scholarly journals THE KINETICS OF CaO ASSISTED PATTUKKU CHARCOAL STEAM GASIFICATION

REAKTOR ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 16
Author(s):  
Takdir Syarif ◽  
H Sulistyo ◽  
Wahyudi B Sediawan ◽  
B Budhijanto
Keyword(s):  
Activation Energy ◽  
Tubular Reactor ◽  
Steam Gasification ◽  
Effect Of Temperature ◽  
Composition Analysis ◽  
Zone Model ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Surface Diffusivity ◽  
Gasification Process

Abstract Coal is a solid fuel that can be converted into syngas through gasification process. To obtain optimum gasification process design and operation, in-depth understanding of the influential parameters is required. This study aims to investigate the effect of temperature on the gasification process and to obtain its kinetics parameters. The study was carried out in a tubular reactor equipped with a heater and a condenser. Steam was used as gasifying agent, while CaO was employed as a CO2 adsorbent. The charcoal from coal was subjected to gasification at temperatures of 600°C, 700°C, and 800°C. The ratio of charcoal and CaO was 1:1. The gasification process lasted for 60 minutes with gas sample was taken every 15 minutes for composition analysis. The results showed that a temperature increase of 100°C caused a proportional increase of conversion of about 75% higher. The value of activation energy (Ea) and exponential factor (ko) were 46.645kJ/mole and 328.3894/min, respectively. For mass transfer parameters, values of activation energy for surface diffusion (Es) and surface diffusivity factor (as) were 81.126 kJ/mole and 0.138/min, respectively. Keywords: gasification; mathematical model; Pattukku coal char; steam; Thin Reaction Zone Model

scholarly journals Thermal decomposition characteristics of foundry sand for cast iron in nitrogen atmosphere

2018 ◽  
Vol 5 (12) ◽  
pp. 181091 ◽  
Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Xiwen Yao ◽  
Jishuo Li ◽  
Li Li
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Cast Iron ◽  
Low Cost ◽  
Temperature Stability ◽  
Nitrogen Atmosphere ◽  
High Temperature Stability ◽  
Kinetics Parameters ◽  
Foundry Sand ◽  
Exponential Factor

Sand casting, currently the most popular approach to the casting production, has wide adaptability and low cost. The thermal decomposition characteristics of foundry sand for cast iron were determined for the first time in this study. Thermogravimetry was monitored by simultaneous thermal analyser to find that there was no obvious oxidation or combustion reaction in the foundry sand; the thermal decomposition degree increased as the heating rate increased. There was an obvious endothermic peak at about 846 K due to the transition of quartz from β to α phase. A novel technique was established to calculate the starting temperature of volatile emission in determining the volatile release parameter of foundry sand for cast iron. Foundry sand does not readily evaporate because its volatile content is only about 2.68 wt% and its main components have high-temperature stability. The thermal decomposition kinetics parameters of foundry sand, namely activation energy and pre-exponential factor, were obtained under kinetics theory. The activation energy of foundry sand for cast iron was small, mainly due to the wide temperature range of thermal decomposition in the foundry sand.

The Research on the Relationship between the Coal Volatile and the Kinetics Parameters by Thermo-Gravimetric Experiment

2012 ◽  
Vol 512-515 ◽  
pp. 1813-1818
Author(s):  
Li Na Qu ◽  
Yuan Gang Jiang ◽  
Ru Le Gao
Keyword(s):  
Activation Energy ◽  
Coal Combustion ◽  
Spontaneous Combustion ◽  
Volatile Matter ◽  
Coal Spontaneous Combustion ◽  
Thermo Gravimetric ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Internal Mechanism ◽  
The Relationship

Coal spontaneous combustion is a common coal mine disaster, the internal mechanism of coal combustion is revealed better by researched the relationship between the coal volatile and the kinetics parameters. Based on the method of non-isothermal, the coal samples from Jinggezhuang9#, Jinggezhuang11#, Qianjiaying, Tangshan and Tunlan are used the thermo-gravimetric experiment. The relationship between the reactive kinetic parameter and the volatile matter are fond out, when the heating rate is 100C/min. The experiment results illustrate that the more the volatile matter is, the less the activation energy (E) and the Pre Exponential factor (A) are, and the difficulty rank of coal samples of spontaneous combustion is Jinggezhuang9#, Jinggezhuang11#, Tangshan, Qianjiaying, Tunlan.

scholarly journals Thermolysis and Kinetics of Scrap Tyre and Bagasse for Energy Utilization

2013 ◽  
Vol 34 (2) ◽  
pp. 94-101
Author(s):  
Petro Ndalila ◽  
Cuthbet F. Mhilu ◽  
Geoffrey R. John
Keyword(s):  
Activation Energy ◽  
Energy Demand ◽  
Energy Production ◽  
Energy Content ◽  
Combustion Process ◽  
High Energy ◽  
Energy Utilization ◽  
Exponential Factor ◽  
Gasification Process ◽  
Kinetics Of

The increase of energy demand has brought concern to find alternative fuel that will at least sustain the requirement. Bagasse and scrap tyre are waste generated in our industrial activities, which can be used in energy production to subsidize the demand. This paper, aim to study the decomposition behaviour and kinetics of biomass (bagasse) and scrap tyre as preliminary stage of fuel sample analysis to be considered for energy production in gasification/combustion or pyrolysis facilities. The behaviour demonstrated with thermogravimetric analyzer (TGA), shows that all samples have high volatile amount release, 84.21% for bagasse and 85.08% for scrap tyre, which means all are suitable for pyrolysis. However, scrap tyre is most suitable for gasification or combustion due to its high energy content, high ash content and low moisture than bagasse. The determined kinetic parameter were activation energy (E) and pre-exponential factor (A) for hemicellulose/oil as first release composite and cellulose/elastomer as second composite of the analyzed bagasse/scrap tyre samples. The hemicelluloses of bagasse exhibited highest value of activation energy and pre-exponential factor (E=178.191 kJ/mol, and A=1.74×10 16 ) than oil of scrap tyre (E=41.113 kJ/mol, and A= 495.5), which means bagasse is suitable candidate for gasification process due to high operating temperature. With this respect of the study, all candidates may be suitable for pyrolysis or gasification/combustion process. However, for environmental consideration scrap tyre is not suitable due to high sulphur (S) and nitrogen (N) content resulting to high emission ofSOX and NOX .

scholarly journals Thermal Decomposition of 3-Nitro-1,2,4-Triazole-5-One (NTO) and Nanosize NTO Catalyzed by NiFe2O4

2022 ◽  
Author(s):  
Pragnesh N. Dave ◽  
Ruksana Sirach ◽  
Riddhi Thakkar ◽  
Shalini Chaturvedi
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Nickel Catalyst ◽  
Nickel Ferrite ◽  
Peak Temperature ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Nanometer Size ◽  
Co Precipitation

Abstract Nanosize Nickel ferrite (NiF) was synthesized by the co-precipitation methods and its effect as a 5 % by mass additive was studied on the thermal decomposition of micrometer and nanometer size NTO. In the presence of 5 % NiF additive, the thermal decomposition peak temperature of NTO was decreased from 276.36 to 260.18 oC and that of nano NTO was decreased from 261.38 to 258.89 oC (β=10 oC min-1). The kinetics parameters confirms the catalytic activity of NiF for the thermal decomposition of NTO, and nNTO as the parameters such as activation energy (NTO=~25.45 % and nNTO=~45.94 % decrement), and pre-exponential factor (NTO=~21.94 % and nNTO=~43.12 % decrement) were decreased when 5 % NiF additive was added to NTO, and nNTO. The rate of the decomposition process was increased in the presence of 5 % NiF catalyst, indicating the faster thermal decomposition of both NTO, and nNTO in the presence of nickel catalyst.

Kinetics Behavior and Sulfur Transformations of Iron Sulfide during Supercritical Water Oxiation

2012 ◽  
Vol 524-527 ◽  
pp. 1939-1942 ◽  
Author(s):  
Hong He Ma ◽  
Shu Zhong Wang ◽  
Lu Zhou
Keyword(s):  
Activation Energy ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Iron Sulfide ◽  
Reaction Pathway ◽  
Batch Reactor ◽  
Supercritical Water Oxidation ◽  
Experimental Conditions ◽  
Exponential Factor ◽  
Gasification Process

Oxidation of iron sulfide in supercritical water was investigated in the batch reactor. Iron sulfide was converted in two parallel processes: gasification by water and oxidation by oxygen. Assuming that the reaction order of H2O was 0, the activation energy and pre-exponential factor of the gasification process were determined to be 43kJ mol-1 and 22.4 min-1, correspondingly. It is found that above 773K the oxidation process was limited by the mass transfer of O2 to particles surface. Below 773K, with an assumption of zero order in H2O concentration and first-order reaction in oxygen concentration, the activation energy and pre-exponential factor for the rate of oxidation were estimated as154kJ mol-1 and 1.7×106m3 mol-1 min-1, respectively. With supercritical water oxidation under the experimental conditions, the sulfur-containing components in the product were sulfide, sulfite and sulfate, in which sulfide and sulfate were predominant. It is likely to completely convert the sulfur to the sulfate by supercritical water oxidation using high temperature and long reaction time. The reaction pathway of iron sulfide could be expressed as: iron sulfide → sulfide → sulfite → sulfate.

Kinetics Parameters Evaluation of Paraffin-Based Fuel

2012 ◽  
Author(s):  
Genivaldo P. Santos ◽  
Pedro T. Lacava ◽  
Susane R. Gomes ◽  
José Atíllio F. F. Rocco
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Thermo Gravimetric Analysis ◽  
Kinetic Mechanism ◽  
Gravimetric Analysis ◽  
Propulsion Systems ◽  
Kinetics Parameters ◽  
Gaseous Oxygen ◽  
Exponential Factor ◽  
Hybrid Propulsion

In recent years, Hybrid Propulsion is turning into a significant alternative to Liquid and Solid Propulsion Systems, it presents attractive features and good balance between performance and environmental impact. Thus, paraffin based propellant grains are indicated as a substitute for hydroxyl-terminated polybutadiene (HTPB), the actual solid propellant fuel grain. Despite being a well-known material, scarce data on the relation of activation energy (Ea) and molecular weight (WCxHy) of paraffin is available. In this work, the kinetic parameters (activation energy and pre-exponential factor) of microcrystalline 140/145°F paraffin have been raised through Thermo Gravimetric Analysis in conjunction with the Arrhenius kinetic mechanism, according to ASTM-E1461 and the dependence of molecular weight with melting point from Etessam and Sawyer approach. The 140/145°F paraffin activation energy calculated in this study was compared with different activation energy from alkanes and substances used as fuel in the propulsion systems field. The analysis indicated that the microcrystalline 140/145°F paraffin, manufactured by Petrobras, presents activation energy of 224 KJ.mol−1 and pre-exponential factor of 5.48×1022 min−1. Ignition was achieved with a 50 W pyrotechnic igniter. The firing test with 140/145°F paraffin fuel and gaseous oxygen (GOX) mass flux of 130 Kg.s−1 m−2 at pressure above 0.80 MPa, was easily sustained.

scholarly journals Effect of ultrasonic field on isothermal kinetics of fullerene polyhydroxylation

2016 ◽  
Vol 48 (2) ◽  
pp. 259-272 ◽  
Author(s):  
Mihajlo Gigov ◽  
Borivoj Adnadjevic ◽  
Jelena Jovanovic
Keyword(s):  
Activation Energy ◽  
Phase Transfer ◽  
Model Fitting ◽  
Ultrasonic Field ◽  
Conventional Heating ◽  
Isothermal Kinetics ◽  
Ammonium Bromide ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Kinetics Of

The isothermal kinetics of fullerene polyhydroxylation under ultrasonic field was investigated. The isothermal kinetic curves of fullerene polyhydroxylation at different temperatures ranging from 293 K to 313 K were determined. By application of the isoconversion method it was established that the reaction of fullerene polyhydroxylation with sodium hydroxide and cetyl trimethyl ammonium bromide as phase transfer catalyst was kinetically an elementary reaction. The model-fitting method confirmed that the kinetics model of first-order chemical reaction best described the kinetics of fullerene polyhydroxylation under ultrasonic field and the kinetics parameters of fullerene polyhydroxylation were determined (Ea,= 29 kJ/mol and lnA=9.4 min-1). It was established that the reaction rate of fullerene polyhydroxylation under ultrasonic field is higher from 1.5 times to 2.2 times than the rate of comparative reaction under the conventional heating. The activation energy is 28% lower than the value of activation energy determined under the conventional heating, whereas the value of pre-exponential factor is 40 times higher. The decreased value of activation energy (Ea,) and pre-exponential factor (lnA) in the ultrasonic field is explained with the increase in the value of ground energy level of the resonant vibration mode (? = 500 cm-1) of C60 molecule (Ag(1) vibrational mode) and toluene molecule (out-of plane bending C-C-C vibration) and with the decreased value of anharmonicity factor.

Municipal Solid Waste Treatment Using Plasma Gasification with the Potential Production of Synthesis Gas (Syngas)

2019 ◽  
Vol 2 (1) ◽  
pp. 8-12
Author(s):  
Angela Hartati ◽  
Diah Indriani Widiputri ◽  
Arbi Dimyati
Keyword(s):  
Waste Treatment ◽  
Composition Analysis ◽  
Energy Agency ◽  
Plasma Gasification ◽  
Gasification Process ◽  
Solid Waste Treatment ◽  
Pre Treatment ◽  
Waste Separation ◽  
Gasification Efficiency ◽  
Arc Plasma Torch

This research was conducted for the purpose to overcome Indonesia waste problem. The samples are classified into garden waste, paper waste, wood, food waste, and MSW with objective to identify which type of waste give out more syngas since there is waste separation in Indonesia. All samples were treated by plasma gasification without pre-treatment (drying). Arc plasma torch used in this experiment was made by National Nuclear Energy Agency (BATAN) and used Argon as the gas source. Then the torch was connected to self-designed gasification chamber and gas washing system before injected into a gas bas for composition analysis. Another objective is to identify factors that may affect the gasification efficiency and the experiment shows that moisture content is not really affecting the efficiency but the duration of the process. The mass reduction of each samples were recorded, then the gas produced from the gasification process were analyzed. The result shows that food has the highest mass percentage reduced and producing the highest amount of hydrogen amongst other samples. However, treating MSW also produce considerably high amount of hydrogen. In conclusion, MSW direct treatment (without separation) using plasma gasification is feasible since it still produces desirable quality of syngas.

Microscopic Interpretation of Arrhenius Parameters

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Activation Energy ◽  
Transition State ◽  
Transition State Theory ◽  
Average Energy ◽  
Zero Point ◽  
State Theory ◽  
Exponential Factor ◽  
Quantum Tunnelling ◽  
Microscopic Interpretation ◽  
The Difference

This chapter reviews the microscopic interpretation of the pre-exponential factor and the activation energy in rate constant expressions of the Arrhenius form. The pre-exponential factor of apparent unimolecular reactions is, roughly, expected to be of the order of a vibrational frequency, whereas the pre-exponential factor of bimolecular reactions, roughly, is related to the number of collisions per unit time and per unit volume. The activation energy of an elementary reaction can be interpreted as the average energy of the molecules that react minus the average energy of the reactants. Specializing to conventional transition-state theory, the activation energy is related to the classical barrier height of the potential energy surface plus the difference in zero-point energies and average internal energies between the activated complex and the reactants. When quantum tunnelling is included in transition-state theory, the activation energy is reduced, compared to the interpretation given in conventional transition-state theory.

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