The demand for fossil fuels is increasing because of globalization and rising energy demands. As a result, many nations are exploring alternative energy sources, and hydrogen is an efficient and ...practical alternative fuel. In the transportation industry, the development of hydrogen-powered cars aims to maximize fuel efficiency and significantly reduce exhaust gas emission and concentration. The impact of using hydrogen as a supplementary fuel for spark ignition (SI) and compression ignition (CI) engines on engine performance and gas emissions was investigated in this study. By adding hydrogen as a fuel in internal combustion engines, the torque, power, and brake thermal efficiency of the engines decrease, while their brake-specific fuel consumption increase. This study suggests that using hydrogen will reduce the emissions of CO, UHC, CO2, and soot; however, NOx emission is expected to increase. Due to the reduction of environmental pollutants for most engines and the related environmental benefits, hydrogen fuel is a clean and sustainable energy source, and its use should be expanded.
Ultrasound is one of the mechanical methods used for disruption of microorganisms. Ultrasonic treatments of microorganisms are sensitive to a wide range of parameters such as net thermal power, ...residence time distribution (RTD), and the biological structure of the target microorganism. A commercial ultrasonic processor attached to a stainless steel processing cell was used in this research work. To evaluate the net heat dissipated in a small volume of the commercial yeast
Saccharomyces cerevisiae
, the suspension was subjected to 117 W at 20 kHz; the ultrasound cell was operated in a batch configuration with a Perspex base. Mixing of the yeast suspension and the RTD were evaluated using image processing techniques. The results of the present study showed that the heat lost through the stainless steel wall, Perspex base, and the Sonotrode (Titanium) was around 13.5 % of the total power. The yeast disruption results were found to be positive. The yeast disruption test showed that complete yeast reduction can be achieved at 117 W and a specific energy of 1,146 kJ kg
−1
. Further study is needed to understand the real causes of microorganism disruption using ultrasound.
•Effects of fuel on the energy and exergy balance in bi-fuel SI engine investigated.•1st and 2nd laws efficiency of CNG are 5.4% & 3.18% more than gasoline respectively.•Destructed exergy in gasoline ...case is about 5.8% higher than CNG case, averagely.•Gaseous fuel produces lower CO emission while its NOx is higher than gasoline.
In this study, the effect of fuel type; gasoline or natural gas on the energy and exergy balance as well as the performance of spark ignition engine was experimentally investigated. The experiments were conducted using a four cylinder, naturally aspirated CNG–gasoline bi-fuel engine at wide open throttle (WOT) operating condition. The results showed that when engine was fed with gasoline, the output power was higher than that of gaseous fuel by 4.2kW on average throughout the engine speed range. Thermal efficiency of the engine with natural gas was higher than that of the gasoline by approximately 5.4% throughout the engine speed range. In addition, CNG fuel showed higher exergetic efficiency than gasoline, and based on these results second law efficiency of CNG engine was higher than that of gasoline engine by 3.18% on average. This was largely due to combustion temperature increase in CNG case. For all operating points, the percentage of energy and exergy transfer through exhaust gases and the cooling system in gasoline are lower than CNG. However the destructed exergy of gasoline was higher than CNG by about 5.8%, averagely.
The best Weibull distribution methods for the assessment of wind energy potential at different altitudes in desired locations are statistically diagnosed in this study. Seven different methods, ...namely graphical method (GM), method of moments (MOM), standard deviation method (STDM), maximum likelihood method (MLM), power density method (PDM), modified maximum likelihood method (MMLM) and equivalent energy method (EEM) were used to estimate the Weibull parameters and six statistical tools, namely relative percentage of error, root mean square error (RMSE), mean percentage of error, mean absolute percentage of error, chi-square error and analysis of variance were used to precisely rank the methods. The statistical fittings of the measured and calculated wind speed data are assessed for justifying the performance of the methods. The capacity factor and total energy generated by a small model wind turbine is calculated by numerical integration using Trapezoidal sums and Simpson's rules. The results show that MOM and MLM are the most efficient methods for determining the value of k and c to fit Weibull distribution curves.
Algae can be converted directly into energy, such as biodiesel, bioethanol and biomethanol and therefore can be a source of renewable energy. There is a growing interest for biodiesel production from ...algae because of its higher yield non-edible oil production and its fast growth that does not compete for land with food production. About 50% of algae weight is oil that this lipid oil can be used to make biodiesel. Algae is capable of yielding 30 times more oil per acre than the crops currently used in biodiesel production. Processes for biodiesel production from algae-oil are similar to food and non-food crops derived biodiesel processes. Because of disadvantages of fossil fuels, renewable energy sources are getting importance for sustainable energy development and environmental protection. Among the renewable sources, Iran has high biofuel energy potential. The Iranian government is considerable attention to the utilization of renewable energy, especially biofuels. Iran has enough land in order to algae cultivation that does not compete with food production. A salt lake (Lake Orumieh) in Iran's West Azarbaijan province, Maharlu salt lake in Iran's Fars province, Qom salt lake in Iran's Qom province have given rise to a new species of algae for biofuel. Algae are frequent in the shallow-marine lime stones in Zagros Mountains in north of Fars province. Greenish blooms of algae can be seen in the Persian Gulf and Caspian Sea, south and north of Iran respectively. This study presents a brief introduction to the resource, status and prospect of algae as a sustainable energy source for biodiesel production in Iran. The main advantages of using algae for biodiesel production in Iran are described.
Biodiesel is a recognized replacement for diesel fuel in compressed ignition engines due to its significant environmental benefits. The purpose of this study is to investigate the engine performance ...and emissions produced from Jatropha curcas, Ceiba pentandra and Calophyllum inophyllum biodiesel in compressed ignition engine. The biodiesel production process and properties are discussed and a comparison of the three biodiesels as well as diesel fuel is undertaken. After that, engine performance and emissions testing was conducted using biodiesel blends 10%, 20%, 30% and 50% in a diesel engine at full throttle load. The engine performance shows that those biodiesel blends are suitable for use in diesel engines. A 10% biodiesel blend shows the best engine performance in terms of engine torque, engine power, fuel consumption and brake thermal efficiency among the all blending ratios for the three biodiesel blends. Biodiesel blends have also shown a significant reduction in CO2, CO and smoke opacity with a slight increase in NOx emissions.
•The properties of JCME, CPME and CIME fulfill ASTM standard.•Engine performance and emission was conducted for JCME, CPME and CIME.•The B10 is the best engine performance and reduce in exhaust emission.
Adoption of hydrogen energy as an alternative to fossil fuels could be a major step towards decarbonising and fulfilling the needs of the energy sector. Hydrogen can be an ideal alternative for many ...fields compared with other alternatives. However, there are many potential environmental challenges that are not limited to production and distribution systems, but they also focus on how hydrogen is used through fuel cells and combustion pathways. The use of hydrogen has received little attention in research and policy, which may explain the widely claimed belief that nothing but water is released as a by-product when hydrogen energy is used. We adopt systems thinking and system dynamics approaches to construct a conceptual model for hydrogen energy, with a special focus on the pathways of hydrogen use, to assess the potential unintended consequences, and possible interventions; to highlight the possible growth of hydrogen energy by 2050. The results indicate that the combustion pathway may increase the risk of the adoption of hydrogen as a combustion fuel, as it produces NOx, which is a key air pollutant that causes environmental deterioration, which may limit the application of a combustion pathway if no intervention is made. The results indicate that the potential range of global hydrogen demand is rising, ranging from 73 to 158 Mt in 2030, 73 to 300 Mt in 2040, and 73 to 568 Mt in 2050, depending on the scenario presented.
This article assesses the impact of n-butanol (nB) and iso-butanol (isoB) as components of a butanol-acetone (BA) mixture on spray, combustion, engine performance and emission characteristics. The ...macroscopic spray characteristics including spray penetration, spray cone angle and spray volume of n-/iso-BA-diesel blends were measured at two injection pressures 300 bar and 500 bar. A direct visualisation technique high speed camera was used to analyse the images that were obtained. The spray results show that both n- and iso-BA-diesel blends achieved a slightly higher penetration distance compared to pure diesel, resulting in a better fuel-air distribution and mixing. Two blend ratios (10% and 20%) of iso- and n-BA-diesel blends were tested in a single-cylinder DI diesel engine at three engine speeds: 1400, 2000 and 2600 rpm at full load. The engine performance included measuring the following parameters: pressure inside the combustion cylinder; brake power (BP); and brake specific fuel consumption (BSFC). The exhaust gas emissions included measuring the following parameters: exhaust gas temperature (EGT); oxide of nitrogen (NOx); unburnt hydrocarbons (UHC); carbon monoxide (CO); and carbon dioxide (CO2). The results from the blended diesel with iso- and n- BA were also compared to pure diesel as a baseline. The results for 10 iso-BA-90 diesel showed a slight improvement in BP by 4% at medium speed, while the BP of 20iso-BA-diesel, 10 and 20 n-BA-diesel was slightly lower and comparable with pure diesel at all engine speeds. The highest peak in-cylinder pressure was measured for the iso-BA-diesel blends. BSFC and BTE were increased for both iso- and n-BA-diesel blends. CO emission reduced with the increase in both n-BA and iso-BA ratios in diesel blend. Both NOx emissions and EGT were decreased at all n-BA and iso-BA-diesel blends compared to pure diesel. UHC and NOx emissions concentration of n-BA-diesel blends were lower compared to that of the iso-BA-diesel blend. Thus, it can be concluded that iso-BA-diesel blends showed slight improvement in brake power and higher in-cylinder pressure, while n-BA-diesel blends resulted in lower emission levels in regard to NOx and UHC. Therefore, using n-BA and iso-BA blended together as an additive for diesel fuel could be a suitable blend to obtain optimum results in regard to engine performance.
•Using BA as a mixture reduces the butanol production cost.•Spray penetration of both n- and iso-BA-diesel is slightly higher than pure diesel fuel.•Iso-BA-diesel blend showed high peak in-cylinder pressure and slight improvement in brake power.•N-BA-diesel produced lower UHC and NOx emissions iso-BA-diesel blend showed much lower CO emissions.
In the present research work, a neural network model has been developed to predict the exhaust emissions and performance of a compression ignition engine. The significance and novelty of the work, ...with respect to existing literature, is the application of sensitivity analysis and an artificial neural network (ANN) simultaneously in order to predict the engine parameters. The inputs of the model were engine load (0, 25, 50, 75 and 100%), engine speed (1700, 2100, 2500 and 2900 rpm) and the percent of biodiesel fuel derived from waste cooking oil in diesel fuel (B0, B5, B10, B15 and B20). The relationship between the input parameters and engine cylinder performance and emissions can be determined by the network. The global sensitivity analysis results show that all the investigated factors are effective on the created model and cannot be ignored. In addition, it is found that the most emissions decreased while using biodiesel fuel in the compression ignition engine.
The performance of a natural gas fueled spark ignition engine was studied to investigate the effect of hydrogen enrichment on the engine operating range and combustion characteristics. A validated ...multi-dimensional CFD model coupled with detailed chemical kinetics mechanism was used to study the combustion process in Hydrogen/CNG engine. Results indicated that misfiring occurs in equivalence ratios of about 0.61, 0.48 and 0.42 for hydrogen fractions of 0%, 30% and 50% respectively. Also, combustion durations were 70, 47 and 45° crank angle for hydrogen fractions of 0%, 30% and 50% respectively with same equivalence ratio (Ф = 0.625). Regarding the emission, the maximum amount of break specific NOx was detected around Ф = 0.83 (λ = 1.2), and this point is almost independent of the hydrogen fraction. It was found that hydrogen fraction decreases the emissions of CO, and HC and CO2. Adding 30% hydrogen reduced CO2 emission by10.2% while 50% hydrogen fraction led to 22.7% CO2 reduction.
•CNG fueled SI engine was studied by coupling the CFD to chemical kinetic model.•Operating range of engine extended about 20% by adding 30% H2 and 39% for 50% H2.•Combustion duration were 70, 47 and 45° CA for H2 fractions of 0%, 30% and 50%.•The Φ that maximum NOx occurred is nearly independent of the hydrogen fraction.•30% H2 reduced 10.2% CO2 emission approximately and 50% H2 led to 22.7% reduction.
PDF
