scholarly journals Physicochemical, Mineralogy, and Thermo-Kinetic Characterisation of Newly Discovered Nigerian Coals under Pyrolysis and Combustion Conditions

2020 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro ◽  
Segun Ajayi Akinyemi ◽  
Hasan Mohd Faizal ◽  
Mohammed Baba Nasirudeen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Energy Recovery ◽  
Major Elements ◽  
Industrial Applications ◽  
Physicochemical Analysis ◽  
Kinetic Properties ◽  
Exponential Factor ◽  
Minor Elements ◽  
Low Levels

Abstract In this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three (3) newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values (HHV) ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surfaces, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (M L ) ranges from 30.51% – 87.57% and residual mass (R M ) from 12.44% – 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter, vitrinite, inertinite and liptinite macerals. Kinetic analysis revealed that the coal samples are highly reactive under the non-isothermal oxidative and non-oxidative conditions based on the Coats-Redfern Model. The activation energy ( E a ) ranged from 23.81 kJ/mol – 89.56 kJ/mol whereas the pre-exponential factor ( k o ) ranged from 6.77×10 -04 min -1 – 1.72×10 03 min -1 under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either industrial applications or energy recovery.

scholarly journals Physicochemical, Mineralogy, and Thermo-Kinetic Characterisation of Newly Discovered Nigerian Coals under Pyrolysis and Combustion Conditions

2020 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro ◽  
Segun Ajayi Akinyemi ◽  
Hasan Mohd Faizal ◽  
Mohammed Baba Nasirudeen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Energy Recovery ◽  
Major Elements ◽  
Industrial Applications ◽  
Physicochemical Analysis ◽  
Kinetic Properties ◽  
Exponential Factor ◽  
Minor Elements ◽  
Low Levels

Abstract In this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three (3) newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values (HHV) ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surfaces, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (ML) ranges from 30.51% – 87.57% and residual mass (RM) from 12.44% – 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter, vitrinite, inertinite and liptinite macerals. Kinetic analysis revealed that the coal samples are highly reactive under the non-isothermal oxidative and non-oxidative conditions based on the Coats-Redfern Model. The activation energy (Ea) ranged from 23.81 kJ/mol – 89.56 kJ/mol whereas the pre-exponential factor (ko) ranged from 6.77×10 -04 min -1 – 1.72×10 03 min -1 under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either industrial applications or energy recovery.

scholarly journals Physicochemical, mineralogy, and thermo-kinetic characterisation of newly discovered Nigerian coals under pyrolysis and combustion conditions

2021 ◽  
Author(s):  
Bemgba B. Nyakuma ◽  
Aliyu Jauro ◽  
Segun A. Akinyemi ◽  
Hasan M. Faizal ◽  
Mohammed B. Nasirudeen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Energy Recovery ◽  
Major Elements ◽  
Industrial Applications ◽  
Physicochemical Analysis ◽  
Kinetic Properties ◽  
Texture Surface ◽  
Exponential Factor ◽  
Minor Elements ◽  
Low Levels

AbstractIn this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surface, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (ML) ranges from 30.51% to 87.57% and residual mass (RM) from 12.44% to 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter and macerals (vitrinite, inertinite and liptinite). Kinetic analysis revealed the coals are highly reactive under the oxidative and non-oxidative conditions based on the Coats–Redfern Model. The activation energy (Ea) ranged from 23.81 to 89.56 kJ/mol, whereas the pre-exponential factor (ko) was from 6.77 × 10–4/min to 1.72 × 103/min under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either energy recovery or industrial applications.

scholarly journals Pyrolysis and Combustion Characteristics of Newly Discovered Coals from Nigeria: Physicochemical, Microstructure, Mineralogy, and Thermal Properties

2020 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro ◽  
Segun Ajayi Akinyemi ◽  
Hasan Mohd Faizal ◽  
Mohammed Baba Nasirudeen ◽  
...  
Keyword(s):  
Energy Recovery ◽  
Electricity Generation ◽  
Sedimentary Basins ◽  
Major Elements ◽  
Physicochemical Analysis ◽  
Sustainable Growth ◽  
Oxidative Pyrolysis ◽  
Coal Deposits ◽  
Generation Capacity ◽  
Low Levels

Abstract Despite Nigeria’s vast mineral and energy resources, the nation lacks sufficient electricity generation capacity to stimulate sustainable growth and infrastructural development. However, the discovery of vast coal deposits across the nation’s sedimentary basins could provide cheap, reliable, and abundant energy supplies. However, the lack of comprehensive data on the fuel characteristics, energy recovery, and potential emissions of Nigeria’s coals currently hampers the quest for coal-fired electricity generation. Hence, this study examined the physicochemical, microstructural, mineralogical, and thermal fuel properties of three (3) newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria for potential energy recovery through combustion and pyrolysis. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values ranged from 18.65 MJ/kg for AKZ to 26.59 MJ/kg for SHG. Microstructure analysis revealed rough textured and surfaced particles with a glassy lustre ascribed to metals (such as Ti and Fe), quartz, and kaolinite. Mineralogical analyses revealed the major elements (C, O, Si, and Al), along with minor (Ca, Cu, Fe, K, Mg, S, and Ti) associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass losses (ML) ranging from 30.51% to 87.57% and residual mass (RM) from 12.44% to 69.49% under oxidative (combustion) and non-oxidative (pyrolysis) conditions due to the thermal degradation of organic matter and macerals (vitrinite, inertinite and liptinite) during TGA. Overall, the coals are potential feedstocks for energy recovery through pyrolysis and combustion.

Immobilization of Purified Fungal Laccase on Cost Effective Green Coconut Fiber and Study of its Physical and Kinetic Characteristics in Both Free and Immobilized Form

2019 ◽  
Vol 8 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Priyanka Ghosh ◽  
Uma Ghosh
Keyword(s):  
Activation Energy ◽  
Gel Filtration ◽  
Cost Effective ◽  
Industrial Applications ◽  
Kinetic Properties ◽  
Coconut Fiber ◽  
Immobilized Laccase ◽  
Sds Page ◽  
Glutaraldehyde Solution ◽  
Laccase Enzyme

Background: Laccases are important enzymes that have numerous applications in different biotechnological sectors. Objective: The aim was to purify laccase from Aspergillus flavus PUF5, successfully immobilize it on coconut fiber and characterize different physical and kinetic properties under both free and immobilize conditions. Methods: Laccase from A. flavus PUF5 was purified using ammonium sulfate precipitation, followed by DEAE column chromatography and gel filtration using Sephadex G100. The molecular weight was determined through SDS-PAGE (12%). It was immobilized on pretreated coconut fiber through crosslinking by glutaraldehyde (4% v/v). Physical and kinetic parameters like optimum temperature, pH, thermostability, the effect of additives, activation energy, Km and Vmax for free and immobilized laccase were also analyzed. Recycling stability of the immobilized laccase was further determined. Results: The extracellular laccase (65 kDa) was purified up to homogeneity and was immobilized on acid-pretreated coconut fiber by 4% (v/v) glutaraldehyde solution at 30°C, pH 5.0. Activation energy (Ea) of free and immobilized laccase for oxidation of guaiacol was found to be 24.69 and 32.76 kJ mol-1 respectively. Immobilized laccase showed higher melting temperature (Tm) of (82.5°C) than free enzyme (73°C). Km and Vmax for free and immobilized laccase were found to be 0.67 mM, 0.70 mM and 280 U/mg, 336 U/mg respectively when guaiacol was used as substrate. Additionally, in immobilized condition laccase retained ˃80% of its initial activity after use till six repeated cycles. Conclusion: The purified laccase enzyme and the cheap immobilization seem to be a prospective process for different biotechnological and industrial applications.

scholarly journals Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

2015 ◽  
Vol 60 (2) ◽  
pp. 1357-1359 ◽  
Author(s):  
Y. Hongbo ◽  
C. Meiling ◽  
W. Xu ◽  
G. Hong
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Layered Double Hydroxides ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Thermal Kinetic Parameters ◽  
Double Hydroxides ◽  
Kinetics Of ◽  
Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

Study on Kinetics of Nano-Ni(OH)2 Powder Ethanol Desorption Process

2014 ◽  
Vol 1015 ◽  
pp. 509-512
Author(s):  
Feng Pan ◽  
Zai Yuan Li ◽  
Chun Ji Li
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Shape Factor ◽  
Peak Shape ◽  
Desorption Process ◽  
Exponential Factor ◽  
Mechanism Function ◽  
Thermal Analysis Kinetics ◽  
Kinetics Of ◽  
Tga Analysis

This paper studies on the thermal analysis kinetics of nanometer powders ethanol desorption process.The DTA-TG-DTG curves obtain by SDT 2960 Simultaneous DSC-TGA analysis apparatus. Under the condition of N2atmosphere operation and rise temperature velocity was 10°C·min-1. The mechanism functionis used to calculate the kinetics factors. Reaction progressionnwas obtained by calculation of the kissinger peak shape factor method. The results showed that the apparent activation energy of nano-Ni(OH)2was 73.210 kJ·mol-1, the pre-exponential factor was 2.349×1012, the reaction progression was obtained as 1.2767, the kinetic equation is

scholarly journals Kinetics Properties and Thermal Behavior of Pine Sawdust and Municipal Solid Waste

2019 ◽  
pp. 1-9
Author(s):  
Arthur M. Omari ◽  
Baraka Kichonge ◽  
Zephania A. Chaula
Keyword(s):  
Activation Energy ◽  
Waste Management ◽  
Thermal Behavior ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Energy Recovery ◽  
Human Society ◽  
Exponential Factor ◽  
Pine Sawdust ◽  
Temperature Ranges

Waste resulting from economic activities has been an integral part of every human society. Effective waste management is considered to be consistent with improved quality of life through removal of potential hazards of uncontrolled disposal. Recent years has witnessed a number of sustainable energy recovery technologies developed to divert solid waste destined for landfills. Waste management is a global problem and therefore development of energy recovery technologies and at the same time serving dual purpose in its reduction has become a priority in recent years. The present study reports kinetics properties and thermal behavior of pine sawdust and municipal solid waste (MSW) using thermogravimetric analysis (TGA) and thus providing theoretical basis for development of energy recovery technologies. Results of this study have shown that the activation energy of both MSW and pine sawdust varies with temperature. The analysis of pine sawdust shows that it has activation energy (Ea) values of 26.19 kJ/mol., 87.46 kJ/mol. and 54.46 kJ/mol. At respective temperature ranges between 350 – 400K, 550 – 650K and 700 800K.  MSW has activation energy between 72.91 kJ/mol. and 139.1 kJ/mol. at temperature ranges between 700 – 900 K and 500 – 600 K respectively. The estimated value of pre-exponential factor for pine sawdust was determined to have the values of 2.46 x 104, 1.6 x 1010 and 5.32 x 1016 (s-1) with temperature ranges between 350 – 400 K, 550 – 650 K and 700 800 K respectively. Municipal solid waste has the values of 3.01 x 1012 and 7.31 x 103 (s-1) with a temperature range of 500 – 600 K and 700 – 900 K respectively. From these findings, it has been determined that MSW and pine sawdust available in Arusha and Kilimanjaro possess energy recovery potentials.

scholarly journals Laser Induced Breakdown Spectroscopy and PIXE for Differentiation Between Different Tungsten Alloys

2019 ◽  
Vol 16 (1) ◽  
pp. 212-220
Author(s):  
Ahmed Galmed
Keyword(s):  
Major Elements ◽  
Industrial Applications ◽  
Tungsten Alloys ◽  
Analytical Technique ◽  
Breakdown Spectroscopy ◽  
Minor Elements ◽  
Analysis Technique ◽  
Laser Induced Breakdown ◽  
Increasing Demand ◽  
Trace And Minor Elements

Tungsten is one of the hardest metals that has high melting point and high thermal conductivity. These unique properties make it suitable for many industrial applications. The increasing demand for using tungsten made the need for a fast and reliable analytical technique for tungsten to increase. In this paper we are comparing the ability of LIBS as a multi-elemental analysis technique to PIXE which is a well known established multi-elemental technique in the analysis of tungsten alloys. It was found that LIBS has the advantage over PIXE in the detection of the trace and minor elements. While PIXE is better than LIBS in the detection of major elements in the samples.

scholarly journals EVALUASI KINETIKA DEKOMPOSISI TERMAL PROPELAN KOMPOSIT AP/HTPB DENGAN METODE KISSINGER, FLYNN WALL OZAWA DAN COATS - REDFREN

2018 ◽  
Vol 15 (2) ◽  
pp. 115
Author(s):  
Wiwiek Utami Dewi
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Catalytic Effect ◽  
Nitrogen Atmosphere ◽  
Decomposition Kinetic ◽  
Exponential Factor ◽  
Random Nucleation ◽  
Mechanism And Kinetics ◽  
The Individual ◽  
Individual Particles

Decomposition of propellant Mechanism and kinetics have been investigated by using DTG/TA with three different methods: Kissinger, Flynn Wall Ozawa and Coats & Redfern. This research aims to determine decomposition kinetic parameters of LAPAN’s propellant. The propellants have different composition of Al and AP modal. RUM propellant consist of AP/HTPB. 450 propellant consists AP/HTPB/Al (bimodal). Meanwhile 1220 propellant consists of AP/HTPB/Al (trimoda). Thermal analysis takes place at 30 – 400oC and nitrogen atmosphere flow rate is 50 ml/min. The result according showed that propellant was decomposed by F1 mechanism (random nucleation with one nucleus on the individual particles). Activation energy of propellants are in range between 100.876 – 155.156 kJ/mol meanwhile pre-exponential factor are in range between 4.57 x 107 – 3.46 x 1012/min. Activation energy (E) as well as pre-exponential factor for 1220 propellant is the lowest among the others. AP trimodal application generates catalytic effect which decreases activation energy. 1220 propellant is easier to decompose (easier to react) than RUM and 450 propellant. AbstrakMekanisme dan kinetika dekomposisi propelan telah diinvestigasi menggunakan DTG/TA dengan tiga jenis metode yang berbeda yaitu Kissinger, Flynn Wall Ozawa dan Coats & Redfern. Penelitian ini bertujuan untuk mengetahui parameter kinetika dekomposisi propelan LAPAN. Propelan yang digunakan memiliki perbedaan komposisi Al dan jenis moda AP. Propelan RUM adalah propelan AP/HTPB. RX 450 adalah AP/HTPB/ Al (bimoda). Sementara itu, RX 1220 adalah AP/HTPB/ Al (trimoda). Pengujian termal berlangsung pada suhu 30 - 400oC dan atmosfer nitrogen berlaju alir 50 ml/menit. Hasil penelitian mengungkapkan bahwa semua jenis propelan terdekomposisi dengan mekanisme F1 (nukleasi acak dengan satu nukleus pada partikel individu). Energi aktivasi propelan berkisar antara 100,876 – 155,156 kJ/mol sementara faktor pre-eksponensial berkisar antara 4,57 x 107 – 3,46 x 1012/min. Energi aktivasi (E) dan faktor pre-eksponensial (A) RX 1220 adalah terendah dari ketiga sampel. Penggunaan jenis AP trimodul menciptakan efek katalitik yang menurunkan besarnya energi aktivasi. Propelan RX 1220 lebih mudah terdekomposisi (lebih mudah bereaksi) daripada propelan RUM dan RX 450. 

PHASE EQUILIBRIUM IN THE AS2TE3-TM2TE3 SYSTEM.

2020 ◽  
Vol 5 (8(77)) ◽  
pp. 65-68
Author(s):  
Teymur Mammad Ilyasly ◽  
Rahman Hasanaga Fatullazade ◽  
Zakir Islam Ismailov ◽  
Nigar Nadir Jafarova
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Phase Equilibrium ◽  
Physicochemical Properties ◽  
Thermal Effects ◽  
Isothermal Annealing ◽  
Intermediate Phase ◽  
Physicochemical Analysis ◽  
Two Phases

The synthesis of alloys of the system was carried out stepwise in rotary furnaces. The synthesis mode was selected based on the physicochemical properties of the elementary components. For homogenization, the alloys were subjected to isothermal annealing at 750 and 1275 K, depending on the Tm2Te3 concentration, for 250 h after homogenization of the alloys, they were subjected to physicochemical analysis. The results of differential thermal analysis showed that reversible thermal effects are observed in the alloys of the system. In alloys in a 1: 1 ratio, a new intermediate phase is formed with a composition corresponding to the TmAsTe3 compound. The homogeneity area is observed in the concentration range 52.5-47.5. It was found that in the concentration range 98.5-52.5 Tm2Te3 there are two phases - a mixture of β and of the solid solution, and in the concentration range of 47.51 mol% Tm2Te3 phases and α are in equilibrium. ) 66 The eutectic has coordinates of 11.5 mol Tm2Te3 at a temperature of 575 K.

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