scholarly journals Catalytic properties of a composite material based on belarusian dolomites in relation to the decomposition of pyrolysis tar

2021 ◽  
Vol 66 (4) ◽  
pp. 440-448
Author(s):  
S. V. Vasilevich ◽  
M. V. Malko ◽  
D. V. Degterov ◽  
A. N. Asadchyi
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Composite Material ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Thermochemical Conversion ◽  
Homogeneous Process ◽  
Composite Catalysts ◽  
Heterogeneous Catalytic ◽  
Pyrolysis Tar

The paper discusses results of an experimental study of the thermal decomposition of pyrolysis tar in a homogeneous process and in the presence of a catalyst. Experiments on thermal decomposition of pyrolysis tar were carried out under isothermal conditions in a laboratory setup at temperatures of 300, 400, 450 and 500 °C. The rate of the homogeneous process of thermal decomposition of tar and maximal degrees of decomposition were determined. According to the data of this work, the activation energy of the homogeneous process was 320 kJ/mol. It was found that the rate of thermal decomposition of the tar increases in the case of introducing samples of natural dolomites into the reaction zone, as well as a composite material based on them. This increase is due to the occurrence of a heterogeneous catalytic decomposition reaction of the pyrolysis tar. The apparent activation energy of this process was 210 kJ/mol (when using dolomites) and 202 kJ/mol (when using composites). It was noted that the composite material has significantly more favorable mechanical properties than dolomite. Based on the established data, it was concluded that the creation of composite catalysts for the thermal decomposition of heavy hydrocarbons formed in the processes of thermochemical conversion of biomass is promising.

Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models

2019 ◽  
Vol 38 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Ghulam Ali ◽  
Jan Nisar ◽  
Munawar Iqbal ◽  
Afzal Shah ◽  
Mazhar Abbas ◽  
...  
Keyword(s):  
Activation Energy ◽  
Copper Oxide ◽  
Solid Waste ◽  
Thermodynamic Parameters ◽  
Model Fitting ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Inert Atmosphere ◽  
Heating Rates ◽  
Model Free

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin−1, 10°Cmin−1, 15°Cmin−1 and 20°Cmin−1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats–Redfern) and model free methods (Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats–Redfern, Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman models were found in the ranges 105–148.48 kJmol−1, 99.41–140.52 kJmol−1, 103.67–149.15 kJmol−1 and 99.93–141.25 kJmol−1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

scholarly journals Improvement in Carbonization Efficiency of Cellulosic Fibres Using Silylated Acetylene and Alkoxysilanes

Fibers ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 84
Author(s):  
Maria Mironova ◽  
Igor Makarov ◽  
Lyudmila Golova ◽  
Markel Vinogradov ◽  
Georgy Shandryuk ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Comparative Studies ◽  
Decomposition Reaction ◽  
Activation Energies ◽  
Composite Fibers ◽  
Carbon Yield ◽  
Pyrolysis Reaction ◽  
Cellulosic Fibres

Comparative studies of the structure and thermal behavior of cellulose and composite precursors with additives of silyl-substituted acetylene and alkoxysilanes were carried out. It is shown that the introduction of silicon-containing additives into the cellulose matrix influenced the thermal behavior of the composite fibers and the carbon yield after carbonization. Comparison of the activation energies of the thermal decomposition reaction renders it possible to determine the type of additive and its concentration, which reduces the energy necessary for pyrolysis. It is shown that the C/O ratio in the additive and the presence of the Si–C bond affected the activation energy and the temperature of the beginning and the end of the pyrolysis reaction.

Thermal Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites

2019 ◽  
Vol 956 ◽  
pp. 181-191
Author(s):  
Jian Lin Xu ◽  
Bing Xue Ma ◽  
Cheng Hu Kang ◽  
Cheng Cheng Xu ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Flame Retardant ◽  
Mass Loss Rate ◽  
Decomposition Reaction ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
Polybutylene Terephthalate ◽  
Kinetics Of

The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).

scholarly journals Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 968 ◽  
Author(s):  
Abdenacer Benhammada ◽  
Djalal Trache ◽  
Mohamed Kesraoui ◽  
Salim Chelouche
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Analytical Techniques ◽  
Decomposition Reaction ◽  
Decomposition Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Catalyst ◽  
Average Size ◽  
A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

Thermogravimetric Studies on Bimetallic Dithiocarbamate Complexes

1992 ◽  
Vol 47 (9) ◽  
pp. 1297-1299 ◽  
Author(s):  
G. S. Sodhi ◽  
J. Kaur
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Decomposition Reaction ◽  
Activation Entropy ◽  
Acid Base ◽  
Thermal Stabilities ◽  
Tg Studies ◽  
Thermogravimetric Studies ◽  
Soft Acid ◽  
Hsab Theory

Thermogravimetric (TG) studies have been carried out for some bimetallic dithiocarbamate complexes of the type ZnML4 and NiM′L′4 [M = Co(II), Cu(II); M′ = Zn(II), Hg(II); L = N-methylcyclohexyldithiocarbamate; L′ = N-ethylcyclohexyldithiocarbamate]. From TG curves, the order, apparent activation energy and apparent activation entropy for the thermal decomposition reaction have been calculated. The thermal stabilities have been correlated with the structures of the complexes on the basis of hard and soft acid base (HSAB) theory.

Synthesis and Determination of the Kinetic Parameters for Non-Isothermal Decomposition of Complexes Ln(thd)3phen

2006 ◽  
Vol 530-531 ◽  
pp. 506-512 ◽  
Author(s):  
Wilton Silva Lopes ◽  
Crislene Rodrigues da Silva Morais ◽  
A.G. de Souza
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Lanthanide Complexes ◽  
Reaction Order ◽  
Decomposition Reaction ◽  
Cylindrical Symmetry ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Kinetics Of

In this work the kinetics of the thermal decomposition of two ß-diketone lanthanide complexes of the general formula Ln(thd)3phen (where Ln = Nd+3 or Tm+3, thd = 2,2,6,6- tetramethyl-3,5-heptanodione and phen = 1,10-phenantroline) has been studied. The powders were characterized by several techniques. Thermal decomposition of the complexes was studied by non-isothermal thermogravimetry techniques. The kinetic model that best describes the process of the thermal decomposition of the complexes it was determined through the method proposed by Coats-Redfern. The average values the activation energy obtained were 136 and 114 kJ.mol-1 for the complexes Nd(thd)3phen and Tm(thd)3phen, respectively. The kinetic models that best described the thermal decomposition reaction the both complexes were R2. The model R2 indicating that the mechanism is controlled by phase-boundary reaction (cylindrical symmetry) and is defined by the function g(α) = 2[1-(1-a)1/2], indicating a mean reaction order. The values of activation energy suggests the following decreasing order of stability: Nd(thd)3phen > Tm(thd)3phen.

scholarly journals Homogeneous and heterogeneous catalytic ozonation of endosulfan with activated carbon as catalyst

2018 ◽  
Vol 6 (3) ◽  
pp. 676
Author(s):  
E Enjarlis ◽  
Setijo Bismo ◽  
S Slamet ◽  
Roekmijati W Soemantojo
Keyword(s):  
Activated Carbon ◽  
Environmental Concern ◽  
Heterogeneous Reaction ◽  
Organic Pollutant ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Catalytic Ozonation ◽  
Heterogeneous Catalytic ◽  
Neutral Ph ◽  
Organic Chlorine

Homogeneous and heterogeneous  catalytic ozonation of endosulfan with activated carbon as catalystCatalytic ozonation of endosulfan with the presence of activated carbon as catalyst was investigated at neutral pH and different temperatures. The model kinetics was developed based on the mechanism of catalytic decomposition ozone, namely homogeneous and heterogeneous decomposition reaction. This study focuses on determining the contribution of homogeneous and heterogeneous reaction to endosulfan removal in catalytic ozonation with activated carbon as catalyst. Endosulfan was selected as a target of study because it is organic pollutant and organic chlorine pesticide (OCPs) groups that may cause a serious environmental concern. The use of activated carbonfrom Bogar Forest Centre actually provides a slightly contribution in enhancing endosulfan oxidation reaction with ozone. This is because endosulfan has sulfide group or sulfur element that is very reactive to ozone. Even though, the amount of OH increases because of ozonation with activated carbon use. The heterogeneous and homogeneous reaction contributions at  neutral  pH and temperature range of 20- 30oC  were 11-21% and 79- 89% from overall endosulfan removal in catalytic ozonation with promoted by of activated carbon, respectively.Keywords: Activated Carbon, Catalytic Ozonation, Endosulfan AbstrakOzonasi katalitik endosulfan dengan adanya katalis karbon aktif dilakukan pada pH netral dan suhu yang berbeda-beda. Persamaan kinetika reaksi dikembangkan berdasarkan mekanisme reaksi dekomposisi ozon secara katalitik yaitu reaksi homogen dan heterogen. Penelitian ini ditujukan terutama untuk menentukan kontribusi reaksi homogen dan heterogen terhadap penyisihan endosulfan di dalam ozonasi katalitik dengan karbon aktif sebagai katalis.Endosulfan dipilih sebagai sasaran penelitian karena merupakan polutan organik dan kelompok pestisida organoklorida (OCPs) yang menjadi perhatian serius di lingkungan. Karbon aktif yang digunakan berasal dari Balai Hutan Bogar yang ternyata memberikan pengaruh kecil terhadap peningkatan reaksi oksidasi endosulfan dengan ozon. Hal ini disebabkan endosulfan mempunyai gugus sulfida atau sulfur yang sang at reaktif terhadap ozon. Meskipun, jumlah OH meningkat disebabkan penggunaan ozonasi dengan karbon aktf. Kontribusi reaksi homogen dan heterogen terhadap penyisihan endosulfan pada kondisi pH netral dan suhu 20-30 oC  masing-masing sebesar 79- 89% dan 11- 21% dari total penyisihan endosulfan dalam ozonasi katalitik dengan dipromosikan oleh karbon aktifKata kunci: Endosulfan, Karbon Aktif, Ozonasi Katalitik

scholarly journals DETERMINATION OF THERMAL DECOMPOSITION REACTION CHARACTERISTICS (A, E) OF WOOD SAMPLES FOR FIRE DYNAMICS SIMULATION

2013 ◽  
Vol 1 (2) ◽  
pp. 13-24 ◽  
Author(s):  
László Beda ◽  
Attila Szabó
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Decomposition Reaction ◽  
Dynamics Simulation ◽  
Fire Dynamics ◽  
Exponential Factor ◽  
Decomposition Reactions ◽  
Reaction Characteristics ◽  
Reaction Activation Energy

Abstract The purpose of this work is to determine the pre-exponential factor (A) and the reaction activation energy (E) of decomposition reactions that are needed for Fire Dynamics Simulation (FDS) using Derivatograph Q 1500D. The materials we investigated: Pine Wood Board (PWB), Multilayered Parquet Board (MPB), Particleboard Core (PBC) and Oriented Standard Board (OSB).

THE THERMAL DECOMPOSITION OF DIPHENYLACETIC ACID

1960 ◽  
Vol 38 (8) ◽  
pp. 1271-1276 ◽  
Author(s):  
Margaret H. Back ◽  
A. H. Sehon
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Rate Constant ◽  
Phenylacetic Acid ◽  
Decomposition Reaction ◽  
Temperature Range ◽  
Diphenylacetic Acid

The pyrolysis of diphenylacetic acid was investigated over the temperature range 515-636° C using the toluene-carrier technique. The main products of this system were similar to those formed in the thermal decomposition of phenylacetic acid. The rate constant for the reaction[Formula: see text]was calculated as k′ = 8 × 1012.exp(−52,000/RT) sec−1.The over-all decomposition reaction was found to be partly heterogeneous and, therefore, the activation energy for reaction [1] may be only tentatively identified with D[(C6H5CH)2—COOH].

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