Search Results (41)

Although oily sludge is an industrial waste and difficult to separate, its calorific value can still reach 6000 cal/g, thus possessing significant recycling value. This study compares various types of non-thermal plasma for refining oily sludge. The pre-treatment technology utilized filtration combined with solvent extraction to extract the oil portion from the oily sludge. Subsequently, two types of non-thermal plasma, DC streamer discharge and dielectric plasma discharge, were used to crack and activate the oily sludge under different operating conditions. The fuel compositions and properties of the refined fuel treated by two types of non-thermal plasma were compared. The elemental carbon and oxygen of the oily sludge after treatment in a direct DBD plasma reactor for 8 min were 1.96 wt.% less and 1.38 wt.% higher than those of commercial diesel. The research results indicate that the pre-treatment process can effectively improve the refined fuel properties. After pre-treatment, the calorific value of the primary product from the oily sludge can reach 10,598 cal/g. However, the carbon residue of the oily sludge after pre-treatment remained as high as 5.58 wt.%, which implied that further refining processes are required. The streamer discharge plasma reactor used a tungsten needle tip as a high-voltage electrode, leading to a rather small treated range. Corona discharge and arc formation are prone to being produced during the plasma action. Moreover, the addition of quartz glass beads can form a protruding area on the surface of the oily sludge, generating an increase in the reacting surface of the oily sludge, and hence an enhancement of treatment efficiency, in turn. The direct treatment of DBD plasma can thus have a wider and more uniform operating range of plasma generation and a superior efficiency of plasma reaction. Therefore, a direct DBD type of non-thermal equilibrium plasma reactor is preferable to treat oily sludge among those three types of plasma reactor designs. Additionally, when the plasma voltage is increased, it effectively enhances fuel properties. Full article

The amendment to MARPOL Annex VI, which limits the sulfur content in marine fuels to a maximum of 0.5 wt.%, came into effect in January 2020. This includes reducing sulfur oxide (SO_X) emissions and establishing nitrogen oxide (NO_X) emission standards (Tiers I, II, and III) based on the ship’s engine type and construction date. Furthermore, the regulations require oil tankers to control volatile organic compound (VOC) emissions and prohibit the installation of new equipment containing ozone-depleting substances. After a four-year exploration phase, global shipping companies still lack consistent evaluation criteria for the selection and use of alternative fuels, resulting in divergence across the industry. According to the latest data, methanol can reduce NO_X, SO_X, and particulate matter (PM) emissions by approximately 80%, 99%, and 95%, respectively, compared to traditional heavy fuel oil. Furthermore, green methanol has the potential for near-zero greenhouse gas emissions and can meet the stringent standards of Emission Control Areas. Therefore, this study adopts a cost-benefit analysis method to evaluate the feasibility and implementation benefits of two promising strategies: methanol dual fuel and very low-sulfur fuel oil (VLSFO). A 6600-TEU container ship was selected as a representative case, and the evaluation was conducted by replacing an older ship with a newly built one. The reductions in total pollutants and CO₂-equivalent emissions of the container ship, as well as the cost-effectiveness of each specific strategy, were calculated. This study found that, in the first five years of operation, the total incremental cost of Vessel A, which uses 100% VLSFO, will be significantly lower than that of Vessel B, which uses a blend of 30% e-methanol + 70% VLSFO as fuel. Furthermore, compared to a scenario without any improvement strategies, the total incremental cost for Vessels A and B will increase by 69.90% and 178.15%, respectively, over five years. Vessel B effectively reduced the total greenhouse gas emission equivalent (CO₂e) of CO₂, CH_4, and N₂O by 24.72% over five years, while Vessel A reduced the CO₂e amount by 12.18%. Furthermore, the cost-benefit ratio (CBR) based on total pollutant emission reduction is higher for Vessel A than for Vessel B within five years of operation. However, in terms of the cost-effectiveness of CO₂e emission reduction, the CBR of Vessel A becomes lower than Vessel B after 4.7 years of operation. Therefore, Vessel A’s strategy should be considered a short-term option for reducing CO₂e within 4.7 years, whereas the strategy of Vessel B is more suitable as a long-term solution for more than 4.7 years. Full article

A projection lens with a 30-degree field of view is developed for use in augmented reality (AR) glasses, including a waveguide combiner designed for a 0.35-inch LCoS panel. The entrance pupil diameter of the lens is 14 mm and the lens has an effective focal length of 16.443 mm; an F-number of 1.175. This paper has four key issues: optical projection lens design, lens manufacturing and assembly tolerance analysis, projection lens resolution testing, and AR glasses system resolution testing of panel images projected by the projection lens. After lens manufacture, the lens was tested, achieving a central field image quality of 57 cycles/mm, an angular resolution of 33 pixels per degree (PPD), a 0.7 field image quality of 40.3 cycles/mm, and an angular resolution of 23 pixels per degree (PPD). Imaging performance testing based on a diffraction-type waveguide shows a resolution of 57 cycles/mm in the center area and an angular resolution of 33 PPD. Full article

Biodiesel is a renewable and sustainable alternative fuel to petrol-derived diesel. Decreasing the operating costs by improving the catalyst’s characteristics is an effective way to increase the competitiveness of biodiesel in the fuel market. An aqueous solution of sodium methoxide (CH₃ONa), which is a traditional alkaline catalyst, was immersed in nanometer-sized particles of titanium dioxide (TiO₂) powder to prepare the strong alkaline catalyst TiO₂/CH₃ONa. The immersion method was used to enhance the transesterification reaction. The mixture of TiO₂ and CH₃ONa was calcined in a high-temperature furnace in a range between 150 and 450 °C continuously for 4 h. The heterogeneous alkaline catalyst TiO₂/CH₃ONa was then used to catalyze the strong alkaline transesterification reaction of palm oil with methanol. The highest content of fatty acid methyl esters (FAMEs), which amounted to 95.9%, was produced when the molar ratio of methanol to palm oil was equal to 6, and 3 wt.% TiO₂/CH₃ONa was used, based on the weight of the palm oil. The FAMEs produced from the above conditions were also found to have the lowest kinematic viscosity of 4.17 mm²/s, an acid value of 0.32 mg KOH/g oil, and a water content of 0.031 wt.%, as well as the highest heating value of 40.02 MJ/kg and cetane index of 50.05. The lower catalyst amount of 1 wt.%, in contrast, resulted in the lowest cetane index of 49.31. The highest distillation temperature of 355 °C was found when 3 wt.% of the catalyst was added to the reactant mixture with a methanol/palm oil molar ratio of 6. The prepared catalyst is considered effective for improving the fuel characteristics of biodiesel. Full article

A strong alkaline catalyst, sodium methoxide (CH₃ONa), is commonly used to catalyze the transesterification reaction for biodiesel production. Meanwhile, titanium dioxide (TiO₂) anatase with a bandgap of 3.2 eV is a highly competitive photocatalyst after the absorption of sufficient energy from ultraviolet light. There has been no published report on the synergistic catalyst effects of CH₃ONa and TiO₂ on further facilitating the transesterification reaction. Hence, an impregnating method was used in this study to prepare the heterogeneous photocatalyst comprising TiO₂ nanoparticles embedded with a CH₃ONa catalyst. The TiO₂ nanoparticles were first immersed in an aqueous solution of CH₃ONa so that CH₃ONa could diffuse into the interior surfaces of the TiO₂ porous structure. The mixture of TiO₂ and CH₃ONa was then calcined in the temperature range from 150 °C to 450 °C for 4 h to produce the TiO_2/CH₃ONa photocatalyst. Various characteristics of the catalyst were analyzed to determine the optimum preparation conditions. The Fourier transform infrared spectroscopy spectra revealed that the absorption peaks of CH₃ONa appeared in the wavelength range of 600 cm⁻¹ and 1500 cm⁻¹. The X-ray diffractometer analysis showed that the calcined CH₃ONa did not alter the crystal structure of the catalyst carrier TiO₂. At the calcined temperatures between 100 °C and 800 °C, no intermediate or pyrolyzed product of CH₃ONa was detected, as revealed by the thermogravimetric analyzer spectra. In addition, about 5~9 wt.% elemental calcium in the CH₃ONa solution could be calcined onto the surface of TiO₂. In addition, the FTIR spectra confirmed the successful sintering and bonding of CH₃ONa onto the TiO₂ nanoparticles. The energy dispersive spectrometry result revealed that the interior surface of the TiO₂ nanoparticles was filled with the CH₃ONa compound. Full article

Bioglycerol is a major by-product of the biodiesel manufacturing process. Various chemical derivatives from bioglycerol would enhance its economic value. An antifreeze of glycerine acetate was chemically converted from an esterification reaction of bioglycerol with acetic acid. The photocatalyst TiO₂/SO₄²⁻ irradiated with ultraviolet light assisted the chemical conversion reaction. The molar ratio of acetic acid/bioglycerol was varied to obtain the optimum composition of the derived antifreeze product. Different cosolvents were considered to enhance the homogeneous extent between the antifreeze of glycerine acetate and biodiesel, and thus, the anti-freezing effect. The cosolvent/glycerine acetate, at various volumetric ratios from 0 to 0.25 vol.%, was blended into a commercial biodiesel. After 5 vol.% antifreeze of the glycerine acetate/cosolvent mixture of the biodiesel was added to the commercial biodiesel, the fuel properties of the biodiesel were analyzed. The effects of the cosolvent types and the blended volumetric ratio of cosolvent to the antifreeze of glycerine acetate on the fuel properties of the commercial biodiesel were analyzed to determine the optimum cosolvent type and volumetric composition of the cosolvent/glycerine acetate. The experimental results show that the antifreeze of glycerine acetate produced from the reaction of acetic acid/glycerol at a molar ratio equal to 8 under UV-light irradiation appeared to have the lowest freezing point. The UV-light irradiation on the TiO₂/SO₄²⁻ catalyst also caused higher triacylglycerol (TAG) and diacylglycerol (DAG) and lower monoacylglycerol (MAG) formation. In addition, the low-temperature fluidity was the most excellent when the volumetric percentage of the methanol/glycerine acetate was equal to 0.25 vol.%, at which the cold filter plugging point (CFPP) of the biodiesel was reduced from 3 °C for the neat biodiesel to −2 °C for the biodiesel blended with the mixture. In contrast, the effect of adding the antifreeze on the CFPP of the biodiesel was inferior; it was reduced from 3 °C for the neat biodiesel to 1 °C for the biodiesel when butanol cosolvent was added. The increase in the volumetric ratio of cosolvent/antifreeze increased the acid value and cetane index while it decreased the kinematic viscosity and CFPP. The heating value was observed to increase for butanol while decreasing for methanol with the increase in the volumetric ratio of cosolvent/antifreeze. In comparison to butanol, the cosolvent methanol caused a higher cetane index and acid value but a lower kinematic viscosity, heating value, and CFPP of the blended commercial biodiesel. Full article

The purity of crude glycerol, a by-product of biodiesel production, may be as low as 50%. Thus, it has relatively low economic value without previously applying adequate physical purification or chemical conversion processes. A solid-state sulfated acid photocatalyst, TiO₂/SO₄²⁻ was prepared in this study to catalyze the chemical conversion of bioglycerol with acetic acid to produce an antifreeze of glycerine acetate to improve the low-temperature fluidity of liquid fuel. The experimental results show that similar X-ray intensity structures appeared between the catalysts of TiO₂/SO₄²⁻ and SO₄²⁻. An infrared spectra analysis using a Fourier transform infrared (FTIR) spectrometer confirmed the successful sintering of SO₄²⁻ and ligating with TiO₂ for preparing TiO₂/SO₄²⁻. The effects of the photocatalyst were further excited by the irradiation of ultraviolet light. The highest weight percentage of glycerine acetate was obtained under a reaction time and reaction temperature of 10 h and 120 °C, respectively. In addition, it was observed that the glycerol conversion ratio reached 98.65% and the triacylglycerols compound amounted to 40.41 wt.% when the reacting molar ratio was 8. Moreover, the freezing point of the product mixture of glycerine acetate under the same molar ratio reached as low as −46.36 °C; the lowest among the products made using various molar ratios of acetic acid/glycerol. The UV light irradiation rendered higher triacylglycerols and diacylglycerols with lower diacylglycerol formation ratios than those without light irradiation. Full article

The maritime industry is recognized as a major pollution source to the environment. The use of low- or zero-carbon marine alternative fuel is a promising measure to reduce emissions of greenhouse gases and toxic pollutants, leading to net-zero carbon emissions by 2050. Hydrogen (H₂), fuel cells particularly proton exchange membrane fuel cell (PEMFC), and ammonia (NH₃) are screened out to be the feasible marine gaseous alternative fuels. Green hydrogen can reduce the highest carbon emission, which might amount to 100% among those 5 types of hydrogen. The main hurdles to the development of H₂ as a marine alternative fuel include its robust and energy-consuming cryogenic storage system, highly explosive characteristics, economic transportation issues, etc. It is anticipated that fossil fuel used for 35% of vehicles such as marine vessels, automobiles, or airplanes will be replaced with hydrogen fuel in Europe by 2040. Combustible NH₃ can be either burned directly or blended with H₂ or CH₄ to form fuel mixtures. In addition, ammonia is an excellent H₂ carrier to facilitate its production, storage, transportation, and usage. The replacement of promising alternative fuels can move the marine industry toward decarbonization emissions by 2050. Full article

The global trend towards net-zero carbon emissions from burning fuels in combustion engines alerts us to the alternative role of biodiesel. The manufacturing cost of biodiesel hinders the fast development of various types of biofuels. Feedstock cost is one of the major determining factors of biodiesel cost and thus the extent of its competitiveness in the fuel market with other available alternative fuels or fossil fuels. Some low-cost feedstocks such as high-acid oil, which is produced from the acidifying processes of soybean soapstock, frequently contain high contents of free fatty acids (FFAs) and water. Hence, those feedstocks cannot be used to produce biodiesel through strong alkaline catalyst transesterification on an industrial scale. In contrast, the water can be converted to hydroxyl radicals to enhance the formation of esters from the dissociation of the FFA in a supercritical reacting tank. Hence, cheap high-acid oils containing high amounts of water and FFAs were used to produce biodiesel through a supercritical transesterification reaction system. The engine emission characteristics of using the biodiesel produced in this study were analyzed and compared with those of commercial biodiesel and super-low sulfur diesel (SLSD). A naturally aspirated, direct-injection, four-stroke, four-cylinder marine diesel engine associated with an eddy-current dynamometer was used to carry out the engine emission measurement. In comparison with super-low sulfur diesel (SLSD), the biodiesel had lower CO₂ and CO emissions and black smoke opacity but higher emissions of O₂ and NO_x. The higher engine speed caused lower emissions of O₂ and NO_x but higher CO₂ emissions. The supercritical-transesterification biodiesel appeared to be a competitive alternative fuel to fossil diesel. Full article

For many years, the Suez Canal (also known as the Suez Route) has been the main route connecting Europe and Asia. However, compared with the Suez Route, the Northeast Passage could save up to 41% of the journey. The ship carbon intensity index (CII) rating system of the International Maritime Organization (IMO) came into effect in 2023. This study took an existing bulk carrier on the Europe–Asia route as an example to calculate the attained CII values at different sailing speeds. It was found that, regardless of external factors, when the ship speed dropped from 14.4 knots (85% maximum continuous rating (MCR)) to 12.6 knots (55% MCR), the corresponding attained CII value decreased from 6.48 g/ton·nm to 5.19 g/ton·nm. Therefore, sailing speed was the key factor influencing the attained CII value, and it was independent of the shipping distance. In addition, when the ship’s sailing output power was between 85% MCR and 75% MCR, for every 5% decrease in MCR, its attained CII value would decrease by 0.13 g/ton·nm, and the fuel consumption amount would decrease by 1 ton/day. However, when the ship sailed at an output power of 75% MCR to 55% MCR, for every 5% decrease in MCR, the attained CII value would decrease even more, up to 0.26 g/ton·nm. In addition, the attained CII value would be reduced by up to 100% and fuel consumption amount would be reduced by up to 1.5 ton/day, resulting in a 50% fuel saving effect. Therefore, to obtain a better CII rating, the optimal ship speed should be set between 75% MCR and 55% MCR according to the wave and wind strengths. However, although slow-speed sailing is the most efficient factor, the number of sailing days would also be extended. Through the ratio created by dividing the distance of the Northeast Passage by the Suez Route, whether the Northeast Passage has the benefit of balancing shipping schedules could be judged. The outcome indicated that a ratio lower than 1 would result in a more balanced shipping schedule. Compared with 2019, the number of ships sailing through the Northeast Passage in 2021 increased significantly by 132%, and the average dead weight tonnage of the ships also rose from 18,846 tons to 23,736 tons. This study found that, with the implementation of the carbon reduction policy of the CII rating, ships sailing through the Northeast Passage could continue to develop toward the trend of large-sized vessels and steady increase in ship number. Full article

Emulsions that mix two or more immiscible phases are broadly applied in pharmaceutics, chemistry, and industries. The phase inversion temperature (PIT) method is an emulsifying approach to preparing an emulsion with low energy consumption and cheap equipment. The effects of surfactant characteristics and processes of cooling or heating on the fuel properties of emulsions composed of silicone oil by the emulsifying method, such as mean droplet sizes of the de-ionized water phase, were considered herein. The application of the silicone oil emulsion as engine fuel was first evaluated. The results show that the emulsions added with the polyol surfactant mixture appeared to have a larger mean water-droplet size, a larger number of dispersed water droplets, a wider range of dispersed-water sizes, and lower kinematic viscosity than those with Brij 30 surfactant. Increasing the surfactant concentration of either Tween 20 mixed with Span 80 or Brij 30 surfactant increased kinematic viscosity and the number of dispersed droplets while decreasing mean droplet sizes. After being subjected to fast heating and then fast cooling, the silicone oil emulsion appeared to form many smaller dispersed droplets than those being proceeded with slow cooling. The emulsion of silicone oil was found to have adequate engine fuel properties. Full article

The effects of emulsification variables, such as surfactant type and heating/cooling emulsion processes, on the emulsification characteristics of silicone oil’s emulsions prepared by the phase inversion temperature method were investigated in this study. The water-in-oil (W/O) emulsions have been widely applied to enhance burning efficiency and reduce both pollutant emissions and fuel consumption. The silicone oil was emulsified with de-ionized water with the assistance of nonionic surfactants to form oil-in-water (O/W) emulsions. The hydrophilic–lipophilic balance (HLB) value of the Span 80 and Tween 20 surfactant mixture was set equal to 10 based on their weight proportions and the respective HLB values of the two surfactants. The experimental results show that the emulsions with the Span 80/Tween 20 surfactant mixture appeared to have a higher phase inversion temperature and a larger electrical conductance. On the other hand, it has a lower emulsification stability and a narrower range of phase inversion temperature than the emulsions prepared with a Brij 30 surfactant (polyoxyethylene (4) lauryl ether). The increase in surfactant concentration from 1 wt.% to 10 wt.% decreased the electrical conductance and phase inversion temperature while increasing the suspensibility and absorbance value for the emulsions prepared with either Span 80/Tween 20 mixture or Brij 30. Full article

The engine performance and emission characteristics of burning emulsions of soybean oil biodiesel in a compression-ignition diesel engine prepared through the phase inversion temperature method were compared with those of neat soybean oil biodiesel and the emulsion prepared by the mechanical homogenization method. The engine torque was set constantly at 98 N·m with varying engine speeds. The experimental results show that the emulsion prepared by the method of phase inversion temperature had higher O₂ and NOx emissions, a higher excess air ratio, a higher exhaust gas temperature, and a higher brake fuel conversion efficiency than the emulsion prepared by the mechanical homogenization method, which had lower CO and CO₂ emissions, a lower equivalence ratio, and lower brake-specific fuel consumption. While the neat soybean oil biodiesel was found to have the lowest fuel consumption rate, brake-specific fuel consumption, and CO and CO₂ emissions, it had the highest exhaust gas temperature and brake fuel conversion efficiency, NOx and O₂ emissions, and excess air ratio among those three fuels. Therefore, the phase inversion temperature method is considered promising for preparing fuel emulsions as an alternative to petro-derived diesel for compression-ignition engines. Full article

Biodiesel is considered an environmentally friendly alternative to petro-derived diesel. The cetane number indicates the degree of difficulty in the compression-ignition of liquid fuel-powered engines. The allylic position equivalent (APE), which represents the unsaturated degree of fatty acid esters, was one of the key parameters for the cetane number of biodiesel. Due to the significant attributes of APE for biodiesel properties, the impact of APE on engine performance and emission characteristics was investigated in this study. The engine characteristics could be improved by adjusting the biodiesel fuel structure accordingly. A four-stroke and four-cylinder diesel engine accompanied by an engine dynamometer and a gas analyzer were used to derive the optimum blending ratio of the two biodiesels from soybean oil and waste cooking oil. Three fuel samples composed of various proportions of those two biodiesels and ultra-low sulfur diesel (ULSD) were prepared. The amounts of saturated fatty acids and mono-unsaturated fatty acids of the biodiesel made from waste cooking oil were significantly higher than those of the soybean-oil biodiesel by 9.92 wt. % and 28.54 wt. %, respectively. This caused a higher APE of the soybean-oil biodiesel than that of the biodiesel from waste cooking oil. The APE II biodiesel appeared to have the highest APE value (80.68) among those fuel samples. When the engine speed was increased to 1600 rpm, in comparison with the ULSD sample, the APE II biodiesel sample was observed to have lower CO and O₂ emissions and engine thermal efficiency by 15.66%, 0.6%, and 9.3%, while having higher CO₂ and NOx emissions, exhaust gas temperature, and brake-specific fuel consumption (BSFC) by 2.56%, 13.8%, 8.9 °C, and 16.67%, respectively. Hence, the engine performance and emission characteristics could be enhanced by adequately adjusting the degree of unsaturation of fatty acid esters represented by the APE of biodiesel. Full article

Mitral regurgitation (MR), the disruption of the mitral valve, contributes to heart failure (HF). Under conditions of volume overload, excess mineralocorticoids promote cardiac fibrosis. The mineralocorticoid receptor antagonist spironolactone is a potassium-sparing diuretic and a guideline-recommended therapy for HF, but whether it can ameliorate degenerative MR remains unknown. Herein, we investigate the efficacy of spironolactone in improving cardiac remodeling in MR-induced HF compared with that of a loop diuretic, furosemide. Using a novel and mini-invasive technique, we established a rat model of MR. We treated the rats with spironolactone or furosemide for twelve weeks. The levels of cardiac fibrosis, apoptosis, and stress-associated proteins were then measured. In parallel, we compared the cardiac remodeling of 165 patients with degenerative MR receiving either spironolactone or furosemide. Echocardiography was performed at baseline and at six months. In MR rats treated with spironolactone, left ventricular function—especially when strained—and the pressure volume relationship significantly improved compared to those of rats treated with furosemide. Spironolactone treatment demonstrated significant attenuation of cardiac fibrosis and apoptosis in left ventricular tissue compared to furosemide. Further, spironolactone suppressed the expression of apoptosis-, NADPH oxidase 4 (NOX4)- and inducible nitric oxide synthase (iNOS)-associated proteins. Similarly, compared with MR patients receiving furosemide those prescribed spironolactone demonstrated a trend toward reduction in MR severity and showed improvement in left ventricular function. Collectively, MR-induced cardiovascular dysfunction, including fibrosis and apoptosis, was effectively attenuated by spironolactone treatment. Our findings suggest a potential therapeutic option for degenerative MR-induced HF. Full article