scholarly journals Thermal Decomposition of Olive-Mill Byproducts: A TG-FTIR Approach

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4123
Author(s):  
Małgorzata Wzorek ◽  
Robert Junga ◽  
Ersel Yilmaz ◽  
Bohdan Bozhenko
Keyword(s):  
Isoconversional Methods ◽  
Phase System ◽  
Heating Rates ◽  
Two Phase ◽  
Model Free ◽  
Three Phase ◽  
Different Types ◽  
Temperature Ranges ◽  
Ftir Technique ◽  
Olive Mill

In this study, the combustion of olive byproducts was investigated using the TG-FTIR technique. Different types of olive biomass were considered: twigs, leaves, olive-mill waste from the two-phase decanting method, and wastewater from the three-phase system. The reaction regions, ignition, and burnout temperatures at different heating rates were determined using TG/DTG analysis and the thermogravimetry results. Comprehensive combustion, ignition, burnout, and flammability indexes were also calculated. The highest combustion index values were obtained for waste from the three-phase system, followed by the two-phase decanting method, then with leaves and small twigs. The order of the index values indicated that the sample from the three-phase process ignited more quickly and yielded faster. The changes in activation energy calculated using different model-free isoconversional methods—Friedman, Ozawa–Flynn–Wall, and Kissinger–Akahira–Sunose—fell within the range of 130–140 kJ/kmol. FTIR analyses presented differences in the exhaust gas composition for specific combustion temperature ranges.

Bioethanol production from thermochemically pre-treated olive mill solid residues using the yeast Pachysolen tannophylus

2013 ◽  
Vol 14 (2) ◽  
pp. 118-124 ◽  
Keyword(s):  
Olive Oil ◽  
Ethanol Yield ◽  
Solid Residue ◽  
Residual Oil ◽  
Edible Fungi ◽  
Pachysolen Tannophilus ◽  
Three Phase ◽  
Different Types ◽  
Pre Treatment ◽  
Olive Mill

Olive oil mill solid residue (OMSR) is the solid waste generated during olive oil production process in three-phase olive mills. It consists of the remaining pulp of olive processing after the extraction of oil, as well as the cracked seeds of the olive fruits, containing thus mainly lignocellulose and residual oil. The commonly used practice for OMSR management is combustion, after having extracted the residual oil by secondary extraction using organic solvents. Other proposed ways of OMSR management are their exploitation as substrate for edible fungi production and compost, and as feedstock for biofuels generation such as methane and bioethanol. In the latter case, the complex carbohydrates (cellulose and hemicellulose) of the lignocellulose of OMSR have to be degraded towards their simple sugars and further fermented via microorganisms. The purpose of the present study was to investigate the effect of thermochemical pre-treatment of OMSR, on the final ethanol yield from the yeast Pachysolen tannophilus. Nine different types of OMSR-based substrates were tested i.e. raw OMSR, hydrolysates generated from pretreated OMSR with NaOH (0.5 %, 1.5 % w/v) and H2SO4 (0.5 %, 1.5 % v/v), and pretreated OMSR with NaOH (0.5 %, 1.5 % w/v) and H2SO4 (0.5 %, 1.5 % v/v) whole biomass. It was shown that in all cases pretreatment enhanced the consumption of carbohydrates as well as ethanol final yields.

Activity coefficients, densities, dipole moments, and surface tensions of the system triethylamine–methylethylketone–water

1981 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alan N. Campbell
Keyword(s):  
Surface Layer ◽  
Dipole Moments ◽  
Phase System ◽  
Constant Composition ◽  
Two Phase ◽  
Three Phase ◽  
Wide Range ◽  
Isothermal System ◽  
Total Composition ◽  
Two Phases

The properties named in the title have been determined by standard methods. Viscosity, molar volume, and orientation polarisation all indicate abnormalities of the nature of association between the components.The most interesting result is that of surface tension which indicates that, in the case of the binary system triethylamine–water, a surface layer of constant composition is formed over a wide range of total composition. When, by a rise in temperature of two or three degrees, this layer becomes unstable, it splits into two phases of different composition. The surface layer may then be instantaneously reformed and so on. A mechanism for the generation of a two-phase system is thus established. The data for the three-phase, isothermal, system are not so convincing, for reasons that are suggested.

Influence of biomass on hydrodynamics of an internal loop airlift reactor

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
M. Juraščík ◽  
M. Hucík ◽  
I. Sikula ◽  
J. Annus ◽  
J. Markoš
Keyword(s):  
Aspergillus Niger ◽  
Gluconic Acid ◽  
Solid Phase ◽  
Biomass Concentration ◽  
Airlift Reactor ◽  
Phase System ◽  
Two Phase ◽  
Experimental Conditions ◽  
Internal Loop ◽  
Three Phase

AbstractThe effect of the biomass presence on the overall circulation velocity, the linear velocities both in the riser and the downcomer and the overall gas hold-up was studied in a three-phase internal loop airlift reactor (ILALR). The measured data were compared with those obtained using a two-phase system (air—water). All experiments were carried out in a 40 dm3 ILALR at six different biomass concentrations (ranging from 0 g dm−3 to 7.5 g dm−3), at a temperature of 30°C, under atmospheric pressure. Air and water were used as the gas and liquid model media, respectively. Pellets of Aspergillus niger produced during the fermentation of glucose to gluconic acid in the ILALR were considered solid phase. In addition, liquid velocities were measured during the fermentation of glucose to gluconic acid using Aspergillus niger. All measurements were performed in a bubble circulation regime. At given experimental conditions the effect of the biomass on the circulation velocities in the ILALR was negligible. However, increasing of the biomass concentration led to lower values of the total gas hold-up.

Influence of Compressed Carbon Dioxide on the Oxidation of Cyclohexane with Hydrogen Peroxide in Acetic Acid

2006 ◽  
Vol 59 (3) ◽  
pp. 225 ◽  
Author(s):  
Liang Gao ◽  
Tao Jiang ◽  
Buxing Han ◽  
Baoning Zong ◽  
Xiaoxin Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Binary System ◽  
Reaction System ◽  
Phase Region ◽  
Phase Behaviour ◽  
Phase System ◽  
Two Phase ◽  
Three Phase

The oxidation of cyclohexane with H2O2 in a compressed CO2/acetic acid binary system was studied at 60.0 and 80.0°C, at pressures up to 18 MPa, and with the zeolite TS-1 as catalyst. The phase behaviour of the reaction system was also observed. There are three fluid phases in the reaction system at lower pressure but two at higher pressures. In the three-phase region the yields of the products, cyclohexanol and cyclohexanone, increase considerably with increasing pressure and reaches a maximum near the phase-separating pressure. CO2 can thus enhance the reaction effectively. However, the effect of pressure on the yield is very limited after the transition to a two-phase system.

scholarly journals Kinetic Analysis of the Thermal Degradation of Recycled Acrylonitrile-Butadiene-Styrene by non-Isothermal Thermogravimetry

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 281 ◽  
Author(s):  
Rafael Balart ◽  
David Garcia-Sanoguera ◽  
Luis Quiles-Carrillo ◽  
Nestor Montanes ◽  
Sergio Torres-Giner
Keyword(s):  
Thermal Degradation ◽  
Kinetic Analysis ◽  
Acrylonitrile Butadiene Styrene ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Integral Model ◽  
Heating Rates ◽  
Exponential Factor ◽  
Model Free ◽  
Butadiene Styrene

This work presents an in-depth kinetic study of the thermal degradation of recycled acrylonitrile-butadiene-styrene (ABS) polymer. Non-isothermal thermogravimetric analysis (TGA) data in nitrogen atmosphere at different heating rates comprised between 2 and 30 K min−1 were used to obtain the apparent activation energy (Ea) of the thermal degradation process of ABS by isoconversional (differential and integral) model-free methods. Among others, the differential Friedman method was used. Regarding integral methods, several methods with different approximations of the temperature integral were used, which gave different accuracies in Ea. In particular, the Flynn-Wall-Ozawa (FWO), the Kissinger-Akahira-Sunose (KAS), and the Starink methods were used. The results obtained by these methods were compared to the Kissinger method based on peak temperature (Tm) measurements at the maximum degradation rate. Combined Kinetic Analysis (CKA) was also carried out by using a modified expression derived from the general Sestak-Berggren equation with excellent results compared with the previous methods. Isoconversional methods revealed negligible variation of Ea with the conversion. Furthermore, the reaction model was assessed by calculating the characteristic and functions and comparing them with some master plots, resulting in a nth order reaction model with n = 1.4950, which allowed calculating the pre-exponential factor (A) of the Arrhenius constant. The results showed that Ea of the thermal degradation of ABS was 163.3 kJ mol−1, while ln A was 27.5410 (A in min−1). The predicted values obtained by integration of the general kinetic expression with the calculated kinetic triplet were in full agreement with the experimental data, thus giving evidence of the accuracy of the obtained kinetic parameters.

MODEL FREE KINETICS ANALYSIS OF IMPERATA CYLINDRICA (LALANG)

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Olagoke Oladokun ◽  
Arshad Ahmad ◽  
Tuan Amran Tuan Abdullah ◽  
Bemgba Bevan Nyakuma ◽  
Syie Luing Wong
Keyword(s):  
Activation Energy ◽  
Biomass Conversion ◽  
Frequency Factor ◽  
Isoconversional Methods ◽  
Green Energy ◽  
Imperata Cylindrica ◽  
Heating Rates ◽  
Model Free ◽  
Solid Biofuel ◽  
Kinetics Of

This study is the first attempt at investigating the solid state decomposition and the devolatilization kinetics of Imperata cylindrica (lalang) grass termed the “farmer’s nightmare weed” as a potential solid biofuel of the future. Biomass conversion technologies such as pyrolysis and gasification can be utilized for future green energy needs. However an important step in the efficient utilization and process optimizing of biomass conversion processes is understanding the thermal decomposition kinetics of the feedstock. Consequently, thermogravimetric analysis (TGA) of Imperata cylindrica was carried out in the temperature range of 30-1000 °C at four heating rates of 5, 10, 15, and 20 K min-1 using Nitrogen at a flow rate of 20 L min-1 as purge gas. Using the TGA results, the kinetic parameters activation energy (Ea) and pre-exponential frequency factor (ko) of the grass were estimated via the model free or isoconversional methods of Kissinger and Starink. The results obtained for Kissinger model were 151.36 kJ moI-1 and 5.83 x 109 min-1 for activation energy and pre-exponential frequency factor respectively. However, Starink model activation energy and pre-exponential frequency factor were a function of conversion (α) with average values of 159.93 kJ mol-1 and 6.33 x 1022 min-1 respectively. 

Kinetic Studies on the Thermal Synthesis of Fluorapatite: Model Free and Model-Fitting Methods

2018 ◽  
Vol 28 ◽  
pp. 75-89
Author(s):  
Hamid Reza Javadinejad ◽  
Sayed Ahmad Hosseini ◽  
Mohsen Saboktakin Rizi ◽  
Eiman Aghababaei ◽  
Hossein Naseri
Keyword(s):  
Activation Energy ◽  
Model Fitting ◽  
Kinetic Studies ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Heating Rates ◽  
Thermal Synthesis ◽  
Exponential Factor ◽  
Model Free ◽  
Master Plots

The kinetic study for the synthesis of Fluorapatite has been done using the thermogravimetric technique under non-isothermal conditions and at four heating rates of 5, 10, 15 and 20 °C. Both model free and model-fitting methods were used to investigate kinetic parameters. Calcium oxide, phosphorus pentoxide and calcium fluoride were used as the precursor materials. The activation energy values were calculated through model-fitting and isoconversional methods and were used to predict the reaction model and pre-exponential factor. In this case several techniques were considered such as master plots and compensation effects. The results indicated that the reaction mechanism was chemically controlled with second and third order reaction models in the whole range of conversion which the activation energy varied from 25 to 43 kJ/mol.

Decomposition Kinetics of Switchgrass: Estimating Activation Energy

2014 ◽  
Vol 881-883 ◽  
pp. 726-733
Author(s):  
Gui Ying Xu ◽  
Jiang Bo Wang ◽  
Ling Ping Guo ◽  
Guo Gang Sun
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Apparent Activation Energy ◽  
High Purity ◽  
Isoconversional Methods ◽  
Decomposition Kinetics ◽  
Heating Rates ◽  
Model Free ◽  
Chemical Utilization ◽  
Kinetics Of

TG analysis was used to investigate the thermal decomposition of switchgrass, which is a potential gasification feedstock. 10 mg switchgrass sample with the particles between 0.45 and 0.70 mm was linearly heated to 873 K at heating rates of 10, 20, 30 K/min, respectively, under high-purity nitrogen. The Kissinger method and three isoconversional methods including Friedman, Flynn-wall-Ozawa, Vyazovkin and Lenikeocink methods were used to estimate the apparent activation energy of switchgrass. With the three isoconversional methods, it can be concluded that the activation energy increases with increasing conversion. The four model free methods reveal activation energies in the range of 70-460 kJ/mol. These activation energy values provide the basic data for the thermo-chemical utilization of the switchgrass.

scholarly journals Thermal decomposition of a molecular material {N(n-C4H9)4[FeIIFeIII(C2O4)3]}∞ leading to ferrite: A reaction kinetics study

2013 ◽  
Vol 78 (4) ◽  
pp. 523-536 ◽  
Author(s):  
Ashis Bhattacharjee ◽  
Debasis Roy ◽  
Madhusudan Roy ◽  
Arunabha Adhikari
Keyword(s):  
Thermal Decomposition ◽  
Isoconversional Methods ◽  
Reaction Pathways ◽  
Heating Rates ◽  
Model Free ◽  
Molecular Precursor ◽  
Probable Reaction Mechanism ◽  
Mechanism Of Thermal Decomposition ◽  
Rate Of Reaction ◽  
Probable Reaction

A multi-step thermal decomposition of a molecular precursor, {N(n-C4H9)4[FeIIFeIII(C2O4)3}? has been studied using non-isothermal thermogravimetry (TG) measurements in the temperature range 300 to ~800 K at multiple heating rates (5, 10 and 20 K min-1). The thermal decomposition of the oxalate-based complex proceeds stepwise through a series of intermediate reactions. Two different isoconversional methods, namely, improved iterative method and model-free method are employed to evaluate the kinetic parameters: activation energy and rate of reaction, and the most probable reaction mechanism of thermal decomposition is also determined. The different reaction pathways leading to different steps in the TG profile have also been explored which are supplemented by earlier experimental observations of the present authors.

scholarly journals Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

2014 ◽  
Vol 68 (4) ◽  
pp. 483-490
Author(s):  
Milena Knezevic ◽  
Dragan Povrenovic
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Solid Particles ◽  
Phase System ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Dispersion ◽  
Operation Conditions ◽  
Three Phase ◽  
Different Types

Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm). The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density) have a major impact on oxygen mass transfer in three phase systems.

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