scholarly journals Co-Combustion Studies of Low-Rank Coal and Refuse-Derived Fuel: Performance and Reaction Kinetics

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3796
Author(s):  
Mudassar Azam ◽  
Asma Ashraf ◽  
Saman Setoodeh Setoodeh Jahromy ◽  
Sajjad Miran ◽  
Nadeem Raza ◽  
...  
Keyword(s):  
Activation Energy ◽  
Waste Management ◽  
Energy Demand ◽  
Power Plants ◽  
Combustion Process ◽  
Isoconversional Methods ◽  
Low Rank ◽  
Heating Rates ◽  
Average Activation Energy ◽  
Refuse Derived Fuel

In connection to present energy demand and waste management crisis in Pakistan, refuse-derived fuel (RDF) is gaining importance as a potential co-fuel for existing coal fired power plants. This research focuses on the co-combustion of low-quality local coal with RDF as a mean to reduce environmental issues in terms of waste management strategy. The combustion characteristics and kinetics of coal, RDF, and their blends were experimentally investigated in a micro-thermal gravimetric analyzer at four heating rates of 10, 20, 30, and 40 °C/min to ramp the temperature from 25 to 1000 °C. The mass percentages of RDF in the coal blends were 10%, 20%, 30%, and 40%, respectively. The results show that as the RDF in blends increases, the reactivity of the blends increases, resulting in lower ignition temperatures and a shift in peak and burnout temperatures to a lower temperature zone. This indicates that there was certain interaction during the combustion process of coal and RDF. The activation energies of the samples were calculated using kinetic analysis based on Kissinger–Akahira–Sunnose (KAS) and Flynn–Wall–Ozawa (FWO), isoconversional methods. Both of the methods have produced closer results with average activation energy between 95–121 kJ/mol. With a 30% refuse-derived fuel proportion, the average activation energy of blends hit a minimum value of 95 kJ/mol by KAS method and 103 kJ/mol by FWO method.

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.

scholarly journals Activation Energy Determination in Case of Independent Complex Kinetic Processes

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 738 ◽  
Author(s):  
Luciano ◽  
Svoboda
Keyword(s):  
Activation Energy ◽  
Kinetic Data ◽  
Kinetic Curve ◽  
Real Life ◽  
Isoconversional Methods ◽  
Heating Rates ◽  
Complex Process ◽  
Inflection Points ◽  
Kinetic Processes ◽  
Energy Determination

Theoretically simulated kinetic data were used to evaluate the performance of the most common isoconversional methods of kinetic analysis in complex-process scenarios with two independent overlapping processes exhibiting nucleation-growth kinetics, and further expand the conclusions for the autocatalytic kinetic processes with positive asymmetry. In close-to-real-life situations all the integral isoconversional methods provided practically indistinguishable E-α outcomes. The Friedman and incremental modified Vyazovkin methods results in significant over- and undershoots. However, the combined utilization of the integral and differential isoconversional methods was demonstrated to greatly contribute to the interpretation of the E-α dependences and estimation of E1 and E2—the conceptual evaluation involving positions of inflection points and plateaus is introduced. The influence of the range of applied heating rates q+ on the course of E-α dependences was studied. In this regard, the performance of the isoconversional methods changes significantly with both, the consistence of the shape of the complex kinetic curve and weighted presence of full overlaps of the involved sub-processes.

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 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 Coal deposits of Turkey: properties and importance on energy demand

2013 ◽  
Vol 47 (4) ◽  
pp. 2111 ◽  
Author(s):  
R. G. Oskay ◽  
H. Inaner ◽  
A. I. Karayigit ◽  
K. Christanis
Keyword(s):  
Energy Supply ◽  
Energy Demand ◽  
Electricity Generation ◽  
Power Plants ◽  
Fossil Fuels ◽  
Thermal Power ◽  
Low Rank ◽  
Coal Deposits ◽  
Coal Reserves ◽  
Low Rank Coals

In the last two decades electricity generation and consumption in Turkey was increasing steadily. Around 80% of the electricity generated is derived from fossil fuels such as imported natural gas and oil, and domestic coal. As the energy policy now is focusing on reducing the dependency on imported fuels, coal, particularly this of low-rank, is becoming important for the country. Latest explorations showed that total coal reserves of Turkey reach to 13 Gt with low-rank coals (i.e. lignite and sub-bituminous) being dominant. Coal deposits, formed under various conditions and in various geological times, are widely spread over the territory. The most significant deposits are of Tertiary, especially Neogene age. Neogene coals are most appropriate for combustion in the thermal power plants due to the high total reserves despite the high ash yields and the low calorific values. We imply that applying reasonable exploitation planning and appropriate washing techniques, coal will play a key role in future energy supply of the country.

scholarly journals Utilization of Refuse Derived Fuel for Energy Recovery Processes: Prediction of Environmental Emissions and Thermal Behaviour in Combustion Processes

2021 ◽  
Author(s):  
Deepak Kumar Singhal ◽  
Divya Gupta ◽  
Anurag Garg
Keyword(s):  
Power Plants ◽  
Combustion Process ◽  
Calorific Value ◽  
Environmental Parameters ◽  
Fuel Mixture ◽  
Gravimetric Analysis ◽  
Recovery Processes ◽  
Refuse Derived Fuel ◽  
Environmental Emissions ◽  
Msw Composition

Abstract In the present study, the environmental emissions from co-combustion of refuse derived fuel (RDF) in cement plants and coal-fired power plants are predicted using mass and energy flow modeling. Mumbai was considered as study area and RDF characteristics were assessed using MSW composition in Mumbai. The modeling results suggested that with increase in RDF share in fuel mixture, significant reduction in environmental parameters such as winter smog, global warming and acidification potentials could be achieved, though the electricity and heat generation were reduced. This problem can be overcome by improving the quality of RDF. Moreover, thermal gravimetric analysis (TGA) of individual RDF components (compostable organic matter, paper, wood and plastic) was carried out in oxidative environment to understand their thermal stability. Average activation energies for plastic, wood and compostable organics (98.6–183 kJ/mol) were comparable to those reported for coal. The results suggest that coal and RDF co-combustion should not affect the combustion profile. Moreover, high plastic content in RDF can assist in control of combustion process and also can enhance its calorific value.

scholarly journals Experimental and Numerical-Driven Prediction of Automotive Shredder Residue Pyrolysis Pathways toward Gaseous Products

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1779
Author(s):  
Rafał Ślefarski ◽  
Joanna Jójka ◽  
Paweł Czyżewski ◽  
Michał Gołębiewski ◽  
Radosław Jankowski ◽  
...  
Keyword(s):  
Laminar Flame ◽  
Flame Temperature ◽  
Combustion Process ◽  
Calorific Value ◽  
Pyrolysis Process ◽  
Heating Rates ◽  
Shredder Residue ◽  
Gaseous Products ◽  
Refuse Derived Fuel ◽  
Automotive Shredder Residue

There has been a gradual increase in the field of parts recovery from cars that are withdrawn from use. However, the disposal of automotive shredder residue (ASR) still remains a significant problem. ASR is refuse derived fuel (RDF), which contains mainly plastics, fiber sponges, and rubbers in different proportions, and therefore a thermal treatment of selected waste samples is applied. The presented research includes thermogravimetry (TG) analysis and differential thermogravimetric (DTG) analysis, as well as a proximate and an ultimate analysis of the ASR samples. The obtained results were processed and used as an input for modelling. The numerical calculations focused on the identification of the ASR’s average composition, the raw pyrolysis process product, its dry pyrolytic gas composition, and the combustible properties of the pyrolytic gases. The TGA analysis with three heating rate levels covered the temperature range from ambient to 800 °C. The thermal decomposition of the studied samples was in three stages confirmed with three peaks observed at the temperatures 280, 470, and 670 °C. The amount of solid residue grew with the heating rates and was in the range of 27–32 wt%. The numerical calculation of the pyrolysis process showed that only 0.46 kg of dry gas were formed from 1 kg of ASR. The gas yield increased with the rising temperature, and, at the same time, its calorific value decreased from 19.22 down to 14.16 MJ/m3. This is due to the decomposition of C6+ hydrocarbons and the promotion of CO formation. The thermodynamic parameters of the combustion process for a pyrolytic gas air mixture, such as the adiabatic flame temperature and laminar flame speed, were higher than for methane and were, respectively, 2073 °C and 1.02 m/s.

scholarly journals Kinetics of walnut shells through Pyrolysis Assessed as an alternative Bio-fuel

2020 ◽  
Vol 9 (5) ◽  
pp. 593-601
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Potential Candidate ◽  
Heating Rates ◽  
Degradation Behaviour ◽  
Exponential Factor ◽  
Average Activation Energy ◽  
Walnut Shells ◽  
Biomass Residues ◽  
Reaction Processes

Biomass residues have potential to be used as an alternative solid fuel for various processes, also will be responsible for the optimization of the pyrolysis reaction processes, giving insight into the pyrolysis mechanisms and aiding in engineering efforts. There are different methods for production of bio-fuel from biomass residues; however before the production of bio-fuels from biomass it is important to understand their thermal degradation and kinetics. In the present work the Kinetics studies of four different walnut shells, namely, paper (PSW), thin (TSW), medium (MSW) and hard (HSW) shelled walnuts have been studied. Thermal degradation behaviour of walnut shells is investigated using thermogravimetric analysis (TGA) under three different heating rates (30, 60 and 100 0Cmin−1 ) in an oxidizing atmosphere to understand the kinetic behavior. Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) methods were used to estimate the kinetic parameters such as Pre-exponential factor (R) and average activation energy (Ea ) using TGA data of active zone. The average activation energy of biomass obtained from PSW, TSW, MSW and HSW using KAS method were 198.25, 184.21, 180.93, and 152.79 kJ mol−1 , respectively. Whereas by OFW method the values were found to be 204.10, 186.28, 188.39 and 153.78 kJ mol−1 respectively. Thus the present investigation may be useful for its use as a renewable energy source and potential candidate for fuel production by thermo-chemical processes.

scholarly journals The environmental impact of refuse derived fuel co-combustion with lignite

2018 ◽  
Vol 240 ◽  
pp. 05013
Author(s):  
Piotr Krawczyk ◽  
Krzysztof Badyda ◽  
Aleksandra Mikołajczak
Keyword(s):  
Environmental Impact ◽  
Power Plants ◽  
Combustion Process ◽  
Combustion Products ◽  
Legal Regulations ◽  
Environmental Footprint ◽  
Energy Potential ◽  
Environmental Footprints ◽  
Refuse Derived Fuel ◽  
Refuse Derived Fuels

Legal regulations on waste disposal require waste producers to limit landfilling and to find different ways of waste management, the preferred methods being recycling of material and energy potential. Currently, in Poland, the only consumers of refuse-derived fuels (RDF) are cement plants. However, their ability to utilize alternative fuel is far from the estimated potential. One solution would be to redirect the excess fuel to power and heat production facilities. Unfortunately, these sectors are facing a number of problems related to the thermal treatment of waste, mainly formal nature. Co-combustion of waste in power plants raises a lot of concern among their employees and local communities. Especially significant is the harmfulness of usage of fuel from waste for the people’s lives or health, or the environment. The article compares the environmental footprints of the combustion process of: waste - based fuel (RDF) and lignite. The analysis was performed for a standard pulverized coal fired boiler. Comparative assessment was made by analyzing the total environmental impact of all combustion products of the two fuels. Final results have shown, that the environmental footprint of waste-based fuels can be similar or even smaller than traditional coal-based fuels

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