scholarly journals Application of a New Statistical Model for the Description of Solid Fuel Decomposition in the Analysis of Artemisia apiacea Pyrolysis

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5789
Author(s):  
Tianbao Gu ◽  
Torsten Berning ◽  
Chungen Yin
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Statistical Model ◽  
Solid Fuel ◽  
Conversion Rate ◽  
Reaction Model ◽  
Thermochemical Conversion ◽  
Conversion Degree ◽  
Heating Rates ◽  
Artemisia Apiacea

Pyrolysis, one of the key thermochemical conversion technologies, is very promising to obtain char, oil and combustible gases from solid fuels. Kinetic modeling is a crucial method for the prediction of the solid conversion rate and analysis of the pyrolysis process. We recently developed a new statistical model for the universal description of solid fuel decomposition, which shows great potential in studying solid fuel pyrolysis. This paper demonstrates three essential applications of this new model in the analysis of Artemisia apiacea pyrolysis, i.e., identification of the conversion rate peak position, determination of the reaction mechanism, and evaluation of the kinetics. The results of the first application show a very good agreement with the experimental data. From the second application, the 3D diffusion-Jander reaction model is considered as the most suitable reaction mechanism for the description of Artemisia stem pyrolysis. The third application evaluates the kinetics of Artemisia stem pyrolysis. The evaluated kinetics vary with the conversion degree and heating rates, in which the activation energies and pre-exponential factors (i.e., lnA vs. Ea) show a linear relationship, regardless of the conversion and heating rates. Moreover, the prediction of the conversion rate using the obtained kinetics shows an excellent fit with the experimental data.

scholarly journals Pyrolysis Kinetic Properties of Thermal Insulation Waste Extruded Polystyrene by Multiple Thermal Analysis Methods

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5595
Author(s):  
Ang Li ◽  
Wenlong Zhang ◽  
Juan Zhang ◽  
Yanming Ding ◽  
Ru Zhou
Keyword(s):  
Reaction Mechanism ◽  
Thermal Insulation ◽  
Conversion Rate ◽  
Model Fitting ◽  
Pso Algorithm ◽  
Energy Utilization ◽  
Kinetic Properties ◽  
Insulation Material ◽  
Heating Rates ◽  
Model Free

Extruded polystyrene (XPS) is a thermal insulation material extensively applied in building systems. It has attracted much attention because of outstanding thermal insulation performance, obvious flammability shortcoming and potential energy utilization. To establish the reaction mechanism of XPS’s pyrolysis, thermogravimetric experiments were performed at different heating rates in nitrogen, and multiple methods were employed to analyze the major kinetics of pyrolysis. More accurate kinetic parameters of XPS were estimated by four common model-free methods. Then, three model-fitting methods (including the Coats-Redfern, the iterative procedure and masterplots method) were used to establish the kinetic model. Since the kinetic models established by the above three model-fitting methods were not completely consistent based on different approximations, considering the effect of different approximates on the model, the reaction mechanism was further established by comparing the conversion rate based on the model-fitting methods corresponding to the possible reaction mechanisms. Finally, the accuracy of the above model-fitting methods and Particle Swarm Optimization (PSO) algorithm were compared. Results showed that the reaction function g(α) = (1 − α)−1 − 1 might be the most suitable to characterize the pyrolysis of XPS. The conversion rate calculated by masterplots and PSO methods could provide the best agreement with the experimental data.

Thermal decomposition of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate. Part 1: kinetics of nonisothermal dehydration of un-irradiated and γ-ray irradiated Ho(CH3COO)3⋅4H2O

2018 ◽  
Vol 106 (9) ◽  
pp. 775-785 ◽  
Author(s):  
Norhan Farghly Rashwan ◽  
Hossam Wahid ◽  
AbdelRahman AbdelMonem Dahy ◽  
Refaat Mohamed Mahfouz
Keyword(s):  
Thermal Decomposition ◽  
Absorbed Dose ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Host Lattice ◽  
Isothermal Kinetics ◽  
Conversion Degree ◽  
Acetate Tetrahydrate ◽  
Heating Rates ◽  
Γ Ray

Abstract Nonisothermal dehydration of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate with 103 kGy total γ-ray dose absorbed was studied in air atmosphere. The thermal decomposition experiments were conducted at heating rates of (5, 7.5 and 10°C/min). The results showed that for un-irradiated material, the dehydration process proceeds in two decomposition steps with the elimination of 3.0 and 1.0 moles of H2O, respectively. The apparent activation energy, Ea, as given by both linear and nonlinear isoconversional methods showed dependence upon the conversion degree, α, in the range of 0.2–0.75 for the two dehydration steps. In the first dehydration step, the Ea decreases from 228.0 kJ/mol at the beginning of the decomposition to ≈64.0 kJ/mol at the end of the process. In the second dehydration step, the Ea increases from 42.0 to 72.0 kJ/mol by progressively increasing in α. Compared with solid state reaction models, the two reactions are best described by diffusion (D4) and nucleation (A3) models for the first and second dehydration steps, respectively. The results derived from nonisothermal data present a reliable prediction of isothermal kinetics. Straight lines and reduced time plots methods were applied for the determination of the kinetic triplet [Ea, ln A, and reaction model f(α)] from predicted isothermal data. For γ-ray irradiated samples of Ho(CH3COO)3⋅4H2O with 103 kGy total absorbed dose, the dehydration proceeds in two overlapped steps controlled by D3 model. X-ray data showed phase transformation from monoclinic (SG P2/m) to tetragonal phase (SG P4/mmm) by the elimination of water content from the entire structure of Ho(CH3COO)3⋅4H2O. γ-Ray irradiation effects on the thermal decomposition of Ho(CH3COO)3⋅4H2O were evaluated and discussed based on the formation of trapped electrons, point defects, cation and anion vacancies and cluster imperfections in the host lattice of Ho(CH3COO)3⋅4H2O.

scholarly journals Kinetic Analysis of the Curing of a Partially Biobased Epoxy Resin Using Dynamic Differential Scanning Calorimetry

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 391 ◽  
Author(s):  
Diego Lascano ◽  
Luis Quiles-Carrillo ◽  
Rafael Balart ◽  
Teodomiro Boronat ◽  
Nestor Montanes
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
Curing Kinetics ◽  
Reaction Model ◽  
Diglycidyl Ether ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Model Free

This research presents a cure kinetics study of an epoxy system consisting of a partially bio-sourced resin based on diglycidyl ether of bisphenol A (DGEBA) with amine hardener and a biobased reactive diluent from plants representing 31 wt %. The kinetic study has been carried out using differential scanning calorimetry (DSC) under non-isothermal conditions at different heating rates. Integral and derivative isoconversional methods or model free kinetics (MFK) have been applied to the experimental data in order to evaluate the apparent activation energy, Ea, followed by the application of the appropriate reaction model. The bio-sourced system showed activation energy that is independent of the extent of conversion, with Ea values between 57 and 62 kJ·mol−1, corresponding to typical activation energies of conventional epoxy resins. The reaction model was studied by comparing the calculated y(α) and z(α) functions with standard master plot curves. A two-parameter autocatalytic kinetic model of Šesták–Berggren [SB(m,n)] was assessed as the most suitable reaction model to describe the curing kinetics of the epoxy resins studied since it showed an excellent agreement with the experimental data.

scholarly journals Kinetic analysis of the termal decomposition of colombian vacuum residua by termogravimetry

2015 ◽  
Vol 35 (3) ◽  
pp. 19-26 ◽  
Author(s):  
Fabian Andrey Diaz Mateus ◽  
Arlex Chaves ◽  
Maria Paola Maradei ◽  
David Alfredo Fuentes ◽  
Alexander Guzman ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Analysis ◽  
Reaction Order ◽  
Calculated Data ◽  
Reaction Model ◽  
Vacuum Residue ◽  
Font Size ◽  
Heating Rates ◽  
Thermogravimetric Analyzer ◽  
Single Reaction

<p style="margin: 0cm 0cm 0pt; text-align: justify; line-height: normal;"><span style="letter-spacing: -0.1pt; font-family: 'Century Gothic','sans-serif'; font-size: 8pt; mso-bidi-font-size: 9.5pt; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-fareast-language: ES; mso-bidi-language: EN-US;">Five different Colombian vacuum residues were thermally decomposed in a thermogravimetric analyzer. Three heating rates were employed to heat the sample up to 650°C. The kinetic analysis was performed by the Coats-Redfern method to describe the non-isothermal pyrolysis of the residua, a reaction model where the reaction order gradually increases from first to second order is proposed and an excellent agreement of the experimental with the calculated data is presented. The results also indicate that the pyrolysis of a vacuum residue cannot be modeled by a single reaction mechanism.</span></p>

Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

2017 ◽  
Vol 899 ◽  
pp. 173-178 ◽  
Author(s):  
Ronydes Batista Jr. ◽  
Bruna Sene Alves Araújo ◽  
Pedro Ivo Brandão e Melo Franco ◽  
Beatriz Cristina Silvério ◽  
Sandra Cristina Danta ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Large Scale ◽  
Catalytic Pyrolysis ◽  
Petroleum Products ◽  
Reaction Model ◽  
Heating Rates ◽  
Coffee Grounds ◽  
One Step ◽  
Global Reaction ◽  
The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

scholarly journals Evaluation of an empirical model used for deriving the fluidization velocity of binary mixtures of biomasses and sand

2020 ◽  
Vol 9 (9) ◽  
pp. e49996648
Author(s):  
David da Silva Vasconcelos ◽  
Sirlene Barbosa Lima ◽  
Ana Cristina Morais da Silva ◽  
José Mário Ferreira Júnior ◽  
Carlos Augusto de Moraes Pires
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Mass Fraction ◽  
Binary Systems ◽  
Particle Diameter ◽  
Data Representation ◽  
The Other ◽  
Experimental Planning ◽  
Fluidization Velocity ◽  
Planning Technique

In a previous study, a statistical model was developed using the experimental planning technique for evaluating the influence of its variables on fluidization velocity. In this study, we investigated the Vasconcelos-statistical model (VSM) in data representation, considering fluidization with and without segregation. The methodology used was based on the simulation of the fluidization velocity of nine binary systems, comprising sand, and eight biomasses published by six authors. In addition, the results obtained using VSM were compared with those obtained using five other models, reported by different authors, but adjusted to the experimental data of these biomasses. The result obtained by the proposed models mainly indicated a discrepancy between the experimental and calculated fluidization velocities. VSM, using only three variables (particle size, particle diameter, and biomass mass fraction), yielded results of smaller discrepancy values in all simulations (2.23–12.51%), as opposed to the other comparative models, which presented more significant numbers of variables. Thus, VSM is defined as one of the most interesting models for predicting the fluidization velocity of several biomasses.

scholarly journals PYROLYSIS OF SOLID WASTE AND ITS COMPONENTS IN A LAB SCALE INDUCTION-HEATING REACTOR

Detritus ◽  
2021 ◽  
pp. 107-112
Author(s):  
Oscar Sosa ◽  
Sylvie Valin ◽  
Sébastien Thiery ◽  
Sylvain Salvador
Keyword(s):  
Beech Wood ◽  
Fast Pyrolysis ◽  
Fluidized Bed Reactor ◽  
Thermochemical Conversion ◽  
Homogeneous Distribution ◽  
The Novel ◽  
Reaction Products ◽  
Heating Rates ◽  
Fast Heating ◽  
Novel Device

The present study investigates the thermochemical conversion of Solid Recovered Fuel (SRF), represented by selected “model materials”. A laboratory-scale induction heated device was specifically developed to achieve fast pyrolysis conditions close to those encountered in a fluidized bed reactor. The novel device can handle up to 5 grams of solid, allowing fast heating rates (near 70°C/s) and a homogeneous distribution of temperature all along the reactor. Pyrolysis tests of a SRF sample and four model materials (Polyethylene, Polyethylene Terephthalate, beech wood, cardboard) were performed at 800°C. The yield and composition of the produced gas for each sample were determined. Experimental results will help to elucidate the relation between the initial components of waste derived fuels and the obtained reaction products.

Statistical Model of a Thin Film Formation

2021 ◽  
Vol 887 ◽  
pp. 597-602
Author(s):  
E.L. Kuleshov ◽  
Vladimir S. Plotnikov ◽  
Evgenii V. Pustovalov ◽  
T.S. Ostachenova
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Probability Distribution ◽  
Amorphous Alloy ◽  
Statistical Model ◽  
Pareto Distribution ◽  
Film Formation ◽  
Informational Entropy ◽  
Thin Film Formation ◽  
Conditional Unit

This paper presents a model of a thin film formation process of an amorphous alloy as a sequential procedure when a conditional unit of substance is randomly thrown onto a substrate at each next step. The islands of a precipitant are generated on the substrate with an increase of number of steps (density defects of substance). We determine the probability distribution of an island area, which shows the maximum informational entropy. An algorithm for computing estimates of parameters of this distribution is obtained. The results of processing experimental data are presented. We demonstrate that the proposed distribution is more consistent with the experimental data than the Pareto distribution.

Modeling the Densification of FeSi Sintered Magnetic Alloys

2012 ◽  
Vol 727-728 ◽  
pp. 175-180 ◽  
Author(s):  
José Adilson de Castro ◽  
Gilberto V. Concilio ◽  
Daniel Rodrigues ◽  
Livia S. Santomauro ◽  
Marcos Flavio de Campos
Keyword(s):  
Experimental Data ◽  
Grain Size ◽  
Sintering Temperature ◽  
Process Parameter ◽  
Model Parameters ◽  
Important Process ◽  
Sintering Process ◽  
Heating Rates ◽  
Magnetic Alloys ◽  
Sintered Alloys

An important process parameter in FeSi sintered alloys is the sintering temperature. If the sintering temperature can be reduced, the sintering process could be performed in less expensive furnaces. A densification model is here applied to experimental data. The model considers both grain size and density. After the model is applied to experimental data, the acquired model parameters allow the simulation of densification for other situations of temperature and heating rates. The model can be helpful to find suitable sintering temperatures in these alloys.

Microstructure and Reaction Mechanism of Multi-Laminated Ti-(SiCp/Al) Composites Subjected to Annealing at 1300°C

2013 ◽  
Vol 762 ◽  
pp. 526-530
Author(s):  
Jin Cheng Pang ◽  
Lin Geng ◽  
G.H. Fan ◽  
A.B. Li ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Reaction Mechanism ◽  
Scanning Electron Microscope ◽  
Reaction Model ◽  
Hot Press ◽  
Roll Bonding ◽  
X Ray ◽  
Al Composite ◽  
Reaction Annealing ◽  
Scanning Electron

The multi-laminated Ti-(SiCp/Al) composite was produced by hot press and subsequent hot roll bonding of Ti and SiCp/Al foils. The microstructure evolution of the composite in reaction annealing was investigated by scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDX) and X-ray diffractometer (XRD). The results show that after the reaction annealing at 1300°C for 3h, the Ti and SiCp/Al foils were completely consumed and transformed into the TiAl composite with a microlaminated structure. The microlaminated microstructure of the composite is composed of Ti3Al/(TiAl+Ti5Si3p)/Ti5Si3/duplex-phase (TiC+Ti3AlC) layers. The reaction mechanism is elucidated by employing the reaction model.

Sign in / Sign up

Export Citation Format

Share Document