; Guarini et al, 1973; Bares et al, 1970; Marecek et al, 1970).…”

Section: Scopementioning

confidence: 99%

“…A second advaritage is that the reaction of sulfur dioxide occurs rapidly a t 373 to 473 K, while about 1,173 K is required for reaction with limestones. Bares et al (1970) and Marecek et al (1970) discovered that the reactivity of sodium carbonate is very high when it is prepared by thermal decomposition of sodium bicarbonate a t temperatures from 393 to 453 K. Also, there is a fourfold decrease in solid volume in conversion of two moles of NaHCO, to one mole of Na,CO,. This greatly increases the pore volume.…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Kinetics of sodium bicarbonate decomposition

et al. 1986

View full text Add to dashboard Cite

A thermal gravimetric method was used to measure rates of decomposition of NAHCO, particles. Such decomposition produces a highly porous Na,Co, that reacts with SO, rapidly and completely at moderate temperatures. Hence, NaHCO, decomposition provides a reactant with attractive features for SO, removal. The rapid rate of decomposition combined with the high heat effect prevented determining intrinsic rates by constant temperature runs when the temperature level was above 400 K. However, rising-temperature runs, which allowed time for heat transfer to equilibrate temperatures of the thermocouple and particles, gave reliable results at high temperatures. The activation energy was 102 kJ/mol. Porosimeter data verified the large increase in pore volume (from 0.03 to 0.39 x lo-, m3/kg) on converting the NaHCO, particles to Na,CO,.First-order kinetics were observed up to high conversions, after which the apparent order decreased. However, the sodium bicarbonate could be completely converted to Na,CO,. SCOPEIt has been well established that thermal decomposition of NaHCO, particles can produce a highly porous Na,CO, product that reacts rapidly with SO, in waste gases (Bares et at., 1970; Marecek et al., 1970 Our objective was to determine the rate of decomposition of a sample of NaHCO, particles at temperatures from 373 to 473 K over the complete range of conversion. A TGA apparatus was employed since this allowed very small sample masses to be used (leading to accurate rates) and the effect of heat and mass of transfer processes could usually be eliminated. Porevolume data also were obtained on NaHCO, and Na,CO, particles. CONCLUSIONS AND SIGNIFICANCEThe rapid rate of decomposition of NaHCO, combined with a large, endothermic heat effect required careful choice of operating conditions to obtain rates unaffected by heat transfer. At temperatures above 400 K this required the TGA experiments to be conducted by the rising-temperature method. The results showed that intrinsic kinetics were first-order in mass of NaHCO, up to high conversions. The retardation of the rate beyond this point may be due to changes in the AIChE JournalSeptember 1986 nature of the remaining Na,CO,, or the structure of the Na,CO, product surrounding the unreacted Na,HCO,. However, the rate remained high at high conversions so that the NaHCO, was completely converted to the carbonate. The data also showed that the rate decreased when the decomposition temperature was reduced from 473 to 373 K. Corresponding pore-volume data indicated that the surface area was greater for particles decomposed at 373 K.

show abstract

Section: Scopementioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Kinetics of sodium bicarbonate decomposition

et al. 1986

View full text Add to dashboard Cite

show abstract

“…Limited attention to date was dedicated in the literature to investigate the heterogeneous reaction process of sodium bicarbonate with acid gases, at least compared to the vast literature on acid gas removal with calcium-based sorbents at low, medium, and high temperature. Bares et al 12 were probably among the first researchers to investigate the reaction between sodium carbonate and SO 2 , by analyzing the sorption of 0.5−1 vol % SO 2 on a fixed bed of Na 2 CO 3 at 150 °C, reporting an influence of SO 2 concentration on reaction rate. Keener and Davis 13 explored the effect of temperature on the reaction between NaHCO 3 and SO 2 (2.45 vol %), finding a reverse temperature relationship between 150 and 400 °C.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Reactivity of Sodium Bicarbonate toward Hydrogen Chloride and Sulfur Dioxide at Low Temperatures

Pozzo

Moricone

Tugnoli

et al. 2019

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The use of sodium bicarbonate (NaHCO 3) as a solid reactant for the removal of acid pollutants in industrial flue gas streams is a simple and effective process solution. Nonetheless, despite its technological maturity, the industrial application of NaHCO 3-based flue gas treatment is still highly empirical. A better knowledge of the heterogeneous reaction process could allow process optimization, resulting in a reduction both in the consumption of reactants and in the generation of solid waste products. In the present study, the reactivity of NaHCO 3 toward HCl and SO 2 was investigated in the temperature range between 120 and 300°C. The key role of thermal activation in determining the reactivity of the sorbent was confirmed. The choice of the optimal temperature for acid gas sorption results from a trade-off: higher temperatures increase the reaction kinetics, but induce the sintering of the activated sodium carbonate. The occurrence of sintering is particularly detrimental for high removal efficiency toward SO 2 , possibly due to the role of the sodium sulfite layer originated by SO 2 sorption. As a consequence, the optimal operating temperature resulted as 150°C for SO 2 and 210°C for HCl. The choice of operating temperature in industrial dry sorbent injection units for acid gas abatement is discussed in view of the present findings.

show abstract

“…The sintering trend can be estimated from the sintering temperature point ( T s ) of the solid. , T S is considered to be significantly lower than the Tammann temperature (425 °C, i.e., half its melting point), the temperature at which the lattice starts to change, and this temperature range is expected to be between 200 and 300 °C. , Sintering below T S has no observable effect, but after the temperature exceeds T S , the sintering rate increases exponentially, and the time to complete sintering rapidly decreases . As mentioned above, the experimental temperature was higher than the calculated sintering temperature.…”

Section: Resultsmentioning

confidence: 87%

Experimental Study on the Removal of Low-Concentration SO₃ by Trona at Medium Temperatures

Tang

Zhang

Luo

2021

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Spraying trona in a selective catalytic reduction system is an effective way to control SO 3 emission. However, its application in the industry is often hindered by sintering at high temperatures, which reduces the reactivity and limits its wide application. Therefore, in this paper, we study the reaction characteristics of homemade sodium carbonate (Na 2 CO 3 ) with SO 3 in flue gas on a fixed-bed reactor. The mechanism of SO 3 removal by trona was studied. It was found that with an increase in internal diffusion resistance, the rate control step of the reaction gradually changed from the joint control of external diffusion and chemical reaction to that of internal diffusion control. The increase in temperature accelerates the decreasing trend of the internal diffusion coefficient. This is mainly due to the sintering of Na 2 CO 3 caused by high temperatures. When the temperature increases from 260 to 380 °C, the conversion rate decreases by 30%. By improving the pore structure, the sintering of Na 2 CO 3 caused by high temperatures has been alleviated. The carbonation degree increases from 0 to 100%, and the conversion rate increases by 20%. Meanwhile, the competitive reaction caused by SO 2 is also explored, and it is found that the increase in SO 2 concentration only slightly reduces the absorption of SO 3 .

show abstract

Kinetic of the reaction between the solid sodium carbonate and the gaseous sulphur dioxide. III. Study in an integral fixed-bed reactor

Cited by 18 publications

References 0 publications

Kinetics of sodium bicarbonate decomposition

Kinetics of sodium bicarbonate decomposition

Experimental Investigation of the Reactivity of Sodium Bicarbonate toward Hydrogen Chloride and Sulfur Dioxide at Low Temperatures

Experimental Study on the Removal of Low-Concentration SO₃ by Trona at Medium Temperatures

Contact Info

Product

Resources

About

Kinetic of the reaction between the solid sodium carbonate and the gaseous sulphur dioxide. III. Study in an integral fixed-bed reactor

Cited by 18 publications

References 0 publications

Kinetics of sodium bicarbonate decomposition

Kinetics of sodium bicarbonate decomposition

Experimental Investigation of the Reactivity of Sodium Bicarbonate toward Hydrogen Chloride and Sulfur Dioxide at Low Temperatures

Experimental Study on the Removal of Low-Concentration SO3 by Trona at Medium Temperatures

Contact Info

Product

Resources

About

Experimental Study on the Removal of Low-Concentration SO₃ by Trona at Medium Temperatures