Distributed Activation Energy Model Method Research Articles

Evaluating two stages of silicone-containing arylene resin oxidation via experiment and molecular simulation

Silicon-containing aryl acetylene resin (PSA) is a new type of high-temperature resistant resin with excellent oxidation resistance, whereas antioxidant reaction mechanism of PSA resin under ultra-high temperatures still remains unclear. Herein, the oxidation behavior and mechanisms of PSA resin are systematically investigated combining kinetic analysis and ReaxFF molecular dynamics (MD) simulations. Thermogravimetric analysis indicates that the oxidation process of PSA resin undergoes two main steps: oxidative weight gain and oxidative degradation. The Distributed Activation Energy Model (DAEM) is employed for describing oxidation processes and the best-fit one is obtained using genetic algorithms and differential evolution. DAEM model demonstrates that the oxidative weight gain stage is dominated by two virtual reactants and the oxidative degradation stage consists of three virtual reactants. Correspondingly, the observation of MD reaction pathways indicates that oxygen oxidation of unsaturated structures occurs in the initial stage, which results in the formation of PSA resin oxides. Furthermore, cracked pieces react with O2 to generate CO and other chemicals in the second step. The resin matrix's great antioxidation resilience is illustrated by the formation of SiO2. The analysis based on MD simulations exhibits an efficient computational proof with the experiments and DAEM methods. Based on the results, a two-stage reaction mechanism is proposed, which provides important theoretical support for the subsequent study of the oxidation behavior of silica-based resins.

Distributed activation energy model of pyrolysis kinetics of starch and lignin with blast furnace slag as heat carriers

Molten blast furnace slag (BFS) can be used as heat carrier for biomass pyrolysis, which has high industrial value. Lignin (LG) and starch (ST) were chosen as model compounds of lignocellulosic biomass, which were mixed with different proportions of BFS, respectively. Thermogravimetry-process mass spectrometry studied the characteristics of LG-BFS and ST-BFS pyrolysis. The activation energies were obtained by Kissinger-Akahira-Sunose (KAS) method and four kinds of Distributed Activation Energy Model (DAEM) methods. The results showed BFS has little effect on the temperature of LG and ST pyrolysis. The average activation energy of LG-BFS-30% and ST-BFS-50% calculated by KAS method was 167.74 and 155.57 kJ∙mol−1 respectively, which meant the addition of 30% and 50% BFS promoted the pyrolysis of LG and ST, respectively. The activation energy distribution (AED) obtained by the four kinds of DAEM methods could reflect the actual pyrolysis process more completely. The results showed that the Double Gaussian distribution (GAUSS-2)and the distribution-free method (DAEM-NM) were more closer to the pyrolysis process of LG-BFS and ST-BFS. Compared with the pure LG, the CO2 content in pyrolysis gas decreased by 9.61%, and the CO content increased by 22.14% in the LG-BFS-30% pyrolysis. Compared with ST-BFS and LG-BFS, LG-BFS-30% was more conducive to the generation of CO.

Determination of thermal degradation behavior and kinetics parameters of chemically modified sun hemp biomass

Sun hemp fibers are natural fibers obtained from plants grown in India and nearby countries. It is lignocellulosic biomass having the complex structure of hemicelluloses, cellulose and lignin. Chemical treatment of natural fibers is in practice to enhance the properties being used as reinforcement. Alkaline-treated fiber was sampled and thermal stability along with kinetic parameters was assessed with thermo gravimetric data at heating rates 10, 20 and 30 °C/min using four model-free methods Kissinger–Akahira–Sunose (KAS), Flynn-Wall-Ozawa (FWO), Friedman (FM), Starink (STAR) along with Distributed activation energy model (DAEM) to calculate pre-exponential factor. The calculated activation energy Ea by these model-free methods were in the range of 93.3–104.8 kJ/mol and pre-exponential factor (A) was observed between the range 46.6 x103–90.5 x106/min by the DAEM method. The standard deviation (σ) calculated from average activation energy using all four methods was 4.5 kJ/mol, which showed the consistency in the methods employed to determine the activation energy of sun hemp.

Preparation of a Transient Thermal Expansion Rock Cracking Agent by Deposition Method and Its Nonisothermal Kinetics Study with Isoconversional Procedure and DAEM.

Cracking agents are indispensable and important products for national energy exploitation and large-scale infrastructure construction. Transient thermal expansion rock cracking agent is a new cracking agent product with excellent performance that has just appeared in recent years. However, it is still prepared by mechanical ball milling, which is considered not the best choice among traditional methods for preparing energetic materials. In this paper, a transient thermal expansion rock splitting agent was prepared by the chemical deposition method using carbon black and calcium peroxide as raw materials. The TG/DTG results show that the mass loss of the sample can be divided into four stages with the increase of temperature. It is worth noting that the mass loss of the TG curve of the sample during the entire thermal decomposition process is 93.385%, and the instantaneous weight loss is 78.07% (β = 15 °C/min). Kinetic analysis of the thermal decomposition process of the samples was performed using an isotransformation program and a distributed activation energy model (DAEM). The activation energy E α of the thermal decomposition of the sample was iteratively calculated. The results show that the a-E a curve of the sample can be divided into two stages. The pyrolysis kinetics of the first stage was successfully analyzed by the DAEM method and its thermal conversion behavior was predicted. The thermal decomposition behavior of the second stage was analyzed by a traditional kinetic analysis method.

Kinetic Analysis of Pyrolysis Reaction of Hydrogen-Containing Low Rank Coals Based on Thermogravimetric Method

Based on the combined technology of thermogravimetric analysis-mass spectrometry (TG-MS), the non isothermal kinetic of two low rank coals with high hydrogen content and the release characteristics of H2 in volatiles were explored. The effect of coal species and coal particle size on pyrolysis was studied. The CR (Coats-Redfern) method and the DAEM (Distributed activation energy model) method were used to construct the pyrolysis kinetic model by dividing temperature stages, and the results showed that the mechanisms of pyrolysis process of lower rank coals were mainly 3-D diffusion (G-B) and Growth of nucleation (Avrami-Erofeev, n = 1/3). The use of the DAEM method made up for the shortcomings of the CR method in calculating the activation energy, and the analysis of coal pyrolysis kinetics was more comprehensive. The higher the volatile content the coal contained, the lower activation energy the pyrolysis process would require. The larger the particle size of the coal was, the higher activation energy the pyrolysis process would need. The release law of H2 in low rank coal during the pyrolysis process was analyzed by mass spectrometry, and results were presented: the first peak occurs at 500 °C and the second at 750 °C, which was mainly generated by the condensation and dehydrogenation reactions of aromatic compounds.

Research on the pyrolysis characteristics and kinetics of two typical inferior heavy oils

• Isoconversional methods and DAEM were used to calculate kinetic parameters. • Major weight loss of heavy oil pyrolysis occurred in active pyrolytic stage. • DAEM method had a high applicability to the pyrolysis of heavy oil. The present study deals with the pyrolysis characteristics of two typical inferior heavy oils slurry oil (SO) and deoiled asphalt (DOA) based on thermogravimetric data at multiple heating rates of 5, 10, 15 and 20 °C/min. Three isoconversional methods (Friedman, FWO and KAS) and distributed activation energy model (DAEM) method were used to evaluate the kinetics. The results showed that major mass loss of SO and DOA occurred in active pyrolytic stage, at which the mass loss rate reached up to 90.9 wt% (SO) and 55.5 wt% (DOA), respectively. The emissions of CH 4 , H 2 O, CO and CO 2 in the temperature range 400–600 °C contributed to the mass loss of DOA, whereas the mass loss of SO was ascribed to the cracking and condensation. The average activation energy ( E ) of SO and DOA were 101.48 and 219.32 kJ/mol for Friedman, 89.51 and 191.90 kJ/mol for FWO, 82.05 and 190.07 kJ/mol for KAS, respectively. DAEM method had a high applicability to the pyrolysis process of SO and DOA. The calculated peak proportions of four independent hypothetical components basically conformed to the fraction proportions of SO and DOA. The weighted E of DAEM method was higher than the average E of three isoconversional methods, explaining the four components of heavy oil was not single chemical reactions during pyrolysis, but interactive reaction.

Comparative study on pyrolysis kinetics of agroforestry biomass based on distributed activation energy model method

Pyrolysis behavior and kinetics of three typical agroforestry biomasses including apricot shell, wheat straw and poplar sawdust were investigated by thermogravimetric mass spectrometry (TG-MS). The results show that the differences of the main components make the three biomasses exhibit different characteristics in the main reaction range (200–450 °C). It is found that the average activation energy of apricot shell, straw and sawdust is 188.22, 220.77, and 175.87 kJ/mol, respectively based on the typical isoconversional methods. The average activation energy of each component in biomass was calculated by the distributed activation energy model (DAEM) method, indicating that there is a fourth component with high average activation energy in biomass (297.44 kJ/mol for apricot shell, 284.35 kJ/mol for straw and 309.96 kJ/mol for sawdust). The activation energy of hemicellulose and cellulose shows an increasing order of straw < apricot shell < sawdust. The two kinds of kinetics methods are complementary to each other. The overall calculation results by the isoconversional method are close to those by the single-component distributed activation energy model method, but the isoconversional method is simpler; while the distributed activation energy model method can be used to obtain the kinetic parameters of different components of raw materials, which makes up for the deficiency of the isoconversional method. A combined use of the two methods can form a more comprehensive understanding of the pyrolysis reaction.

Effects of heating rate on thermal degradation behavior and kinetics of representative thermoplastic wastes

Waste thermoplastics are the most common solid wastes, and thermal degradation has excellent advantages in the disposal of these wastes and obtaining valuable hydrocarbon fuels. As a significant factor, the heating rate is crucial to the thermal degradation process. Consequently, thermal degradation behavior and kinetics of representative thermoplastics under different heating rates were investigated by using thermogravimetric analysis and differential scanning calorimetry in the air. Kinetic parameters were estimated by using the Coats-Redfern method. Subsequently, the Shuffled Complex Evolution (SCE) method was used to optimize kinetic parameters, and the optimized results were compared with the calculated kinetics of distributed activation energy model (DAEM) method to find the effects of heating rate on kinetic parameters. The results showed that with the increase of heating rate, thermogravimetric curves moved to the right, which corresponded to a higher temperature range. The number of mass loss rate peaks and exothermic peaks decreased. Additionally, activation energy was the same at the determined minimum and maximum heating rates, and other heating rates had little effect on kinetic parameters. Moreover, the calculated activation energy of the DAEM method at the minimum heating rate of 5 K/min was closest to the optimized values of the SCE method, indicating that the lower the minimum heating rate was, the more accurate the activation energy was.

Thermogravimetry and associated characteristics of pearl millet cob and eucalyptus biomass using differential thermal gravimetric analysis for thermochemical gasification

Thermal decomposition behaviour of two different biomasses and their degradation kinetics were investigated by using thermogravimetric (TG) analysis under non-isothermal conditions. Pearl millet cob (PMC), an agro-waste that has not been studied adequately for gasification, and eucalyptus (EU) were pyrolytically degraded at three different heating rates, 10, 15, and 20 °C/min, in inert atmosphere from temperatures ambient to 1000 °C.Differential thermogravimetric analysis (DTG) was carried out to study componential degradation of the biomass components (cellulose, hemicellulose, and lignin). Higher cellulose and hemicellulose in PMC had a quicker pyrolysis rate than EU with higher lignin content. Flynn–Wall–Ozawa (FWO) and Distributed Activation Energy Model (DAEM) methods were used to study the kinetic characteristics of the biomasses. The activation energies obtained for PMC and EU were 75–196 and 172–208 kJ/mol by FWO method. The average values were found as 149.63 and 201.65 kJ/mol. The activation energy obtained using DAEM method for PMC and EU were found as 77–197 and 185–219 kJ/mol, respectively with average values being 150.71 and 205.06 kJ/mol, respectively. The PMC has the higher degradable fraction and a lower activation energy, indicating PMC is more appropriate biomass for producer gas generation as compared to EU.

TG-FTIR study on co-combustion of bituminous coal semicoke and lignite

The combustion behaviors and pollutants emission characteristics during co-combustion of bituminous coal semicoke and lignite were investigated by thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR). Results showed the addition of lignite could lower the ignition and burnout temperature and also enhance the comprehensive combustion performance of blends. High heating rate could improve the combustion intensity and corresponding combustion characteristic indexes. The activation energy analysis by distributed activation energy model (DAEM) and Ozawa–Flynn–Wall (OFW) methods at lignite blend ratio of 40% indicated its distribution was consistent with the combustion process of blends. An obvious activation energy jump occurred at conversion rate range of 0.4–0.55 due to the poor ignition performance of semicoke. The average activation energy obtained by DAEM and OFW methods was 101.69 kJ mol−1 and 109.12 kJ mol−1, respectively. With the increase of lignite blend ratios, CO and CO2 emission gradually decreased. Meanwhile, NO emission increased, while NO2 and SO2 emission ascended after an initial decline. Semicoke had certain suppression effect on NOx and SO2 emission. The minimum NO2 and SO2 emission was obtained at lignite blend ratio of 20%.

Thermogravimetric analysis and reaction kinetics of lignocellulosic biomass pyrolysis

The elucidation of the biomass pyrolysis characteristics will provide valuable guidance for the design of pyrolysis devices. The pyrolysis kinetics characteristics of lignocellulosic biomass were studied by thermogravimetric analysis, and the main influencing factors, including biomass particle size, heating rate, and metal ion, were investigated. With a decrease in the particle size of rice straw and pine sawdust, the initial and final pyrolysis temperatures and the temperature of the maximum weight loss ratio decreased. Opposite results were obtained for Phoenix tree leaves. Furthermore, the initial release temperature of volatile matter and the temperature corresponding to the peak of the derivative thermogravimetric curves increased with an increase in heating rate. Moreover, the pyrolysis activity of rice straw decreased significantly after deashing but increased with the addition of potassium. The pyrolysis kinetics parameters were calculated by the Coats–Redfern, Doyle, and the distributed activation energy model (DAEM) methods. The apparent activation energy of pyrolysis was the lowest, varying between 30 and 70 kJ/mol, according to the fitting results of the Coats–Redfern method. The apparent activation energies calculated by the DAEM and Doyle methods are similar, and are 67.6, 245.8, and 271.8 kJ/mol for rice straw, pine sawdust and Phoenix tree leaves, respectively.

Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs).

In this study, the pyrolysis behaviour of nonmetal fraction of waste printed circuit boards (NMF-WPCBs) was studied based on five model-free methods and distributed activation energy model (DAEM). The possible decomposition mechanism was further probed using the Criado method. Thermogravimetric analysis indicated that the NMF-WPCBs pyrolysis process could be divided into three stages with temperatures of 37-330°C, 330-380°C and 380-1000°C. The mass loss at different heating rate was determined as 26.85-29.98%, 13.47-24.21% and 20.43-23.36% for these stages, respectively. The activation energy (Eα) from various model-free methods first increased with degree of conversion (α) increasing from 0.05 to 0.275, and then decreased beyond this range. The coefficient (R) from the Flynn-Wall-Ozawa (FWO) method was higher, and the resulting Eα fell into the range of 214.947-565.660 kJ mol-1. For the DAEM method, the average Eα value was determined as 337.044 kJ mol-1, comparable with 329.664 kJ mol-1 from the FWO method. The thermal decomposition kinetics of NMF-WPCBs could be better described by the second-order reaction.

Comparative study on the pyrolysis kinetics of polyurethane foam from waste refrigerators.

Thermal treatment offers advantages of significant volume reduction and energy recovery for the polyurethane foam from waste refrigerators. In this work, the pyrolysis kinetics of polyurethane foam was investigated using the model-fitting, model-free and distributed activation energy model methods. The thermogravimetric analysis indicated that the polyurethane foam decomposition could be divided into three stages with temperatures of 38°C-400°C, 400°C-550°C and 550°C-1000°C. Peak temperatures for the major decomposition stage (<400°C) were determined as 324°C, 342°C and 344°C for heating rates of 5, 15 and 25 K min-1, respectively. The activation energy (Eα) from the Friedman, Flynn-Wall-Ozawa and Tang methods increased with degree of conversion (α) in the range of 0.05 to 0.5. The coefficients from the Flynn-Wall-Ozawa method were larger and the resulted Eα values fell into the range of 163.980-328.190 kJ mol-1 with an average of 206.099 kJ mol-1. For the Coats-Redfern method, the diffusion models offered higher coefficients, but the E values were smaller than that from the Flynn-Wall-Ozawa method. The Eα values derived from the distributed activation energy model method were determined as 163.536-334.231 kJ mol-1, with an average of 206.799 kJ mol-1. The peak of activation energy distribution curve was located at 205.929 kJ mol-1, consistent with the thermogravimetric results. The Flynn-Wall-Ozawa and distributed activation energy model methods were more reliable for describing the polyurethane foam pyrolysis process.

Evaluation on activation energy of deposited clay based on thermo-gravimetric analysis (TGA) and four kinetics models

In order to evaluate and compare the accurate activation energy variations of two kinds of deposited clays (i.e. non-organic clay and organic clay), thermo-gravimetric analysis (TGA) was firstly conducted to study the reaction characteristics of the two clay samples. Two periods of weight losses were observed according to each TGA curve for both clay samples. The first period happened due to water evaporation, while the second period was mainly caused by the composition reactions of clay minerals, especially influenced by the de-hydroxylation of kaolinite. An obvious phenomenon is that the organic clay with a high soil organic matter (SOM) has a higher activity energy. Then, four common kinetics models [i.e. the Coats-Redfern method, the Doyle integral method, the maximum rate method, and the distributed activation energy model (DAEM)] were used to calculate and compare the activation energy values. And the Doyle integral method and the DAEM method are considered as two recommended models to analyze the activation energy performance during thermal treatment. Some interesting conclusions can be summarized as: (1) The multi-period reactions of deposited clays during the heating process are common, especially for organic clay. It would be beneficial knowing its biomass resource feasibility concerning the second weight loss; (2) The high SOM has a significant influence on the potential energy unitization of deposited clays, while the variations of activity energy for deposited clays are influenced by the mineral compositions and microstructure features; (3) It is possible to evaluate the accurate activity energy of deposited clays combined with TGA tests and two recommended models (i.e. the Doyle integral method and DAEM method).

Kinetic triplet determination and modified mechanism function construction for thermo-oxidative degradation of waste polyurethane foam using conventional methods and distributed activation energy model method

Rapid growth of waste polymers attracts increasing attentions nowadays, and pyrolysis technology is acknowledged as an effective handling way. In this study, waste rigid polyurethane (RPU) was selected to conduct thermogravimetric analysis experiments with four different heating rates. Results showed that the thermo-oxidative degradation of RPU presents a two-main-stage process. Subsequently, thermal degradation kinetics were analyzed by model free, model fitting, and distributed activation energy model (DAEM) fitting methods. Isoconversional methods were used to obtain the apparent activation energy. Pyrolysis kinetic parameters were calculated through selected reaction models by model fitting method. Then the experimental kinetic function was obtained, based on which the proper theoretical reaction models were modified by the accommodation function. The best reaction model from the alternative reconstructed functions was optimized for two steps respectively. Distributed activation energy model was firstly introduced to fit the experimental data of RPU pyrolysis. The results of this study have implications concerning kinetic triplet determination method and reaction models modification, especially guiding to waste polymers pyrolysis kinetics and reaction model construction.

Thermal behavior and kinetics of pyrolysis of areca nut husk

ABSTRACTPyrolysis of agricultural crop residues is making rapid strides in the overall lignocellulosic biomass utilization for the recovery of energy. In the present work, physicochemical properties of areca nut husk such as proximate and ultimate analysis, lignocellulosic composition, and thermal analysis have been carried out. Pyrolysis of areca nut husk was studied using thermogravimetric analysis to determine the kinetic parameters at five different heating rates, viz. 2, 5, 10, 15, 20°C/min. The major mass loss (44.4 wt%) of AH was found to be in the temperature range of 220–370ºC. The kinetic parameters pertaining to pyrolysis of areca nut husk were calculated using distributed activation energy model (DAEM) and model-free isoconversional Flynn-Wall-Ozawa (FWO) method. Miura and Maki integral method was employed to estimate f(E) and k0(E) in this study. The peak of f(E) curve for the areca nut husk was obtained at 240 kJ/mol and the frequency factor (k0) increased from an order of 1013–1022 min−1, while the activation energy ranged from 87.5 to 514.08 kJ/mol. The variation in activation energy values with progressing conversion indicates the existence of a complex multi-step mechanism that occurs during the thermal decomposition of AH. The average activation energy obtained by FWO method was 230.707 kJ/mol (with a range of 62.35–591.972 kJ/mol) which is close to 240 kJ/mol obtained via DAEM method from f(E) curve and hence the results can be said to be reliable and predictive.

Kinetic analysis and modeling of coal pyrolysis with model-free methods

Knowledge about the rate of coal pyrolysis is of great importance because it exerts remarkable effect on its thermal conversions such as combustion, gasification and liquefaction. Different approaches can be used to obtain the kinetics of coal pyrolysis, the simplest are empirical and global kinetics, where Arrhenius expression is used to correlate the mass loss with temperature. This work conducted pyrolysis of a lignite and a bituminite at various heating rates with a thermo-gravimetric analyzer (TGA). Thermogravimetry coupled with mass spectroscopy (TG-MS), solid state 13C Cross Polarization/ Magic Angle Spinning nuclear magnetic resonance (13C CP/MAS NMR) and Raman analyses were also conducted to correlate the structural characteristics and pyrolysis behavior of the coals. Kinetic analysis was performed by using three model-free methods including Distributed Activation Energy model (DAEM), Ozawa-Flynn-Wall (OFW) and Friedman method. Kinetic modeling was also performed based on the DAEM model with multiple Gaussian sub-distributions of activation energy. The results show that DAEM, OFW and Friedman methods are almost equally effective for analyzing activation energy, which gradually increases with the extent of pyrolysis. Pyrolysis of both the coals can be divided into three stages corresponding to the reactions of various covalent bonds. Three-Gaussian distributed activation energy model (DAEM-G3) is applicable to describing pyrolysis of both coals. The well-matched modeling results with the experimental data over the entire temperature range indicate the validity of DAEM-G3 model in studying and understanding the reaction mechanism of coal pyrolysis.

Evaluation of the critical safety temperature of nitrocellulose in different forms

Evaluating the critical safety temperature of nitrocellulose is necessary to reduce the possibility of nitrocellulose accidents (thermal explosion and fire) and to implement effective loss prevention. In the present study, isothermal and non-isothermal experiments were performed on different forms of nitrocellulose using a differential scanning calorimeter. A scanning electron microscope was utilized to detect the aging process of nitrocellulose under different constant temperatures. Thermodynamic parameters were simulated by thermal safety software, and the results indicated that autocatalytic simulation rather than nth order simulation was applicable to assess the apparent activation energy of nitrocellulose samples. Moreover, iso-conversional methods, including Kissiger–Akahira–Sunose, Ozawa–Flynn–Wall, Friedman, Tang et al. and distributed activation energy model methods, were employed to validate the simulated activation energy. The average activation energy calculated by the five iso-conversional methods was lower than that simulated by autocatalytic simulation. Moreover, critical storage temperatures, including the time to maximum rate and the time to conversion limit, were evaluated. It was found that the critical storage temperatures of nitrocellulose in white chip form were lower than that of nitrocellulose in white silky fibre form. Finally, the critical thermal explosion temperatures of two samples were calculated, and it was concluded the temperature of nitrocellulose in white silky fibre form was about 5.0 °C higher than that of nitrocellulose in white chip form.

Thermal behavior and kinetic study on the pyrolysis of lean coal blends with thermally dissolved coal

In this paper, we use organic solvent N-methyl pyrrolidone (NMP) to thermally dissolve Kelan (KL) coal. The final product is thermally dissolved coal (TDC). The thermal behavior and non-isothermal kinetics of Guandi (GD) coal and TDC, as well as the co-pyrolysis of coal blends, have been studied by three methods (Friedman method (FR), Flynn–Wall–Ozawa method (FWO) and distributed activation energy model (DAEM)). Obtained results show that TDC has a higher maximum devolatilization rate and lower temperature corresponding to the starting and maximum rates of pyrolysis, compared to GD coal. The addition of TDC not only improves the maximum devolatilization rate of coal blends, but also reduces the temperature corresponding to the maximum devolatilization rate. Obtained results indicate that synergistic reactions may occur between the temperatures corresponding to the maximum devolatilization rates of GD and TDC. In this study, the apparent activation energy E obtained by FR, FWO and DAEM methods of coal blends with various addition of TDC almost increased with increasing conversion. There is a kinetic compensation effect in the kinetic process of coal pyrolysis and the reaction kinetics compensation effect equation.

Prediction of the lignocellulosic winery wastes behavior during gasification process in fluidized bed: Experimental and theoretical study

This work presents studies about the gasification of the lignocellulosic winery wastes in fluidized bed to obtain energy. Based on the exergy analysis, the exergetic improvement potential (IP) and sustainability index (SI) variations with different operational variables were analyzed. IP increases and SI decreases when moisture content, ER and SBR augment. On the other hand, both indexes present contrary behavior with the temperature increasing.Additionally, the kinetic behavior was investigated using a macro thermo-balance. The thermal decomposition of the studied biomass wastes at three heating rate, 5, 10 and 15 °C/min under steam/air mixture atmosphere show that the gasification takes place in three visible stage: water vaporization, pyrolysis and the last step associated with the reaction of the char by CO2. The distributed activation energy model method (DAEM) was used. The decomposition is not a single reaction stage, it includes the contributions of parallel reaction steps on the global reaction rate.Last, the fluidization was analyzed using air at room temperature and local atmospheric pressure. Each experiment was carried out with 100% and 75% v lignocellulosic wastes. Segregation, slugging and channelization in all studied cases. However, the addition of sand particles improves the behavior of both winery wastes.