Combustion characteristics of a turbocharged DI compression ignition engine fueled with petroleum diesel fuels and biodiesel

In this study, the combustion characteristics and emissions of two different petroleum diesel fuels (No. 1 and No. 2) and biodiesel from soybean oil were compared. The tests were performed at steady state conditions in a four-cylinder turbocharged DI diesel engine at full load at 1400-rpm engine speed. The experimental results compared with No. 2 diesel fuel showed that biodiesel provided significant reductions in PM, CO, and unburned HC, the NO(x) increased by 11.2%. Biodiesel had a 13.8% increase in brake-specific fuel consumption due to its lower heating value. However, using No. 1 diesel fuel gave better emission results, NO(x) and brake-specific fuel consumption reduced by 16.1% and 1.2%, respectively. The values of the principal combustion characteristics of the biodiesel were obtained between two petroleum diesel fuels. The results indicated that biodiesel may be blended with No. 1 diesel fuel to be used without any modification on the engine.     

Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends

In this experimental work, tall oil methyl ester-diesel fuel blends as alternative fuels for diesel engines were studied. Tall oil methyl ester was produced by reacting tall oil fatty acids with methyl alcohol under optimum conditions. The blends of tall oil methyl ester-diesel fuel were tested in a direct injection diesel engine at full load condition. The effects of the new fuel blends on the engine performance and exhaust emission were tested. It was observed that the engine torque and power output with tall oil methyl ester-diesel fuel blends increased up to 6.1% and 5.9%, respectively. It was also seen that CO emissions decreased to 38.9% and NO(x) emissions increased up to 30% with the new fuel blends. The smoke opacity did not vary significantly.     

Improvement of engine emissions with conventional diesel fuel and diesel-biodiesel blends

In this report combustion and exhaust emissions with neat diesel fuel and diesel-biodiesel blends have been investigated. In the investigation, firstly biodiesel from non-edible neem oil has been made by esterification. Biodiesel fuel (BDF) is chemically known as mono-alkyl fatty acid ester. It is renewable in nature and is derived from plant oils including vegetable oils. BDF is non-toxic, biodegradable, recycled resource and essentially free from sulfur and carcinogenic benzene. In the second phase of this investigation, experiment has been conducted with neat diesel fuel and diesel-biodiesel blends in a four stroke naturally aspirated (NA) direct injection (DI) diesel engine. Compared with conventional diesel fuel, diesel-biodiesel blends showed lower carbon monoxide (CO), and smoke emissions but higher oxides of nitrogen (NOx) emission. However, compared with the diesel fuel, NOx emission with diesel-biodiesel blends was slightly reduced when EGR was applied.     

Influence of tall oil biodiesel with Mg and Mo based fuel additives on diesel engine performance and emission

The purpose of this study is to investigate influences of tall oil biodiesel with Mg and Mo based fuel additives on diesel engine performance and emission. Tall oil resinic acids were reacted with MgO and MoO(2) stoichiometrically for the production of metal-based fuel additives (combustion catalysts). The metal-based additives were added into tall oil biodiesel (B60) at the rate of 4 micromol/l, 8 micromol/l and 12 micromol/l for preparing test fuels. In general, both of the metal-based additives improved flash point, pour point and viscosity of the biodiesel fuel, depending on the rate of additives. A single cylinder DI diesel engine was used in the tests. Engine performance values did not change significantly with biodiesel fuels, but exhaust emission profile was improved. CO emissions and smoke opacity decreased by 56.42% and by 30.43%, respectively. In general, low NO(x) and CO(2) emissions were measured with the biodiesel fuels.     

PAHs and their Carcinogenic Potencies in Diesel Fuel and Diesel Generator Exhaust

The PAH profile was characterized in diesel fuel samples collected from different service stations in Agra (India) by using a gas chromatograph equipped with a flame ionization detector (FID). The low molecular weight PAHs were predominant, ranging from 4.4 × 10² to 1.7 × 10³ mg l^{? 1} in fuel. Exhaust emissions from a diesel generator and a four-stroke engine (Skoda) powered by these fuels were monitored by a stack sampler and quantified for PAHs. The high molecular weight PAHs (DbA+IP, BghiP, and BaP, BbF+BkF) were the dominant PAHs in exhaust emissions. Differences in PAH emission factors for the two engines were found and these differences could be related to the combustion conditions affecting the temperature of flue gas. Emission factors and output/input ratio for individual PAHs suggest that the low molecular weight compounds in the fuel contribute to pyrosynthesis of high molecular weight in exhaust. Unburnt fuel partially contributes to low molecular weight PAHs in exhaust. Further, the relative carcinogenic contributions of each compound in the fuel and exhaust were calculated using the TEF approach. DbA + IP and BaP were significant contributors to the carcinogenicity of the PAH mixture in the exhaust.     

The effect of fuel composition on the mutagenicity of diesel engine exhaust

The effect of fuel composition on the mutagenicity of diesel engine emission was investigated. To this end, a fuel matrix comprising fuels with different contents of aromatic and naphthenic compounds was used. Extracts of the organic phase of raw exhausts obtained with different fuels were tested for mutagenicity in bacterial reversion assays. The results obtained demonstrate that the mutagenicity of diesel exhaust is largely dependent on the aromatic content of the fuel. In fact, mutagenicity was greatly reduced when the aromatic content of the fuel was lowered by hydrogen treatment. Conversely, mutagenicity was enhanced when the fuel was enriched with fractions of di- or triaromatic compounds. The addition of di- and trinaphthenic compounds only produced borderline mutagenicity. No clear relationship was observed between sulfur content of the fuel and mutagenicity of the exhaust. Assays in bacterial strains with different sensitivity to nitroaromatic compounds suggest a low contribution of the highly mutagenic dinitropyrenes to the responses observed, and a relatively greater contribution of 1-nitropyrene or other nitroaromatics processed by the same bacterial nitroreductase.     

Emissions of Total Volatile Organic Compounds from Anthropogenic Sources in India

Volatile organic compounds (VOCs) have a direct bearing on the levels of ozone and other reactive chemicals in the atmosphere and play an important role in determining air quality Anthropogenic emission of VOCs has greatly increased due to growing consumption of fossil fuels and related activities. This article presents an emissions inventory for VOCs emitted from anthropogenic soutres in India. VOC emissions factors for important source categories and activities are assembled from the literature and an effort is made to use Indian emission factors as far as possible. Important sources of VOCs include livestock, combustion of firewood and fossil fuels, rice paddy fields, manufacturing. petroleum (production and refining), natural gas (production and distribution), vehicular exhaust, and coal mining. The annual anthropogenic VOC emissions for India have been estimated to be 21 million metric tons (mt). A comparison of VOC emissions inventories for a group of countries varying in their industrial and economic development, in terms of income (gross domestic product, or GDP), population, and land area, reflects the differences among the countries. This VOC emissions inventory provides baseline information for comparisons over time and across countries. In addition, it may serve as an important tool for formulating national VOC control policies.     

Combustion behaviors of a compression-ignition engine fueled with diesel/methanol blends under various fuel delivery advance angles

A stabilized diesel/methanol blend was described and the basic combustion behaviors based on the cylinder pressure analysis was conducted in a compression-ignition engine. The study showed that increasing methanol mass fraction of the diesel/methanol blends would increase the heat release rate in the premixed burning phase and shorten the combustion duration of the diffusive burning phase. The ignition delay increased with the advancing of the fuel delivery advance angle for both the diesel fuel and the diesel/methanol blends. For a specific fuel delivery advance angle, the ignition delay increased with the increase of the methanol mass fraction (oxygen mass fraction) in the fuel blends and the behaviors were more obvious at low engine load and/or high engine speed. The rapid burn duration and the total combustion duration increased with the advancing of the fuel delivery advance angle. The centre of the heat release curve was close to the top-dead-centre with the advancing of the fuel delivery advance angle. Maximum cylinder gas pressure increased with the advancing of the fuel delivery advance angle, and the maximum cylinder gas pressure of the diesel/methanol blends gave a higher value than that of the diesel fuel. The maximum mean gas temperature remained almost unchanged or had a slight increase with the advancing of the fuel delivery advance angle, and it only slightly increased for the diesel/methanol blends compared to that of the diesel fuel. The maximum rate of pressure rise and the maximum rate of heat release increased with the advancing of the fuel delivery advance angle of the diesel/methanol blends and the value was highest for the diesel/methanol blends.     

Life cycle assessment for the implementation of emission control measures for the freight traffic with heavy duty vehicles in Germany

The Life cycle inventory analysis (LCI) for the freight traffic with heavy duty vehicles in Germany was determined for the reference year 1995 and the target year 2010 by application of ISO 14040 and ISO 14041. Based on these results and under consideration of the dynamic development of road freight traffic with German heavy duty vehicles of >14 t max laden weight and composition of the German heavy duty vehicles fleet in this class the LCI for the introduction of various scenarios for reducing emissions from freight traffic was generated. Special emphasis was placed in the determination of the LCI for the implementation of primary, secondary and a combination of primary and secondary emission reduction measures for heavy duty diesel engines such as variation of diesel fuel characteristics, engine-based measures for exhaust gas optimisation, urea selective catalytic reduction (SCR) process with and without fuel consumption optimised diesel engines and particulate trap for exhaust gas optimised diesel engines with low sulphur diesel fuel. The overall environmental effects of the investigated measures on the other phases of the product life cycle of the freight traffic with heavy duty vehicles and on associated and new products to be introduced was included in the generated results for the LCI of each variant. For the implementation of the urea SCR process the results are based on manufacturer data for the overall production process of SCR honeycomb catalysts and SCR application measurements in engine and field test after a travelled distance of between 187,825 and 325,178 km under road traffic conditions with typical EURO 2 standard diesel engines for heavy duty vehicles with a max laden weight of >32 t under control of and data certification by TüV Automotive Bayern Sachsen GmbH. Phase 2: Life Cycle Impact Assessment (DOI: http://dx.doi.Org/10.1065/ Ica2000.12.044.2) Phase 3: Life Cycle Interpretation (DOI: http://dx.doi.orq/10.1065/ Ica2000.12.044.3)     

Diesel particulate emissions from used cooking oil biodiesel

Two different biodiesel fuels, obtained from waste cooking oils with different previous uses, were tested in a DI diesel commercial engine either pure or in 30% and 70% v/v blends with a reference diesel fuel. Tests were performed under a set of engine operating conditions corresponding to typical road conditions. Although the engine efficiency was not significantly affected, an increase in fuel consumption with the biodiesel concentration was observed. This increase was proportional to the decrease in the heating value. The main objective of the work was to study the effect of biodiesel blends on particulate emissions, measured in terms of mass, optical effect (smoke opacity) and size distributions. A sharp decrease was observed in both smoke and particulate matter emissions as the biodiesel concentration was increased. The mean particle size was also reduced with the biodiesel concentration, but no significant increases were found in the range of the smallest particles. No important differences in emissions were found between the two tested biodiesel fuels.     

Effect of Medium Composition on the Denitrification of Nitrate by Paracoccus denitrificans

The course of denitrification of nitrate in static cultures of Paracoccus denitrificans was studied. Reduction of nitrate to gaseous nitrogen without accumulation of nitrite because of parallel and balanced activities of nitrate and nitrite reductases was observed in nutrient broth. In minimal liquid cultures supplemented with either methanol, acetate, or ethanol as a sole carbon source, substantial amounts of nitrite (up to 70%) accumulated. The reduction in nitrite concentration began just after the transformation of nitrate to nitrite was completed. The addition of some growth factors to minimal media shortened the bacterial biomass doubling time. A correlation coefficient of 0.71 between the doubling time and the amount of accumulated nitrite in cultures was found. My results indicated that the type of denitrification carried out by P. denitrificans is not stable and depends on the nutritional composition of the culture medium.     

广州市城乡梯度森林公园雨季空气PM2.5浓度及水溶性离子特征

2012年雨季（4-9月）,收集广州市城市区、近郊区和远郊区森林公园的PM_2.5样品,测定PM_2.5质量浓度,分析了其中SO₄^2-、NO₃^-、NO₂^-、Cl^-、F^-、Na⁺、NH₄⁺、Ca²⁺、K⁺、Mg²⁺ 共10种水溶性无机离子含量.结果表明：帽峰山（远郊）、大夫山（近郊）、火炉山（城区）PM_2.5质量浓度的日变化分别为17.2～66.5、19.4～156.3、21.8～161.7 μg·m^-3,平均值分别为44.4、49.8、55.9 μg·m^-3.SO₄^2-、Na⁺和NH₄⁺为水溶性无机离子主要组分,其中,SO₄^2-含量最大,并从城区至郊区呈递减趋势.固定源对3个森林公园空气中SO₂和NO_x的贡献大于移动源,从城区至远郊呈递减趋势,说明机动车对城区空气中SO₂和NO_x的贡献大于近郊和远郊森林公园.采样期间,海盐对大夫山空气PM_2.5中水溶性组分的贡献最大,其中K⁺受海盐的影响超过其他元素.NH₄⁺当量浓度远小于SO₄^2-和NO₃^-的当量浓度,中和度远小于1,反映PM_2.5酸性较强,且从远郊至城区PM_2.5粒子酸性呈增强趋势.     

Development of a new in vitro system for continuous in vitro exposure of lung tissue to complex atmospheres: Application to diesel exhaust toxicology

The purpose of this study was the development of a new incubation system that can allow continuous exposure of lung tissue to complex atmospheres as a tool for the assessment of aerial environmental lung toxicology. To assess the pertinence of this new exposure system, we studied the impact of diesel engine exhausts as a complex atmosphere containing both gaseous and particulate fractions and have been able to discriminate between the toxicological impacts of the gaseous phase and particulate matter from diesel exhausts. Continuous flow-through rotating chambers with controlled pO₂, pCO₂, and hygrometry have been designed in which lung slices are positioned in rolling inserts that allow free access of atmosphere to the exposed lung tissue. Under control conditions, cell viability was preserved for at least 48 h as assessed by intracellular ATP, GSH, and K⁺ levels and slice O₂ consumption levels. Short-term exposure (1 h) to diesel whole exhausts did not affect intracellular potassium or slice O₂ consumption, while intracellular ATP and GSH levels were markedly decreased. Exposure to filtered exhausts showed less marked effects on both ATP and GSH levels. Superoxide dismutase activity was decreased in a similar way by both total and filtered exhausts while Se⁺-dependent glutathione peroxidase activity was induced by filtered exhausts to a larger extent than after total exhaust exposure, showing different response patterns of lung tissue after exposure to whole or filtered exhausts. In conclusion, this newly designed model opens a promising area in in vitro environmental lung toxicology testing.     

Emission performance and combustion efficiency of a conical fluidized-bed combustor firing various biomass fuels

This paper summarizes the results of an experimental study on combustion of three distinct biomass fuels (sawdust, rice husk and pre-dried sugar cane bagasse) in a single fluidized-bed combustor (FBC) with a conical bed using silica sand as the inert bed material. Temperature, CO, NO and O2 concentrations along the combustor height as well as in flue (stack) gas were measured in the experimental tests. The effects of fuel properties and operating conditions (load and excess air) on these variables were investigated. Both CO and NO axial profiles were found to have a maximum whose location divides conventionally the combustor volume into formation (lower) and reduction (upper) regions for these pollutants. Based on CO emission and unburned carbon content in fly ash, the combustion efficiency of the conical FBC was quantified for the selected biomass fuels fired under different operating conditions.     

Oxidative stress-induced DNA damage by particulate air pollution

Exposure to ambient air particulate matter (PM) is associated with pulmonary and cardiovascular diseases and cancer. The mechanisms of PM-induced health effects are believed to involve inflammation and oxidative stress. The oxidative stress mediated by PM may arise from direct generation of reactive oxygen species from the surface of particles, soluble compounds such as transition metals or organic compounds, altered function of mitochondria or NADPH-oxidase, and activation of inflammatory cells capable of generating ROS and reactive nitrogen species. Resulting oxidative DNA damage may be implicated in cancer risk and may serve as marker for oxidative stress relevant for other ailments caused by particulate air pollution. There is overwhelming evidence from animal experimental models, cell culture experiments, and cell free systems that exposure to diesel exhaust and diesel exhaust particles causes oxidative DNA damage. Similarly, various preparations of ambient air PM induce oxidative DNA damage in in vitro systems, whereas in vivo studies are scarce. Studies with various model/surrogate particle preparations, such as carbon black, suggest that the surface area is the most important determinant of effect for ultrafine particles (diameter less than 100 nm), whereas chemical composition may be more important for larger particles. The knowledge concerning mechanisms of action of PM has prompted the use of markers of oxidative stress and DNA damage for human biomonitoring in relation to ambient air. By means of personal monitoring and biomarkers a few studies have attempted to characterize individual exposure, explore mechanisms and identify significant sources to size fractions of ambient air PM with respect to relevant biological effects. In these studies guanine oxidation in DNA has been correlated with exposure to PM(2.5) and ultrafine particles outdoor and indoor. Oxidative stress-induced DNA damage appears to an important mechanism of action of urban particulate air pollution. Related biomarkers and personal monitoring may be useful tools for risk characterization.     

Effects of biodiesel on emissions of a bus diesel engine

This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel (D2) under various operating regimes. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of D2. The obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. The injection characteristics are determined numerically under the operating regimes, corresponding to the 13 mode ESC test. The fuel spray is obtained experimentally under peak torque condition. Engine characteristics are determined experimentally under 13 mode ESC test conditions. The results indicate that, by using biodiesel, harmful emissions (NO(x), CO, smoke and HC) can be reduced to some extent by adjusting the injection pump timing properly.     

Treatment of waste gas from the breather vent of a vertical fixed roof p-xylene storage tank by a trickle-bed air biofilter

This study applied a pilot-scale trickle-bed air biofilter (TBAB) system for treating waste gas emitted from the breather vent of a vertical fixed roof storage tank containing p-xylene (p-X) liquid. The volatile organic compound (VOC) concentration of the waste gas was related to ambient temperature as well as solar radiation, peaking at above 6300 ppmv of p-X and 25000 ppmv of total hydrocarbons during the hours of 8 AM to 3 PM. When the activated carbon adsorber was employed as a VOC buffer, the peak waste gas VOC concentration was significantly reduced resulting in a stably and efficiently performing TBAB system. The pressure drop appeared to be low, reflecting that the TBAB system could be employed in the prolonged operation with a low running penalty. These advantages suggest that the TBAB system is a cost-effective treatment technology for VOC emission from a fixed roof storage tank.     

Mutagenicity of urine from rats after 1-nitropyrene and 2-nitrofluorene administration using new sensitive Salmonella typhimurium strains YG1012 and YG1024

1-Nitropyrene (1-NP) and 2-nitrofluorene (2-NF), two of the most abundant nitro-substituted polycyclic aromatic hydrocarbons (nitro-PAH) present in combustion products such as diesel engine exhaust, were administered intraperitoneally to rats at a dose of 5 mg per animal. Urine samples, 1-NP and 2-NF were tested in the Ames assay using the newly developed Salmonella typhimurium strains YG1012 and YG1024 (overproducing O-acetyltransferase) and their parent strains TA1538 and TA98. In urine, collected over 3 periods of 24 h after administration, most of the mutagens appeared during the first 24 h. The mutagenicity was found to be a factor 2-30 higher in the YG strains when compared to the TA strains. Addition of S9 mix and rat liver cytosol both with and without beta-glucuronidase increased the mutagenicity of urine samples from 1-NP-treated rats. Addition of beta-glucuronidase revealed that a considerable part of the mutagenic metabolites of 1-NP and 2-NF were excreted as glucuronide conjugates. The increase in mutagenicity of urine samples from 2-NF-treated rats after the addition of rat liver cytosol referred to N,O-acyl transfer as a step in activating 2-NF to strong mutagens. The high sensitivity of the YG tester strains indicated that these strains might be used to explore environments where people are exposed to nitro-PAH, such as work places with diesel emission sources.