Search Results (232)

Green methanol is widely regarded as a technically feasible low-carbon marine fuel for sustainable shipping in the medium term, but its economic viability remains constrained by fuel price and supply-scale uncertainty. This study develops a dynamic total cost of ownership (TCO) model for a methanol dual-fuel container ship with a nominal capacity of 15,000 twenty-foot equivalent units (TEUs) operating on the Ningbo–Zhoushan–Valencia green shipping corridor. The model integrates capital expenditure, operating expenditure, fuel costs, European Union Emissions Trading System (EU ETS) carbon costs, FuelEU Maritime compliance costs, and green premium revenue. It evaluates a 15-year baseline, 25- and 30-year extensions, speed scenarios, probabilistic parameter uncertainty, and purchase-versus-charter thresholds. Under baseline assumptions (carbon price of 73.5 EUR/tCO2 and green methanol price of 1500 USD/t), the 15-year present-value cost of the green methanol case is 134.4% higher than that of the very low sulfur fuel oil (VLSFO) case. Annual costs may cross in 2045, 2040, and 2037 under baseline, optimistic, and accelerated decarbonization scenarios, respectively, but cumulative discounted cost advantage is not achieved within 30 years. Across 5000 Monte Carlo simulations, the probability of cumulative methanol cost advantage is 0% at 15, 25, and 30 years; methanol price and its decline rate remain the dominant uncertainty drivers. Slower speeds reduce the absolute cost gap but do not reverse the fuel ranking. These results show that carbon pricing or green premium revenue alone cannot close the corridor-level cost gap under the tested conditions. They also provide corridor-level evidence for methanol procurement, bunkering-capacity planning, and coordination among ship operators, ports, fuel suppliers, and cargo owners. Shipowners and port planners can update the framework as fuel prices, policy parameters, and bunkering conditions change. Full article

The instability of marine low-sulfur fuel oil caused by asphaltene precipitation poses significant operational challenges in the shipping industry. This study systematically investigates the dispersing effects of biodiesel derived from three different feedstocks—palm oil, waste cooking oil (WCO), and microalgae oil—and their individual fatty acid methyl ester components on asphaltenes extracted from VLSFO. Biodiesel was selected as a dispersant due to its renewable nature, polar ester functional groups, and variable unsaturation levels, which enable favorable interactions with asphaltene molecules through hydrogen bonding and π-π stacking. Using UV–Visible spectrophotometry, the dispersion performance was quantitatively evaluated under various conditions including dispersant concentration, temperature, storage time, and molecular structural characteristics. The results demonstrate that microalgae oil biodiesel exhibits the most superior asphaltene dispersion capability among the three biodiesels, with a dispersion improvement index of 35% at 12 g/L, compared to 28% and 22% for waste cooking and palm oil biodiesels. Optimal performance is achieved at 80 °C, where the asphaltene concentration increases by 68% relative to the control, and remains stable within the first 10 days of storage but deteriorates significantly after 30 days due to oxidative degradation. Among individual FAME components, the dispersion effectiveness increases with alkyl chain length from C10 to C20, with the latter reaching a 30% improvement index. Functional group polarity plays a critical role, with carboxylic acid exhibiting a 45% improvement at 14 g/L, substantially outperforming alcohol at 32% and ester at 28%. The degree of unsaturation further enhances dispersion, as the improvement index rises progressively from 20% for saturated methyl stearate to 42% for tri-unsaturated methyl linolenate, representing a 2.1-fold increase. Dynamic light scattering (DLS) measurements confirm that biodiesel addition reduces asphaltene particle size from the micrometer range of 2 to 5 μm down to submicron levels of 200 to 500 nm, while microscopic observations reveal inhibited aggregation. These findings provide theoretical foundations for biodiesel application in marine fuel systems. Full article

The study evaluated 6 mm pellets derived from whole hemp plants (Cannabis sativa L., cv. Futura 75) to assess their potential as a solid biofuel. The pellets had a low moisture content of 6.3–7.0% on an analytical basis, which is favorable for storage and combustion. Ash content was approximately 4.0–4.3%, while gross calorific values ranged from 17.3 MJ·kg⁻¹ as received to 19.4 MJ·kg⁻¹ on a dry ash-free basis. The net calorific values ranged from 16.1 to 17.5 MJ·kg⁻¹. Based on the elemental analysis, the carbon content was 46.8–49.4%, the hydrogen content was 5.5%, the nitrogen content was 0.68–0.73%, and the sulfur content was 0.05%. Compared with many agricultural biomass fuels, hemp pellets contained relatively low sulfur and moderate nitrogen contents. Hemp pellets from whole plants show favorable physicochemical properties, making them a viable renewable solid biofuel resource. Full article

Biomass oxy-fuel combustion based on circulating fluidized bed (CFB) technology is one of the important pathways to achieving carbon neutrality due to its potential in carbon capture and negative carbon emissions. Combining biomass, as a substitute for coal, with oxy-fuel combustion technology can enrich CO₂ while helping to control NOx emissions and carbon stock. In this study, a three-dimensional numerical model of a 20 t/h biomass CFB boiler was established based on the computational particle fluid dynamics (CPFD) method. Under an oxy-fuel atmosphere of 30% O₂/65% CO₂/5% H₂O, the combustion characteristics of three typical biomass fuels—corn straw, rice husk, and poplar wood—were systematically compared, with emphasis on the furnace temperature distribution and the formation and emission of CO, NO_X, and SO₂. The results show that the axial temperature profiles all exhibit a rapid increase to a peak, followed by a gradual decrease. The peak temperatures in descending order are poplar wood (1091 K), corn straw (1084 K), and rice husk (1047 K), and the differences are mainly attributed to variations in volatile content, ash content, and calorific value. CO is primarily concentrated in the dense phase zone; it increases first and then decreases along the furnace height. CO generated from poplar wood combustion has the highest concentration at the furnace outlet, while the steady-state outlet mass fraction of NO is the lowest for poplar wood. Corn straw combustion yields the highest NO emission. Overall, the carbon stock of the three fuels is very low, and total CO emission is extremely low. NO concentration is jointly regulated by fuel nitrogen content and CO reduction, while SO₂ emission is directly related to fuel sulfur content—corn straw and rice husk show significantly higher SO₂ emission than poplar wood due to their higher sulfur content. In summary, fuel characteristics play a decisive role in the temperature field and pollutant formation during oxy-fuel combustion. This study provides a theoretical basis for the fuel selection and operational optimization of biomass oxy-fuel CFB boilers. Full article

Cement clinker production is a thermal- and emissions-intensive process requiring high-temperature heat for drying, calcination, and sintering. This review provides a process-based assessment of refuse-derived fuel (RDF), solid recovered fuel (SRF), tire-derived fuel (TDF), and biomass as partial substitutes for coal and petcoke in modern dry-process cement kilns. The study synthesized the evidence from plant-scale trials, pilot and laboratory experiments, process modeling, computational fluid dynamics, emissions studies, life-cycle assessment (LCA), techno-economic analysis (TEA), and regional case studies to evaluate alternative fuels across fuel properties, kiln-zone suitability, process stability, clinker quality, emissions performance, and environmental outcomes. The review shows that stable co-processing generally requires fuels with net calorific values above 14 MJ kg⁻¹ and moisture contents below 15%, although TDF can provide 26–33 MJ kg⁻¹ and sustain high-energy kiln duty when sulfur, zinc, and steel residues are controlled. RDF, SRF, and biomass require pre-processing, homogenization, calibrated dosing, and continuous fuel-quality monitoring to limit incomplete burnout, deposit formation, volatile circulation, and clinker-quality variation. LCA studies show that 20% RDF thermal substitution can reduce global warming potential by about 3.3–4.2%, increasing to approximately 6.7% when avoided landfill methane credits are included. Modern abatement systems can maintain particulate matter at about 10–30 mg Nm⁻³ and PCDD/F below 0.1 ng TEQ Nm⁻³ under stable operation. The review concludes that alternative fuels are quality-dependent co-processing options whose mitigation role is complementary to clinker-factor reduction, energy-efficiency improvement, low-clinker binders, electrified heating, oxy-fuel calcination, and carbon capture. Full article

Air pollution is primarily caused by human activities such as industrial emissions, road traffic, waste incineration, and fossil fuel power plants. Pollution refers to the presence of harmful substances in the air, such as nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), carbon monoxide (CO), and other environmental pollutants. Some pollutants pose health risks even at low doses. Given the critical importance of air quality, monitoring air pollution has become an urgent and essential subject. Air quality monitoring relies on accurate data, so changeable environments and sensor issues make using interval diagnostic techniques for addressing uncertainty in systems interesting. In this article, we focus on three key aspects to achieve precise and efficient results: (1) the use of an accurate fault detection method that accounts for data uncertainty while maintaining model symmetry, (2) the implementation of a reliable detection index invariant to symmetric sensor behaviors, and (3) the combination of both to improve fault localization accuracy. This paper presented a fault detection and localization framework designed for uncertain and nonlinear monitoring environments. A novel fault-sensitive detection index was developed and integrated into an elimination-based localization strategy within a reduced-rank interval kernel PCA (RR-IKPCA) model. By exploiting information contained in modified residual subspaces and explicitly accounting for measurement uncertainty, the proposed approach enhances fault sensitivity while preserving robust localization capability, as validated on the AIRLOR air quality monitoring network. Full article

The composition and type of polymers used as feedstocks in the pyrolysis of plastic waste determine the decomposition process and the proportions of the final products. This paper examines the effect of feedstock heterogeneity on pyrolysis efficiency and pyrolysis gas composition. Four types of plastic waste were considered: real polyolefin waste of municipal origin, LDPE, Alu-PEX laminates, and an alternative refuse-derived fuel (RDF). Low-temperature pyrolysis (450 °C) was conducted in a laboratory reactor, and the gas composition was analyzed using GC-TCD/FID gas chromatography, which allowed for the determination of light hydrocarbons, oxygenates, and sulfur content. Compared to RDF, both municipal and LDPE polyolefin wastes produced gas with a higher calorific value and a predominance of light C₁–C₄ hydrocarbons, while Alu-PEX laminates produced gas rich in C₁–C₂ and low in sulfur, suitable for direct use. RDF was characterized by increased CO₂ and non-flammable gas production and significantly higher sulfur content, requiring advanced purification. The results emphasize the importance of feedstock segregation and standardization and demonstrate that pyrolysis of polyolefins and Alu-PEX laminates can provide higher-quality energy gas than RDF, supporting the circular economy and energy self-sufficiency of industrial installations. Full article

The increasing generation of organic and liquid wastes calls for sustainable strategies to convert residues into valuable energy resources. This study investigates waste Oxytree biomass (Paulownia Clon In Vitro 112^®) as a sorbent for producing impregnated solid fuels from selected liquid wastes, including used cooking oil, spent mineral oil, and pyrolysis condensate, targeting industrial energy applications. Oxytree biomass was selected due to its high and predictable yield, uniform composition, and favorable physical properties compared to conventional lignocellulosic residues such as pine sawdust. Biomass and liquid wastes were characterized in terms of fuel properties and elemental composition. Several empirical combinations of sorbent and liquid fractions were tested to optimize homogeneity and fuel quality, resulting in a final composition of sorbent:used cooking oil:used machine oil:pyrolytic condensate equal to 3:1:1:3. The temporal stability of this selected fuel was verified over 24 h, 3 days, and 1 week. The resulting fuels exhibited an energy value of approximately 15 MJ/kg, low ash content (<1%), and minimal concentrations of chlorine and sulfur (<0.08%). Overall, the findings demonstrate that Oxytree waste biomass can serve as an effective sorbent for integrating problematic liquid wastes into solid fuels, providing a practical route for waste valorization and supporting circular economy principles, and establishing a foundation for further research on sustainable energy applications of biomass and industrial residues. Full article

The effective utilization and effective valorization of various organic industrial wastes have become increasingly important issues. One significant area for enhancing the circular economy is the processing of waste generated from vegetable oils and animal fats. This article focuses on the processing and use of soapstocks, which result from the chemical reaction between fatty acids and alkali. These soapstocks represent the most significant portion (approximately 70–90 wt% by weight) of waste produced by the oil and fat industry. The raw material for this study was soapstock obtained from the neutralization of sunflower oil at the PJSC “Zaporizhzhya Oil and Fat Plant,” designed by the Belgian company “De Smet.” The soapstock yield was found to be 9.95 wt% based on 100 wt% oil. Through a series of treatments involving water, acid, and multiple washes, a low-sulfur fuel component was produced that nearly meets the standards for boiler fuels as outlined in DSTU 4058-2001 and PN-C-96024:2020, except for the heat of combustion. It fully complies with the requirements specified in ISO 8217:2024. The sulfur content of the final product was determined to be 0.12 wt%. Additionally, the fuels produced contained 75.33 wt% carbon, 11.64 wt% hydrogen, and 12.00 wt% oxygen. Due to the relatively low oxygen content, the resulting product exhibits approximately twice the heat of combustion of similar fuels derived from other waste streams in the oil and fat industry. Full article

Growing interest in developing sustainable materials that reduce dependence on fossil resources has led to increased development of bio-based elastomers that can compete with traditional materials in terms of performance when reinforced with additives. This study shows that functionalizing graphene oxide with different alkylamine chains (C8, C12, and C16) enables precise, multidimensional modulation of polymyrcene rubber (PMy) composite behavior. The main finding is that there is a critical concentration of ~1.5–2.0 phr and an optimal chain length of C16 that maximizes mechanical strength, elongation, and toughness simultaneously, thus avoiding the classic trade-off between stiffness and extensibility. Additionally, the study reveals biphasic behavior of graphene oxide modified with dodecylamine (GO_A12) on curing kinetics. At low concentrations, GO_A12 slows vulcanization by competing with accelerators, while at higher concentrations, it accelerates vulcanization via Zn–amine–sulfur complexes. This duality is reflected consistently in the crosslink density, Payne effect, and tensile properties, establishing a coherent structure–property correlation. Identifying an optimal crosslinking regime of ~8.5 × 10⁻⁴ mol/cm³ as the common denominator of the best formulations provides a rational design guide for high-performance elastomers based on renewable matrices and graphene-derived reinforcements. The decrease in tan δ observed through mechanical dynamic analysis suggests potential applications in the tire industry due to increased energy dissipation, which would improve fuel efficiency. Full article

The liner shipping industry is thriving in the low-carbon transition, and optimizing operational strategies for liquefied natural gas (LNG) dual-fuel ships has become a research hotspot. This research examines the impacts of the carbon tax, emission control area (ECA) policies, fuel price discounts and methane slip rate on fuel management strategies. Firstly, to reduce liner operating costs and adhere to ECA policies, this study develops a basic optimization model. Further, the model is extended to take into account the impact of fuel price discounts. Secondly, by linearizing multiple nonlinear terms, the operational strategies are obtained. Thirdly, taking a real vessel sailing between the Far East and Northwest Europe as a case study, this study identifies the ports for LNG and very low sulfur fuel oil (VLSFO) bunkering, determines the bunkering amounts and calculates the planned speeds. Furthermore, sensitivity analyses are conducted on fuel price difference, carbon tax rate and methane slip rate. Results show that fuel price difference, carbon tax rate, methane slip rate and fuel price discount exert a significant impact on ship operational decisions. To ensure the effectiveness of maritime decarbonization regulations, authorities should monitor ship engines with high methane slip rates. This study offers important references for shipping enterprises to meet ship emission policies and simultaneously cut operational costs. Full article

In this study, we develop a game-theoretic optimization framework to analyze competing vessels’ technology choices between shore power (SP) and low-sulfur fuel oil (LSFO) within a maritime supply chain which is regulated by a cap-and-trade mechanism. Using a Stackelberg game approach, we construct two models—one port-led and the other vessel-led—to derive closed-form equilibrium for pricing, service quantities, profits, emissions, and social welfare. The results reveal three key findings. First, the leader in either Stackelberg structure always achieves higher profits, while total supply chain profits remain identical across power structures. Second, at low carbon prices, LSFO-equipped vessels provide more services and earn higher profits due to cost advantages. As the carbon price rises—which directly incentivizes emission reduction and accelerates maritime decarbonization—SP becomes more attractive and eventually dominates in profitability despite higher initial investment. Notably, although SP has lower unit emissions, its total emissions may surpass those of LSFO at certain carbon-price thresholds because the SP-equipped vessel optimally expands output. Third, intensified competition reduces service quantities, profits, and emissions, with a more substantial reduction effect on LSFO vessels. Overall, our results provide mathematically grounded insights for optimizing low-carbon technology adoption in maritime transport and offer actionable policy implications for carbon pricing that balance environmental objectives and supply chain efficiency. This research contributes specifically to the United Nations’ Sustainable Development Goals (SDGs), specifically SDG 13 (Climate Action) and SDG 9 (Industry, Innovation and Infrastructure). Full article

Rapid urbanization and anthropogenic activities have led to a significant deterioration of air quality, adversely affecting human health and ecosystems. The study of transboundary river basins, where air pollution is exacerbated by political and socio-economic factors, is of particular relevance. This paper presents the results of an analysis of the spatiotemporal distribution of pollutants (Aerosol Index (AI), Methane (CH₄), Carbon Monoxide (CO), Formaldehyde (HCHO), Nitrogen Dioxide (NO₂), Ozone (O₃), Sulfur Dioxide (SO₂)) in the ambient air within the Orontes River basin across Lebanon, Syria, and Turkey for the period 2019–2024. The research is based on satellite monitoring data (Copernicus Sentinel-5P), processed using the Google Earth Engine (GEE) cloud-based platform and GIS technologies (ArcGIS 10.8). The dynamics of population density (LandScan) and the impact of military operations in Syria on air quality were additionally analyzed using media content analysis. The results showed that the highest concentrations of pollutants were recorded in Syria, which is associated with the destruction of infrastructure, military operations, and unregulated emissions. The main sources of pollution were: explosions, fires, and destruction during the conflict (aerosols, CO, NO₂, SO₂); methane (CH₄) leaks from damaged oil and gas facilities; the use of low-quality fuels and waste burning. Atmospheric circulation contributed to the eastward transport of pollutants, minimizing their spread into Lebanon. Population density dynamics are related to changes in concentrations of pollutants (e.g., nitrogen dioxide). The results of the study highlight the need for international cooperation to monitor and reduce air pollution in transboundary regions, especially in the context of armed conflicts. The obtained data can be used to develop measures to improve the environmental situation and protect public health. Full article

Sulfur dioxide (SO₂) is a colorless, pungent gas that is a significant contributor to air pollution, with well-documented environmental and health impacts. It is emitted both naturally (e.g., in volcanic activities) and anthropogenically (e.g., fossil fuel combustion, sulfuric acid production, papermaking, and wine preservation). Inhalation represents the primary route of human exposure, particularly in urban and industrial settings. Acute SO₂ exposure can lead to airway irritation, laryngospasm, bronchoconstriction, pulmonary edema, and death in severe cases. Chronic exposure, even at low concentrations, can contribute to the development of pulmonary and extrapulmonary diseases. Despite its classification as a hazardous air pollutant, a comprehensive understanding of dose-response relationships, exposure thresholds, and mechanisms of toxicity for SO₂ remains limited. This review synthesizes current knowledge on environmental sources, exposure routes, mechanisms of toxicity, and health impacts of SO₂, highlighting findings from epidemiological, toxicological, and mechanistic studies. We also discuss gaps in knowledge regarding SO₂, approaches to monitor and assess SO₂ exposure in ambient environments, the emerging role of SO₂ as a gasotransmitter, and areas where further research is needed to better understand health risks and support evidence-based public health decision-making. Full article

Based on the pressing need to develop efficient desulfurization technologies for fuel oils, this study presents a novel photoresponsive adsorbent for the removal of refractory thiophenic sulfides. Conventional hydrodesulfurization exhibits limited efficiency for such compounds, while adsorption–desorption processes often suffer from high energy consumption during regeneration. Inspired by natural stimuli-responsive systems, we designed a photothermal adsorbent by incorporating silver nanoparticles (Ag NPs) into a porous aromatic framework (PAF) via a green photoreduction method. The resulting materials, denoted as Ag(0)PBPAF-n (n = 1, 2, 3), were thoroughly characterized to confirm successful synthesis and structural integrity. The introduced Ag NPs serve as adsorption sites, enhancing uptake capacity through weak interactions with sulfur atoms in thiophenic molecules. More significantly, under light irradiation, the localized surface plasmon resonance (LSPR) of Ag NPs enables efficient photothermal conversion, triggering rapid desorption without conventional heating. Adsorption–desorption tests demonstrated that up to 48% of adsorbed thiophenic sulfur could be released upon illumination. Fixed-bed experiments further verified that light can effectively stimulate regeneration and improve energy efficiency. This work offers a promising strategy for designing recyclable adsorbents with low-energy regeneration driven by clean solar energy. Full article