Combustion By-products Research Articles

Leaf carbon monoxide emissions under different drought, heat, and light conditions in the field.

Carbon monoxide (CO) is known primarily as a globally emitted by-product of incomplete combustion from the industry and biomass burning. However, CO is also produced in living plants and acts as a stress-signalling molecule in animals and plants. While CO emissions from soil and litter decomposition have been studied, research on the CO flux from living vegetation is scarce, particularly under field conditions. Here, we present a year-long field study on the effects of light, heat, and seasonal drought on leaf CO production and flux using automated twig chambers on mature Pinus halepensis trees grown under summer-droughted and nondroughted (irrigated) conditions. We found CO buildup in drought-stressed tree leaves, with emissions linked to the heat-controlled biogenic production of CO rather than to photodegradation. In irrigated trees, CO fluxes occurred through open stomata, whereas in droughted trees, CO buildup overcame stomatal closure to result in a flux. The results support the role of CO in heat stress response and the likely mitigation of damage induced by reactive oxygen species. We highlight the need for further research into the mechanistic basis for CO flux from living plants.

Analysis Of The Effect Of Co-Firing On Boiler Loading Limitations Using Computational Fluid Dynamic (CFD) Methods

The increasing depletion of high-calorific coal resources has driven coal-fired power plants (PLTU) to switch to low-calorific coal with calorific values ranging from 4,200 to 4,800 kcal/kg. Simultaneously, the Indonesian government aims to achieve a renewable energy mix of 23% by 2025 and 31.2% by 2050, promoting the co-firing of biomass with coal at rates of 5% to 12%. However, this transition presents operational challenges, such as altered combustion characteristics, overheating in superheater zones, and increased slagging and fouling potential. This study aims to analyze the impact of co-firing biomass with coal on boiler performance at a 600 MW PLTU using Computational Fluid Dynamics (CFD) simulations. Data inputs include coal specifications and biomass mixing ratios of 3%, 5%, 8%, and 12%. Simulations were conducted using Ansys Fluent software to assess variations in temperature, pressure, and flow distribution. The results indicate that increasing biomass percentages reduces combustion temperatures and alters the distribution of key combustion byproducts, such as H₂O and SO₂. A higher biomass ratio mitigates the risk of overheating but requires careful operational adjustments to maintain efficiency. The findings support the optimization of co-firing operations, contributing to reduced carbon emissions and compliance with Indonesia’s renewable energy targets. This study provides actionable insights for improving PLTU performance while aligning with sustainable energy goals.

Effective Mechanical Properties of a Composite Material Reinforced by Oil Shale Ash Particles

This study determined the elastic properties of composites and concretes reinforced with oil shale ash (OSA) particles, a byproduct of oil shale combustion in an electric power plant in Estonia (Auvere). Since 2018, OSA has no longer been classified as hazardous waste in the EU, enabling its reuse in sustainable materials. The present research examined the effect of OSA on the elastic properties of epoxy–OSA and concrete–OSA composites. The experimental results show that the elastic modulus of epoxy resin increases with an increase in the ash concentration, while it decreases in concrete with a higher OSA content. Theoretical models, including the rule of mixtures, finite element method (FEM), Mori–Tanaka method, and Halpin–Tsai method, were used to predict these properties numerically. The rule of mixtures and FEM generally overestimated the modulus for epoxy–OSA, whereas the Mori–Tanaka and Halpin–Tsai methods provided closer predictions. For concrete–OSA, the compressive strength tests followed the LVS EN 12390-3:2019 standards, with elastic modulus conversions being made via IS 456:2000 Clause 6.2.3.1, which showed a variable decrease across different strength classes. The findings highlight the potential of OSA as a reinforcing filler in construction materials, promoting environmental sustainability by repurposing industrial waste while offering mechanical benefits.

Эколого-технологические аспекты выпуска угольной продукции потребителям арктических районов Республики Саха (Якутия)

Integrated development of the Russian Arctic regions constitutes a very complex long-term strategy aimed not only at exploring and developing new territories and mining useful minerals, but also at preserving the unique natural environment and improving the resource-saving technologies adapted to extreme climatic conditions. Production and use of coal for heat energy generation cause significant damage to the environment and represent one of the most dangerous human activities. For this reason, there is a need to assess the impact of the coal supply chain on the growth of the localized pollution zones in the natural ecosystems of the Arctic. Coal produced in the harsh conditions of the Far North loses its original quality, especially due to its transshipment, storage, and long-term transportation. The original particle size distribution primarily changes, significantly increasing the share of fine coal. An analysis of the coal supply chain to consumers in the Arctic regions of the Sakha Republic (Yakutia) revealed that using low-grade coals with a high content of fines results in significant emissions of harmful solid substances. By studying satellite images and calculating the natural loss of coal, an assessment of the pollution zones was made, based on which a comprehensive set of measures was developed to reduce the causes of pollution with coal dust and combustion by-products in the Arctic territories of the Republic.

Differentiation and environmental implications of trace elements in coal combustion by-products: A case study of several power plants

Differentiation and environmental implications of trace elements in coal combustion by-products: A case study of several power plants

The Mechanical Properties of Laterite Substituted with Cement and Bottom Ash

Bottom ash (BTA), a by-product of coal combustion in electric power plants, is commonly regarded as waste, presenting challenges in its management. Conversely, laterite, typically used in road construction, has become increasingly expensive due to its high quality. This study aims to investigate the mechanical properties of laterite replaced with BTA and cement. The replacement of BTA ranged from 10% to 50% of the dry weight of laterite, with cement contents of 1% and 3% of the dry weight of the laterite-BTA mixture. Experimental tests, including unconfined compressive strength (USC) and splitting tensile strength (STS), were conducted. The results indicate that replacing laterite with BTA and cement enhances strength by 2 to 8 times that of unstabilized laterite, with 20% BTA replacement yielding the highest strengths. This approach not only provides cost-effective road construction materials but also contributes to sustainable practices by conserving natural resources and reducing pollution.

Effects of Fine Particle Size on the Characteristics of Coal Bottom Ash as an Environmentally Friendly Material in Concrete Production

In the current era, concern about the responsible disposal of industrial waste and its reuse has increased in all societies from the industry. Therefore, the researchers’ institution is focusing its efforts on developing more environmentally friendly products from recycled waste, particularly in the area of sustainable construction. For instance, one of recycled waste is Coal Bottom Ash (CBA), a by-product of coal combustion that is produced in large quantities from thermal power plants. The aims of this study to investigate the physical, chemical and element characteristics of CBA obtained from thermal power plant in Malaysia. Also, CBA compared with cement characteristics to be used as cement replacement in the concrete mixture. Therefore, numerous tests have been performed to investigate CBA’s physical and chemical characteristics. For physical properties such as specific gravity, particle size analysis, fineness modulus, bulk density and loss on ignition. For chemical properties such as X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) in an effort to obtain sustainable materials from thermal power plant waste. Based on the findings in this study, it can be concluded that CBA can be utilized as cement substitute in the production of concrete mixtures.

Review on Gallium in Coal and Coal Waste Materials: Exploring Strategies for Hydrometallurgical Metal Recovery.

Gallium, a critical and strategic material for advanced technologies, is anomalously enriched in certain coal deposits and coal by-products. Recovering gallium from solid residues generated during coal production and utilization can yield economic benefits and positive environmental gains through more efficient waste processing. This systematic literature review focuses on gallium concentrations in coal and its combustion or gasification by-products, modes of occurrence, gallium-hosting phases, and hydrometallurgical recovery methods, including pretreatment procedures that facilitate metal release from inert aluminosilicate minerals. Coal gangue, and especially fly ashes from coal combustion and gasification, are particularly promising due to their higher gallium content and recovery rates, which can exceed 90% under optimal conditions. However, the low concentrations of gallium and the high levels of impurities in the leachates require innovative and selective separation techniques, primarily involving ion exchange and adsorption. The scientific literature review revealed that coal, bottom ash, and coarse slag have not yet been evaluated for gallium recovery, even though the wastes can contain higher gallium levels than the original material.

Physicochemical Surface Modification and Characterisation of Coal Fly Ash for Application in Rubber Composites

This study evaluated the capability of coal fly ash (untreated and physicochemically modified) when utilised as a filler in cis-1,4-polyisoprene rubber. Physicochemical modification of the ash was achieved using two techniques: (1) ammonium sulphate roasting followed by controlled aqueous dissolution and (2) sulphuric acid leaching. In addition, the effectiveness of a silane-coupling agent (Si-69) in enhancing the compatibility of untreated and physically modified ash samples with natural rubber was investigated. The ammonium sulphate roasting route increased the surface area and roughness and decreased the particle–particle agglomeration of the fly ash sample. Sulphuric acid treatment decreased the particle–particle agglomeration. However, no increase in surface roughness was observed. The untreated fly ash samples were not significantly reinforcing, and the properties they imparted were inferior to the least reinforcing carbon black. Silane treatment resulted in improved dispersion and wetting of the fly ash in the rubber matrix, leading to improved reinforcement compared to neat rubber. In situ addition of the silane during preparation of the vulcanisates led to composites with better mechanical properties than the composites containing silane-pre-treated fly ash. Composites filled with ammonium sulphate-roasted-and-leached ash performed better than the composites filled with untreated ash and sulfuric acid-leached ash. These findings suggest that modified fly ash holds promise as an effective filler for rubber materials, offering potential environmental and economic benefits by repurposing coal combustion by-products.

Charcoal-production, Air Pollutant Impacts on Ambient Environment and Associated Health Risks: A Systematic Review

Charcoal is a widely utilised fuel produced from the carbonisation of organic materials, such as wood and other biomass sources. Regrettably, airborne contaminants from traditional charcoal producing techniques can negatively impact human health and the environment. This research explore air pollutant emissions from traditional charcoal producing methods and their impacts on human health and the environment. This study utilised a qualitative synthesis methodology, incorporating case studies, archival research, and discourse analysis, to elucidate the impacts of charcoal production. The results demonstrate that the traditional charcoal production method results in substantial carbon loss from fuelwood and emits by-products of incomplete combustion, exacerbating serious health risks and degrading air quality associated with community health problems. Empirical evidence indicates that the majority of charcoal manufacturing workers lack awareness of the health risks associated with their working circumstances and the respiratory problems they face. Unsustainable environmental practices highlight the social and ecological repercussions of charcoal production. It is advisable to apply air pollution mitigation methods around charcoal kiln facilities to protect environmental and community health. The Environmental Protection Agency must actively implement effective oversight and integrated management to improve air quality and safeguard communities from air hazards. This study recommends testing high-efficiency technologies in communities capable of maintaining and assessing their effects on environmental degradation. Both governmental entities and humanitarian organisations should prioritise educational activities centred on effective land management approaches, as this study's findings suggest.

Sustainable Use of Recycled Plastic and Coal Bottom Ash in the Development of Construction Material

Mineral coal bottom ash (CBA) is a by-product of coal combustion in power plants. Its potential use in building materials has attracted interest due to its beneficial properties and environmental implications. The aim of this study is to assess the feasibility of using mineral coal slag from the Anou Araren coal company in Niger (Sonichar), in combination with plastic waste, in various construction applications. In this case, the focus is on compressive strength and slip potential for floor coverings. Following a technical characterization of the various elements involved in the production of the proposed material, 02 firing methods are described, with the advantages and disadvantages of each. Mixtures with varying proportions of plastic waste and bottom ash (30%/70%, 40%/70% and 50%/50%) were studied. For the mix selected, the results show that the CBA/plastic waste material has good compressive strength and low slip potential, making it suitable for use in a variety of construction applications.

Exploring the Use of Fly Ash and Marble Coarse Aggregates as Eco-Friendly Replacements in Concrete Production

Abstract This study investigates the feasibility of utilizing fly ash and marble coarse aggregates as sustainable substitutes in concrete production, responding to the increasing demand for infrastructure and the necessity to diminish the carbon footprint of construction materials. By partially substituting cement, a material that generates substantial greenhouse gas emissions, fly ash, a by-product of coal combustion, recognizes its capacity to reduce CO2 emissions. The stone processing industry produces marble waste, which, by repurposing otherwise wasted byproducts, offers an environmentally sustainable solution, simultaneously reducing the use of natural resources in the manufacture of traditional aggregates. The research aims to assess the effects of incorporating various ratios of fly ash, ranging from 10% to 50%, and marble coarse aggregates, ranging from 10% to 90%, on the workability, compressive strength, split tensile strength, and flexural strength. The results show a moderate decrease in a slump, with an 18.66% reduction at 50% marble coarse aggregates and 30% fly ash, and a significant increase in compressive strength, with a 60.22% improvement at 56 days with 40% fly ash and 70% marble coarse aggregates. Split tensile strength also improved by 35.50% to 36.66%. Non-destructive tests confirmed the structural integrity of the concrete. This study emphasizes the potential of fly ash and marble coarse aggregates as eco-friendly substitutes in concrete production.

SYNTHESIS AND CHARACTERIZATION OF ZEOLITES FROM COAL FLY ASH WASTE

South Sumatra had coal production through PT Bukit Asam Tbk, which had coal production since 1950. Tanjung Enim Steam Power Plant (PLTU) is the largest coal ash producer because coal is the primary fuel. Coal combustion by-products include coal fly ash (CFA) and coal bottom ash (CBA). The current utilization of the CFA Tanjung Enim Steam Power Plant is for a cement mixture of PT Semen Baturaja and planting media. This work attempts to optimize zeolite synthesis from CFA by examining the effects of hydrothermal duration on reducing coal waste. This research studies the effect of hydrothermal time with time variations of 5, 12, and 24 on the morphology and phase of zeolite obtained. CFA from the Tanjung Enim Steam Power Plant contains SiO₂ and Al₂O₃, which account for 47.7% and 28.7% of the total composition, respectively. The SEM characterization result shows that the synthesized zeolite forms aggregates with a particle size of about 8-15 μm. Based on XRD characterization of CFA hydrothermal time of 5 hours, the dominant phase is the gibbsite phase, but there is a sodalite phase. The 12-hour hydrothermal time showed the formation of quartz, gibbsite, and sodalite phases. The 24-hour hydrothermal time shows that the dominant phase is sodalite, but there are gibbsite and quartz phases. The peak of the quartz phase decreases the longer the hydrothermal time. In this study, the duration of the hydrothermal process affects the formation of the zeolite phase.

Carbon monoxide poisoning: assessment and actions for nurses working in service users' homes.

Carbon monoxide is a colourless, tasteless and odourless gas that is a by-product of incomplete combustion of hydrocarbons such as gas or coal. Carbon monoxide poisoning is associated with high levels of mortality and morbidity, although the symptoms of exposure are non-specific and difficult to diagnose. Historically, healthcare professionals who work directly in service users' homes have faced a higher risk of exposure to environments contaminated with carbon monoxide. Despite improved heating engineering and greater protective legislation, there still remains a tangible risk for community nurses and service users, particularly in homes still using open fires, old heating systems and poorly maintained heating appliances. This article provides a scientific summary of carbon monoxide poisoning for nurses working in the community setting. It outlines evidence-based guidance on prevention and initial treatment actions, along with safety instructions to follow in the event of exposure to carbon monoxide.

Review: Effect of Material Characteristics, and Process Conditions in Reducing Gaseous Pollutants Using Fly Ash (FA)-Based Adsorbent

The intensive use of fossil fuels has led to a significant increase in air pollution, which negatively affects human health and the environment. Fly ash (FA), a byproduct of coal combustion, has great potential as an adsorbent for hazardous gas pollutants due to its physical and chemical properties. This research aims to evaluate the effectiveness of fly ash as an adsorbent in reducing gas pollutants such as CO2, SO2, and NO2, as well as to examine the influence of temperature and material characteristics on adsorption capacity. The results indicate that the maximum adsorption capacity for each gas pollutant is achieved at different temperatures, fly ash demonstrating the highest performance at 150 °C for CO2 adsorption, achieving an efficiency of 94.7%. For SO2 and NO2, the optimum temperatures are 200 °C, with efficiencies of 72.17% and 100%, respectively. This study also emphasizes the importance of selecting the appropriate characteristics of the adsorbent material to enhance adsorption efficiency. This finding has the potential to support the development of more efficient and sustainable air pollution reduction technologies in the future, by utilizing industrial waste such as fly ash as an innovative solution.

Endocrine-Disrupting Compounds in Urban Soils of Malaysia: Occurrence, Contamination, and Impacts on Health and the Environment

Endocrine-disrupting compounds (EDCs) have garnered increasing concern in recent years due to their association with severe health issues and significant environmental impacts. EDCs, which can interfere with endogenous hormone systems, are diverse in structure and are often characterized by low molecular mass and halogen substitutions. Their presence in the environment, originating from both natural and synthetic sources, has been well-documented in water bodies, but studies on their occurrence in soils remain limited. This review provides a comprehensive overview of the occurrence, contamination, and impacts of EDCs in the urban soils of Malaysia. The paper discusses the primary sources of EDCs, including pharmaceuticals, pesticides, industrial chemicals, and combustion byproducts, and examines the pathways through which these compounds enter the soil. Health risks associated with exposure to EDCs, as well as their ecological consequences, are also explored. The review highlights the current status of EDCs contamination in Malaysian soils, identifies gaps in research, and outlines the challenges in monitoring and mitigating these contaminants. Understanding the dynamics of EDCs in soil is crucial for developing effective strategies to protect human health and the environment in urban settings.

Structural Integrity, Environmental Sustainability, and Cost-Effectiveness of Fly Ash Bricks

The construction industry and environmental advocates have increasingly focused on sustainable, long-lasting, and cost-effective building materials in modern construction. Clay bricks and concrete, traditional construction materials, are used extensively, but their environmental impact and resource-intensive production processes are raising concerns. Fly ash bricks, created from industrial waste, have emerged as a promising alternative, offering a unique combination of structural integrity, environmental sustainability, and cost-effectiveness, making them an appealing option for the construction industry. Fly ash, a by-product of coal combustion mainly from power plants was previously considered a pollutant and a disposal challenge. However, the innovative use of fly ash in brick production has transformed this waste into a valuable resource. As awareness of sustainability and eco-friendly building practices has grown, fly ash bricks have gained widespread recognition as a greener alternative to traditional materials like clay bricks and concrete blocks

Compaction Characteristics of Fly Ash and Pond Ash: A Comparative Analysis

This study investigates the compaction characteristics of Fly Ash and Pond Ash, which are by-products of coal combustion in thermal power plants. Thermal power plants generate three types of ash: (a) Fly Ash, (b) Pond Ash, and (c) Bottom Ash. Fly Ash consists of fine particles carried out of the boiler with flue gases, while Bottom Ash is the residue that settles at the bottom of the boiler. In most coal plants, Fly Ash is captured using electrostatic precipitators and other filtration equipment before the flue gases are released through the chimney. Pond Ash, on the other hand, is a by-product of thermoelectric power plants, often regarded as waste material, posing significant environmental disposal challenges. The compaction characteristics of Fly Ash and Pond Ash are influenced by various factors, including specific gravity, moisture content, compaction energy, layer thickness, and mold area. In this study, Fly Ash collected from NTPC Sipat , Chhattisgarh exhibited an Optimum Moisture Content (OMC) ranging from 18% to 27% and a Maximum Dry Density (MDD) ranging from 0.90 to 1.59 gm/cc under standard Proctor compaction energy. Similarly, Pond Ash demonstrated an OMC ranging from 33% to 46% and an MDD ranging from 0.856 to 1.248 gm/cc under the same conditions. The findings indicate that variations in these factors significantly affect the dry density of both Fly Ash and Pond Ash. The study also aims to determine the geotechnical properties of these materials, providing insights into their potential applications in engineering and environmental management

Breast Cancer-Related Chemical Exposures in Firefighters.

To fill a research gap on firefighter exposures and breast cancer risk, and guide exposure reduction, we aimed to identify firefighter occupational exposures linked to breast cancer. We conducted a systematic search and review to identify firefighter chemical exposures and then identified the subset that was associated with breast cancer. To do this, we compared the firefighter exposures with chemicals that have been shown to increase breast cancer risk in epidemiological studies or increase mammary gland tumors in experimental toxicology studies. For each exposure, we assigned a strength of evidence for the association with firefighter occupation and for the association with breast cancer risk. We identified twelve chemicals or chemical groups that were both linked to breast cancer and were firefighter occupational exposures, including polycyclic aromatic hydrocarbons, volatile aromatics, per- and polyfluoroalkyl substances, persistent organohalogens, and halogenated organophosphate flame retardants. Many of these were found at elevated levels in firefighting environments and were statistically significantly higher in firefighters after firefighting or when compared to the general population. Common exposure sources included combustion byproducts, diesel fuel and exhaust, firefighting foams, and flame retardants. Our findings highlight breast-cancer-related chemical exposures in the firefighting profession to guide equitable worker's compensation policies and exposure reduction.

Enhancing Concrete Properties through Fly Ash Pelletized Aggregates and Fibre Reinforcement - A Review

This literature review examines recent studies in Lightweight Aggregate Concrete (LWAC), specifically focusing on utilizing fly ash pelletization and fibre reinforcement to enhance concrete properties. Fly ash, a by-product of coal combustion, has gathered attention because of its potential to be put forward as a critical component in creating lightweight aggregates. The process of pelletization, which involves forming fly ash into small, spherical pellets, has been shown to improve the mechanical properties of the resulting concrete. The process mainly includes the cold-bonded pelletization method, which consumes energy and is easy to use. The review gives fusion findings from various studies examining fly ash's role in producing lightweight aggregates and the impact of different additives and processes on the resulting material properties. Key insights reveal that incorporating silica fume, fly ash, and steel fibres remarkably improves concrete's compressive and bonding strengths. Additionally, the cold-bonded pelletization of fly ash and cement, especially when combined with Polypropylene (PP) and steel fibres, leads to enhanced aggregate properties, including strength, density, and water absorption. The review also highlights the importance of optimizing pelletization parameters and binder usage to improve the quality of lightweight aggregates and enhance the properties of concrete. Moreover, integrating hybrid fibres, such as carbon and polypropylene, enhances concrete's postpeak performance and flexibility. The findings suggest that these innovations in fly ash pelletization and fibre reinforcement improve mechanical performance and contribute to more sustainable and cost-effective concrete production. This review provides a comprehensive overview of the current state of research, offering insights into the future direction of LWAC development.