Abstract: In maize growing technologies, tillage technological operations are the most time-consuming and require the greatest fuel input. Substitution of conventional tillage, involving deep ploughing, by other reduced tillage methods can reduce technological production costs, diminish soil degradation and environmental pollution from greenhouse gas emissions, as well as improve economic competitiveness of agricultural produce.
Experiments designed to assess energy and environmental aspects associated with different reduced tillage systems, applied in maize cultivation were conducted at Aleksandras Stulginskis University taking into account Lithuania’s economic and climate conditions. The study involved 5 tillage treatments: deep ploughing (DP, control), shallow ploughing (SP), deep cultivation (DC), shallow cultivation (SC) and no-tillage (NT).
Our experimental evidence suggests that with the application of reduced tillage systems it is feasible to reduce fuel consumption by 13-58% and working time input by 8.4% to nearly 3-fold, to reduce the cost price of maize cultivation technological operations, decrease environmental pollution with CO2 gas by 30 to 146 kg ha-1, compared with the deep ploughing.
Abstract: Renewable energy, including bio energy are an alternative to fossil fuel depletion and a way to fight against the harmful effects of climate change. It is possible to develop common dates of low commercial value, and put on the local and international market a new generation of products with high added values such as bio ethanol. Besides its use in chemical synthesis, bio ethanol can be blended with gasoline to produce a clean fuel while improving the octane.
Abstract: We are interested in this paper to the thermal effects occurring during the filling of hydrogen tanks. The consequence of this heating on the storage performance of these speakers was appreciated. The motivation comes from the fact that the development of hydrogen as an energy carrier of the future will require strong evolution in the field of storage modes to smaller, less expensive lighter, with a strong security interest and considerable autonomy.
Abstract: Considering the increasing need of biofuels in Europe and the legislative requirements of the European Union it is needed to quantify the greenhouse gas emissions of biofuels life cycle. In this article a carbon footprint analysis to quantify these gases emitted during production and use of Romanian rapeseed oil (RO) and biodiesel from rapeseed oil (RME) was conducted. The functional unit was considered the LHV of diesel oil of 42.8 MJ·kg-1 corresponding to 1.15kg. of RO and 1.10 kg. of RME. When the 3 fuels were compared, the results show important benefits when using rapeseed oil or biodiesel instead of diesel. The most impacting stage in terms of GHG emissions is the use of the fuels. In this stage, rapeseed oil registers a total quantity of 3,229 kg CO2eq.·FU-1 and biodiesel register a total quantity of 3,088 kg CO2eq.·FU-1 while mineral diesel registers a total quantity of 3,156 kg CO2eq.·FU-1 emitted in the air. Taking into account that rape plant absorbed during growth stage the same quantity of CO2 as emitted into atmosphere during usage stage of the fuel, when compared the three fuels, rapeseed oil and biodiesel obtain obvious benefits against fossil diesel. Results show that by substituting diesel with RO a total quantity of 5,663 kg. CO2eq.·FU-1 would be saved while using biodiesel a total quantity of 5,570 kg. CO2eq.·FU-1 can be saved.
Abstract: Worldwide interests for the renewable energy are increasing due to environmental and climate changes from traditional petroleum related energy sources. To account for these social needs, ligneous biomass energy is considered as one of the environmentally friend energy solutions. The wood torrefaction process is a feasible method to improve the properties of the biomass fuel and makes the wood have low moisture, lower smoke emission and increased heating value. In this work, therefore, the moisture evaporation model which largely affects energy efficiency of ligneous biomass through moisture contents and heating value relative to its weight is studied with numerical modeling approach by analyzing the effects of torrefaction furnace temperature. The results show that the temperature and moisture fraction of wood decrease by increasing the furnace temperature. When the torrefaction temperature is lower than 423K, there were little changes of the moisture fraction in the wood. Also, it can be found that charcoal is produced more slowly when the torrefaction temperature is lower than 573K.
Abstract: In the present study, the effects of bioethanol-unleaded gasoline blends on engine performance were investigated in a spark ignition engine. Fuel containing 100% ethanol (E100), fuel blend containing 40% bioethanol by volume (E40) and 100% unleaded gasoline (E0) were tested and the test results were compared. As the result of the study, it was found that the use of unleaded gasoline and bioethanol-unleaded gasoline blends as fuel did not cause a significant change in engine performance. The results of the engine tests showed that the use of unleaded gasoline-bioethanol blends as fuel caused a decrease in engine torque and engine power depending on the increase in the ratio of bioethanol in the fuel blend. As the result of these decreases, increases of up to 30% were observed in the specific fuel consumption of the engine.
Abstract: Hydrogen is an important chemical in many industries and it is expected to become one of the major fuels for energy generation in the future. Unfortunately, hydrogen does not exist in its elemental form in nature and therefore has to be produced from hydrocarbons, hydrogen-containing compounds or water.
Above its critical point (374.8oC and 22.1MPa), water has lower density and viscosity, and a higher heat capacity than those of ambient water. Mass transfer in supercritical water (SCW) is enhanced due to its increased diffusivity and transport ability. The reduced dielectric constant makes supercritical water a better solvent for organic compounds and gases. Hence, due to the aforementioned desirable properties, there is a growing interest toward studies regarding the gasification of organic matter containing biomass or model biomass solutions in supercritical water.
In this study, hydrogen and biofuel production by the catalytic gasification of 2-Propanol in supercritical conditions of water was investigated. Ru/Al2O3 was the catalyst used in the gasification reactions. All of the experiments were performed under a constant pressure of 25 MPa. The effects of five reaction temperatures (400, 450, 500, 550 and 600oC) and five reaction times (10, 15, 20, 25 and 30 s) on the gasification yield and flammable component content were investigated.
Abstract: Hydrogen fuel is a zero-emission fuel which uses electrochemical cells or combustion in internal engines, to power vehicles and electric devices. Methods of hydrogen storage for subsequent use span many approaches, including high pressures, cryogenics and chemical compounds that reversibly release H2 upon heating. Most research into hydrogen storage is focused on storing hydrogen as a lightweight, compact energy carrier for mobile applications. With the accelerating demand for cleaner and more efficient energy sources, hydrogen research has attracted more attention in the scientific community. Until now, full implementation of a hydrogen-based energy system has been hindered in part by the challenge of storing hydrogen gas, especially onboard an automobile. New techniques being researched may soon make hydrogen storage more compact, safe and efficient. In this overview, few hydrogen storage methods and mechanism of hydrogen uptake in carbon nanotubes are summarized.
Abstract: This study focused on the estimation of carbon released to the atmosphere from dry dipterocarp forest (DDF) fires in Thailand. Laboratory experiments were conducted using a cone calorimeter to simulate the DDF fires. The leaf litter collected from DDF in western Thailand was used as biomass fuel. Three different masses of leaf litter were employed, 7g, 10g and 13g, to estimate the carbon released from this type of vegetation fire to the atmosphere. The chemical analysis of the leaf litter showed that the carbon content in the experimental biomass fuel was 46.0±0.1%. From the experiments, it was found that more than 95% of the carbon input was converted to carbon released to the atmosphere, while less than 5% were left in the form of residues, and returned to soil. From the study, the carbon released amounted 440.213±2.243 g/kgdry biomass, and the carbon retained in the residues was 19.786±2.243 g/kgdry biomass. The quantity of biomass fuel consumed to produce 1 g of carbon released was 2.27±0.01gkgdry biomass. Using these experimental data of carbon produced by the DDF fires, it was estimated that this type of fires in 2009 contributed to 4.659 tonnes of carbon released to the atmosphere, and 0.229 tonnes of carbon in the residues to be returned to soil in Thailand.
Abstract: This research is aimed to find optimal values of parameters of acacia wood chips combustion in a bubbling fluidized bed for electrification within the area of the Royal Thai Navy in Sattahip, Chonburi province, Thailand. The size of wood chips falls in the range of 25 mm in diameter. The bed temperature is set within the range of 800±10 oC with the air flow rate of 2.1-3.1 m/min corresponding to the air-fuel ratio between 0.71 to 1.03. The resulting thermal efficiency is approximately 95% with a thermal output of 474.76 kWth, which produced the electricity 0.131 kW-hr.
Abstract: According to biodiesel from microalgae is an attractive fuel for several reasons such as renewable, biodegradable and environmental friendly. Thus, this study, green microalgae Scenedesmus acutus PPNK1 isolated from natural water, was selected based on high growth rates, easy cultivation and high lipid content. The Nile red fluorescence method has been successfully applied to the determination of lipids in S. acutus PPNK1. The combination of the method to the lipid composition in algal cells showed the yellow fluorescence under fluorescent microscope. Interestingly, maximum cell numbers and biomass concentration were obtained at 5.44´107 cells/mL and 1.60 g/L when it was cultivated in BG-11 medium while in case of BG-11 with nitrogen deprivation (N 0.25 g/L), accumulated lipid content in cells (44.67%) was achieved that was higher than that found in case of BG-11 medium at about 2 times (22.63%).
Abstract: Combustion of fuels in industrial and transport sector has lead to an alarming release of polluting gases to the atmosphere. Carbon monoxide is one such pollutant, which is formed as a result of incomplete oxidation of the fuel. In order to analyze the effect of catalyst on the reduction of CO emissions to the atmosphere, two catalysts Mn2O3 and Hopcalite are considered. A model was formed based on mass and energy balance equations. Results show that Hopcalite catalyst as compared to Mn2O3 catalyst helped in faster conversion of the polluting gas as the operating temperature of the hopcalite catalyst is much lower as compared to the operating temperature of Mn2O3 catalyst.
Abstract: The electrical power systems of aircrafts have made
serious progress in recent years because the aircrafts depend more
and more on the electricity. There is a trend in the aircraft industry to
replace hydraulic and pneumatic systems with electrical systems,
achieving more comfort and monitoring features and enlarging the
energetic efficiency. Thus, was born the concept More Electric
Aircraft. In this paper is analyzed the integration of a fuel cell into
the existing electrical generation and distribution systems of an
aircraft. The dynamic characteristics of fuel cell systems necessitate
an adaptation of the electrical power system. The architecture studied
in this paper consists of a 50kW fuel cell, a dc to dc converter and
several loads. The dc to dc converter is used to step down the fuel
cell voltage from about 625Vdc to 28Vdc.
Abstract: Themain goal of this article is to find efficient
methods for elemental and molecular analysis of living
microorganisms (algae) under defined environmental conditions and
cultivation processes. The overall knowledge of chemical
composition is obtained utilizing laser-based techniques, Laser-
Induced Breakdown Spectroscopy (LIBS) for acquiring information
about elemental composition and Raman Spectroscopy for gaining
molecular information, respectively. Algal cells were suspended in
liquid media and characterized using their spectra. Results obtained
employing LIBS and Raman Spectroscopy techniques will help to
elucidate algae biology (nutrition dynamics depending on cultivation
conditions) and to identify algal strains, which have the potential for
applications in metal-ion absorption (bioremediation) and biofuel
industry. Moreover, bioremediation can be readily combined with
production of 3rd generation biofuels. In order to use algae for
efficient fuel production, the optimal cultivation parameters have to
be determinedleading to high production of oil in selected
cellswithout significant inhibition of the photosynthetic activity and
the culture growth rate, e.g. it is necessary to distinguish conditions
for algal strain containing high amount of higher unsaturated fatty
acids. Measurements employing LIBS and Raman Spectroscopy were
utilized in order to give information about alga Trachydiscusminutus
with emphasis on the amount of the lipid content inside the algal cell
and the ability of algae to withdraw nutrients from its environment
and bioremediation (elemental composition), respectively. This
article can serve as the reference for further efforts in describing
complete chemical composition of algal samples employing laserablation
techniques.
Abstract: A numerical study on the effect of side-dump angle on
fuel droplets sizing and effective mass fraction have been
investigated in present paper. The mass of fuel vapor inside the
flammability limit is named as the effective mass fraction. In the first
step we have considered a side-dump combustor with dump angle of
0o (acrossthe cylinder) and by increasing the entrance airflow velocity
from 20 to 30, 40 and 50 (m/s) respectively, the mean diameter of
fuel droplets sizing and effective mass fraction have been studied.
After this step, we have changed the dump angle from 0o to 30o,45o
and finally 60o in direction of cylinderand also we have increased the
entrance airflow velocity from 20 up to 50 (m/s) with the amount of
growth of 10(m/s) in each step, to examine its effects on fuel droplets
sizing as well as effective mass fraction. With rise of entrance airflow
velocity, these calculations are repeated in each step too. The results
show, with growth of dump-angle the effective mass fraction has
been decreased and the mean diameter of droplets sizing has been
increased. To fulfill the calculations a modified version of KIVA-3V
code which is a transient, three-dimensional, multiphase,
multicomponent code for the analysis of chemically reacting flows
with sprays, is used.
Abstract: The national economy development affects the vehicle
ownership which ultimately increases fuel consumption. The rise of
the vehicle ownership is dominated by the increasing number of
motorcycles. This research aims to analyze and identify the
characteristics of fuel consumption, the city transportation system,
and to analyze the relationship and the effect of the city
transportation system on the fuel consumption. A multivariable
analysis is used in this study. The data analysis techniques include: a
Multivariate Multivariable Analysis by using the R software. More
than 84% of fuel on Java is consumed in metropolitan and large
cities. The city transportation system variables that strongly effect the
fuel consumption are population, public vehicles, private vehicles and
private bus. This method can be developed to control the fuel
consumption by considering the urban transport system and city
tipology. The effect can reducing subsidy on the fuel consumption,
increasing state economic.
Abstract: In recent years fuel cell vehicles are rapidly appearing
all over the globe. In less than 10 years, fuel cell vehicles have gone
from mere research novelties to operating prototypes and demonstration
models. At the same time, government and industry in development
countries have teamed up to invest billions of dollars in partnerships
intended to commercialize fuel cell vehicles within the early
years of the 21st century.
The purpose of this study is evaluation of model and performance
of fuel cell hybrid electric vehicle in different drive cycles. A fuel
cell system model developed in this work is a semi-experimental
model that allows users to use the theory and experimental relationships
in a fuel cell system. The model can be used as part of a complex
fuel cell vehicle model in advanced vehicle simulator (ADVISOR).
This work reveals that the fuel consumption and energy efficiency
vary in different drive cycles. Arising acceleration and speed in a
drive cycle leads to Fuel consumption increase. In addition, energy
losses in drive cycle relates to fuel cell system power request. Parasitic
power in different parts of fuel cell system will increase when
power request increases. Finally, most of energy losses in drive cycle
occur in fuel cell system because of producing a lot of energy by fuel
cell stack.
Abstract: Microscopic emission and fuel consumption models
have been widely recognized as an effective method to quantify real
traffic emission and energy consumption when they are applied with
microscopic traffic simulation models. This paper presents a
framework for developing the Microscopic Emission (HC, CO, NOx,
and CO2) and Fuel consumption (MEF) models for light-duty
vehicles. The variable of composite acceleration is introduced into
the MEF model with the purpose of capturing the effects of historical
accelerations interacting with current speed on emission and fuel
consumption. The MEF model is calibrated by multivariate
least-squares method for two types of light-duty vehicle using
on-board data collected in Beijing, China by a Portable Emission
Measurement System (PEMS). The instantaneous validation results
shows the MEF model performs better with lower Mean Absolute
Percentage Error (MAPE) compared to other two models. Moreover,
the aggregate validation results tells the MEF model produces
reasonable estimations compared to actual measurements with
prediction errors within 12%, 10%, 19%, and 9% for HC, CO, NOx
emissions and fuel consumption, respectively.
Abstract: The central recirculation zone (CRZ) in a swirl
stabilized gas turbine combustor has a dominant effect on the fuel air
mixing process and flame stability. Most of state of the art swirlers
share one disadvantage; the fixed swirl number for the same swirler
configuration. Thus, in a mathematical sense, Reynolds number
becomes the sole parameter for controlling the flow characteristics
inside the combustor. As a result, at low load operation, the
generated swirl is more likely to become feeble affecting the flame
stabilization and mixing process. This paper introduces a new swirler
concept which overcomes the mentioned weakness of the modern
configurations. The new swirler introduces air tangentially and
axially to the combustor through tangential vanes and an axial vanes
respectively. Therefore, it provides different swirl numbers for the
same configuration by regulating the ratio between the axial and
tangential flow momenta. The swirler aerodynamic performance was
investigated using four CFD simulations in order to demonstrate the
impact of tangential to axial flow rate ratio on the CRZ. It was found
that the length of the CRZ is directly proportional to the tangential to
axial air flow rate ratio.
Abstract: Non-premixed turbulent combustion Computational Fluid Dynamics (CFD) has been carried out in a simplified methanefuelled coaxial jet combustor employing Large Eddy Simulation (LES). The objective of this study is to evaluate the performance of LES in modelling non-premixed combustion using a commercial software, FLUENT, and investigate the effects of the grid density and chemistry models employed on the accuracy of the simulation results. A comparison has also been made between LES and Reynolds Averaged Navier-Stokes (RANS) predictions. For LES grid sensitivity test, 2.3 and 6.2 million cell grids are employed with the equilibrium model. The chemistry model sensitivity analysis is achieved by comparing the simulation results from the equilibrium chemistry and steady flamelet models. The predictions of the mixture fraction, axial velocity, species mass fraction and temperature by LES are in good agreement with the experimental data. The LES results are similar for the two chemistry models but influenced considerably by the grid resolution in the inner flame and near-wall regions.