scholarly journals Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 516 ◽  
Author(s):  
Michela Lucian ◽  
Maurizio Volpe ◽  
Luca Fiori
Keyword(s):  
Experimental Data ◽  
Reaction Kinetics ◽  
Reaction Pathway ◽  
Hydrothermal Carbonization ◽  
Kinetics Model ◽  
Transient Phase ◽  
Lumped Model ◽  
Gaseous Products ◽  
Best Fitting ◽  
Kinetics Of

Olive trimmings (OT) were used as feedstock for an in-depth experimental study on the reaction kinetics controlling hydrothermal carbonization (HTC). OT were hydrothermally carbonized for a residence time τ of up to 8 h at temperatures between 180 and 250 °C to systematically investigate the chemical and energy properties changes of hydrochars during HTC. Additional experiments at 120 and 150 °C at τ = 0 h were carried out to analyze the heat-up transient phase required to reach the HTC set-point temperature. Furthermore, an original HTC reaction kinetics model was developed. The HTC reaction pathway was described through a lumped model, in which biomass is converted into solid (distinguished between primary and secondary char), liquid, and gaseous products. The kinetics model, written in MATLABTM, was used in best fitting routines with HTC experimental data obtained using OT and two other agro-wastes previously tested: grape marc and Opuntia Ficus Indica. The HTC kinetics model effectively predicts carbon distribution among HTC products versus time with the thermal transient phase included; it represents an effective tool for R&D in the HTC field. Importantly, both modeling and experimental data suggest that already during the heat-up phase, biomass greatly carbonizes, in particular at the highest temperature tested of 250 °C.

scholarly journals Mechanism of reaction of silica and carbon for producing silicon carbide

2019 ◽  
Vol 45 ◽  
pp. 146867831989141
Author(s):  
Bahador Abolpour ◽  
Rahim Shamsoddini
Keyword(s):  
Experimental Data ◽  
Silicon Carbide ◽  
Reaction Kinetics ◽  
Direct Effect ◽  
Solid Reaction ◽  
Carbon Reduction ◽  
Temperature Range ◽  
Carbon Particles ◽  
Mechanism Of Reaction ◽  
Kinetics Of

The reaction kinetics of carbon reduction of silica were investigated using thermodynamic concepts and by fitting to relevant models the experimental data obtained for this reduction using a thermogravimetric unit in the temperature range of 1566 to 1933 K. The results show that the only way to produce SiC in this reduction is the reaction of Si, SiO, or SiO2 at the surface or by diffusion of SiO inside the carbon particles while CO and CO2 have no direct effect on the process. The controlling step of this reduction at temperatures lower than 1750 K is the chemical gas–solid or solid–solid reaction at the surface of the carbon particles, while at higher temperatures, the rate of SiO diffusing inside the carbon particles controls the rate of this reduction.

Reaction kinetics of 1,2-diaminobenzene with ethyl 2-oxopropanoate and 2,3-butanedione

1988 ◽  
Vol 53 (12) ◽  
pp. 3154-3163 ◽  
Author(s):  
Jiří Klicnar ◽  
Jaromír Mindl ◽  
Ivana Obořilová ◽  
Jaroslav Petříček ◽  
Vojeslav Štěrba
Keyword(s):  
Reaction Kinetics ◽  
Acid Catalysis ◽  
Reaction Pathway ◽  
Hydroxide Ion ◽  
Tetrahedral Intermediate ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
General Acid ◽  
Rate Limiting ◽  
Kinetics Of

The reaction of 1,2-diaminobenzene with 2,3-butanedione is subject to general acid catalysis in acetate and phosphate buffers (pH 4-7). The rate-limiting step of formation of 2,3-dimethylquinoxaline consists in the protonation of dipolar tetrahedral intermediate. In the case of the reaction of 1,2-diaminobenzene with ethyl 2-oxopropanoate, the dehydration of carbinolamine gradually becomes rate-limiting with increasing pH in acetate buffers, whereas in phosphate buffers a new reaction pathway makes itself felt, viz. the formation of amide catalyzed by the basic buffer component and by hydroxide ion.

General equations for the reaction kinetics of solids

1976 ◽  
Vol 29 (1) ◽  
pp. 27
Author(s):  
JH Taplin
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Reaction Kinetics ◽  
Theoretical Basis ◽  
Reaction Equation ◽  
Kinetics Of

The index-of-reaction equation (i.r.e.): dF/dtZ = kZ(l - βF)m is compared with a generalized Prout-Tompkins equation (g.P.T.e.): dF/dt = kn(l - βF)y With the boundary condition F = 0, t = 0 the equations are equivalent for z = 2 or m = 0 or β ≤ 1 and the i.r.e, is closely approximated by the g.P.T.e. for other values of the parameters by use of the following approximation ∫(1- F)-m dF ≈ AF(1-BF)5 The parameter s is a function of m. Both A and B are close to unity for 1/3 < m < 3. The i.r.e. is recommended as being more useful than the g.P.T.e. because the i.r.e. has a better theoretical basis and because it is more readily integrated and fitted to experimental data.

Reaction kinetics of hydrothermal carbonization of loblolly pine

2013 ◽  
Vol 139 ◽  
pp. 161-169 ◽  
Author(s):  
M. Toufiq Reza ◽  
Wei Yan ◽  
M. Helal Uddin ◽  
Joan G. Lynam ◽  
S. Kent Hoekman ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Loblolly Pine ◽  
Hydrothermal Carbonization ◽  
Kinetics Of

Pseudo-Homogenous Kinetics Model for the Synthesis of Dimethyl Carbonate from Urea and Methanol with Heterogeneous Catalyst

2011 ◽  
Vol 233-235 ◽  
pp. 481-486
Author(s):  
Wen Bo Zhao ◽  
Ning Zhao ◽  
Fu Kui Xiao ◽  
Wei Wei
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Dimethyl Carbonate ◽  
Side Reaction ◽  
Order Reaction ◽  
Zero Order ◽  
Kinetics Model ◽  
First Order ◽  
Zero Order Reaction ◽  
Kinetics Of

The synthesis of dimethyl carbonate (DMC) from urea and methanol includes two main reactions: one amino of urea is substituted by methoxy to produce the intermediate methyl carbamate (MC) which further converts to DMC via reaction with methanol again. In a stainless steel autoclave, the kinetics of these reactions was separately investigated without catalyst and with Zn-containing catalyst. Without catalyst, for the first reaction, the reaction kinetics can be described as first order with respect to the concentrations of methanol and methyl carbamate (MC), respectively. For the second reaction, the results exhibit characteristics of zero-order reaction. Over Zn-containing catalyst, the first reaction is neglected in the kinetics model since its rate is much faster than second reaction. After the optimization of reaction condition, the macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model, in which a side reaction of DMC synthesis is incorporated since it decreases the yield of DMC drastically at high temperature. The activation energy of the reaction from MC to DMC is 104 KJ/mol while that of the side reaction of DMC is 135 KJ/mol.

scholarly journals Anionic Polymerization of ε-Caprolactam under the Influence of Water: 2. Kinetic Model

2020 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Rainer Wendel ◽  
Philipp Rosenberg ◽  
Michael Wilhelm ◽  
Frank Henning
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Reaction Kinetics ◽  
Water Content ◽  
Anionic Polymerization ◽  
Polyamide 6 ◽  
External Influences ◽  
Influence Of Water ◽  
Kinetics Of

The reaction kinetics of anionic polymerization for the production of anionic polyamide 6 (aPA6) are widely understood. It is also known that this reaction is very sensitive to external influences such as water. This paper analyzes and quantifies the influence of water on the reaction of ε-caprolactam to anionic polyamide 6. A kinetic model is developed in which the reactive molecules of the activator and catalyst are defined as variables and the concentrations of activator and catalyst as well as water content are considered. A model for the calculation of the reaction kinetics is established and validated with experimental data. The developed model can be used to predict the influence and compensation of water by addition of surplus activator and catalyst during the polymerization of ε-caprolactam.

scholarly journals KINETIKA FOTODEGRADASI METHYLENE BLUE MENGGUNAKAN KOMPOSIT Ag3PO4/Ag/HAp TULANG IKAN KAKAP MERAH (Lutjanus sp.)

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Stoflly E. M. Pangajow ◽  
Audy Wuntu ◽  
Meiske S. Sangi
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Reaction Kinetics ◽  
Fish Bone ◽  
Order Reaction ◽  
Kinetics Model ◽  
Light Radiation ◽  
Second Order Reaction ◽  
Bone Powder ◽  
Kinetics Of

ABSTRAKTujuan dari penelitian ini untuk mengkaji kinetika fotodegradasi methylene blue (MB) menggunakan komposit Ag3PO4/Ag/HAp tulang ikan kakap merah (Lutjanus sp.).  Serbuk tulang ikan yang dikalsinasi hingga 1000ºC dan direaksikan dengan AgNO3 dengan rasio mol 5:1 (Ag:HAp) dan dihasilkan komposit Ag3PO4/Ag/HAp. Larutan MB diinteraksikan dengan komposit dengan variasi waktu 5-180 menit dibawah radiasi cahaya tampak. Konsentrasi MB yang tersisa ditentukan ditentukan dengan spektrofotometer UV-Vis dan data yang diperoleh dianalisis dengan model kinetika reaksi orde ke-1 dan ke-2. Hasil penelitian menunjukkan bahwa fotodegradasi MB oleh komposit Ag3PO4/Ag/HAp mengikuti model kinetika fotodegradasi orde ke-2. ABSTRACT The purpose of this research was to study the kinetics of methylene blue (MB) photodegradation using composite Ag3PO4/Ag/HAp bone fish of red snapper (Lutjanus sp.). Fish bone powder which was calcined to 1000ºC and reacted with AgNO3 with mole ratio of 5 : 1 (Ag: HAp) and produced Ag3PO4/Ag/HAp composite. MB solution was interacted with composites with variation of time 5-180 minutes under visible light radiation. The remaining MB concentrations determined were determined by a UV-Vis spectrophotometer and the data obtained were analyzed with first and second order reaction kinetics model. The results showed that MB photodegradation by Ag3PO4/Ag/HAp composites followed the 2nd order photodegradation kinetics model. 

Modeling biomass hydrothermal carbonization by the maximum information entropy criterion

2021 ◽  
Author(s):  
Alberto Gallifuoco ◽  
Alessandro Antonio Papa ◽  
Luca Taglieri
Keyword(s):  
Experimental Data ◽  
Network Modeling ◽  
Reaction Network ◽  
Hydrothermal Carbonization ◽  
Reaction Conditions ◽  
Maximum Information ◽  
Good Accordance ◽  
Maximum Information Entropy ◽  
Entropy Criterion ◽  
Kinetics Of

The kinetics of biomass hydrothermal carbonization is modeled by the MaxEnt principle, without assuming a reaction network. Modeling is in good accordance with the experimental data concerning a broad range of biomass and reaction conditions.

Kinetic and Thermodynamic Aspects of the Bainite Reaction in a Silicon Steel

1983 ◽  
Vol 21 ◽  
Author(s):  
G. Papadimitriou ◽  
J.M.R. Genin
Keyword(s):  
Experimental Data ◽  
Silicon Carbide ◽  
Reaction Kinetics ◽  
Silicon Content ◽  
Silicon Steel ◽  
Tentative Model ◽  
Secondary Stage ◽  
Two Stages ◽  
Kinetics Of ◽  
And Diffusion

ABSTRACTThe bainite reaction in an Fe - 3.85 wt pct Si - 0.9 wt pct C steel is studied by several experimental techniques in the range of 250–450°C.The high silicon content prevents the formation of cementite, so that the reaction is separated to two clearly distinct stages. In the primary stage ferrite forms alone, except at temperatures lower than 310°C where some carbides precipitate in it, and austenite becomes enriched in carbon. In the secondary stage occurring only above 400°C, the enriched austenite decomposes to ferrite and an unknown silicon carbide.The microstructure, the enrichment of the austenite and the overall reaction kinetics of the two stages are studied and are found to be consistent with a displacive mechanism of the bainite reaction.A tentative model, accounting for the competition of shear and diffusion, is proposed in order to fit our experimental data.

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