scholarly journals Structural and Gasification Kinetic Studies on Co-pyrolysis Chars of Coal and Biomass

2021 ◽  
Author(s):  
Lang Liu ◽  
Jingsong Zeng ◽  
Qingrui Jiao ◽  
Shan Ren ◽  
Jian Yang ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Porous Structure ◽  
Kinetic Studies ◽  
Activation Energies ◽  
Biomass Composition ◽  
Pore Model ◽  
Gasification Reactivity ◽  
Char Gasification ◽  
The Relationship ◽  
Kinetics Of

Abstract In the present study, the CO2 gasification behaviours of the co-pyrolysis chars with coal and biomass as feedstock were investigated using isothermal thermogravimetric analysis (TGA) at 950–1150 °C. The TGA results demonstrated that the char gasification reactivity was improved at higher biomass composition. In addition, the char characteristics results evaluation revealed that biomass promoted the development of a porous structure and inhibited the formation of graphite-like carbon during the co-pyrolysis of coal and biomass. Moreover, an extended random pore model (eRPM) was proposed to define the char gasification kinetics of coal and biomass. It was found that the activation energies of chars decreased with increasing biomass composition. Lastly, the relationship between the gasification reactivity and char characteristics was evaluated.

Co-gasification of Hydrochar and Petroleum Coke Blended With Different Ratios

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Nan Zhang ◽  
Xiaojun Ning ◽  
Guangwei Wang ◽  
Jianliang Zhang ◽  
Jian Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Petroleum Coke ◽  
Activation Energies ◽  
Research Results ◽  
Char Gasification ◽  
Gasification Process ◽  
Two Stages

Abstract The co-gasification characteristics of petroleum coke (PC), hydrochar (PS), and their blends with different ratios were studied by using thermogravimetric analysis. The Coats–Redfern model was employed to calculate the gasification activation energies of different samples. The results manifested that the gasification process of PS and blends could be classified into two stages: pyrolysis and char gasification, but for PC, there was only one primary char gasification stage. The activation energy of the pyrolysis stage was significantly smaller than the char gasification stage. In the latter stage, with the increase in the ratio of PS from 20% to 80%, the activation energy was reduced from 114.1 kJ/mol to 82.8 kJ/mol, which indicated that the PS had a significant promoting influence on the PC gasification. The research results can provide a theoretical guiding significance for the efficient use of PS and PC.

scholarly journals Kinetic studies of metalloporphyrin formation. Part I. Mn(II) with hematoporphyrin

1968 ◽  
Vol 46 (22) ◽  
pp. 3431-3436 ◽  
Author(s):  
Doreen A. Brisbin ◽  
Robert J. Balahura
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Kinetic Studies ◽  
Activation Energies ◽  
Kinetics Of

The kinetics of the formation of Mn(III) hematoporphyrin in glacial acetic acid has been studied spectrophotometrically.On addition of Mn(II) to porphyrin in glacial acetic acid a species which appears to be the monocation immediately is formed and is then converted to Mn(III) hematoporphyrin at a rate suitable for kinetic studies.The rates of reaction were measured at 45, 50, and 55 °C and the activation energies were calculated.

scholarly journals A Modified Random Pore Model for the Kinetics of Char Gasification

BioResources ◽  
2014 ◽  
Vol 9 (2) ◽  
Author(s):  
Jian-Liang Zhang ◽  
Guang-Wei Wang ◽  
Jiu-Gang Shao ◽  
Hai-Bin Zuo
Keyword(s):  
Pore Model ◽  
Char Gasification ◽  
Kinetics Of ◽  
Random Pore Model

scholarly journals THE PHOTOINITIATED ADDITION OF MERCAPTANS TO OLEFINS: III. THE KINETICS OF THE ADDITION OF THIOPHENOL TO STYRENE AND TO 1-OCTENE

1957 ◽  
Vol 35 (7) ◽  
pp. 723-733 ◽  
Author(s):  
R. H. Pallen ◽  
C. Sivertz
Keyword(s):  
Free Radical ◽  
Rate Constants ◽  
Chain Transfer ◽  
Kinetic Studies ◽  
Activation Energies ◽  
Reverse Reaction ◽  
Kinetics Of

Kinetic studies were made of the free radical photoinitiated addition of thiophenol to 1-octene and to styrene in the absence of oxygen. In addition to the usual attack, chain transfer, and termination steps, it is found that a reverse reaction accompanies the attack step, [Formula: see text] The rate constants for the thiophenol–styrene reaction were calculated to be [Formula: see text]kt = 2 × 107 liters.moles−1sec.−1. The over-all activation energies for the two reactions were found to be E (1-octene) = 1.2 kcal., E (styrene) = 2.4 kcal.; suggestions are submitted as to why these activation energies are so low. These reactions are compared with n-butyl mercaptan – olefin reactions.

Study on Kinetics of Straw Stalk Gasification in CO2 with Random Pore Model

2014 ◽  
Vol 618 ◽  
pp. 316-320
Author(s):  
Hua Fei ◽  
Jin Ming Shi ◽  
Yuan Lin Li ◽  
Kai Luo
Keyword(s):  
Experimental Data ◽  
Reaction Model ◽  
Carbon Conversion ◽  
Pore Model ◽  
Different Temperatures ◽  
Shrinking Core ◽  
The Relationship ◽  
Kinetics Of ◽  
Core Reaction ◽  
Random Pore Model

The gasification of straw stalk in CO2 environment was studied by isothermal thermogravimetric analysis. The characteristics of rice straw and maize stalk gasification at different temperatures were examined under CO2 atmosphere. The relationship between reaction time and carbon conversion of two biomass chars was analyzed by the random pore model (RPM), and compared with the simulation of the shrinking core reaction model (SCRM). The results show that the random pore model is better to predict the experimental data at different temperatures. This means that the characteristics of pore structure for the influence of biomass chars gasification is well reflected by parameter ψ used in RPM. It indicates that the RPM can be applied to the comprehensive simulation of biomass chars gasification in CO2 environment.

COMPARATIVE STUDY ON PYROLYSIS BEHAVIOR AND KINETICS OF TWO MACROALGAE BIOMASS (ULVA CF. FLEXUOSA AND HY. EDULIS) USING THERMOGRAVIMETRIC ANALYSIS

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
Amira Nabila Roslee ◽  
Nur Farizan Munajat
Keyword(s):  
Thermogravimetric Analysis ◽  
Activation Energies ◽  
Peninsular Malaysia ◽  
Thermochemical Conversion ◽  
Algae Biomass ◽  
Model Free ◽  
Conversion System ◽  
Apparent Activation Energies ◽  
Kinetics Of ◽  
Macro Algae

Preliminary pyrolysis studies of macroalgae biomass (Ulva cf. flexuosa and Hy. edulis) which were collected from several coastlines of Peninsular Malaysia were performed by using thermogravimetric analysis (TGA). The corresponding kinetic parameters were calculated through three model-free methods, namely Kissinger, Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO). The TGA curves of both species exhibited three degradation stages: dehydration, devolatilization, and residual decomposition. The devolatilization stage is where the main pyrolysis occurred at a temperature around 150-590oC and released the total volatiles of 56.93% and 54.92% for Ulva cf. flexuosa and Hy. Edulis.  The calculation of activation energy from Kissinger method for Ulva cf. flexuosa was 180.24 kJ/mol while 194.86 kJ/mol for Hy. edulis. The apparent activation energies for KAS and FWO methods are increased by increasing the pyrolysis conversion with average activation energies of 241.17 kJ/mol and 253.65kJ/mol for Ulva cf. flexuosa, while for Hy. edulis, are 244.75 kJ/mol and 258.9 kJ/mol. This study provides the basis for the further application for designing and modeling in thermochemical conversion system of macro algae biomass.

THERMOGRAVIMETRIC ANALYSIS OF THE KINETICS OF THE REACTION OF ALKOXYSILANE WITH SILICA

2014 ◽  
Vol 87 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Yuk Yu Law ◽  
Donald L. Feke ◽  
Ica Manas-Zloczower
Keyword(s):  
Thermogravimetric Analysis ◽  
Reaction Kinetics ◽  
Surface Functionalization ◽  
Reaction Model ◽  
Activation Energies ◽  
Temperature Range ◽  
Polymer Interactions ◽  
Kinetics Of ◽  
Arrhenius Analysis

ABSTRACT The surface functionalization of silica by alkoxysilane can improve its dispersion into polymers by beneficially modifying interparticle and particle–polymer interactions. Thermogravimetric analysis (TGA) has been used to study the kinetics of binding a bifunctional alkoxysilane onto silica over the temperature range of 50 to 110 °C. Derivative TGA curves of the reacted silica show distinct peaks, which correspond to the alkoxysilane bound to one or two surface silanol sites. Binding at two silanol sites is postulated to occur in a two-step series reaction model. An Arrhenius analysis for the alkoxysilane binding reactions shows that the activation energies of the two reaction steps are similar, which is expected because the alkoxysilane contains two identical binding groups. This work demonstrates the suitability of the TGA technique to investigate the reaction kinetics for modifying the surface of silica.

Porous Structure and Transport Properties of a Carbonized Phenolic Resin

1995 ◽  
Vol 60 (2) ◽  
pp. 172-187 ◽  
Author(s):  
Pavel Fott ◽  
František Kolář ◽  
Zuzana Weishauptová
Keyword(s):  
Porous Structure ◽  
Transport Properties ◽  
Phenolic Resin ◽  
Arrhenius Equation ◽  
Mercury Porosimetry ◽  
Micropore Volume ◽  
Microporous Structure ◽  
Wetting And Drying ◽  
Phenolic Resins ◽  
Kinetics Of

On carbonizing phenolic resins, the development of porous structure takes place which influences the transport properties of carbonized materials. To give a true picture of this effect, specimens in the shape of plates were prepared and carbonized at various temperatures. The carbonizates obtained were studied by adsorption methods, electron microscopy, and mercury porosimetry. Diffusivities were evaluated in terms of measuring the kinetics of wetting and drying. It was found out that the porous structure of specimens in different stages of carbonization is formed mostly by micropores whose volumes were within 0.06 to 0.22 cm3/g. The maximum micropore volume is reached at the temperature of 750 °C. The dependence of diffusivity on the carbonization temperature is nearly constant at first, begins to increase in the vicinity of 400 °C, and at 600 °C attains its maximum. The experimental results reached are in agreement with the conception of the development and gradual closing of the microporous structure in the course of carbonization. The dependence of diffusivity on temperature can be expressed by the Arrhenius equation. In this connection, two possible models of mass transport were discussed.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

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