Calcination Rate Research Articles

Self-acceleration effect of Mn/Ce-modified carbide slag in CO2 absorption for CaO/CaCO3 energy storage

Carbide slag, a solid waste from the chlor-alkali industry, can be used for CO2 capture and energy storage. Herein, the cyclic reaction activity of Mn/Ce-modified carbide slag under energy storage conditions was studied. The Mn/Ce-modified carbide slag shows energy storage density over 2100 kJ/kg and CO2 absorption capacity of 0.52 g CO2/g sorbent after 30 cycles. Notably, both carbonation and calcination rates are accelerated with the number of cycles. This self-acceleration effect is related to the evolution of oxygen vacancy concentration and texture structure of Mn/Ce-modified carbide slag during the cycles. In the cycles, CaMnO3 in the Mn/Ce-modified carbide slag reacts with the formed CaCO3 in the carbonation stage to produce more Ca2MnO4. The formation of Ca2MnO4 increases oxygen vacancies in the Mn/Ce-modified carbide slag, significantly enhancing its CO2 absorption capacity. Thus, the release of the increased CO2 in the calcination stage generates more pores in the 10–100 nm diameter range in the modified carbide slag, facilitating rapid carbonation. Thus, the Mn/Ce-modified carbide slag exhibits good prospect for CaO/CaCO3 thermochemical energy storage.

Insight into the mechanism of H2O promoted CaCO3 decomposition in CO2 atmosphere

Calcium looping is one of the most promising CO2 capture technology. The flus gas during the calcination stage of the calcium looping contains both CO2 and H2O. However, the effect of H2O on the decomposition of carbonation in the CO2 atmosphere remains inconclusive. This study employed the Reactive Force Field molecular dynamics (ReaxFF-MD) simulations to investigate the influence of H2O on the decomposition of calcium carbonate in a CO2 atmosphere. The TGA experiments demonstrated that H2O increases the decomposition rate of calcium carbonate and also reduces the reaction temperature. Subsequently, the effects of varying CO2 and H2O concentrations on the decomposition of calcium carbonate were examined using ReaxFF-MD simulations. The simulation results for calcium carbonate decomposition, with the addition of CO2 and H2O, aligned with the experimental trends, verifying the reliability of the models. By tracking and labeling carbon, oxygen and hydrogen atom sources in the simulation, the decomposition, carbonation and hydrolysis reaction network for the CaCO3 decomposition in CO2 atmosphere was systematically constructed. Analysis of the chemical reactions and atomic distribution indicated that H2O primarily facilitates calcium carbonate decomposition by generating HCO3− through surface hydrolysis, which reduces the activation energy of the reaction. Moreover, the hydroxyl groups formed by hydrolysis compete with atmospheric CO2 for active sites on CaO, further inhibiting the carbonation reaction and increasing the calcination rate.

High-Entropy Fluorite Oxide-Modified CaO-Based Sorbent Pellets for Enhanced High-Temperature CO2 Capture.

The calcium looping technology employing CaO-based sorbents is pivotal for capturing CO2 from flue gas. However, the intrinsic low thermodynamic stability of CaO-based sorbents and the requisite molding step induce severe sintering issues, diminishing their cyclic stability. Herein, a high-entropy fluorite oxide (HEFO) inert stabilizer premised on entropy stabilization and synergistic effect strategies is introduced. HEFO-modified, CaO-based sorbent pellets are synthesized via a rapid cigarette butt-assisted combustion process (15 min) combined with the graphite molding method. Post-multiple cycles, their CO2 capture capacity reaches 0.373g g-1, which is 2.6-fold superior to that of pure CaO, demonstrating markedly enhanced anti-sintering properties. First, the subtle morphological and crystallographic modifications suggest that the inherent entropy stability of HEFO imparts robust thermal resistance. Concurrently, the disordered structure of single-phase HEFO exhibits a high affinity for CaO, resulting in an interface binding energy of -1.83eV, in sharp contrast to the -0.112eV of pure CaO, thereby restricting CaO migration. Additionally, the multi-element synergistic effect of HEFO reduces the energy barrier by 0.15eV, leading to a 40% and 140% increase in carbonation and calcination rates, respectively. This work presents highly efficient and rapidly synthesized CaO-based sorbent pellets, showcasing promising potential for industrial application.

The effect of different temperature rate on sol-gel approach derived M-type hexagonal BaFe12O19 using D-mannose as a fuel: Synthesis, structural, thermal gravimetric and magnetic properties

In this article, we reported that the BaFe12O19 powders were prepared using the effective sol-gel process under different calcination temperatures, i.e., 700–900 °C for 2 h. The structural effects of the temperature rate on the phase formation, morphological and magnetic properties of the as-prepared powders have been analyzed and discussed. The X-ray diffraction pattern confirmed the hexaferrite phase formation at calcined temperature range of 800 °C with no secondary phase and the particles size are about 45 nm–65 nm. The Fourier-transform infrared (FT-IR) spectra show that the intensity frequencies for hexaferrite site stretching were observed at 601 and 443 cm−1 from Fe–O and Ba–O bonds, respectively. The micro-sized flakes morphological structure with particle sizes ranging from 45 to 65 nm by strongly agglomerated powders of the hexaferrite phase is examined through the field emission scanning electron microscopy (FESEM) technique for the good-quality calcined 800 °C. Additionally, the effect of the calcination rates at 800 °C on the material features was analyzed by the energy-dispersive X-ray, X-ray photoelectron spectroscopy (XPS), etc. The magnetic properties, such as saturation magnetization and coercive field of the as-prepared nanomaterials were analyzed using the vibrating sample magnetometry (VSM) technique. The hysteresis loop of the BaFe12O19 nanomaterials calcined at 800 °C for 2 h showed excellent magnetic properties, with a higher saturation magnetization curve of 55.774 emu/g and a coercivity (Hc) of 5079 kOe. The dark brown colored annealed 800 °C nanomaterials can be useful as a ceramic color pigment, which has several industrial applications.

Experimental investigation of integrated CO2 capture and conversion to syngas via calcium looping coupled with dry reforming of CH4

Calcium looping integrated with dry reforming of CH4 is a promising strategy for CO2 capture and in situ conversion to syngas. This intensified process is usually conducted with bifunctional materials that combine CO2 capture (CaO) and catalytic (Ni) active sites. Herein, the integrated calcium looping/dry reforming process was examined by investigating various bifunctional materials and operating conditions. The Ni loading of materials affected the interaction between active and inert phases, while adding a CaZrO3 promoter enhanced the CO2 capture and catalytic activities and the resistance toward sintering. Conducting experiments with a fluidized bed reactor (700 °C, 3% CH4 in feed) led to nearly complete CH4 conversion and ∼52% utilization of captured CO2 toward syngas production with steady H2/CO ratio close to unity. Temperature comprised a decisive parameter, with low values enabling high degrees of CO2 conversion up to ∼80%. The increase of CH4 concentration in the gas feedstock enhanced the rate of calcination and the conversion of CO2 over its desorption in the gas phase. Co-feeding O2 with CH4 was proposed to mitigate the energy demand, which reduced the reforming selectivity for the partial oxidation reaction and increased the H2/CO ratio of syngas.

Dissolution Behavior of Lime with Different Properties into Converter Slag.

China's 2022 crude steel production soared to an impressive 1.018 billion tons, and steel slag constituted approximately 10% to 15% of this massive output. However, a notable hindrance to the comprehensive utilization of steel slag arises from the fact that it contains 10% to 20% of free calcium oxide (f-CaO), resulting in volume instability. To address this challenge, our study delved into the dynamic transformation of the interface between lime and slag, as well as the fluctuations in the dissolution rate of lime. An Electron Probe Micro Analyzer, equipped with an energy-dispersive spectrometer, was employed for the analysis. Our findings revealed that the configuration of the reaction interface between quicklime and slag underwent alterations throughout various phases of converter smelting. At a temperature of 1400 °C, several significant transformations occurred, including the formation of a CaO-FeO solid solution, (Ca, Mg, Fe) olivine, and low-melting point (Ca, Mg) silicate minerals. With the gradual reduction in FeO content, a robust and high-melting 2CaO·SiO2 layer emerged, generated through the interaction between CaO and (Ca, Mg, Fe) olivine. Furthermore, for lime with a particle size of 20 mm and a calcination rate of 0%, the thickest layer of 2CaO·SiO2 was observed after 120 s of dissolution in slag A2 at 1400 °C. Overall, the dissolution rates of lime with different particle sizes in slag A1 to A4 showed a gradual increase. On the other hand, the dissolution rates of lime with different calcination rates in slag A1 to A4 exhibited an initial increase, followed by a decrease, and then another increase. The formation of a high-melting point and continuous dense 2CaO·SiO2 layer during the dissolution process hindered the mass transfer between lime and slag.

Enhancing structural properties of simple perovskite materials based on zirconate and titanate prepared by sol-gel method

A simple and effective method is used in this study in order to obtain lead and lead-free simple perovskite structures. The perovskite materials BaTiO3, BaZrO3, PbTiO3 and PbZrO3 were synthesized via the sol-gel method. The main aim of this study is to investigate the effects of calcination temperature and rate on the material's properties. The structural phase formation of the prepared materials was characterized using X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The results gathered show that perovskite compounds based on barium occur at higher crystallization temperature, 900 and 1000 °C for BaTiO3 and BaZrO3 respectively, than the ones based on lead, 680 °C for PbTiO3 and PbZrO3. On the other hand, zirconate materials begin to crystallize at relatively high temperatures (1000 °C for BaZrO3 and 680 °C PbZrO3), than titanate-based materials (900 °C for BaTiO3 and 600 °C for PbTiO3). Also, the results showed, the obtaining of the non-centrosymmetric perovskite structure, indicating that piezoelectric property is present for all the elaborated materials.

Biotemplating of Al2O3-Doped, CaO-Based Material from Bamboo Fiber for Efficient Solar Energy Storage

The high-temperature sintering of CaO-based materials leads to the serious decay of energy storage performance during the calcination/carbonation cycle. To overcome the loss in porosity problem, an efficient CaO-based material for thermal energy storage was synthesized using bamboo fiber as the biotemplate. The synthesis parameters (bamboo fiber addition, pyrolysis, Al2O3 loading) and the energy storage reaction characteristics of CaO-based energy storage material were optimized on the basis of cyclic calcination/carbonation experiments. The results show that the sacrificed biotemplate enhances the porosity of the synthetic material, denoting improved energy storage density. The cumulative energy storage density of the templated material over 50 cycles is 24,131.44 kJ/kg higher than that of limestone. The carbonation conversion and energy storage density of the templated CaO-based material doped with 5 wt.% Al2O3 and 0.5 g bamboo fiber reach 0.75 mol/mol and 2368.82 kJ/kg after 10 cycles, respectively, which is 2.7 times as high as that of original limestone. The maximum apparent carbonation rate of the templated CaO-based materials in the 1st cycle corresponds to a 240% increment compared to limestone. The maximum calcination rate of the synthetic CaO-based material in the 12th cycle remains 93%, as compared with the initial cycle. The microstructure analysis reveals that the hierarchically-stable structure during the cycle is beneficial for a more effective exposure of surface reactive sites for CaO and inward/outward diffusion for CO2 molecules through CaO. The method using the sacrificed biological template provides an advanced approach to fabricate porous materials, and the composite CaO-based material provides high-return solar energy storage for a potential application in industrial scale.

Unrevealing the influence that preparation and reaction parameters have on Ni/Al2O3 catalysts for dry reforming of methane

Six types of alumina-support Ni catalysts were studied in dry reforming of methane to find out the influence that calcination rate, calcination temperature, and reduction temperature had on the activity and stability of the catalysts. BET, XRD, H2-TPR, TGA-DTA were carried out to analyzed the physicochemical properties of these catalysts. The H2-TPR results indicated that the proper parameters in preparing and reaction process could increase the amount of Ni reduced from NiAl2O4. And Ni reduced from NiAl2O4 could decrease the amount of inert carbon forming on catalysts' surfaces, so it was crucial to Ni/Al2O3 catalysts’ performance. Also, the results showed that the best condition was 5 °C/min calcination rate, 600 °C calcination temperature, and 700 °C reduction temperature. With this condition, TGA-DTA results showed that carbon deposition could be less and active.

Effects of calcination rate and temperature on microstructure and gaseous iodine capture capacity of 3DOM-SiO2 aerogels

Three-dimensional ordered macropores silica (3DOM-SiO2) aerogels prepared by the sol-gel and colloidal crystal template technology have attracted wide attention in the field of gaseous radioiodine capture. 3DOM effectively reduces the diffusion resistance of gas, increases the specific surface area and improves the capture capacity of the aerogels. The optimization of the calcination process for removing colloidal crystal templates is very important for the construction of 3DOM. The effects of calcination rate and calcination temperature on the microstructure, specific surface area, surface official energy group, phase composition, and iodine adsorption capacity of 3DOM-SiO2 were systematically investigated. The results showed that the calcination rate and temperature affected the iodine capture capacity of 3DOM-SiO2 by affecting the formation of macropores, mesopores, and micropores and the content of adsorbed water in the pore structure. The optimization of the 3DOM preparation process provides a scientific basis for the capture and application of radioactive iodine.

Self-template synthesis of Co3O4 nanotube for efficient Hg0 removal from flue gas

The adsorption of elemental mercury (Hg0) is a widely used technology to remove Hg0 from flue gas. The morphology and structure of sorbents, which have serious impacts on the number and availability of adsorption sites and the mass transfer of Hg0, play an important role in Hg0 removal process. Nanotube materials have through-pore structures leading to lower mass transfer resistance and more adsorption sites for Hg0. Given this, organic–inorganic hybrid nanowires were prepared by hydrothermal method as self-template. After calcination with a controlling heating rate and temperature, a series mesoporous Co3O4 nanotube sorbents were obtained. Characterization results show that the heating rate mainly affects the pore structure of the sorbents, while the calcination temperature mainly affects the surface morphology. When the calcination temperature is 400 °C and the calcination rate is 0.5 °C /min, the sorbent (Co3O4-T400-R0.5) has a clear 1D tubular structure which can effectively reduce the mass transfer resistance. And the unique internal surface of the tubular structure can provide more active sites, which can effectively avoid the competitive adsorption of Hg0 and other gas components. Furthermore, Co3O4-T400-R0.5 has the highest Co3+/Co2+ ratio leading to a better redox property, which is of benefit to Hg0 removal process. Therefore, the Hg0 removal efficiency of Co3O4-T400-R0.5 can reach more than 90% with a high gas hourly space velocity of 90,000 h− 1 and 0.02 g loading amount at 250 °C. Furthermore, Co3O4-T400-R0.5 has excellent Hg0 removal efficiencies in different flue gas condition showing a high stability.

Kinetic and thermodynamic analysis of thermo-oxidative degradation of seashell powders with different particle size fractions: compensation effect and iso-equilibrium phenomena

The issue of accumulated seashell waste has been increasingly addressed in the studies of its applicability as a secondary source of calcium carbonate. In this work, the mechanism of the thermo-oxidative degradation of two types of mollusk shells (Dosinia exoleta—DE and oyster Ostrea edulis—OE) was investigated using simultaneous thermal analysis. Physicochemical characterization of raw and calcined materials was performed by XRD and SEM techniques. Results show that increasing powder particle size and heating rate affect the degradation of investigated shells differently and have a significant contribution to released quantities of CO2. It was proposed that the calcination rate of DE powders is determined by the strain-induced collapse of CO2-deficient calcite at its interface with crystalline CaO rods-like structure, with simultaneous expulsion of CO2. A much higher CO2 concentration was identified during the degradation of OE powders, favoring the carbonation reaction and, consequently, increasing the temperature and activation energy of the investigated reaction. Under elevated CO2 concentration, the CaO aggregation step is enhanced by slower reaction kinetics at lower temperatures since both CO2 desorption and structural transformations are probably hindered. The proposed mechanism leads to a meaningful correlation between thermodynamic quantities (enthalpy–entropy compensation) in the form of an iso-kinetic relationship.

Calcination thermokinetics of three Brazilian limestones

Abstract Limestone and lime producers inadvertently generate a considerable amount of fine material during their processing, consequently becoming a great environmental liability. As far as the industrial calcination process is concerned, there is still a need for an experimental survey on Arrhenius law parameters, as apparent frequency factor and activation energy, referring to Brazilian limestones. The knowledge of these thermokinetic parameters may contribute to energy saving during the industrial calcination process, as well as for allowing the use of limestone fines in other industrial applications. This study aimed to characterize three Brazilian limestones by focusing on their laboratory-scale calcination using both quasi-isothermal and non-isothermal methods to estimate their kinetic parameters. The non-isothermal method (by thermogravimetric analyses) allowed estimating the activation energy for each limestone through the high calcination rate ranges. However, the kinetic parameters estimated by the quasi-isothermal method turned out in lower values, indicating the need to control the reactor atmosphere.

Dissolution optimization and kinetics of nickel and cobalt from iron‐rich laterite ore, using sulfuric acid at atmospheric pressure

AbstractMore than 70% of the world's nickel reserves are found in laterite ores. In this research, a laterite ore sample, containing Ni, Co, and Fe, was employed to study the recovery of nickel and cobalt. Thus, the effect of calcination, acid concentration, percent solids, and stirring rate on nickel and cobalt recoveries from an iron‐rich laterite sample was investigated. Optimization with response surface methodology and kinetic studies were performed. The calcination of the sample prior to leaching at 500°C for 2 h provided condition for better nickel and cobalt dissolutions. At optimal conditions, the concentration of sulfuric acid, solid‐to‐liquid ratio, stirring speed, temperature, and time test were equal to 5 M, 0.1, 370 rpm, 90°C, and 2 h, respectively. The highest recoveries of nickel and cobalt were 65.9% and 63.1%, respectively. Solids content had a negative effect on Ni and Co recovery, whereas acid concentration was positively affected. Addition of 10% (w/v) NaCl in the presence of 5 M acid concentration, 60°C, 370 rpm, and leaching time of 2 h increased the nickel and cobalt recoveries, 15.3% and 21.4%, respectively. The high dependence of process on temperature indicates chemical control; the activation energies Ea = 59.54 and Ea = 45.74 kJ/mol, respectively, for nickel and cobalt, were also consistent with this conclusion.

Property and mechanism of phenol degradation by biochar activated persulfate

In this study, corn stover was used to prepare biological activated carbon (BAC). First, the calcination temperature of BAC was optimized, and the calcination rate of BAC as the activator was confirmed to be maximal when the heating rate was 5.0°C min−1, the sample was allowed by cool naturally, and the calcination temperature was maintained at 900.0°C for 180min. The oxidants persulfate (PDS) and hydrogen peroxide were compared. In the case of a certain amount of BAC, the PDS was an effective as an oxidant and the dosage was small. The preferred oxidant was thus determined to be PDS. Under the PDS/BAC system, the PDS dosage (PDS/phenol molar ratio of 5:1), the initial pH value of the system (6.45), the temperature of the system (20.0°C), and the initial concentration of phenol were optimized. The effect of BAC was explained. At the end of the experiment, the stability of BAC was verified. The degradation rate of phenol by BAC after four repetitions could still reach 80.50 % (the initial concentration of phenol was 50.00mgL−1), and the degradation effect of the total organic carbon (TOC) of the system within 300min was verified. The degradation rate of TOC was 85.94 %, and the effect was ideal. The results of a simple preliminary analysis of the degradation mechanism are presented.

Preparation and electromagnetic properties of nanosized ZnFe2O4 with various shapes

In this paper, nanosized ZnFe2O4 with different morphologies were prepared by electrospinning method. The choice of initial parameters, such as PVP concentration, metal salt concentration, electrostatic voltage, calcination temperature and calcination rate, were investigated to prepare desired morphologies. The as-prepared samples exhibited various shapes of nano-particle, nano-rods, nano-beads and nano-fiber. The relationship between microstructure and electromagnetic properties was discussed in detail. It has been found that the saturation magnetization of ZnFe2O4 ferrite not changed significantly with the various morphologies and the values were nearly 13 emu/g. However, the coercivity was varied with the different morphologies, and the maximum value of 48.79 Oe was observed in the ZnFe2O4 nano-fiber. Moreover, the magnetic loss capacity of ZnFe2O4 was improved with the enhancement of the morphology anisotropy. The various shaped ZnFe2O4 can be promising lightweight microwave absorbers and it is significant to develop novel microwave absorption mechanism of ZnFe2O4 ferrite.

Computational fluid dynamics of sulfur dioxide and carbon dioxide capture using mixed feeding of calcium carbonate/calcium oxide in an industrial scale circulating fluidized bed boiler

The sulfur dioxide (SO2) and carbon dioxide (CO2) emissions from fuel combustion in a coal-fired power plant constitute a significant source of damage to the environment. Therefore, SO2 and CO2 should be captured before being released into the atmosphere. However, the competitiveness between SO2 and CO2 for calcium carbonate (CaCO3)/calcium oxide (CaO) solid sorbents is still unclear. In this study, unsteady state computational fluid dynamics simulation in a riser of an industrial scale circulating fluidized bed boiler integrated with heterogeneous combustion, carbonation, calcination, and desulfurization reactions using a mixed feeding of CaCO3/CaO solid sorbents was developed in a two-dimensional model to investigate the competition between SO2 and CO2 capture. Then, the effect of three operating variables, the mixed solid CaCO3/CaO sorbent particle size, feed position, and the proportion of inlet fuel velocity on the SO2 and CO2 capture were evaluated using a 23 factorial experimental design. The CaCO3/CaO solid sorbent particle size had a significant effect on the SO2 capture, while the interaction between CaCO3/CaO solid sorbent particle size and feed position had a significant effect on the CO2 capture. The reaction rate for CO2 capture was higher than that for SO2 capture. For SO2 capture, CaO reacted with SO2 faster than CaCO3 while, for CO2 capture, solid sorbents had higher carbonation rate than calcination rate. In addition, the overall level of SO2 and CO2 capture with a mixed CaCO3/CaO solid sorbent feed was higher than those with the conventional CaO solid sorbent.

Kinetics of Siderite Ore Roasting in the Shaft Furnace

Kinetics of the siderite ore roasting in the air, helium and hydrogen flows has been studied in a gasometrical unit with continuous mass variation logging. We have derived the expression for determination of an apparent degree of calcination and identified its dependence on the size of the prill, the heat treatment duration, and gas-phase composition. Using a generalized chemical kinetics equation, we have obtained a formula for calculation of the decomposition period for siderite ore samples. It has been found that calcination rate increases with the temperature rise, irrespective of the sample size and atmospheric composition. Calcination process has been studied at low temperatures. We have demonstrated that it is feasible to describe the process of siderite ore thermal dissociation by a first-order kinetics equation. We have obtained the expression to calculate the duration of this process depending on different parameters. Using a generalized chemical kinetics equation, we have obtained a formula for checking the expressions that describe the experimental data. We have studied kinetics of the reduction of roasted ore samples at various temperatures using different sizes of the samples. The obtained results have been applied for optimization of the design values and operating conditions of the siderite ore roasting in shaft furnaces. These will also be used for designing a shaft furnace consisting of a calcination zone, reduction zone (metallization zone) and metallized product cooling zone, which will increase iron content in the end-product to 65-70%.

Effect of Calcination Rate on Performance of Co-precipitated Cu-MgO Catalyst in Hydrogenation of Furfural

Co-precipitated Cu-MgO catalysts were prepared and evaluated for the gas-phase hydrogenation of furfural. The effect of heating rate at the calcination step was studied by comparing the performance of three catalysts prepared via the same procedure but calcined at different heating rates. The results established that altering the heating rate could influence the structural properties of the catalyst samples and hence their activity and selectivity. An extremely poor catalytic activity and selectivity (lower than 0.1% conversion of furfural and 40% selectivity towards furfuryl alcohol after 240 min time-on-stream) belonged to the catalyst that was prepared with the lowest calcination rate (1 Kmin–1), while the other two catalysts prepared with the calcination rate of 5 and 10 Kmin–1 indicated more than 88% conversion of furfural and 85% furfuryl alcohol selectivity during this run length.

The combined effect of H2O and SO2 on the simultaneous calcination/sulfation reaction in CFBs

The combined effect of H2O and SO2 on the reaction kinetics and pore structure of limestone during simultaneous calcination/sulfation reactions under circulating fluidized bed (CFB) conditions was first studied in a constant‐temperature reactor. H2O can accelerate the sulfation reaction rate in the slow‐sulfation stage significantly but has a smaller effect in the fast‐sulfation stage. H2O can also accelerate the calcination of CaCO3, and should be considered as a catalyst, as the activation energy for the calcination reaction was lower in the presence of H2O. When the limestone particles are calcining, SO2 in the flue gas can react with CaO on the outer particle layer and the resulting CaSO4 blocks the CaO pores, increases the diffusion resistance of CO2, and, in consequence, decreases the calcination rate of CaCO3. Here, gases containing 15% H2O and 0.3% SO2 are shown to increase the calcination rate. This means that the accelerating effect of 15% H2O on CaCO3 decomposition is stronger than the impeding effect caused by 0.3% SO2. The calcination rate of limestone particles was controlled by both the intrinsic reaction and the CO2 diffusion rate in the pores, but the intrinsic reaction rate played a major role as indicated by the effectiveness factors determined in this work. This may explain the synergic effect of H2O and SO2 on CaCO3 decomposition observed here. Finally, the effect of H2O and SO2 on sulfur capture in a 600 MWe CFB boiler burning petroleum coke is also analyzed. The sulfation performance of limestone evaluated by simultaneous calcination/sulfation is shown to be much higher than that by sulfation of CaO. Based on our calculations, a novel use of the wet flue gas recycle method was put forward to improve the sulfur capture performance for high‐sulfur low‐moisture fuels such as petroleum coke. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1256–1268, 2019