Different Partial Pressures Of CO2 Research Articles

Electrochemical investigations on CO2 reduction mechanism in molten carbonates in view of H2O/CO2 co-electrolysis

In order to reduce carbon dioxide emission, one solution is to convert into valuable chemicals or fuels, e.g. transforming CO2 into CO by electrochemical reduction. Thus, this greenhouse gas could be re-used in particular as syngas (CO + H2) by co-electrolysis of CO2/H2O. High temperature electrolysis cells can be the best energetic devices to produce such syngas. In particular, molten carbonates are known to solubilize CO2 very significantly higher than other solvents. Therefore, it is compulsory to investigate and understand the mechanism of CO2 reduction in such media to consider its further use and valorisation. The present study is a critical approach aiming at elucidating the mechanisms for CO2 electroreduction, using an inert Pt electrode in the molten eutectic Li2CO3–K2CO3 (62-38 mol%), at 650 °C, under different partial pressures of CO2. Complementary electrochemical techniques, including sweep square-wave voltammetry and relaxation chronopotentiometry, were carried out. Their combination allowed us to evidence that the electroreduction of CO2 into CO is feasible in oxo-acidic conditions, involving a diffusion-limited quasi reversible system in a one electron-step.

USING WIRE BEAM ELECTRODE (WBE) TO EVALUATE THE CORROSION BEHAVIOR OF ND STEEL IN ACID MEDIUM

In this article, wire beam electrode (WBE) was used to evaluate the corrosion behavior of ND steel in environmental acid atmosphere with different partial pressure of CO2. Meanwhile, corrosion products and surface morphology analysis also used to support this research. The results showed that the corrosion behavior began from the edge of droplet in dew point corrosion, and gradually spread to the center of it. The spread speed would be increasing with CO2 partial pressure enhance, which was 24h in 5% CO2 and 4h in 50% CO2. Corrosion current density in the edge of droplet can form the “cathode-anode-cathode ring” structure and disappears gradually as the corrosion time was going. Corrosion morphology observation results showed three ring shapes region and different elemental composition of different corrosion products, which is correspondence with the “cathode-anode We-cathode ring” structure measured in WBE experiments. The results showed that the reaction gradually transferred to the uniform corrosion on electrode surface when the dew point corrosion reaction reaching the late stage. It comes from the dissolution, diffusion and reaction of gaseous corrosion medium of CO2 and O2.

Evaluation of dew point corrosion in acid atmosphere by wire beam electrode

In this article, wire beam electrode (WBE) was used to evaluate the corrosion behavior of ND steel in environmental acid atmosphere with different partial pressure of CO2. Meanwhile, corrosion products and surface morphology analysis also used to support this research. The results showed that the corrosion behavior began from the edge of droplet in dew point corrosion, and gradually spread to the center of it. The spread speed would increasing with CO2 partial pressure enhance, which was 24h in 5% CO2 and 4h in 50% CO2. Corrosion current density in the edge of droplet can form the “cathode-anode-cathode ring" structure, and disappears gradually as the corrosion time was going. Corrosion morphology observation results showed three ring shapes region and different elemental composition of different corrosion products, which is correspondence with the "cathode-anodWe-cathode ring" structure measured in WBE experiments. The results showed that the reaction gradually transferred to the uniform corrosion on electrode surface when the dew point corrosion reaction reaching the late stage. It comes from the dissolution, diffusion and reaction of gaseous corrosion medium of CO2 and O2.

Investigation of a dual cold-flow fluidized bed for calcium looping gasification process

In this paper, a compact fluidized bed gasifier is proposed for the calcium looping gasification process to produce hydrogen-rich gas with CO2 capture. The design of compact fluidized bed gasifier is according to the adsorption properties of lime under different partial pressure of CO2 and temperature. The compact fluidized bed gasifier consists of two sections: an upper riser and a lower bubbling fluidized bed. The fluid dynamics feasibility of the proposed dual fluidized bed with compact fluidized bed gasifier was evaluated in a cold flow model. The cold flow model can operate in a stable state under designed conditions. Most of the bed materials (>90%) stay in the lower bubbling fluidized bed. The effect of the total solid inventory and the fluidizations in both the lower bubbling fluidized bed and the regenerator on the solid recirculation flux is marginal because of the high resistance in the loop-seal of the lower bubbling fluidized bed to the regenerator. The solid recirculation flux can be controlled effectively by loop-seals, but the fluidization number in the supply section of the loop-seal must be kept lower than 1. No gas leakage was detected in the cold flow model under the designed conditions.

Measurements of the broadening and shift parameters of the carbon monoxide spectral lines in the 1–0 band induced by pressure of carbon dioxide

The absorption spectra of a mixture of CO with CO2 at different partial pressures of CO2 have been recorded at room temperature in the 2000–2300 cm−1 region using a Bruker IFS 125 HR FTIR spectrometer. To obtain the spectral line parameters for the fundamental band of CO molecule, the quadratic speed-dependent Voigt profile was used for the first time. The CO2 pressure induced broadening and shift coefficients for 49 spectral lines have been measured. A comparison with the published data is discussed.

Measurements of the broadening and shift parameters of the water vapor spectral lines in the 10,100–10,800 cm−1 region induced by pressure of carbon dioxide

The absorption spectra of a mixture of H2O with CO2 at different partial pressures of CO2 have been recorded at room temperature in the 10,100–10,800 cm−1 region using a Bruker IFS 125 HR FTIR spectrometer. The multispectrum fitting procedure has been applied to these spectra to recover the broadening and shift parameters of the water vapor spectral lines. To obtain the spectral lines parameters two models of the line shape were used: the Voigt profile and the quadratic speed-dependent Voigt profile. The CO2 pressure induced broadening and shift coefficients for 168 spectral lines with rather large values of the signal to noise ratio have been measured.

Increased pCO2 and temperature reveal ecotypic differences in growth and photosynthetic performance of temperate and Arctic populations of Saccharina latissima.

The Arctic population of the kelp Saccharina latissima differs from the Helgoland population in its sensitivity to changing temperature and CO 2 levels. The Arctic population does more likely benefit from the upcoming environmental scenario than its Atlantic counterpart. The previous research demonstrated that warming and ocean acidification (OA) affect the biochemical composition of Arctic (Spitsbergen; SP) and cold-temperate (Helgoland; HL) Saccharina latissima differently, suggesting ecotypic differentiation. This study analyses the responses to different partial pressures of CO2 (380, 800, and 1500 µatm pCO2) and temperature levels (SP population: 4, 10°C; HL population: 10, 17°C) on the photophysiology (O2 production, pigment composition, D1-protein content) and carbon assimilation [Rubisco content, carbon concentrating mechanisms (CCMs), growth rate] of both ecotypes. Elevated temperatures stimulated O2 production in both populations, and also led to an increase in pigment content and a deactivation of CCMs, as indicated by 13C isotopic discrimination of algal biomass (ε p) in the HL population, which was not observed in SP thalli. In general, pCO2 effects were less pronounced than temperature effects. High pCO2 deactivated CCMs in both populations and produced a decrease in the Rubisco content of HL thalli, while it was unaltered in SP population. As a result, the growth rate of the Arctic ecotype increased at elevated pCO2 and higher temperatures and it remained unchanged in the HL population. Ecotypic differentiation was revealed by a significantly higher O2 production rate and an increase in Chl a, Rubisco, and D1 protein content in SP thalli, but a lower growth rate, in comparison to the HL population. We conclude that both populations differ in their sensitivity to changing temperatures and OA and that the Arctic population is more likely to benefit from the upcoming environmental scenario than its Atlantic counterpart.

Effect of partial pressure on CO2 solubility in ionic liquid mixtures of 1-butyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide

The solubilities of CO2 in ionic liquid mixtures composed of 1-butyl-3-methylimidazolium acetate, [BMIM][AcO] and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide, [BMIM][Tf2N] have been determined at different partial pressures of CO2 balanced with N2 at atmospheric pressure over the temperature range (284–334) K. The solubility of CO2 was proportional to the concentration of [BMIM][AcO], which reacts stoichiometrically with CO2 in [BMIM][Tf2N]. The CO2 absorption mechanism was discussed in terms of the densities, viscosities, and electrical conductivities for the IL mixtures before and after CO2 saturation. It was concluded that 1-butyl-3-methylimidazolium-2-carboxylate zwitterion, [BMIM+-CO2−], is produced with deprotonation of 2-hydrogen in [BMIM]+. This leads to formation of acetic acid, resulting in the viscosity reduction. Moreover, the absorption and desorption experiments for extremely dilute gas mixture (4000 ppm CO2 in N2) in the [BMIM][AcO]-[BMIM][Tf2N] mixtures were carried out. The ionic liquids mixtures can effectively remove CO2 even at such dilute concentrations. The absorption and desorption rates increased with increasing temperature. At higher temperature, the absorption rate also increased with increasing the concentration of [BMIM][AcO]. The multicycle experiments using [BMIM][AcO] between 2 h absorption at 298 K and 2 h desorption under vacuum at 353 K demonstrated the practical efficiency for CO2 separation under extremely dilute conditions. The air purification process using ionic liquids for a limited space such as aerospace has been proposed for one of the promising future applications.

Effects of ocean acidification on embryonic respiration and development of a temperate wrasse living along a natural CO2 gradient.

Volcanic CO2 seeps provide opportunities to investigate the effects of ocean acidification on organisms in the wild. To understand the influence of increasing CO2 concentrations on the metabolic rate (oxygen consumption) and the development of ocellated wrasse early life stages, we ran two field experiments, collecting embryos from nesting sites with different partial pressures of CO2 [pCO2; ambient (∼400 µatm) and high (800-1000 µatm)] and reciprocally transplanting embryos from ambient- to high-CO2 sites for 30 h. Ocellated wrasse offspring brooded in different CO2 conditions had similar responses, but after transplanting portions of nests to the high-CO2 site, embryos from parents that spawned in ambient conditions had higher metabolic rates. Although metabolic phenotypic plasticity may show a positive response to high CO2, it often comes at a cost, in this case as a smaller size at hatching. This can have adverse effects because smaller larvae often exhibit a lower survival in the wild. However, the adverse effects of increased CO2 on metabolism and development did not occur when embryos from the high-CO2 nesting site were exposed to ambient conditions, suggesting that offspring from the high-CO2 nesting site could be resilient to a wider range of pCO2 values than those belonging to the site with present-day pCO2 levels. Our study identifies a crucial need to increase the number of studies dealing with these processes under global change trajectories and to expand these to naturally high-CO2 environments, in order to assess further the adaptive plasticity mechanism that encompasses non-genetic inheritance (epigenetics) through parental exposure and other downstream consequences, such as survival of larvae.

Effect of pressure and gas concentration on CO2 and SO2 capture performance of limestones

Two Greek limestones with different properties were tested to determine their CO2 and SO2 capture performance. The reversibility of the sorbents for CO2 capture was investigated by performing looping cycles in atmospheric and pressurized thermogravimetric reactors, with synthetic gas mixtures containing different partial pressures of CO2 and SO2 to simulate flue gases. The morphological and porosity characteristics of the original and spent sorbent were examined by Scanning Electron Microscopy and Pore Sized Distribution analyses.Increasing pressure from atmospheric to 10bar led to deterioration in CO2 capture performance. Further pressure increment had negligible effect on the CO2 capture performance. SO2 retention, however, improved with increasing pressure. For calcium looping with repeated cycles, sorbents sulphated via the unreacted-core mode converted more available calcium, but this adversely affected the reversibility of cyclic CO2 capture. The reversibility strongly deteriorated when higher total pressure was combined with increased SO2 partial pressure. The CO2 uptake of an unreacted-core sulphated sorbent, previously used for SO2 retention, was mainly affected, apart from pore blockage or sintering, by the occupation of calcium. Sulphation during simultaneous capture resulted in higher CO2 removal efficiency for uniformly and network sulphated particles compared to the sulphur capture via direct sulphation.

CO2 FLUX IN INDONESIAN WATER DETERMINED BY SATELLITE DATA

The oceans was considered to be a major sink for CO2. The improving of quantitative and qualitative description about the ability of sea in uptaking or emitting CO2 is a great scientific concern in meteorological and climatological science. Measurement of the ability of sea in uptake or emitting CO2 could determined by measuring the CO2 exchange coefficient on sea interface and the measuring the different partial pressure of CO2 between the air and sea. In this study, CO2 flux distribution of Indonesian waters in 2007 to 2009 was computed using monthly CO2 exchange and the different partial pressure of CO2 estimated from wind speed, salinity, SST, and sea characteristic, which were obtained from satellite data. The carbon dioxide flux thus was estimated and discussed by two different designs of transfer velocity (k), of Wanninkhof (1992), kW92 relationship and by Nightingale et al. (2000), kN, relationship. The result indicated that generally, Indonesian water was emitting the CO2 to the air. Average CO2 emitting from sea to the air for recent year in 2007 to 2009 are 3.80 (mol m-2year-1) and 2.85 (mol m-2year-1) with kW92 relationship and kN relationship calculation, respectively. The total average CO2 emission from sea to the air in 2007 to 2009 for the Indonesian waters areas are 0.15 (PgC year-1) and 0.12 (PgC year-1) based on kW92 relationship and kN relationship calculations, respectively.
 Keywords: CO2 flux, salinity, SST, sink and sources of CO2.

Experiments and Kinetic Modeling for CO2 Gasification of Indian Coal Chars in the Context of Underground Coal Gasification

Gasification of four Indian coals is carried out in a CO2 atmosphere, using a thermogravimetric analyzer (TGA) to determine the intrinsic kinetics over a temperature range of 800–1050 °C with different partial pressures of CO2. The applicability of three models, viz., the volumetric reaction model, the shrinking core model and the random pore model, is evaluated. Of these three models, the random pore model is found to be the most suitable for all the coals considered in the current study. The dependence of the reaction rate on the gas-phase partial pressures is explained by the Langmuir–Hinshelwood model, and the parameters for the inhibition due to CO and CO2 are determined by performing experiments at different partial pressures. In underground coal gasification, the reaction takes place on reasonably large sized coal particles, wherein diffusion effects are significant. A one-dimensional reaction diffusion model is therefore developed in order to determine the diffusional resistance in the coal partic...

Flax straw char‐CO2 gasification kinetics and its inhibition studies with CO

AbstractChar gasification has been studied in different ways with different feedstock; however, the fundamental studies about the variation of char reactivity with different combination of parameters are still required in order to design the biomass char gasification process in large scale unit. In this work, char from flax straw pyrolysis was used for gasification with different partial pressure of CO2, different temperature and particle size. Results showed that 375‐µm particle sizes of char has higher reactivity compared to other particle sizes and the inhibition effect was also less at 375‐µm particle size. Kinetic parameters varied for gasification reaction with different particle sizes and the average activation energy was 196 kJ/mol and the order of the reaction was approximately 1. Inhibition studies with the addition of CO in the gasifying agent proved that CO molecules interfere significantly and reduced the reactivity. ANOVA test showed that the temperature plays a vital role in char reactivity. The particle sizes of 375 and 800 µm along with the CO2 partial pressure of 0.35 bars are the best combination for achieving the maximum reactivity. © 2012 Canadian Society for Chemical Engineering

On the buffer capacity of CO2 -charged seawater used for carbonation and subsequent mineral sequestration

Successful mineral trapping of carbon dioxide faces the challenge of effectively titrating a CO2-charged acidic injection solution to pH conditions favorable to carbonate precipitation -using the rock as primary alkalinity source. To illustrate the magnitude of this task, buffer capacities of seawater solutions equilibrated with different partial pressure of CO2 are presented, under open and closed conditions. A number of mechanisms can be evoked to overcome the large buffer intensity of the injection fluid, including dilution, dissolution kinetic catalysis and increasing reaction temperature. Buffer capacity – pH plots are presented to aid in understanding how buffer capacity changes as a function of the presence and concentration of key solutes, like fluoride. © 2010 Elsevier Ltd. All rights reserved

Karstification in unconfined limestone aquifers by mixing of phreatic water with surface water from a local input: A model

Summary When water from the surface of a limestone plain seeps down through the fractured rock to the water table of an unconfined aquifer with low hydraulic gradient containing water saturated with respect to calcite, mixing of these waters causes renewed aggressivity. A model is presented, which describes the evolution of karstification by dissolutional widening of the fractures downgradient from the local input of surface water. The model couples flow in the fractures with dissolution rates. Dissolution rates are given by F = k (1 − c (x)/ceq)4, where c (x) is the calcium concentration at distance x from the entrance of the fracture, ceq is the equilibrium calcium concentration of the H2O–CaCO3–CO2 solution in the fracture, and k is a rate constant. The model describes two domains of waters saturated with respect to calcite at different partial pressure of CO2. At the borders of these domains the waters mix and create dissolutional widening of the fractures by mixing corrosion. A channel evolves along the border in the downgradient direction by about 100 m in 100 ky. Below this channel a zone of fractures with aperture widths up to 1 cm has originated. The change of the hydraulic conductivity in the mixing zone shifts the border of the domains, allowing the channel to grow in the downgradient direction. Below it the zone of widened fractures is invaded by saturated phreatic water and dissolution stops. This process continues at the downgradient part of the conduit. In summary, we find cave conduits evolving close to the water table, leaving significant cavernous structures below them. A variety of modelling scenarios with different choices of parameters show that this evolution is typical and changes only in details but not in its basic behaviour.

Effects of carbon dioxide on the coccolithophorid Pleurochrysis carterae in incubation experiments

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 7:59-70 (2009) - DOI: https://doi.org/10.3354/ab00182 Effects of carbon dioxide on the coccolithophorid Pleurochrysis carterae in incubation experiments Beatriz E. Casareto1,2,*, Mohan P. Niraula2,4, Hiroyuki Fujimura3, Yoshimi Suzuki2 1Laboratory of Aquatic Science and Consultant Co., Ltd., Meishin Bldg. Kamiikedai 1-14-1, Ota-ku, Tokyo 145-0064, Japan 2Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan 3Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan 4Institute of Science and Technology, Tribhuvan University Trichandra Campus, Kathmandu, Nepal *Email: casaretobe@aol.com ABSTRACT: Production (abundance and biomass) and net calcification rates of the coccolithophorid Pleurochrysis carterae under different partial pressures of CO2 (pCO2) were examined using short (15, 24 and 39 h), long (7 d) and dark (7 d) incubation experiments. Short incubations were conducted at ambient, 500 and 820 ppm pCO2 levels in natural seawater that was enriched with nutrients and inoculated with P. carterae. Long incubations were conducted at ambient and 1200 ppm pCO2 levels in natural seawater (0.2 µm filtered as well as unfiltered) that was enriched with nutrients and inoculated with P. carterae. Dark incubations were conducted at ambient and 1200 ppm pCO2 in unfiltered seawater that was inoculated with P. carterae. The abundance and biomass of coccolithophorids increased with pCO2 and time. The abundance and biomass of most noncalcifying phytoplankton also increased, and were hardly affected by CO2 inputs. Net calcification rates were negative in short incubations during the pre-bloom phase regardless of pCO2 levels, indicating dissolution of calcium carbonate. Further, the negative values of net calcification in short incubations became less negative with time. Net calcification rates were positive in long incubations during blooms regardless of pCO2 level, and the rate of calcification increased with pCO2. Our results show that P. carterae may adapt to increased (~1200 ppm) pCO2 level with time, and such increase has little effect on the ecology of noncalcifying groups and hence in ecosystem dynamics. In dark incubations, net calcification rates were negative, with the magnitude being dependent on pCO2 levels. KEY WORDS: pCO2 · Pleurochrysis carterae · Noncalcifying phytoplankton · Biomass · Net calcification rates · Adaptation Full text in pdf format PreviousNextCite this article as: Casareto BE, Niraula MP, Fujimura H, Suzuki Y (2009) Effects of carbon dioxide on the coccolithophorid Pleurochrysis carterae in incubation experiments. Aquat Biol 7:59-70. https://doi.org/10.3354/ab00182 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 7, No. 1-2. Online publication date: September 24, 2009 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2009 Inter-Research.

Phase relations of nahcolite and trona at high P-T conditions

Using cold-seal hydrothermal bomb and piston-cylinder apparatus, we have carried out both forward and reversal experiments to investigate the phase boundary between nahcolite (NaHCO3) and trona (NaHCO3·Na2CO3·2H2O). We found that the temperature of this phase boundary remains low at least up to 10 kbar, so that this phase transformation maintains its univariant nature in our investigated P-T space. The locus of this phase boundary in a log(pCO2)-T space is defined as log(pCO2) = 0.0240(±0.0001)T − 9.80(±0.06) (with pCO2 in bar and T in K), in excellent agreement with earlier 1 atm experiments at different partial pressures of CO2 (pCO2) and theoretical calculation. Using this equation and literature thermodynamic data, the entropy of trona at 298.15 K is constrained to be 303.8 J mol−1 K−1, essentially identical to earlier estimates from different methods. Our experimental results have also been used to constrain the genesis of nahcolite in some fluid inclusions of diverse origins, and it is suggested that nahcolite in these occurrences is most likely a daughter mineral which crystallized from the fluids as temperature decreased, rather than an accidentally trapped phase.

Coupling of heterotrophic bacteria to phytoplankton bloom development at different <i>p</i>CO<sub>2</sub> levels: a mesocosm study

Abstract. The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics) affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2): 350 μatm (1×CO2), 700 μatm (2×CO2) and 1050 μatm (3×CO2). The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP) of free-living and attached bacteria as well as cell-specific BPP (csBPP) of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly correlated to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

Response of primary production and calcification to changes of pCO2 during experimental blooms of the coccolithophorid Emiliania huxleyi

Primary production and calcification in response to different partial pressures of CO2 (PCO2) (“glacial,” “present,” and “year 2100” atmospheric CO2 concentrations) were investigated during a mesocosm bloom dominated by the coccolithophorid Emiliania huxleyi. The day‐to‐day dynamics of net community production (NCP) and net community calcification (NCC) were assessed during the bloom development and decline by monitoring dissolved inorganic carbon (DIC) and total alkalinity (TA), together with oxygen production and 14C incorporation. When comparing year 2100 with glacial PCO2 conditions we observed: (1) no conspicuous change of net community productivity (NCPy); (2) a delay in the onset of calcification by 24 to 48 hours, reducing the duration of the calcifying phase in the course of the bloom; (3) a 40% decrease of NCC; and (4) enhanced loss of organic carbon from the water column. These results suggest a shift in the ratio of organic carbon to calcium carbonate production and vertical flux with rising atmospheric PCO2.

Kinetic Model Comparison for Waste Tire Char Reaction with CO2

Pyrolysis has proven to be a useful recycling process for waste tires, and pyrolytic char is ∼40% of initial sample weight. To valorize this solid, the activated carbon production has been studied for the last years from a generation point of view. However, there are only few studies about the kinetics of the reaction. In this paper, four gas−solid models have been applied to CO2 activation of tire char: volume model, modified volume model, changing grain size model, and random pore model. The reactions were performed in a thermobalance with a structural and analytically characterized tire char obtained by pyrolysis in a fixed-bed reactor at a temperature of 1000 °C for 3 h. Experimental conditions were optimized to minimize internal and external mass-transfer phenomena performing experiments with different particle sizes, at different flow rates and initial weights. Finally, to obtain the intrinsic kinetic parameters, several experiments were carried out at different partial pressures of CO2 and temperatures, concluding that the random pore model is the most appropriate model to describe the reaction. The tire char activation was found to be a first-order reaction with respect to CO2. The kinetic results reported in this paper can be useful for tire char activation scaling-up and the process engineering design, so that knowledge of the activation energy and the preexponential factor of the chemical reaction is fundamental to perform the chemical reactor design and the optimization of process parameters.