Search Results (41)

The search for alternative fuels is driven by increasing environmental and health concerns across the globe. Water-in-diesel emulsions (WiDEs) have been explored over the years as a potential fuel for diesel engines to mitigate emissions of greenhouse gases, especially nitrogen oxides and smoke. Researchers have been developing and testing different formulations of emulsified fuels with the common goal of stabilizing the mixture and minimizing pollutant emissions without significantly compromising engine performance. In this work, a novel approach is taken by developing a hydrophilic emulsion formulation optimized for engine operating temperatures, overcoming the storage-related stability issues that most studies focus on. Two different mixtures of WiDE were heated and supplied to a Hatz 1B40 single-cylinder diesel engine. The engine was coupled to an eddy current dynamometer to measure speed, torque, and power values. Emissions of carbon monoxide (CO), carbon dioxide (CO₂), hydrocarbons (HCs), nitric oxide (NO), and oxygen (O₂) were measured by an AVL DiGas 1000 exhaust gas analyzer. Smoke emissions were measured by an AVL DiSmoke 480. This study represents a contribution to the field of alternative fuels for diesel engines by providing experimental evidence that formulating WiDE for operating temperatures can be advantageous and significantly improve thermal efficiency and reduce emissions of NO and smoke at specific engine operating conditions, with a maximum reduction of 46.86% for NO emissions and a maximum reduction of 83.67% for smoke emissions obtained when compared to diesel. Full article

Shipping, as the most efficient, cheapest, and most widespread mode of transporting goods, also generates significant exhaust emissions. This has led to the adoption of stringent regulatory restrictions on emissions from ship propulsion systems. Consequently, the education and training of marine engineers can significantly impact their understanding of how emissions are generated and their potential for reduction. The engine room simulator is an indispensable tool in the training of marine engineers. Since operating conditions and parameters have the greatest impact on NOx emissions, this forms the primary focus of this research. This study tests the accuracy and precision of the engine room simulator in simulating emissions and evaluating the influence of operating conditions on them. Furthermore, the implementation and testing of NOx emission reduction technologies are vital for promoting sustainable shipping, ensuring regulatory compliance, and training personnel to support environmentally conscious maritime operations. Using the example of a two-stroke marine diesel engine, the results obtained are compared with test bench data from similar engines. Special emphasis is placed on simulating the operation of a two-stroke diesel engine at low speed, or low load, where secondary NOx reduction methods cannot be used. Therefore, the simulator is tested using two available technologies: water–fuel emulsion and altering the fuel injection timing to reduce NOx emissions. The simulation results for the water–fuel emulsion show high accuracy in predicting NOx emission trends when changing the water content in the emulsion at nominal power. However, at low load, the results show significant deviations. Testing the effect of altering fuel injection timing under low load using the engine room simulator shows significant differences compared to available research. Nonetheless, research on NOx emissions in this engine mode is limited, presenting a potential area for further study. When comparing the results for nominal power operation, the simulation provides more accurate results, particularly in terms of the influence of fuel injection timing on NOx emissions. However, engine tests on the test bench still reveal more substantial changes in emissions than those obtained using the engine room simulator. Full article

Managing chemical reactivity is crucial for sustainable chemistry and industry, fostering efficiency, reducing chemical waste, saving energy, and protecting the environment. Emulsification is used for different purposes, among them controlling the reactivity of highly reactive chemicals. Thermochemical fluids (TCFs), such as NH₄Cl and NaNO₂ salts, have been utilized in various applications, including the oil and gas industry. However, the excessive reactivity of TCFs limits their applications and consequently negatively impacts the potential success rates. In this study, an emulsification technique was employed to control the high reactivity of TCFs explored at 50% and 70% in diesel, using three distinct emulsifier systems at concentrations of 1%, 3%, and 5% to form water-in-oil emulsions. The reactivity of 4M neat TCFs and emulsified solutions was examined in an autoclave reactor as a function of triggering temperatures of 65–95 °C, volume fraction, and emulsifier type and concentration. Additionally, this study explores an alternative method for controlling TCF reactivity through pH adjustment. It investigates the impact of TCFs at pH values ranging from 6 to 10 and the initial pressure on the resulting pressure, temperature, and time needed to initiate the TCF’s reaction. The results revealed that both emulsification and pH adjustment have the potential to promote sustainability by controlling the reactivity of TCF reactions. The findings from this study can be utilized to optimize various downhole applications of TCFs, enhancing the efficiency of TCF reactions and success rates. This paper presents in detail the results obtained, and discusses the potential contributions of the examined TCFs’ reactivity control techniques to sustainability. Full article

Diesel engines are known for their excellent efficiency and are therefore used in a variety of applications. However, they are also one of the main sources of hazardous emissions such as nitrogen oxides (NO_x) and smoke. Water-in-Diesel Emulsion (WiDE) is an alternative fuel that can possibly reduce some of the pollutant emissions without compromising engine performance. The surfactant formulation for WiDE usually follows the one used in water-in-oil (w/o) emulsions, where low hydrophilic–lipophilic balance (HLB) emulsifiers are preferred for better solubility in the diesel phase and stabilization at storage temperatures. However, by using a hydrophilic blend with a non-ionic surfactant, it is possible to develop an optimized formulation at higher fuel temperatures, which occur during an engine’s operating condition, achieving possibly higher benefits. Across the different speeds, the results for the emulsion show 7.57% mean improvement in specific fuel consumption (SFC), 19.14% mean improvement in thermal efficiency (TE), 5.54% mean reduction in carbon dioxide (CO₂), 20.50% mean reduction in nitric oxide (NO) and 75.19% mean reduction in smoke levels. However, carbon monoxide (CO) and hydrocarbons (HC) emissions were higher, with a mean increase of 81.09% and 93.83%, respectively. Full article

The objective of this study is to investigate the impact of employing water nano-emulsion technology in mitigating pollutants in diesel engines and controlling emissions. The diesel used in this experiment was prepared by blending it with a water-based nano-emulsion, comprising 8% of the total mixture. The integration of the Internet of Things (IoT) facilitated the implementation of a multi-user remote management system for diesel engines, enabling real-time monitoring of emissions. An 8% combination of water-based nano-emulsion (WBNE) reduces oxides of nitrogen and hydrocarbons better than diesel, according to trials using an IoT kit and gas analysers. Full article

This study aims to assess the impact of the water ratio and nanoparticle concentration of neat diesel fuel on the performance characteristics of and exhaust gas emissions from diesel engines. The experimental tests were conducted in two stages. In the first stage, the effects of adding water to neat diesel fuel in ratios of 2.5% and 5% on engine performance and emissions characteristics were examined and compared to those of neat diesel at a constant engine speed of 3000 rpm under three different engine loads. A response surface methodology (RSM) based on a central composite design (CCD) was utilized to simulate the design of the experiment. According to the test results, adding water to neat diesel fuel increased the brake-specific fuel consumption and reduced the brake thermal efficiency compared to neat diesel fuel. In the examination of exhaust emissions, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) in the tested fuel containing 2.5% of water were decreased in comparison to pure diesel fuel by 16.62%, 21.56%, and 60.18%, respectively, on average, through engine loading. In the second stage, due to the trade-off between emissions and performance, the emulsion fuel containing 2.5% of water is chosen as the best emulsion from the previous stage and mixed with aluminum oxide nanoparticles at two dose levels (50 and 100 ppm). With the same engine conditions, the emulsion fuel mixed with 50 ppm of aluminum oxide nanoparticles exhibited the best performance and the lowest emissions compared to the other evaluated fuels. The outcomes of the investigations showed that a low concentration of 50 ppm with a small amount of 11 nm of aluminum oxide nanoparticles combined with a water diesel emulsion is a successful method for improving diesel engine performance while lowering emissions. Additionally, it was found that the mathematical model could accurately predict engine performance parameters and pollution characteristics. Full article

Cogeneration or combined heat and power (CHP) has found wide application in various industries because it very effectively meets the growing demand for electricity, steam, hot water, and also has a number of operational, environmental, economic advantages over traditional electrical and thermal systems. Experimental and theoretical investigations of the afterburning of fuel oil in the combustion engine exhaust gas at the boiler inlet were carried out in order to enhance the efficiency of cogeneration power plants; this was achieved by increasing the boiler steam capacity, resulting in reduced production of waste heat and exhaust emissions. The afterburning of fuel oil in the exhaust gas of diesel engines is possible due to a high the excess air ratio (three to four). Based on the experimental data of the low-temperature corrosion of the gas boiler condensing heat exchange surfaces, the admissible values of corrosion rate and the lowest exhaust gas temperature which provide deep exhaust gas heat utilization and high efficiency of the exhaust gas boiler were obtained. The use of WFE and afterburning fuel oil provides an increase in efficiency and power of the CPPs based on diesel engines of up to 5% due to a decrease in the exhaust gas temperature at the outlet of the EGB from 150 °C to 90 °C and waste heat, accordingly. The application of efficient environmentally friendly exhaust gas boilers with low-temperature condensing surfaces can be considered a new and prosperous trend in diesel engine exhaust gas heat utilization through the afterburning of fuel oil and in CPPs as a whole. Full article

In this work, membranes were synthesized by depositing fluoropolymer coatings onto metal meshes using the hot wire chemical vapor deposition (HW CVD) method. By changing the deposition parameters, membranes with different wetting angles were obtained, with water contact angles for different membranes over a range from 130° ± 5° to 170° ± 2° and a constant oil contact angle of about 80° ± 2°. These membranes were used for the separation of an oil–water emulsion in a simple filtration test. The main parameters affecting the separation efficiency and the optimal separation mode were determined. The results reveal the effectiveness of the use of the membranes for the separation of emulsions of water and commercial crude oil, with separation efficiency values that can reach over 99%. The membranes are most efficient when separating emulsions with a water concentration of less than 5%. The pore size of the membrane significantly affects the rate and efficiency of separation. Pore sizes in the range from 40 to 200 µm are investigated. The smaller the pore size of the membranes, the higher the separation efficiency. The work is of great economic and practical importance for improving the efficiency of the membrane separation of oil–water emulsions. It lays the foundation for future research on the use of hydrophobic membranes for the separation of various emulsions of water and oil products (diesel fuel, gasoline, kerosene, etc.). Full article

Water-in-diesel (W/D) emulsion fuel is a potentially viable diesel fuel that can simultaneously enhance engine performance and reduce exhaust emissions in a current diesel engine without requiring engine modifications or incurring additional costs. In a consistent manner, the current study examines the impact of adding water, in the range of 5–30% wt. (5% increment) and 2% surfactant of polysorbate 20, on the performance in terms of brake torque (BT) and exhaust emissions of a four-cylinder four-stroke diesel engine. The relationship between independent factors, including water addition and engine speed, and dependent factors, including different exhaust released emissions and BT, was initially generated using machine learning support vector regression (SVR). Subsequently, a robust and modern optimization of the sea-horse optimizer (SHO) was run through the SVR model to find the optimal water addition and engine speed for improving the BT and lowering exhaust emissions. Furthermore, the SVR model was compared to the artificial neural network (ANN) model in terms of R-squared and mean square error (MSE). According to the experimental results, the BT was boosted by 3.34% compared to pure diesel at 5% water addition. The highest reduction in carbon monoxide (CO) and unburned hydrocarbon (UHC) was 9.57% and 15.63%, respectively, at 15% of water addition compared to diesel fuel. The nitrogen oxides (NOx) emissions from emulsified fuel were significantly lower than those from pure diesel, with a maximum decrease of 67.14% at 30% water addition. The suggested SVR-SHO model demonstrated superior prediction reliability, with a significant R-Squared of more than 0.98 and a low MSE of less than 0.003. The SHO revealed that adding 15% water to the W/D emulsion fuel at an engine speed of 1848 rpm yielded the optimum BT, CO, UHC, and NOx values of 49.5 N.m, 0.5%, 57 ppm, and 369 ppm, respectively. Finally, these outcomes have important implications for the potential of the SVR-SHO approach to minimize engine exhaust emissions while maximizing engine performance. Full article

Water-in-diesel (W/D) emulsion fuel is a potential alternative fuel that can simultaneously lower NOx exhaust emissions and improves combustion efficiency. Additionally, there are no additional costs or engine modifications required when using W/D emulsion fuel. The proportion of water added and engine speed is crucial factors influencing engine behavior. This study aims to examine the impact of the W/D emulsion diesel fuel on engine performance and NOx pollutant emissions using a compression ignition (CI) engine. The emulsion fuel had water content ranging from 0 to 30% with a 5% increment, and 2% surfactant was employed. The tests were performed at speeds ranging from 1000 to 3000 rpm. All W/D emulsion fuel was compared to a standard of pure diesel in all tests. A four-cylinder, four-stroke, water-cooled, direct-injection diesel engine test bed was used for the experiments. The performance and exhaust emissions of the diesel engine were measured at full load and various engine speeds using a dynamometer and an exhaust gas analyzer, respectively. The second purpose of this study is to illustrate the application of two optimizers, grey wolf optimizer (GWO) and intelligent grey wolf optimizer (IGOW), along with using multivariate polynomial regression (MPR) to identify the optimum (W/D) emulsion blend percentage and engine speed to enhance the performance, reduce fuel consumption, and reduce NO_X exhaust emissions of a diesel engine operating. The engine speed and proportion of water in the fuel mixture were the independent variables (inputs), while brake power (BP), brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and NOx were the dependent variables (outcomes). It was experimentally observed that utilizing emulsified gasoline generally enhances engine performance and decreases emissions in general. Experimentally, at 5% water content and 2000 rpm, the BSFC has a minimal value of 0.258 kJ/kW·h. Under the same conditions, the maximum BP of 11.6 kW and BTE of 32.8% were achieved. According to the IGWO process findings, adding 9% water to diesel fuel and running the engine at a speed of 1998 rpm produced the highest BP (11.2 kW) and BTE (33.3%) and the lowest BSFC (0.259 kg/kW·h) and reduced NOx by 14.3% compared with the CI engine powered by pure diesel. The accuracy of the model is high, as indicated by a correlation coefficient R² exceeding 0.97 and a mean absolute error (MAE) less than 0.04. In terms of the optimizer, the IGWO performs better than GWO in determining the optimal water addition and engine speed. This is attributed to the IGWO has excellent exploratory capability in the early stages of searching. Full article

Techniques such as exhaust gas recirculation (EGR) and water-in-fuel emulsions (WFEs) can significantly decrease NOx emissions in diesel engines. As a disadvantage of adopting EGR, the afterburning period lengthens owing to a shortage of oxygen, lowering thermal efficiency. Meanwhile, WFEs can slightly reduce NOx emissions and reduce the afterburning phase without severely compromising thermal efficiency. Therefore, the EGR–WFE combination was modeled utilizing the KIVA-3V code along with GT power and experimental results. The findings indicated that combining EGR with WFEs is an efficient technique to reduce afterburning and enhance thermal efficiency. Under the EGR state, the NO product was evenly lowered. In the WFE, a considerable NO amount was created near the front edge of the combustion flame. Additionally, squish flow from the piston’s up–down movement improved fuel–air mixing, and NO production was increased as a result, particularly at high injection pressure. Using WFEs with EGR at a low oxygen concentration significantly reduced NO emissions while increasing thermal efficiency. For instance, using 16% of the oxygen concentration and a 40% water emulsion, a 94% drop in NO and a 4% improvement in the Indicated Mean Effective Pressure were obtained concurrently. This research proposes using the EGR–WFE combination to minimize NO emissions while maintaining thermal efficiency. Full article

In this study, chitosan (CT) and naturally occurring acacia gum (AG) blends were employed as emulsifiers to form a series of emulsions developed from diesel and water. Effects of pH level (3, 5, 10, and 12) and various NaCl salt concentrations (0.25–1%) on the stability, viscosity, and interfacial properties of CT-(1%)/AG-(4%) stabilized Pickering emulsions were evaluated. Bottle test experiment results showed that the stability indexes of the CT/AG emulsions were similar under acidic (3 and 5) and alkaline (10 and 12) pH media. On the other hand, the effects of various NaCl concentrations on the stability of CT-(1%)/AG-(4%) emulsion demonstrated analogous behavior throughout. From all the NaCl concentrations and pH levels examined, viscosities of this emulsion decreased drastically with the increasing shear rate, indicating pseudoplastic fluid with shear thinning characteristics of these emulsions. The viscosity of CT-(1%)/AG-(4%) emulsion increased at a low shear rate and decreased with an increasing shear rate. The presence of NaCl salt and pH change in CT/AG solutions induced a transformation in the interfacial tension (IFT) at the diesel/water interface. Accordingly, the IFT values of diesel/water in the absence of NaCl/CT/AG (without emulsifier and salt) remained fairly constant for a period of 500 s, and its average IFT value was 26.16 mN/m. In the absence of salt, the addition of an emulsifier (CT-(1%)/AG-(4%)) reduced the IFT to 16.69 mN/m. When the salt was added, the IFT values were further reduced to 12.04 mN/m. At low pH, the IFT was higher (17.1 mN/M) compared to the value of the IFT (10.8 mN/M) at high pH. The results obtained will help understand the preparation and performance of such emulsions under different conditions especially relevant to oil field applications. Full article

The aim of this work is the combustion of emulsions in two internal combustion diesel engines, instead of residual fuel oil, to reduce pollutant emissions into the atmosphere and fuel consumption for a cleaner energy transition. A methodology was designed that include the planification and implementation of several experiments in a thermoelectric power plant in Madeira Island, that is part of an isolated electricity production system. In the first place, the planification of experiences was developed and the reference points were created. In this case study, three different operating regimes at the nominal speed of 500 rpm were studied: 7.5 MW, 8.5 MW and 9.5 MW, with a gradual increase of the incorporation of water into the emulsions. A comparative analysis of the potential emulsions in diesel engines, instead of fuel oil, were carried out and two process solutions were created in the 8.5 MW regime with 15% v/v of water and 18% v/v of water. The impact on process parameters and the savings obtained were measured. The best result obtained was the reduction of 56.5% of CO, 96.7% of NO₂ and 4.2% of NOx emissions. The specific fuel consumption savings obtained were 2.7%. In conclusion, the experiments and research developed contributed to a more in-depth knowledge about the potential of emulsions in combustion systems; pollutant emissions were reduced; and we designed a new operation regime for the internal combustion engine that are part of an isolated electricity production system. Full article

The characteristics of the collisions of droplets with solid particles (52,100 steel) were experimentally studied when varying the key liquid properties: viscosity (1–6.3 mPa·s), surface tension (72.69–36.1 mN/m) and interfacial (liquid-liquid) tension (3.41–42.57 mN/m). Distilled water, aqueous solutions of glycerol, surfactants and diesel emulsions were used. The experimental conditions corresponded to the following ranges: Weber number 5–450, Ohnesorge number 0.001–0.03, Reynolds number 0.1–1000, capillary number 0.01–0.3. Droplet-particle collision regimes (agglomeration, stretching separation) were identified and the characteristics of secondary liquid fragments (size, number) were determined. Droplet-particle interaction regime maps in the We(Oh) and Re(Ca) systems were constructed. Equations describing the transition boundaries between the droplet-particle interaction regimes were obtained. The equations take the form: We = a · Oh + c. For the conditions of the droplet-particle interaction, the relationship We = 2214 · Oh + 49.214 was obtained. For the interaction with a substrate: We = 1.0145 · Oh + 0.0049. The experimental results were compared with the characteristics of collisions of liquid droplets with each other. Differences in the characteristics of secondary atomization of droplets as a result of collisions were identified. Guidelines were provided for applying the research findings to the development of liquid droplet secondary atomization technologies in gas-vapor-droplet applications. Full article

The application of water-fuel emulsion (WFE) in internal combustion engines enables to reduce the consumption of sulfurous fuel oils, thereby protecting the environment from emissions of sulfur and nitrogen oxides, as well revealing a great potential for the heat utilization of exhaust gases. The efficiency of utilization of exhaust gas heat in exhaust boilers (EGB) depends on their temperature at the outlet of EGB, id est. the depth of heat utilization. Exhaust gas temperature is limited by the rate of low-temperature corrosion (LTC), which reaches a level of 1.2 mm/year at the wall temperature of about 110 °C for the condensing heat exchange surfaces (HES) and reduces the reliability of the HES operation. Therefore, decreasing the corrosion rate of condensing HES at wall temperature below 110 °C to an acceptable level (about 0.2 mm/year) when undergoing WFE combustion will make it possible to reduce the exhaust gas temperature and, consequently, increase the efficiency of EGB and fuel saving during the operation of the ship power plant. The aim of the research is to assess improvements to the reliability, durability and efficient operation of condensing HES in marine EGB undergoing WFE combustion in a diesel engine based on experimental studies of the LTC process. A special experimental setup was developed for investigation. The use of WFE with a decreased wall temperature of HES below 80 to 70 °C would improve the reliability of the EGB along the accepted service life, increase the lifetime of the HES metal by almost six times as well as the overhaul period, and reduce the cost of repairing condensing HES. Furthermore, due to the reducing corrosion rate under WFE combustion, the application of low-temperature condensing HES makes it possible to enhance the efficiency of deeper exhaust gas heat utilization and provide sustainable efficient operation of a diesel engine plant on the whole at a safe thermal and environmentally friendly level. Full article