Bemgba B Nyakuma | Universiti Teknologi Malaysia - UTM (original) (raw)

Papers by Bemgba B Nyakuma

Petroleum & Coal, 2024

In this study, the compositional, structural, mineralogical and thermal characterisation of the n... more In this study, the compositional, structural, mineralogical and thermal characterisation of the newly discovered Duduguru (DDG) coal from Nasarawa State was conducted to examine its fuel and energy utilisation potentials. The compositional examination involved elemental, proximate, and calorific analyses, whereas microstructure/morphology and mineralogy were determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), respectively. The thermal examination involved heating the pulverised DDG coal from 25-900 °C using air (flowrate ɸ = 20 mL/min) to examine its combustion characteristics. Results revealed DDG contains high carbon (>60 wt.%) and hydrogen (>5
wt.%), fixed carbon (>52 wt.%) and higher heating value (>28 MJ/kg) but relatively low nitrogen (<1.5 wt.%) and sulphur (<1 wt.%) contents. TGA revealed that DDG experienced significant thermal degradation, resulting in high weight loss (~83%) and low residual mass (~17%). Weight loss was
ascribed to the degradation of macerals in DDG. The TG plot indicated onset, midpoint, and offset temperatures of 335.54°C, 538.72°C, and 708°C, respectively. The DTG plot revealed thermal degradation occurred in two major phases: stage I (25-200°C) and stage II (200-900°C), which was
ascribed to drying/low-temperature degradation and macerals degradation, respectively. Overall, the findings demonstrate that the newly discovered DDG coal is suitable for energy recovery and utilisation
in future power plants. Future studies could investigate the kinetic and thermodynamic properties of DDG coal often required in reactor design and optimisation for energy generation.

Journal of Natural Fibers, 2022

The generationof biogas from faecal wastes currently offers limited economic and environmental be... more The generationof biogas from faecal wastes currently offers limited economic and environmental benefits to low-income households. The production of biochar from faecal waste is a sustainable alternative to firewood to replace charcoal that is widely utilised for cooking in households in Nigeria. Similarly, biochar production from faecal wastes presents a clean and renewable alternative approachfor creating value from faecal waste. Furthermore, this presents cost-effective recovery, containment, and management of faecal waste. Therefore, the objective of this study is to investigate the existing faecal waste management practices by households in Ogun State, Nigeria. It will also examine perceptions of households to faecal waste as a valuable resource, in either its raw or processed form for energy applications. Based on the multi-stage sampling approach, a total of 165 questionnaires were administered to representative households in the study area. Consequently, a total of 55, 50, an...

DRC Sustainable Future: Journal of Environment, Agriculture, and Energy, 2021

Botanicals are substances extracted from plants for use in various applications, such as the prod... more Botanicals are substances extracted from plants for use in various applications, such as the production of insecticides. Botanical insecticides (BIs) have recently attracted awareness in pest management owing to their potential to substitute synthetic pesticides. BIs are eco-friendly and more sustainable due to their ability to breakdown after use without generating toxic residues and diverse approach actions on targeted pests. Nevertheless, BIs are still not readily accepted, because the supporting proofs are very traditional, raising doubts about their quality. Additionally, the phytochemical variations of plants yield uneven and sometimes unfamiliar pesticide activity. This paper discusses challenges to overcome and presents the most noteworthy knowledge on BIs, their standardization, quality control, and bio- enhancement to be useful in agriculture and to improve human health.

Environmental Progress & Sustainable Energy, 2021

Journal of Criminal Justice Education, 2013

Learning how to effectively write a literature review is a critical tool for success for an acade... more Learning how to effectively write a literature review is a critical tool for success for an academic, and perhaps even professional career. Being able to summarize and synthesize prior research pertaining to a certain topic not only demonstrates having a good grasp on available information for a topic, but it also assists in the learning process. Although literature reviews are important for one's academic career, they are often misunderstood and underdeveloped. This article is intended to provide both undergraduate and graduate students in the criminal justice field specifically, and social sciences more generally, skills and perspectives on how to develop and/or strengthen their skills in writing a literature review. Included in this discussion are foci on the structure, process, and art of writing a literature review. What is a Literature Review? In essence, a literature review is a comprehensive overview of prior research regarding a specific topic. The overview both shows the reader what is known about a topic, and what is not yet known, thereby setting up the rationale or need for a new investigation, which is what the actual study to which the literature review is attached seeks to do. Stated a bit differently (Creswell 1994, pp. 20, 21) explains: The literature in a research study accomplishes several purposes: (a) It shares with the reader the results of other studies that are closely related to the study being reported (Fraenkel & Wallen, 1990. (b) It relates a study to the larger, ongoing dialog in the literature about a topic, filling in gaps and extending prior studies (Marshall & Rossman, 1989). (c) It provides a framework for establishing the importance of the study.

Environmental Science and Pollution Research

Through administrative research and media records, this paper aims to examine and highlight the e... more Through administrative research and media records, this paper aims to examine and highlight the effects of the COVID-19 pandemic on Malaysian workers, property development, construction sites, and the national economy. The development of real estate and the construction industry can significantly impact socioeconomic growth and infrastructure development. Adequate building and infrastructure construction can ensure national economic stability, job creation, community cohesion, and higher living standards. Since the COVID-19 pandemic began in 2019, many countries, including Malaysia, have reported an increased number of virus cases. According to the Ministry of Health, 9316 cases and 314 COVID-19 clusters were discovered in Malaysia, with a 38.55-48.06% prevalence for factories, a 12.55-15.29% prevalence for community spreading, an 8.6-11.56% prevalence for construction sites, a 5.53-7.96% prevalence for educational sites, and a 7.01% prevalence for shopping areas. Several governments-imposed lockdowns, movement, and proximity restrictions during the pandemic due to the high infection rates at property development sites. However, due to inactivity in various sectors such as the construction industry, these measures have significantly impacted the national economy. As a result, the pandemic has had an impact on workers, production costs, and project completion timelines, resulting in operational issues and policy concerns. Overall, the records reviewed revealed that the COVID-19 pandemic has significantly impacted real estate development, the housing market, and the construction industry. As a result, sustained and targeted policies are required to support Malaysia's construction industry's socioeconomic growth and infrastructure development.

Sustainability, 2022

Numerous researchers have described the correlation between the short-term contact of nano-partic... more Numerous researchers have described the correlation between the short-term contact of nano-particulate (NP) matter in diverse coal phases and amplified death or hospitalizations for breathing disorders in humans. However, few reports have examined the short-term consequences of source-specific nanoparticles (NPs) on coal mining areas. Advanced microscopic techniques can detect the ultra-fine particles (UFPs) and nanoparticles that contain potential hazardous elements (PHEs) generated in coal mining areas. Secondary aerosols that cause multiple and complex groups of particulate matter (PM10, PM2.5, PM1) can be collected on dry deposition. In this study, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) were employed to detect and define the magnitude of particulate matters on restaurants walls at coal mines due to weathering interactions. The low cost self-made passive sampler (SMPS) documented several minerals and amorphous phases. The ...

Physics and Chemistry of Solid State, 2022

The objective of this study is to examine the potential product yields and energy recovery of mai... more The objective of this study is to examine the potential product yields and energy recovery of maize cobs (MC) through carbon dioxide-assisted torrefaction using thermogravimetric analysis (TGA). The CO2-assisted torrefaction of MC was performed from 240 °C to 300 °C (Δ 30 °C) for the residence time of 30 minutes based on the selected non-isothermal/isothermal heating program of the TGA. Furthermore, the physicochemical, microstructure and mineral characteristics of MC were examined. The results showed that the CO2-torrefaction of MC resulted in a mass loss (ML) ranging from 18.45% to 55.17%, which resulted in the mass yield (MY) ranging from 81.55% to 44.83%. The HHV of the solid product was in the range from 22.55 MJ/kg to 26 MJ/kg, which indicates the CO2-torrefaction process enhanced the energy content of MC by 40% – 60%. In conclusion, the findings showed that the CO2 torrefaction is a practical, sustainable, and cost-effective approach for the valorization of MC into a clean so...

Chemical engineering transactions, 2017

The National Biomass Strategy was envisioned to foster the efficient valorisation and management ... more The National Biomass Strategy was envisioned to foster the efficient valorisation and management of Oil Palm Waste (OPW) in Malaysia. However, the proposed Circular Energy Economy is hampered by poor OPW fuel properties, inefficient conversion techniques, and process design. This study explored the valorisation of Oil Palm Empty Fruit Bunches (OPEFB) Briquettes through fluidised bed gasification with the aim of exploiting the superior qualities of pelletised biomass and excellent reactor dynamics of fluidised beds. Gasification of OPEFB Briquettes was examined from 600 – 800 °C and equivalence ratio, ER is 0.20 – 0.25 under atmospheric pressure. The fuel properties and chemical exergy of OPEFB briquettes were characterised. The gasification of OPEFB briquettes produced high biochar yield and bio syngas with higher heating value from 1.15 – 3.05 MJ/m3 whereas the Cold Gas Efficiency (CGE) and Carbon Conversion Efficiency (CCE) ranged from 6.54 – 17.34 % and 43.37 – 78.16 %. Bed agglo...

Journal of African Earth Sciences, 2021

Selected coal samples from the Benue Trough Basin (Nigeria) were analysed by X-ray photoelectron ... more Selected coal samples from the Benue Trough Basin (Nigeria) were analysed by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), Fourier transform-infrared spectroscopy (FT-IR), and all the techniques used. The main minerals detected are clays (e.g., kaolinite and illite), quartz, feldspar , hematite and magnetite with traces of calcite, siderite , dolomite, orthoclase and graphite. The authigenic and detrital origins of the clay minerals detected were confirmed by FT-IR analysis. The XPS spectra identified elements similar to the mineral phases observed in the XRD spectra. The contents of Al 2O3, CaO, Fe2O3, K2O, Na2O and P2O5 were below the values reported for US and Chinese coals. The elemental indexes (e.g. Al2O3/TiO2 , Co/Th vs. La/Sc, Cr/Th vs. Sc/Th) showed that the influence of intermediate-mafic materials derived from source-region sediments is negligible. The Ni/Co ratio showed that the c...

The rare earth elements (REE) possess a beneficial combination of chemical and physical propertie... more The rare earth elements (REE) possess a beneficial combination of chemical and physical properties, making them valuable for most advanced branches of engineering and technology. Alternative sources of REE are desirable due to limited reserves of conventional REE containing minerals over the world combined with disproportionate supply over demand in the commodity markets. This study investigated the occurrence of REE and carbon nanotubes (CNTs) in Cretaceous Nigerian coals for prospective industrial applications. Results show that the coals’ crystalline mineral matter comprises quartz, kaolinite, and illite with minor quantities of feldspar, hematite, magnetite, calcite, dolomite, which indicate detrital mineral origins. Elemental relationships (such as Al2O3/TiO2, Cr/Th vs. Sc/Th, and Co/Th vs. La/Sc) suggest sediment-source regions with mafic, intermediate or felsic compositions. REE are either strongly fractionated or characterized by light-enrichment along with outlook coefficie...

Energy Geoscience, 2021

The erratic supply of electricity in Nigeria has renewed interest in the utilisation of coal for ... more The erratic supply of electricity in Nigeria has renewed interest in the utilisation of coal for energy selfsufficiency and diversification of the national energy mix. In this study, selected coal samples from three regions of the Benue Trough Basin were examined through pore water chemistry, X-ray diffraction (XRD), and thermosgravimetric analysis (TGA). The low pH observed for the Lower Benue Trough (LBT) coals indicates the release of sulphur and acids during oxidation. Mineralogical analyses reveal quartz, kaolinite, montmorillonite, albite, pyrite, gypsum and sodium chlorate in the coal samples. The genetic kaolinite species identified in Imeagha (IMG) coal are detrital kaolinite and the highly crystalline neomorphic kaolinite. Gypsum and jarosite minerals occurred in minor quantities in Garin Maiganga (GMG), whereas significant amount of pyrite was detected in Enugu (ENG) coal. Oxidative thermal degradation resulted in the residual mass (R M) ranging between 4.35% and 56.96%) and mass losses (M L) between 43.04% and 95.65%) due to the drying, devolatilization, and coke formation in the samples. The most reactive coal examined was GMG coal, whereas the least reactive was IMG coal. Lamja (LMZ), GMG, and OKB coals are suited for electricity generation, whereas ENG and IMG coals can be utilised for cement production.

Jurnal Teknologi, 2016

Gasification of Oil Palm Empty Fruit Bunches (OPEFB) briquettes was investigated in an air blown ... more Gasification of Oil Palm Empty Fruit Bunches (OPEFB) briquettes was investigated in an air blown 4.5 kW allothermal fluidized bed gasifier to examine the effects of bed temperature (600 – 800 °C) and equivalence ratio (λ = 0.25) on bio-syngas yield and composition. In addition, physicochemical and thermochemical characterization of the fuel properties of the OPEFB briquettes were also examined. The results demonstrate that pelletization improved the solid biomass fuel (SBF) properties of OPEFB including moisture content and higher heating value (HHV). The gasification of OPEFB briquettes produced bio-syngas comprising H2, CO, CO2, CH4 as well as solid biochar with a HHV higher than the original OPEFB briquettes. The highest yield of H2 was obtained at 600 °C while HHV of the bio-syngas was within the range 4 - 8 MJ/Nm3 for air gasification in fluidized bed gasifiers. In addition, agglomeration of bed materials did not occur during OPEFB briquettes gasification despite its high bed a...

Jurnal Teknologi, 2016

This paper investigated the production of biohydrogen from Imperata cylindrica, using stoichiomet... more This paper investigated the production of biohydrogen from Imperata cylindrica, using stoichiometric equilibrium model. The stoichiometric equilibrium model uses biomass ultimate analysis, thermodynamic equilibrium and elemental balance on biomass gasification reaction. The sensitivity analysis was studied over a wide range of operating conditions involving temperature (250 – 1500 °C), pressure (1 – 5 atm) and Steam to fuel ratio (0-5). The result shows biohydrogen and other biogas product were sensitive to temperature and steam-feed ratio, whereas effect of pressure is negligible. The operating condition for optimal biohydrogen production in moles (23%) was atmospheric pressure, temperature, 1500 °C and steam-feed ratio, 5. Biogas product mixtures are H2, 23%, CO, 17%, CO2, 12% CH4, 0% and H2O, 60%. Increase in steam-feed ratio (0, 1, 2, 3, 4 and 5) significantly increase the biohydrogen by 1381%, 90%, 46%, 31% and 24%. The stoichiometry equilibrium model could effectively be used...

Jurnal Teknologi, 2016

This study is the first attempt at investigating the solid state decomposition and the devolatili... more 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 K...

Energy, 2015

The NBP (National Biofuel Policy) of Malaysia was established in 2006 to promote the sustainable ... more The NBP (National Biofuel Policy) of Malaysia was established in 2006 to promote the sustainable production and utilization of environmentally friendly biofuels. Despite numerous government incentives and subsidies, biodiesel exports have declined significantly over the years. This paper seeks to critically examine challenges afflicting the biodiesel industry in Malaysia by analysing the key policies, framework and institutions in the country. High feedstock prices, competition with food, engine compatibility, fuel subsidies and crude oil prices were identified as the challenges hindering biodiesel development in Malaysia. The authors propose that environmental, socioeconomic and technological reforms are required to address the challenges and improve the long term prospects of the Malaysian biodiesel industry. Furthermore, the utilization of biodiesel in the Real sector, biodiesel infrastructure investments and technological innovations will safeguard Malaysia's energy security, promote cleaner environment, improve living standards and stimulate stakeholder participation in the future development, diffusion and adoption of biodiesel in Malaysia.

Chemistry & Chemical Technology, 2016

The study is aimed at investigating the thermal behavior and decomposition kinetics of torrefied ... more The study is aimed at investigating the thermal behavior and decomposition kinetics of torrefied oil palm empty fruit bunches (OPEFB) briquettes using a thermogravimetric (TG) analysis and the Coats-Redfern model. The results revealed that thermal decomposition kinetics of OPEFB and torrefied OPEFB briquettes is significantly influenced by the severity of torrefaction temperature. Furthermore, the temperature profile characteristics; Tonset, Tpeak, and Tend increased consistently due to the thermal lag observed during TG analysis. In addition, the torrefied OPEFB briquettes were observed to possess superior thermal and kinetic properties over the untorrefied OPEFB briquettes. It can be inferred that torrefaction improves the fuel properties of pelletized OPEFB for potential utilization in bioenergy conversion systems.

Petroleum & Coal, 2024

In this study, the compositional, structural, mineralogical and thermal characterisation of the n... more In this study, the compositional, structural, mineralogical and thermal characterisation of the newly discovered Duduguru (DDG) coal from Nasarawa State was conducted to examine its fuel and energy utilisation potentials. The compositional examination involved elemental, proximate, and calorific analyses, whereas microstructure/morphology and mineralogy were determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), respectively. The thermal examination involved heating the pulverised DDG coal from 25-900 °C using air (flowrate ɸ = 20 mL/min) to examine its combustion characteristics. Results revealed DDG contains high carbon (>60 wt.%) and hydrogen (>5
wt.%), fixed carbon (>52 wt.%) and higher heating value (>28 MJ/kg) but relatively low nitrogen (<1.5 wt.%) and sulphur (<1 wt.%) contents. TGA revealed that DDG experienced significant thermal degradation, resulting in high weight loss (~83%) and low residual mass (~17%). Weight loss was
ascribed to the degradation of macerals in DDG. The TG plot indicated onset, midpoint, and offset temperatures of 335.54°C, 538.72°C, and 708°C, respectively. The DTG plot revealed thermal degradation occurred in two major phases: stage I (25-200°C) and stage II (200-900°C), which was
ascribed to drying/low-temperature degradation and macerals degradation, respectively. Overall, the findings demonstrate that the newly discovered DDG coal is suitable for energy recovery and utilisation
in future power plants. Future studies could investigate the kinetic and thermodynamic properties of DDG coal often required in reactor design and optimisation for energy generation.

Journal of Natural Fibers, 2022

The generationof biogas from faecal wastes currently offers limited economic and environmental be... more The generationof biogas from faecal wastes currently offers limited economic and environmental benefits to low-income households. The production of biochar from faecal waste is a sustainable alternative to firewood to replace charcoal that is widely utilised for cooking in households in Nigeria. Similarly, biochar production from faecal wastes presents a clean and renewable alternative approachfor creating value from faecal waste. Furthermore, this presents cost-effective recovery, containment, and management of faecal waste. Therefore, the objective of this study is to investigate the existing faecal waste management practices by households in Ogun State, Nigeria. It will also examine perceptions of households to faecal waste as a valuable resource, in either its raw or processed form for energy applications. Based on the multi-stage sampling approach, a total of 165 questionnaires were administered to representative households in the study area. Consequently, a total of 55, 50, an...

DRC Sustainable Future: Journal of Environment, Agriculture, and Energy, 2021

Botanicals are substances extracted from plants for use in various applications, such as the prod... more Botanicals are substances extracted from plants for use in various applications, such as the production of insecticides. Botanical insecticides (BIs) have recently attracted awareness in pest management owing to their potential to substitute synthetic pesticides. BIs are eco-friendly and more sustainable due to their ability to breakdown after use without generating toxic residues and diverse approach actions on targeted pests. Nevertheless, BIs are still not readily accepted, because the supporting proofs are very traditional, raising doubts about their quality. Additionally, the phytochemical variations of plants yield uneven and sometimes unfamiliar pesticide activity. This paper discusses challenges to overcome and presents the most noteworthy knowledge on BIs, their standardization, quality control, and bio- enhancement to be useful in agriculture and to improve human health.

Environmental Progress & Sustainable Energy, 2021

Journal of Criminal Justice Education, 2013

Learning how to effectively write a literature review is a critical tool for success for an acade... more Learning how to effectively write a literature review is a critical tool for success for an academic, and perhaps even professional career. Being able to summarize and synthesize prior research pertaining to a certain topic not only demonstrates having a good grasp on available information for a topic, but it also assists in the learning process. Although literature reviews are important for one's academic career, they are often misunderstood and underdeveloped. This article is intended to provide both undergraduate and graduate students in the criminal justice field specifically, and social sciences more generally, skills and perspectives on how to develop and/or strengthen their skills in writing a literature review. Included in this discussion are foci on the structure, process, and art of writing a literature review. What is a Literature Review? In essence, a literature review is a comprehensive overview of prior research regarding a specific topic. The overview both shows the reader what is known about a topic, and what is not yet known, thereby setting up the rationale or need for a new investigation, which is what the actual study to which the literature review is attached seeks to do. Stated a bit differently (Creswell 1994, pp. 20, 21) explains: The literature in a research study accomplishes several purposes: (a) It shares with the reader the results of other studies that are closely related to the study being reported (Fraenkel & Wallen, 1990. (b) It relates a study to the larger, ongoing dialog in the literature about a topic, filling in gaps and extending prior studies (Marshall & Rossman, 1989). (c) It provides a framework for establishing the importance of the study.

Environmental Science and Pollution Research

Through administrative research and media records, this paper aims to examine and highlight the e... more Through administrative research and media records, this paper aims to examine and highlight the effects of the COVID-19 pandemic on Malaysian workers, property development, construction sites, and the national economy. The development of real estate and the construction industry can significantly impact socioeconomic growth and infrastructure development. Adequate building and infrastructure construction can ensure national economic stability, job creation, community cohesion, and higher living standards. Since the COVID-19 pandemic began in 2019, many countries, including Malaysia, have reported an increased number of virus cases. According to the Ministry of Health, 9316 cases and 314 COVID-19 clusters were discovered in Malaysia, with a 38.55-48.06% prevalence for factories, a 12.55-15.29% prevalence for community spreading, an 8.6-11.56% prevalence for construction sites, a 5.53-7.96% prevalence for educational sites, and a 7.01% prevalence for shopping areas. Several governments-imposed lockdowns, movement, and proximity restrictions during the pandemic due to the high infection rates at property development sites. However, due to inactivity in various sectors such as the construction industry, these measures have significantly impacted the national economy. As a result, the pandemic has had an impact on workers, production costs, and project completion timelines, resulting in operational issues and policy concerns. Overall, the records reviewed revealed that the COVID-19 pandemic has significantly impacted real estate development, the housing market, and the construction industry. As a result, sustained and targeted policies are required to support Malaysia's construction industry's socioeconomic growth and infrastructure development.

Sustainability, 2022

Numerous researchers have described the correlation between the short-term contact of nano-partic... more Numerous researchers have described the correlation between the short-term contact of nano-particulate (NP) matter in diverse coal phases and amplified death or hospitalizations for breathing disorders in humans. However, few reports have examined the short-term consequences of source-specific nanoparticles (NPs) on coal mining areas. Advanced microscopic techniques can detect the ultra-fine particles (UFPs) and nanoparticles that contain potential hazardous elements (PHEs) generated in coal mining areas. Secondary aerosols that cause multiple and complex groups of particulate matter (PM10, PM2.5, PM1) can be collected on dry deposition. In this study, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) were employed to detect and define the magnitude of particulate matters on restaurants walls at coal mines due to weathering interactions. The low cost self-made passive sampler (SMPS) documented several minerals and amorphous phases. The ...

Physics and Chemistry of Solid State, 2022

The objective of this study is to examine the potential product yields and energy recovery of mai... more The objective of this study is to examine the potential product yields and energy recovery of maize cobs (MC) through carbon dioxide-assisted torrefaction using thermogravimetric analysis (TGA). The CO2-assisted torrefaction of MC was performed from 240 °C to 300 °C (Δ 30 °C) for the residence time of 30 minutes based on the selected non-isothermal/isothermal heating program of the TGA. Furthermore, the physicochemical, microstructure and mineral characteristics of MC were examined. The results showed that the CO2-torrefaction of MC resulted in a mass loss (ML) ranging from 18.45% to 55.17%, which resulted in the mass yield (MY) ranging from 81.55% to 44.83%. The HHV of the solid product was in the range from 22.55 MJ/kg to 26 MJ/kg, which indicates the CO2-torrefaction process enhanced the energy content of MC by 40% – 60%. In conclusion, the findings showed that the CO2 torrefaction is a practical, sustainable, and cost-effective approach for the valorization of MC into a clean so...

Chemical engineering transactions, 2017

The National Biomass Strategy was envisioned to foster the efficient valorisation and management ... more The National Biomass Strategy was envisioned to foster the efficient valorisation and management of Oil Palm Waste (OPW) in Malaysia. However, the proposed Circular Energy Economy is hampered by poor OPW fuel properties, inefficient conversion techniques, and process design. This study explored the valorisation of Oil Palm Empty Fruit Bunches (OPEFB) Briquettes through fluidised bed gasification with the aim of exploiting the superior qualities of pelletised biomass and excellent reactor dynamics of fluidised beds. Gasification of OPEFB Briquettes was examined from 600 – 800 °C and equivalence ratio, ER is 0.20 – 0.25 under atmospheric pressure. The fuel properties and chemical exergy of OPEFB briquettes were characterised. The gasification of OPEFB briquettes produced high biochar yield and bio syngas with higher heating value from 1.15 – 3.05 MJ/m3 whereas the Cold Gas Efficiency (CGE) and Carbon Conversion Efficiency (CCE) ranged from 6.54 – 17.34 % and 43.37 – 78.16 %. Bed agglo...

Journal of African Earth Sciences, 2021

Selected coal samples from the Benue Trough Basin (Nigeria) were analysed by X-ray photoelectron ... more Selected coal samples from the Benue Trough Basin (Nigeria) were analysed by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), Fourier transform-infrared spectroscopy (FT-IR), and all the techniques used. The main minerals detected are clays (e.g., kaolinite and illite), quartz, feldspar , hematite and magnetite with traces of calcite, siderite , dolomite, orthoclase and graphite. The authigenic and detrital origins of the clay minerals detected were confirmed by FT-IR analysis. The XPS spectra identified elements similar to the mineral phases observed in the XRD spectra. The contents of Al 2O3, CaO, Fe2O3, K2O, Na2O and P2O5 were below the values reported for US and Chinese coals. The elemental indexes (e.g. Al2O3/TiO2 , Co/Th vs. La/Sc, Cr/Th vs. Sc/Th) showed that the influence of intermediate-mafic materials derived from source-region sediments is negligible. The Ni/Co ratio showed that the c...

The rare earth elements (REE) possess a beneficial combination of chemical and physical propertie... more The rare earth elements (REE) possess a beneficial combination of chemical and physical properties, making them valuable for most advanced branches of engineering and technology. Alternative sources of REE are desirable due to limited reserves of conventional REE containing minerals over the world combined with disproportionate supply over demand in the commodity markets. This study investigated the occurrence of REE and carbon nanotubes (CNTs) in Cretaceous Nigerian coals for prospective industrial applications. Results show that the coals’ crystalline mineral matter comprises quartz, kaolinite, and illite with minor quantities of feldspar, hematite, magnetite, calcite, dolomite, which indicate detrital mineral origins. Elemental relationships (such as Al2O3/TiO2, Cr/Th vs. Sc/Th, and Co/Th vs. La/Sc) suggest sediment-source regions with mafic, intermediate or felsic compositions. REE are either strongly fractionated or characterized by light-enrichment along with outlook coefficie...

Energy Geoscience, 2021

The erratic supply of electricity in Nigeria has renewed interest in the utilisation of coal for ... more The erratic supply of electricity in Nigeria has renewed interest in the utilisation of coal for energy selfsufficiency and diversification of the national energy mix. In this study, selected coal samples from three regions of the Benue Trough Basin were examined through pore water chemistry, X-ray diffraction (XRD), and thermosgravimetric analysis (TGA). The low pH observed for the Lower Benue Trough (LBT) coals indicates the release of sulphur and acids during oxidation. Mineralogical analyses reveal quartz, kaolinite, montmorillonite, albite, pyrite, gypsum and sodium chlorate in the coal samples. The genetic kaolinite species identified in Imeagha (IMG) coal are detrital kaolinite and the highly crystalline neomorphic kaolinite. Gypsum and jarosite minerals occurred in minor quantities in Garin Maiganga (GMG), whereas significant amount of pyrite was detected in Enugu (ENG) coal. Oxidative thermal degradation resulted in the residual mass (R M) ranging between 4.35% and 56.96%) and mass losses (M L) between 43.04% and 95.65%) due to the drying, devolatilization, and coke formation in the samples. The most reactive coal examined was GMG coal, whereas the least reactive was IMG coal. Lamja (LMZ), GMG, and OKB coals are suited for electricity generation, whereas ENG and IMG coals can be utilised for cement production.

Jurnal Teknologi, 2016

Gasification of Oil Palm Empty Fruit Bunches (OPEFB) briquettes was investigated in an air blown ... more Gasification of Oil Palm Empty Fruit Bunches (OPEFB) briquettes was investigated in an air blown 4.5 kW allothermal fluidized bed gasifier to examine the effects of bed temperature (600 – 800 °C) and equivalence ratio (λ = 0.25) on bio-syngas yield and composition. In addition, physicochemical and thermochemical characterization of the fuel properties of the OPEFB briquettes were also examined. The results demonstrate that pelletization improved the solid biomass fuel (SBF) properties of OPEFB including moisture content and higher heating value (HHV). The gasification of OPEFB briquettes produced bio-syngas comprising H2, CO, CO2, CH4 as well as solid biochar with a HHV higher than the original OPEFB briquettes. The highest yield of H2 was obtained at 600 °C while HHV of the bio-syngas was within the range 4 - 8 MJ/Nm3 for air gasification in fluidized bed gasifiers. In addition, agglomeration of bed materials did not occur during OPEFB briquettes gasification despite its high bed a...

Jurnal Teknologi, 2016

This paper investigated the production of biohydrogen from Imperata cylindrica, using stoichiomet... more This paper investigated the production of biohydrogen from Imperata cylindrica, using stoichiometric equilibrium model. The stoichiometric equilibrium model uses biomass ultimate analysis, thermodynamic equilibrium and elemental balance on biomass gasification reaction. The sensitivity analysis was studied over a wide range of operating conditions involving temperature (250 – 1500 °C), pressure (1 – 5 atm) and Steam to fuel ratio (0-5). The result shows biohydrogen and other biogas product were sensitive to temperature and steam-feed ratio, whereas effect of pressure is negligible. The operating condition for optimal biohydrogen production in moles (23%) was atmospheric pressure, temperature, 1500 °C and steam-feed ratio, 5. Biogas product mixtures are H2, 23%, CO, 17%, CO2, 12% CH4, 0% and H2O, 60%. Increase in steam-feed ratio (0, 1, 2, 3, 4 and 5) significantly increase the biohydrogen by 1381%, 90%, 46%, 31% and 24%. The stoichiometry equilibrium model could effectively be used...

Jurnal Teknologi, 2016

This study is the first attempt at investigating the solid state decomposition and the devolatili... more 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 K...

Energy, 2015

The NBP (National Biofuel Policy) of Malaysia was established in 2006 to promote the sustainable ... more The NBP (National Biofuel Policy) of Malaysia was established in 2006 to promote the sustainable production and utilization of environmentally friendly biofuels. Despite numerous government incentives and subsidies, biodiesel exports have declined significantly over the years. This paper seeks to critically examine challenges afflicting the biodiesel industry in Malaysia by analysing the key policies, framework and institutions in the country. High feedstock prices, competition with food, engine compatibility, fuel subsidies and crude oil prices were identified as the challenges hindering biodiesel development in Malaysia. The authors propose that environmental, socioeconomic and technological reforms are required to address the challenges and improve the long term prospects of the Malaysian biodiesel industry. Furthermore, the utilization of biodiesel in the Real sector, biodiesel infrastructure investments and technological innovations will safeguard Malaysia's energy security, promote cleaner environment, improve living standards and stimulate stakeholder participation in the future development, diffusion and adoption of biodiesel in Malaysia.

Chemistry & Chemical Technology, 2016

The study is aimed at investigating the thermal behavior and decomposition kinetics of torrefied ... more The study is aimed at investigating the thermal behavior and decomposition kinetics of torrefied oil palm empty fruit bunches (OPEFB) briquettes using a thermogravimetric (TG) analysis and the Coats-Redfern model. The results revealed that thermal decomposition kinetics of OPEFB and torrefied OPEFB briquettes is significantly influenced by the severity of torrefaction temperature. Furthermore, the temperature profile characteristics; Tonset, Tpeak, and Tend increased consistently due to the thermal lag observed during TG analysis. In addition, the torrefied OPEFB briquettes were observed to possess superior thermal and kinetic properties over the untorrefied OPEFB briquettes. It can be inferred that torrefaction improves the fuel properties of pelletized OPEFB for potential utilization in bioenergy conversion systems.