Main Decomposition Stage Research Articles

Pyrolysis and combustion of industrial hemp, coal and their blends for thermal analysis by thermogravimetric analysis/Fourier transform infrared spectrometer.

In this study, the thermal behaviours of Cannabis sativa (CS), coal and their five different blends at a heating rate (β) of 10, 20, 30, 40 and 50°C min-1; the synergistic effects between CS and coal; and the distribution of gases formed during pyrolysis and combustion were investigated by using the thermogravimetric analysis/Fourier transform infrared spectrometer (TGA/FTIR) integrated system. The TG and DTG curves showed that the thermal decomposition of pyrolysis and combustion of all feedstocks at all β values had three main decomposition stages. The synergistic effect was observed for DTGmax, mass loss (ML), or final residue (FR) at least once at a given β of each blend; and the synergy was more effective for DTGmax and ML in pyrolysis than in combustion, whereas the opposite was true for FR. The lowest emissions of CO2, CH4, NOx and SO2 except CO during pyrolysis occurred at the blend of 0% CS + 100% Coal. However, the highest emissions of CO, CH4, NOx and SO2 except CO2 during combustion were observed at the blend of 80% CS + 20% Coal. The emissions of CO, CO2, NOx and SO2 from all samples during pyrolysis were lower than that of combustion, indicating that pyrolysis can be preferred due to its lower emission to the environment. Different structural properties of CS, coal and their blends caused different thermal behaviours, synergistic effects and gas products during pyrolysis and combustion by TGA/FTIR, suggesting detailed further investigation for upper-scale pyrolysis and combustion applications.

Kinetic and thermodynamic study of composite with jute fiber as reinforcement

In the present work, engineered by compression molding process via a hydraulic press, the A and B composite samples were carried out with 5% and 10% ratio respectively of Ricinodendron heudelotii oil-based alkyd resin in bio-based matrix made of unsaturated polyester using jute fibers as reinforcement material. The samples’ thermal decomposition was performed through thermogravimetry (TG) and derivative thermogravimetry (DTG) analyses. Both composite samples exhibit two stages of decomposition, where the main occurs at 200 - 550°C. Aiming to study and being able to model the thermal degradation of the elaborated composites, finding the kinetic triplets appears the best option to describe the kinetic process undergo by the composites in order to evaluate the performance application of the composites. Two non-isothermal techniques, Flynn-Wall-Ozawa (FWO) and Kissinger have been used to assess the activation energy Ea, and it is found that the apparent activation energy varies with the degree of conversion indicating that both composites decompose with a multiple step mechanism process. The appropriate reaction model for the second stage of decomposition was best suited with Johnson-Mel-Avrami (n<1) model and has been established, allowing us to model thermal degradation behavior of our elaborated composite material and set predictions. The estimated Arrhenius factor values were respectively about A and B composites, 4.12.1015 min-1 and 10.42.1015 min-1, allowing us to set the final equation characterizing the degradation process for the second and main decomposition stage. Finally, as a result of comparison between A and B composites, A appears to be the more thermally stable due to its lower values of Arrhenius pre-exponential factor over the main stage of decomposition and higher calculated the activation energy values.

Mechanistic insights into co-pyrolysis of waste tires and waste lubricating oil: Kinetics and thermal behavior study

ABSTRACT The co-pyrolysis of waste tires (WT) with waste lubricating oil (WLO) can significantly improve the quality of products. The co-pyrolysis behavior of WT and WLO was investigated by using thermogravimetric analyzer. Three isoconversional methods, Flynn–Wall–Ozawa, Friedman and Kissinger–Akahira–Sunose, were used to calculate the activation energy of the mixture at the heating rates of 5, 10, 15, and 20K/min. The obtained data were used to determine the kinetic model and thermodynamic parameters. The results showed that WLO promoted the pyrolysis of WT. The synergistic effect was shown in the reduction of the activation energy of the mixture by 10%. The mean activation energy of the main decomposition stage is 90.8 kJ/mol. Moreover, the thermodynamic stability of reaction was determined by the calculation of change in entropy, Gibbs free energy, and enthalpy. The value of pre-exponential factor is 2.48 × 107/min, which means that the co-pyrolysis reaction is not a complex interface reaction. Among all the models, the 3D diffusion model best fits the co-pyrolysis mechanism judging by Malek master plot method. The reaction function was also determined. This study will provide basic knowledge into the co-processing of WT and WLO for predicting the performance of reactor and simulating the process.

Preparation of low-nitrogen chlorella based on proteolysis technology and pyrolysis characteristics of the products

The high protein content in the microalgal biomass leads to the high relative content of nitrogen compounds in the pyrolysis oil, which hinders the efficient application of the microalgal pyrolysis oil. In this paper, a method for preparing low-nitrogen chlorella by using alkaline protease based on proteolysis technology was proposed to reduce the nitrogen content of chlorella, and its process conditions were optimized. The results showed that the maximum nitrogen removal rate and yield could reach 20.32% and 52.36 wt%, respectively. The thermal decomposition characteristics of Chlorella and low-nitrogen chlorella were analyzed by TG-DTG technology, and their main thermal decomposition were calculated by Coats-Redfern method. It was found that compared with Chlorella, the low-nitrogen Chlorella had a larger weight loss rate in main thermal decomposition stage and its average activation energy value reduced by 2.23 kJ/mol. The Py-GC-MS technology was further used to study the distribution of pyrolytic products of Chlorella and low-nitrogen Chlorella at 550 °C. It was found that the relative content of nitrogen compounds in pyrolytic products from low-nitrogen Chlorella was 43.02% lower than that of Chlorella. This is because that the proteolysis pretreatment has a significant effect on reducing the relative contents of some nitrogen compounds in bio-oil, such as pyridines, pyrroles and benzyl nitrile. Based on the above experimental results, a brief mechanism of proteolysis pretreatment on removing nitrogen compounds was proposed, mainly through the proteolytic process to reduce the relative content of various amino acids in Chlorella as precursors for the synthesis of nitrile and N-heterocyclic compounds in pyrolysis. In conclusion, proteolysis technology can effectively reduce the relative content of nitrogen compounds in pyrolysis components and improve the potential of microalgal pyrolysis oil as a high-quality alternative fuel.

Thermal Stability of Fluorescent Chitosan Modified with Heterocyclic Aromatic Dyes.

Fluorescent biopolymer derivatives are increasingly used in biology and medicine, but their resistance to heat and UV radiation, which are sterilizing agents, is relatively unknown. In this work, chitosan (CS) modified by three different heterocyclic aromatic dyes based on benzimidazole, benzothiazole, and benzoxazole (assigned as IBm, BTh, and BOx) has been studied. The thermal properties of these CS derivatives have been determined using the Thermogravimetric Analysis coupled with the Fourier Transform Infrared spectroscopy of volatile degradation products. The influence of UV radiation on the thermal resistance of modified, fluorescent chitosan samples was also investigated. Based on the temperature onset as well as the decomposition temperatures at a maximal rate, IBm was found to be more thermally stable than BOx and BTh. However, this dye gave off the most volatile products (mainly water, ammonia, carbon oxides, and carbonyl/ether compounds). The substitution of dyes for chitosan changes its thermal stability slightly. Characteristic decomposition temperatures in modified CS vary by a few degrees (<10 °C) from the virgin sample. Considering the temperatures of the main decomposition stage, CS-BOx turned out to be the most stable. The UV irradiation of chitosan derivatives leads to minor changes in the thermal parameters and a decrease in the number of volatile degradation products. It was concluded that the obtained CS derivatives are characterized by good resistance to heat and UV irradiation, which extends the possibilities of using these innovative materials.

Study of Thermal Decomposition of the Copolymer Based on Polyethylene Glycol Fumarate with Acrylic Acid

Thermal decomposition of the copolymer based on polyethylene glycol fumarate with acrylic acid (p-EGF:AA) at four different heating rates in a nitrogen atmosphere has been investigated by the dynamic thermogravimetry (TGA) method. The TGA curves show that the decomposition process occurs in several stages. The experimental data processed by the Kissinger–Akahira–Sunose and Friedman isoconversion methods made it possible to calculate the activation energy of the main decomposition stage. According to the calculations results, one can see that the values found by these methods do not strongly depend on the conversion. The Achar–Brindley–Sharp method has been applied to determine the compensation parameters. Then, using the compensation effect, the invariant kinetic parameters of the decomposition processes have been found. An experimental curve has been plotted to find the reaction model in comparison with theoretical ones.

Thermal degradation kinetics of polyvinyl chloride in presence of zinc oxide

This work investigates the degradation kinetics and the pyrolysis behavior of Poly (vinyl chloride) (PVC) and its mixture with ZnO using thermogravimetric analysis under an inert atmosphere. The investigation was carried out due to the increased interest in the co-thermal treatment of the hazardous waste electric arc furnace dust (EAFD) which contains significant quantities of ZnO with PVC. The degradation of pure PVC was characterized by three main decomposition stages: PVC de-hydrochlorination (two overlapped stages) and subsequent polyene thermal cracking, while ZnO-PVC mixture (ZPVC) demonstrated four decomposition/volatilization stages. The Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman models were utilized for the extraction of the kinetic parameters. The average activation energy for pure PVC de-hydrochlorination was calculated to be 119.8 ± 12.4 kJ/mol, which changed to 110.6 ± 11.2 kJ/mol when a stoichiometric quantity of ZnO was added to it. The suggested mechanism for the ZPVC de-hydrochlorination starts by chlorine abstraction on ZnO at temperatures well-below 272 °C with an activation energy comparable to that of pure PVC de-hydrochlorination (115.8 kJ/mol). The chlorination of ZnO then yields zinc oxy/hydroxide chloride phases (Zn2OCl2·2H2O/β-Zn(OH)Cl) by the reaction between ZnCl2, ZnO and emitted H2O. These phases then decompose at approximately 222 °C into ZnCl2, ZnO, and H2O with a relatively low energy barrier of 102.2 kJ/mol. Formed ZnCl2 then lowers the activation energy for the polyene thermal cracking of PVC from 218.4 ± 17.7 (PVC) to 87.3 ± 9.7 kJ/mol (ZPVC) due to the physical contribution of volatilization to the overall mass loss.

Thermal Characteristics of Okra Bast and Corn Husk Fibers Extracted via Alkalization

ABSTRACT In this study, fibers were extracted from okra stems and corn husks via alkalization. The obtained fibers were subjected to physical and thermal analyses. It was found that okra bast fibers have better breaking strength and are finer than corn husk fibers. Corn husk fibers show high elongation at break rates. The paper also presents results of thermogravimetric analysis of the okra bast and corn husk fibers. Tests were carried out in oxygen and inert gas atmospheres. The temperature range of the main thermal decomposition stage was determined in the range of 290–400°C for thermo-oxidation and 290–420°C for pyrolysis investigation. Slight differences in the thermal resistances of the tested fibers were found. The maximum temperature in which both types of materials can used is determined. The calculated activation energy values show large-spread ranges.

Thermogravimetric and kinetic analysis of biomass and polyurethane foam mixtures Co-Pyrolysis

Alternative fuels are crucial for the decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is especially interesting since, the co-pyrolysis of waste plastics and biomass was lately introduced as promising method since the synergistic effect might enhance the product properties compared to those from individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption, and even more, it avoids the usage of raw feedstock. Thermogravimetric analysis is performed to determine the thermal degradation behaviour and kinetic parameters of investigated mixtures to find the most appropriate utilisation method. Co-pyrolysis was conducted for three mixtures with the following biomass/polyurethane ratios: 75-25%, 50-50%, 25–75%, over a temperature range of 30–800 °C, at three heating rates 5, 10 and 20 °C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis to determine effective activation energy using the isoconversional model-free methods and provide a detailed analysis of the samples' thermal degradation process. This work aimed to identify the main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and provide the mixture composition's influence on the considered thermochemical conversion process.

Development of Novel Polyamide 11 Multifilaments and Fabric Structures Based on Industrial Lignin and Zinc Phosphinate as Flame Retardants.

Biobased lignin represents one of the possible materials for next-generation flame retardant additives due to its sustainability, environmental benefits and comparable efficiency to other flame retardant (FR) additives. In this context, this study presents the development of FR polyamide 11 (PA11) multifilament yarns and fabric structures containing different industrial lignins (i.e., lignosulfonate lignin (LL), and Kraft lignin (KL)) and zinc phosphinate (ZnP). The combination of ZnP and lignin (KL or LL) at different weight ratios were used to prepare flame retarded PA11 blends by melt mixing using a twin-screw extruder. These blends were transformed into continuous multifilament yarns by the melt-spinning process even at a high concentration of additives as 20 wt%. The mechanical test results showed that the combination of KL and ZnP achieved higher strength and filaments showed regularity in structure as compared to the LL and ZnP filaments. Thermogravimetric (TG) analysis showed the incorporation of lignin induces the initial decomposition (T5%) at a lower temperature; at the same time, maximum decomposition (Tmax) shifts to a higher temperature region and a higher amount of char residue is reported at the end of the test. Further, the TGA-FTIR study revealed that the ternary blends (i.e., the combination of LL or KL, ZnP, and PA11) released mainly the phosphinate compound, hydrocarbon species, and a small amount of phosphinic acid during the initial decomposition stage (T5%), while hydrocarbons, carbonyls, and phenolic compounds along with CO2 are released during main decomposition stage (Tmax). The analysis of decomposition products suggests the stronger bonds formation in the condensed phase and the obtainment of a stable char layer. Cone calorimetry exploited to study the fire behavior on sheet samples (polymer bulk) showed an improvement in flame retardant properties with increasing lignin content in blends and most enhanced results were found when 10 wt% of LL and ZnP were combined such as a reduction in heat release rate (HRR) up to 64% and total heat release (THR) up to 22%. Besides, tests carried out on knitted fabric structure showed less influence on HRR and THR but the noticeable effect on postponing the time to ignition (TTI) and reduction in the maximum average rate of heat emission (MARHE) value during combustion.

Optimizing bioenergy and by-product outputs from durian shell pyrolysis

Durian shells (DS) constitute an abundant agricultural waste stream with a large yield in Southeast Asia and higher heating value. This study aimed to quantify the bioenergy and by-product outputs of the DS pyrolysis as a function of heating rate (5, 10, 20, and 40 K/min) combining thermogravimetric, Fourier transform infrared spectrometry, and pyrolysis–gas chromatography/mass spectrometry analyses. The joint optimizations of multiple responses were also performed as a function of a changing biofeedstock, heating rate, and temperature. The DS pyrolysis composed of three stages, with the main decomposition stage occurring between 141.2 and 616.5 °C. The increased heating rate promoted the DS pyrolysis, while the pyrolysis reaction was more complete at the low heating rate. Activation energy of the pyrolysis reaction was estimated to vary between 221.58 and 245.71 kJ/mol. The major gases evolved from the DS pyrolysis included CO2, CO, CH4, H2O, carbonyl compounds, acids, and NH3. The major pyrolytic by-products were aromatic and alicyclic hydrocarbons, phenolic substances, and N-containing compounds. Joint optimizations pointed to 999 °C, 5 K/min, and aboveground water hyacinth biomass, or DS as the most optimal operational conditions. Our findings provide insights into the optimization and scale-up for the industrial pyrolytic applications of DS.

Thermal Decomposition of Acidic Cobalt(II) Carboxylates with Unsaturated Dicarboxylic Anions

The thermal decomposition of acidic cobalt carboxylates (ACCs) with unsaturated carboxylic anions has been studied by TG/DTA in combination with DSC and mass spectrometry of gaseous thermolysis products. The temperature ranges of the main ACC thermal decomposition stages have been determined as (1) 50–225°С for dehydration (2) 210–450°C for dehydrated carboxylate polymerization, and (3) 370–500°C for decarboxylation. It has been concluded that the listed stages may superimpose on one another and occur simultaneously.

Ammonium Perchlorate Encapsulated with TiO2 Nanocomposite for Catalyzed Combustion Reactions

Ammonium perchlorate (APC) is the most common oxidizer for highly energetic systems. The initial decomposition of APC is an endothermic process. This behavior withstands high activation energy and could render high burning rate. We report on the sustainable fabrication of TiO2 nanoparticles; a novel catalyzing agent for APC. Mono-dispersed TiO2 particles of 10 nm particle size were fabricated using hydrothermal processing. XRD diffractogram demonstrated highly crystalline structure. The synthesized colloidal TiO2 particles were effectively integrated into APC particles via co-precipitation technique. The impact of TiO2 particles (1 wt%) on APC thermal behavior was investigated using DSC and TGA. APC demonstrated an initial endothermic decomposition (with absorption heat of 102.5 J/g) at 242 °C, and two subsequent exothermic decomposition stages at 297.8 and 452.8 °C respectively. TiO2 offered a decrease in APC early endothermic decomposition by 80%. The two main exothermic decomposition stages were merged into one single stage with an increase in total heat release by 18%. These novel features could inherit titanium oxide particles unique catalyzing ability for advanced highly energetic systems.

Experimental studies on gas production rate of in-situ hydrate-bearing clay in thermal recovery and depressurization methods

To understand the gas production characteristics from hydrate-bearing clay (HBC) under certain effective stress by thermal recovery method and depressurization method are significant for recovering natural gas from hydrate reservoirs. In this study, in-situ HBC was shaped in “excess gas method”, and the gas production rate of HBC under certain mean effective stress in thermal recovery method and depressurization method was investigated using a hydrate triaxial apparatus. Gas production rate highly depends on the decomposition temperature, high temperature would significantly boost the hydrate decomposition from HBC in the same mean effective stress. The hydrate saturation shows negligible effect on the gas production rate in the main decomposition stage, however, higher mean effective stress would reduce the gas production rate by preventing the gas discharge. Besides, the depressurization range plays a dominant role in the gas production rate, higher depressurization range would bring about higher gas production rate in higher mean effective stress. In addition, it’s proved that depressurization method is more effective and available than thermal recovery method for gas production from HBC.

Thermal behavior and decomposition kinetics of composite solid propellants in the presence of amide burning rate suppressants

The employment of burning rate suppressants in the solid rocket propellant formulation is long known. Different research activities have been conducted to well understand the mechanism of suppression, but literature about the action of oxamide (OXA) and azodicarbonamide (ADA) on the thermal decomposition of composite propellant is still scarce. The focus of this study is on investigating the effect of burning rate suppressants on the thermal behavior and decomposition kinetics of composite solid propellants. Thermogravimetric analysis (TG) and differential thermal analysis have been used to identify the changes in the thermal and kinetic behaviors of coolant-based propellants. Two main decomposition stages were observed. It was found that OXA played an inhibition effect on both stages, whereas the ADA acts as a catalyst in the first stage and as coolant in the second one. The activation energy dependent on the conversion rate was estimated by two model-free integral methods: Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) based on the TG data obtained at different heating rates. The mechanism of action of coolants on the decomposition of solid propellants was confirmed by the kinetic investigation as well.

Potential of Pyrolysis for the Recovery of Heavy Metals and Bioenergy from Contaminated Broussonetia papyrifera Biomass

Heavy metal contaminated biomass is a severe environmental problem. Presently, the disposal of heavy metal contaminated biomass tends to seek the recovery of both heavy metals and bioenergy. In this study, pyrolysis technology was employed to pyrolyze contaminated biomass to elucidate the influence and fate of the heavy metals and the potential for recovering bioenergy. The results showed that heavy metals in biomass reduced the reaction energy in the main decomposition stage by approximately 10%, while 25% of the biomass decomposed to solid products. Moreover, 63.2% to 68.2% of the Cd and 69.0% to 77.9% of the Cu were retained in the solid, and the metals in the residues existed as metal elements that can be recovered by general smelting. The majority of the biomass (75%) generated volatile products and was only slightly influenced by heavy metals. Compared with the uncontaminated biomass, the component of bioenergy was reduced only slightly, which suggests strong potential for recovering bioenergy. The finding of this paper can be a theoretical foundation to support the responsible disposal, through pyrolysis, of biomass contaminated by heavy metals.

Evidence of quasi-intramolecular redox reactions during thermal decomposition of ammonium hydroxodisulfitoferriate(III), (NH4)2[Fe(OH)(SO3)2]·H2O

Synthesis of ammonium hydroxodisulfitoferriate(III), (diammonium catena-{bis(μ 2-sulfito-κO,κO)-μ 2-hydroxo-κ2O}ferrate(III) monohydrate) (NH4)2[Fe(OH)(SO3)2]·H2O (compound 1) and its thermal behavior is reported. The compound is stable in air. Its thermal decomposition proceeds without the expected quasi-intramolecular oxidation of sulfite ion with ferric ions. The disproportionation reaction of the ammonium sulfite, formed from the evolved NH3, SO2 and H2O in the main decomposition stage of 1, results in the formation of ammonium sulfate and ammonium sulfide. The ammonium sulfide is unstable at the decomposition temperature of 1 (150 °C) and transforms into NH3 and H2S which immediately forms elementary sulfur by reaction with SO2. The formation and decomposition of other intermediate compounds like (NH4)2SnOx (n = 2, x = 3 and n = 3, x = 6) results in the same decomposition products (S, SO2 and NH3). Two basic iron sulfates, formed in different ratios during synthesizing experiments performed under N2 or in the presence of air, have been detected as solid intermediates which contain ammonium ions. The final decomposition product was proved to be α-Fe2O3 (mineral name hematite).

Comparative studies on the pyrolysis of cellulose, hemicellulose, and lignin based on combined kinetics

The thermal degradation behavior and pyrolytic mechanism of cellulose, hemicellulose, and lignin are investigated at different heating rates from 10 Kmin−1 to 100 Kmin−1 with a step-size of 10 Kmin−1 using thermogravimetric analysis (TGA) equipment. It is observed that there are one, two, and three stages of pyrolytic reactions takes place in cellulose, hemicellulose, and lignin respectively. Isoconversional method is not suitable to analyse pyrolysis of hemicellulose and lignin as it involves multi-step reactions. The activation energies of the main decomposition stage for cellulose, hemicellulose, and lignin are 199.66, 95.39, and 174.40 kJ mol−1 respectively. It is deduced that the pyrolysis reaction of cellulose corresponds to random scission mechanism while the pyrolysis reaction of hemicellulose and lignin follows the order based reaction mechanisms.

Comparative study on the pyrolysis behaviour and kinetics of two macroalgae biomass (Gracilaria changii and Gelidium pusillum) by thermogravimetric analysis

Macroalgae are often referred as seaweed and could be significant biomass resource for the production of numerous energy carriers including biofuels. In this study, the chemical composition of Gracilaria changii (G. changii) and Gelidium pusillum (G. pusillum) were determined through proximate and ultimate analysis and the thermal degradation behaviour of G. changii and G. pusillum were investigated via thermogravimetric analysis (TGA) in determining the important main composition to be considered as biomass fuels. It has found the pyrolysis of G. changii and G. pusillum consists of three stages and stage II is the main decomposition stage with major mass loss of around 52.16% and 44.42%, respectively. The TGA data were then used for determination of kinetic parameters of the pyrolysis process using three model-free methods: Kissinger, Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO). The apparent activation energy calculated by using Kissinger method for G. changii was lower than G. Pusillum, i.e.173.12 kJ/mol and 193.22 kJ/mol, respectively. The activation energies calculated from KAS and FWO methods were increased with increasing the pyrolysis conversion with average activation energies of 172.32 kJ/mol and 181.19 kJ/mol for G. changii while for G. pusillum (177.42 kJ/mol and 187.4 kJ/mol). G. pusillum has lower and wider distribution of activation energy and revealed that the pyrolysis process for G. changii was easier than G. pusillum. These data provide information for further application for designing and modelling in thermochemical conversion system of macroalgae biomass.

Microalgae decomposition in CO2 atmospheres by thermogravimetric analysis

In this study, the effect of highly purified CO2 atmospheres on the thermal degradation processes of Chlorella vulgaris (a genus of unicellular green microalgae) was investigated by a thermogravimetric analysis (TGA) at the heating rate of 10 °C·min-1 from room temperature to 1000°C. The results indicated that the decomposition process of C. vulgaris in CO2 atmosphere could be divided into four stages and two main discrete decomposition stages were observed. In addition, the kinetics of C. vulgaris in CO2 atmosphere could be described by the pseudo multi-component overall model (PMOM). With the PMOM, the C. vulgaris considered as three pseudo components could be individually decomposed over a specify temperature range. The kinetic parameters, which calculated by Coats–Redfern method, showed that in CO2 atmosphere, the apparent activation energy (E) of C. vulgaris was in the between 9.863 and 309.381 kJmol-1 and the reaction order (n) was varied from 1.1 to 7, while the pre-exponential factor (A) was from 2.361 to 6.520×1017min-1.