Search Results (10,210)

In this study, the combined combustion characteristics and gaseous product emissions of coal slime and corn stover were compared at different blending ratios. The TG-DTG curves indicate that the optimal performance is achieved when the corn straw blending ratio is 20%. Furthermore, the TG-FTIR coupling results demonstrated an increase in gas species as the blending ratio increased. The composition analysis of ash samples formed at various combustion temperatures using XRD and XRF indicated that a portion of KCl in the fuel was released as volatile matter, while another part reacted with Al₂O₃ and SiO₂ components in the slime to form silica–aluminate compounds and other substances. Notably, interactions between the components of slime and potassium elements in corn stover primarily occurred within the temperature range of 800–1000 °C. These findings contribute to a comprehensive understanding of biomass and coal co-firing combustion chemistry, offering potential applications for enhancing energy efficiency and reducing emissions in industrial processes. Full article

In this paper, a heating device is implemented by considering two large factors in a 100 cmm RTO design. First, when the combustion chamber is used for a long time with a high temperature of 750–1100 °C depending on the high concentration VOC gas capacity, there is a problem that the combustion chamber explodes or the function of the rotary is stopped due to the fatigue and load of the device. To prevent this, the 100 cmm RTO design with a changed rotary position is improved. Second, an RTO design with a high-heating element is implemented to combust VOC gas discharged from the duct at a stable temperature. Through this, low-emission combustion emissions and energy consumption are reduced. By implementing a high heat generation device, the heat storage combustion oxidation function is improved through the preservation of renewable heat. Over 177 h of demonstration time, we improved the function of 100 cm by discharging 99% of VOC’s removal efficiency, 95.78% of waste heat recovery rate, 21.95% of fuel consumption, and 3.9 ppm of nitrogen oxide concentration. Full article

The aim of this research is to investigate the environmental emission effects and combustion properties of burning different types of FAME biodiesel fuels in an industrial oil burner. These burner heads are used in many areas of industry for heating various boilers and tube furnaces. The fuels used, the area of use, the emission norm values, and the climatic conditions are key factors in this investigation. In this research, two plant-based oils are examined, the properties of which have been compared to standard commercial heating oil. The raw material of the two tested bio-based components was rapeseed. The main gas emission parameters CO, THC, CO₂, O₂, HC, water content, and consumption data were measured. The measurements were performed in an AVL engine brake platform infrastructure, where gas emissions were measured with an AVL AMA i60 FTIR emission gas analyzer, fuel consumption was meticulously gauged using a fuel flow meter, fuel temperature was monitored using an AVL 745 fuel temperature conditioning system, and air consumption was measured with an AVL Flowsonix intake air flow meter. The measurement results showed that both tested biofuels can be burned stably in industrial oil burners, have favorable properties in terms of ignition and flame extinction tendencies, and there is no significant difference in emission parameters compared to standard fuel oil. Full article

Hydrogen is a promising zero-carbon fuel, and its application in the micro-combustor can promote carbon reduction. The structural design of micro-combustors is crucial for combustion characteristics and thermal performance improvement. This study investigates the premixed combustion characteristics of hydrogen/air in a micro-cylindrical combustor with double ribs, using an orthogonal design method to assess the impact of various geometric parameters on thermal performance. The results indicate that the impact of rib height, rib position, and inclined angle is greater than rib width and their interactions, while their influence decreases in that order. Increased rib height improves mean wall temperature and exergy efficiency due to an expanded recirculation region and increased flame–wall contact, but negatively affects temperature uniformity and combustion efficiency. Although double ribs enhance performance, placing them too close may reduce heat transfer due to the low-temperature region between the ribs. When the double ribs are positioned at the axial third equinoxes of the micro-combustor, the highest mean wall temperature is achieved. Meanwhile, with a rib height of 0.3 and an inclined angle of 45°, the micro-combustor achieves optimal thermal performance, with the mean wall temperature increasing by 61.32 K. Full article

Pharmaceutical packaging is one of the most used packaging types which contains aluminum and plastics. Due to increasing amounts of waste and rising environmental concerns, recycling approaches are being investigated. Since blisters usually contain a balanced amount of plastics and metals, most of the approaches focus on recycling only one material. Therefore, more sustainable recycling approaches which recover both plastic and aluminum fractions are needed. This study investigates the thermal behavior and degradation mechanisms of plastic-rich and aluminum-rich pharmaceutical blisters using various analytical techniques. Structural characterization revealed that plastic-rich blisters have a thicker profile with plastic and aluminum layers, while aluminum-rich blisters consist of plastic layers between aluminum sheets. Thermal degradation analysis showed two main stages for both types: plastic-rich blisters (polyvinyl chloride) exhibited significant weight loss and long-chain hydrocarbon formation between 210 and 285 °C, and aluminum-rich blisters (polyamide/nylon) degraded from 240 to 270 °C. Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy analyses confirmed the endothermic behavior of such a transformation. The gas emissions analysis indicated an increased formation of gasses from the thermal treatment of plastic-rich blisters, with the presence of oxygen leading to the formation of carbon dioxide, water, and carbon monoxide. Thermal treatment with 5% O₂ in the carrier gas benefited plastic-rich blister treatment, reducing organic waste by up to 80% and minimizing burning risk, leveraging pyrolytic carbon for protection. This method is unsuitable for aluminum-rich blisters, requiring reduced oxygen or temperature to prevent pyrolytic carbon combustion and aluminum oxidation. Full article

Traditional and modern coatings play a key role in enhancing the fire resistance of ancient Chinese buildings. However, further comparative analysis is needed on the fire properties of the two coatings and their effects on different timber structural components. This study focuses on the main hall of the Shanxi Changzhi Xianqing Temple, a typical traditional column and beam construction built between the Song and Jin periods. Firstly, the combustion characteristics of various timber structural component samples with different surface treatments (traditional “Yi-ma-wu-hui” and modern flame retardants) were analyzed using cone calorimeter. Secondly, the fire development process of the Xianqing Temple building model was analyzed by a fire dynamics simulator (FDS), and the effect mechanism of different surface treatments on the burning process was further studied. The results show that the fire resistance of timber structural components is significantly improved after modern and traditional surface treatments. The traditional method is more effective in delaying the peak heat release rate and reducing the surface temperature during combustion, while the modern surface treatment significantly prolongs the ignition time of the timber structural components. The FDS results confirm that modern and traditional surface treatments significantly improve the fire resistance of the building, delaying the flashover time by about 300 s, with no collapse occurring within 800 s. In addition, the fire resistance of buildings after traditional surface treatment is better compared to traditional methods. The above research results can provide direct data support for the selection and optimization of fireproof coatings and treatment methods for ancient buildings. Full article

Combustible gases, such as CO, CH₄, and H₂, are produced during spontaneous coal combustion in goaf, which may cause an explosion under the stimulation of an external fire source. It is of great significance to study the influence of combustible gases, such as CO and H₂, on the characteristics of a gas explosion. In this study, CHEMKIN software (Version 17.0) and the GRI-Mech 3.0 reaction mechanism were used to study the influences of different concentration ratios between CO and H₂ on the ignition delay time, free radical concentration, and key reaction step of a gas explosion. The results show that the increase in the initial CH₄ and CO concentrations prolonged the ignition delay time, while the increase in the H₂ concentration shortened the time and accelerated the explosion reaction. The addition of H₂ promoted the generation of free radicals (H·, O·, ·OH) and accelerated the occurrence of the gas explosion. CO generated ·OH free radicals and dominated the methane consumption through the R119 and R156 reactions. As the concentrations of CO and H₂ increased, the R38 reaction gradually became the main driving factor of the gas explosion. Full article

CO, H₂, and other combustible gases will be produced during coal oxidation in coal mines, which will increase the risk of explosion when mixed with methane. Therefore, it is very important to understand the production characteristics of combustible gas during coal oxidation. In this paper, a programmed temperature gas test system is built to study the impact of lignite on the production of gases at different particle sizes and temperatures, and the release characteristics of gases are also analyzed. The result shows that the production of combustible gas is influenced by the coal particle size significantly when the temperature is above 200 °C, and it decreases as the particle size increases. CO is the main gas during the early stage of coal spontaneous combustion, and the release of CH₄ and H₂ increases after 300 °C. The fitted equations of gas generation and temperature are consistent with the experimental results. The research results are helpful in understanding the hazards of coal spontaneous combustion and have a certain guiding significance for coal mine monitoring and prevention of coal spontaneous combustion. Full article

The lithium-ion battery (LIB) thermal runaway (TR) emits a wide size range of particles with diverse chemical compositions. When inhaled, these particles can cause serious adverse health effects. This study measured the size distributions of particles with diameters less than 10 µm released throughout the TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. The chemical composition of fine particles (PM_2.5) and some acidic gases were also characterized from filter samples. The emission factors of particle number and mass as well as chemical components were calculated. Particle number concentrations were dominated by those smaller than 500 nm with geometric number mean diameters below 130 nm. Mass concentrations were also dominated by smaller particles, with PM₁ particles making up 81–95% of the measured PM₁₀ mass. A significant amount of organic and elemental carbon, phosphate, and fluoride was released as PM_2.5 constituents. The emission factor of gaseous hydrogen fluoride was 10–81 mg/Wh, posing the most immediate danger to human health. The tested LFP cells had higher emission factors of particles and HF than the LCO cells. Full article

A notable trend in the modern automotive market is the increased interest in hybrid cars. Hybrid cars combine a standard internal combustion engine with an electric motor solution. Research into increasing the energy efficiency of a conventional unit while meeting increasingly stringent exhaust emission standards is becoming a key postulate in this matter. This article discusses an analysis of modifying the fuel used by hybrid vehicles using the example of a selected drive unit equipped with a spark-ignition engine. This effect was tested after the Eco Fuel Shot liquid catalyst was added to the fuel. The research process was carried out in two stages, as follows: in road conditions using the Dynomet road dynamometer; and on the V-tech VT4/B2 chassis dynamometer. Tests were carried out to replicate road tests with a catalytic additive in the fuel. A mathematical model was created and the following energy efficiency parameters of the hybrid vehicle were calculated: the torque of the internal combustion engine, electric motor, and generator; the rotational speeds of the internal combustion engine, electric motor, and generator; the power of the internal combustion engine, electric motor, and generator; the equivalent fuel consumption of the electric motor and generator; the fuel consumption of the internal combustion engine, electric motor, and generator; and the mileage fuel consumption of the internal combustion engine, electric motor, and generator. The results of the tests made it possible to identify the benefits of using the tested liquid catalyst on the operation of the drive system of the analyzed hybrid vehicle. This research will be of benefit to both the demand side in the form of users of this category of vehicles, and the supply side represented by the manufacturers of power units. Full article

Blowoff limits are essential in establishing the combustor operating envelope. Hence, there is a great demand for practical aero-engines to extend the blowoff limits further. In this work, the behavior of non-premixed swirling flames under fuel flow rate oscillations was investigated experimentally close to its blowoff limits. The methane flame was stabilized on the axisymmetric bluff body and confined in a square quartz enclosure. External acoustic forcing at 400 Hz was applied to the fuel flow to induce a fuel mass flow rate fluctuation (FMFRF) with varying amplitudes. A high-speed burst-mode laser and cameras ran at 20 kHz for OH*-chemiluminescence (CL), CH₂O-, and SO₂-PLIF measurements, offering the visualization of the two-dimensional flame structure and heat release distribution, temporally and spatially. The results show that the effect of FMFRF is predominantly along the central axis without altering the time-averaged flame structure and blowoff transient. However, the blowoff limits are extended due to the enhanced temperature and longer residence time induced by FMFRF. This work allows us to explore the mechanism of flame instability further. Full article

Decarbonising transport is a crucial element of the UK’s strategy to achieve net-zero carbon emissions by 2050, as the transport sector is currently the largest contributor to the UK’s greenhouse gas emissions. Rural communities face distinct challenges in this effort due to their reliance on internal combustion engines (ICEs) across vehicles and machinery essential for daily life, including farming equipment and private transport. While the upcoming ban on new petrol and diesel vehicles paves the way for the adoption of Electric Vehicles (EVs), this solution may not fully address the unique needs of rural areas where infrastructure limitations and specific mobility requirements pose significant barriers. In this context, synthetic fuels, produced using renewable energy sources, offer a potential alternative. These fuels can be used directly in existing internal combustion engines without requiring major modifications and have the added benefit of reducing overall greenhouse gas emissions by capturing CO₂ during production. This entry explores the potential advantages of adopting synthetic fuels, particularly in rural areas, and examines how community-based buying cooperatives could support their wider use through bulk purchasing, cost reduction, and community empowerment. Full article

This study aimed to calculate the impact of inlet valve geometry and spray angle on the performance of internal combustion engines using computational fluid dynamics (CFD) analysis. CFD analysis was performed to explore the fuel flow dynamics within a combustion chamber at critical stages, considering factors such as swirl and tumble. This study investigated the role of the intake port’s geometry and spray angles in creating squish and swirl, which is crucial for enhancing combustion efficiency and overall engine performance. The analysis employed the Finite Volume Method (FVM), solved within ANSYS Fluent 2021 software, utilizing the standard k-ε turbulence model. Design Modeler was used for the geometry design and ANSYS Fluent facilitated the CFD analysis of the injection. Four distinct cases were explored to assess engine performance across various designs, examining parameters such as pressure, temperature, and velocity. These performance parameters were evaluated against the existing literature, enabling the identification of optimal configurations. This study identified optimal performance parameters based on the existing literature. The best design was further validated against existing designs under identical boundary conditions. This research demonstrates improved engine performance across all parameters compared to existing values in the literature. This suggests the efficacy of the proposed inlet valve geometry and spray angle configurations in increasing internal combustion engine efficiency. Full article

According to the requirements of the small double-pulse solid rocket motor, a compartmentalized isolation device has been designed. This device consists of a metal diaphragm and a support frame. An experimental study and numerical simulation were used to verify the bidirectional working process of the metal diaphragm during operation of the double-pulse motor. The results show that the pressure-bearing capacity of the metal diaphragm meets the requirements under the working conditions of pulse I without affecting pulse II, because the metal diaphragm can provide insulation and flame retardancy. The metal diaphragm can be cracked in the direction of the preset V-groove in a relatively short time under the working conditions of pulse II, which allows the gas to flow to the first pulse combustion chamber normally. This indicates that the metal diaphragm can meet the requirements of bidirectional working process in dual-pulse motors. Full article

The effects of torrefaction of the biopellets made from hardwood chip residue (HW), camellia oilseed cake (CO), and pruning remnants of the toothache tree (TA) and mulberry tree (MT) were evaluated. Torrefaction of the biopellets reduced the volatile matter content of biopellets by 18–58% and increased their heating value by 18–58% without negatively impacting durability or fines content. Torrefaction also reduced the initial ignition time of biopellets by 50–59% and prolonged their combustion duration by 15–24%. Regardless of the type of feedstock, all biopellets exhibited mass yields in the range of 60–80% and energy yields ranging from 80–95%. The novelty of this study lies in the application of torrefaction to already-formed biopellets, which enhances pellet quality without the need for binders, and the use of unused forest biomass and wood chip residue from pulp mills. The use of unused forest biomass and wood chip residue from pulp mills for biopellet production not only provides a sustainable and efficient method for waste utilization but also contributes to environmental conservation by reducing the reliance on fossil fuels. Overall, the torrefaction of biopellets represents a promising technology for producing high-quality solid biofuel from a variety of woody biomass feedstocks without compromising pelletizing efficiency. Full article