Study on microstructure and extinction characteristics of particulate matter in diesel engine fueled with different biodiesels

Environmental Science and Pollution Research - Biodiesel combustion particulate matter (PM) is different from diesel combustion PM in terms of microscopic morphology, which directly affects the...     

Comparison of carbonyl compounds emissions from diesel engine fueled with biodiesel and diesel

The characteristics of carbonyl compounds emissions were investigated on a direct injection, turbocharged diesel engine fueled with pure biodiesel derived from soybean oil. The gas-phase carbonyls were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges from diluted exhaust and analyzed by HPLC with UV detector. A commercial standard mixture including 14 carbonyl compounds was used for quantitative analysis. The experimental results indicate that biodiesel-fueled engine almost has triple carbonyls emissions of diesel-fueled engine. The weighted carbonyls emission of 8-mode test cycle of biodiesel is 90.8 mg (kW h)^?1 and that of diesel is 30.7 mg (kW h)^?1. The formaldehyde is the most abundant compound of carbonyls for both biodiesel and diesel, taking part for 46.2% and 62.7% respectively. The next most significant compounds are acetaldehyde, acrolein and acetone for both fuels. The engine fueled with biodiesel emits a comparatively high content of propionaldehyde and methacrolein. Biodiesel, as an alternative fuel, has lower specific reactivity (SR) caused by carbonyls compared with diesel. When fueled with biodiesel, carbonyl compounds make more contribution to total hydrocarbon emission.     

Biochemical biomarkers in Nile tilapia (Oreochromis niloticus) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends

Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1 mL L⁻¹. The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7 d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7 d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota.     

Influence of constant and fluctuating temperature on biodegradation rates of fish biodiesel blends contaminating Alaskan sand

Bioremediation of sandy soil contaminated with fish-biodiesel, conventional diesel, and blends of both was studied in microcosm experiments at different temperatures, simulating the subarctic environment. While distinct lag, exponential, and stationary phases were observed at 20 °C, degradation at 6 °C was slow and the lag phase continued throughout the 4-week experiment. A three-phase 1st order kinetic model successfully described respiration at 20 °C, a one-phase model was sufficient at 6 °C. For temperatures fluctuating between ∼6 and ∼20 °C, higher than expected microbial activity persisted at 6 °C for several days, due to the presence of active cultures, even though the soil temperature closely followed the air temperature. At 20 °C, respiration peaked already after 1 week, and 18-51% of the initially added fuel was mineralized within 4 weeks, whereby degradation was higher at higher biodiesel percentages. Biodiesel addition accelerated mineralization of blends with regular diesel beyond expectations. In blends with 20% biodiesel, the degradation rate constant was twice as high as for conventional diesel. These synergistic effects are likely due to an active microbial population. Addition of biodiesel to conventional diesel could reduce the impact of diesel spills.     

Particulate Emissions from a Stationary Engine Fueled with Ultra-Low-Sulfur Diesel and Waste-Cooking-Oil-Derived Biodiesel

ABSTRACT

Stationary diesel engines, especially diesel generators, are increasingly being used in both developing countries and developed countries because of increased power demand. Emissions from such engines can have adverse effects on the environment and public health. In this study, particulate emissions from a domestic stationary diesel generator running on ultra-low-sulfur diesel (ULSD) and biodiesel derived from waste cooking oil were characterized for different load conditions. Results indicated a reduction in particulate matter (PM) mass and number emissions while switching diesel to biodiesel. With increase in engine load, it was observed that particle mass increased, although total particle counts decreased for all the fuels. The reduction in total number concentration at higher loads was, however, dependent on percentage of biodiesel in the diesel-biodiesel blend. For pure biodiesel (B100), the reduction in PM emissions for full load compared to idle mode was around 9%, whereas for ULSD the reduction was 26%. A large fraction of ultrafine particles (UFPs) was found in the emissions from biodiesel compared to ULSD. Nearly 90% of total particle concentration in biodiesel emissions comprised ultrafine particles. Particle peak diameter shifted from a smaller to a lower diameter with increase in biodiesel percentage in the fuel mixture.

IMPLICATIONS There has been an increased usage of stationary diesel engines, especially backup power generators to meet the growing energy demand. Biodiesel derived from waste cooking oil has received increasing attention as an alternative fuel. However, data are only sparsely available in the literature on particulate emissions from stationary engines, fueled with blends of diesel and biodiesel. This study provides insights into the influence of waste-cooking-oil-derived biodiesel on engine performance and the particulate emissions from a stationary engine. The results of the study form a scientific basis to evaluate the impact of biodiesel emissions on the environment and human health.     

Biochemical responses in armored catfish (Pterygoplichthys anisitsi) after short-term exposure to diesel oil,pure biodiesel and biodiesel blends

Biodiesel fuel is gradually replacing petroleum-based diesel oil use. Despite the biodiesel being considered friendlier to the environment, little is known about its effects in aquatic organisms. In this work we evaluated whether biodiesel exposure can affect oxidative stress parameters and biotransformation enzymes in armored catfish (Pterygoplichthys anisitsi, Loricariidae), a South American endemic species. Thus, fish were exposed for 2 and 7 d to 0.01 mL L⁻¹ and 0.1 mL L⁻¹ of pure diesel, pure biodiesel (B100) and blends of diesel with 5% (B5) and 20% (B20) biodiesel. Lipid peroxidation (malondialdehyde) levels and the activities of the enzymes glutathione S-transferase, superoxide dismutase, catalase and glutathione peroxidase were measured in liver and gills. Also, DNA damage (8-oxo-7, 8-dihydro-2′-deoxyguanosine) levels in gills and 7-ethoxyresorufin-O-deethylase activity in liver were assessed. Pure diesel, B5 and B20 blends changed most of the enzymes tested and in some cases, B5 and B20 induced a higher enzyme activity than pure diesel. Antioxidant system activation in P. anisitsi was effective to counteract reactive oxygen species effects, since DNA damage and lipid peroxidation levels were maintained at basal levels after all treatments. However, fish gills exposed to B20 and B100 presented increased lipid peroxidation. Despite biodiesel being more biodegradable fuel that emits less greenhouse gases, the increased lipid peroxidation showed that biofuel and its blends also represent hazards to aquatic biota.     

Predicting the combustion behaviour of compression ignition engine fuelled with biodiesel from Stoechospermum marginatum,a macro algae

Environmental Science and Pollution Research - Biodiesel is one among the recent developments in the field of renewable energy research. To enhance the combustion characteristics of compression...     

Diesel emissions in Vienna

The aerosol in a non-industrial town normally is dominated by emissions from vehicles. Whereas gasoline-powered cars normally only emit a small amount of particulates, the emission by diesel-powered cars is considerable. The aerosol particles produced by diesel engines consist of graphitic carbon (GC) with attached hydrocarbons (HCs) including also polyaromatic HCs. Therefore the diesel particles can be carcinogenic. Besides diesel vehicles, all other combustion processes are also a source for GC; thus source apportionment of diesel emissions to the GC in the town is difficult.A direct apportionment of diesel emissions has been made possible by marking all the diesel fuel used by the vehicles in Vienna by a normally not occurring and easily detectable substance. All emitted diesel particles thus were marked with the tracer and by analyzing the atmospheric samples for the marking substance we found that the mass concentrations of diesel particles in the atmosphere varied between 5 and 23 μg m⁻³. Busy streets and calm residential areas show less difference in mass concentration than expected. The deposition of diesel particles on the ground has been determined by collecting samples from the road surface. The concentration of the marking substance was below the detection limit before the marking period and a year after the period. During the period when marked diesel fuel was used, the concentrations of the diesel particles settling to the ground was 0.012–0.07 g g⁻¹ of collected dust.A positive correlation between the diesel vehicle density and the sampled mass of diesel vehicles exists. In Vienna we have a background diesel particle concentration of 11 μg m⁻³. This value increases by 5.5 μg m⁻³ per 500 diesel vehicles h⁻¹ passing near the sampling location.The mass fraction of diesel particles of the total aerosol mass varied between 12.2 and 33%; the higher values were found in more remote areas, since diesel particles apparently diffuse easily.Estimates of diesel particle concentration by emission inventory or by using lead concentrations as an indicator for vehicle emissions gave similar values to those obtained in this study.Using available cancer risk data and diesel particle concentration found in this study, 1–2.6 additional lung cancers per 100,000 persons yr⁻¹ breathing diesel emissions in the measured concentration the whole lifetime can be expected.     

Pulmonary Function Desensitization on Repeated Exposures to the Combination of Peroxyacetyl Nitrate and Ozone

During three separate studies involving characterization of diesel particulate matter, carbon nanotubes (CNTs) were found among diesel exhaust particles sampled onto transmission electron microscopy (TEM) grids. During these studies, samples were collected from three different diesel engines at normal operating conditions with or without an iron catalyst (introduced as ferrocene) in the fuel. This paper is to report the authors’ observation of CNTs among diesel exhaust particles, with the intent to stimulate awareness and further discussion regarding the formation mechanisms of CNTs during diesel combustion.

Implications: Increased attention is being given to CNTs and other nanomaterials and a recent review paper showed that CNTs are capable of inflammation in the lung when inhaled. For this reason and because diesel engines are so common, it is important to acknowledge the existence of CNTs among diesel particles and possible regulation and online measurement method development.     

Effects of Fuel Variables on Diesel Emissions

The body of information presented in this paper is directed towards engineers in the field of environmental sciences involved in measuring and/or evaluating the emissions from a variety of diesel engines or vehicles. This paper summarizes recent data obtained by EPA on identification and quantification of different emissions (i.e. characterization) from a variety of diesel engines.

Extensive work has been done comparing emissions from some light duty diesel and gasoline passenger cars. The work on the diesel vehicles was expanded to include tests with five different diesel fuels to determine how fuel composition affects emissions. This work showed that use of a poorer quality fuel frequently made emissions worse. The investigation of fuel composition continued with a project in which specific fuel parameters were systematically varied to determine their effect on emissions. EPA is presently testing a variety of fuels derived from coal and oil shale to determine their effects on emissions.

EPA has also tested a heavy duty Volvo diesel bus engine designed to run on methanol and diesel fuel, each injected through its own injection system. The use of the dual fuel resulted in a reduction in particulates and NO _x but an increase in HC and CO compared to a baseline Volvo diesel engine running on pure diesel fuel.

Finally, some Ames bioassay tests have been performed on samples from the diesel passenger cars operated on various fuels and blends. An increase in Ames test response (mutagenicity) was seen when the higher aromatic blend was used and also when a commercial cetane improver was used. Samples from the Volvo diesel bus engine fueled with methanol and diesel fuel showed that use of a catalyst increased the Ames response.     

Techno-economic assessment of coconut biodiesel as a potential alternative fuel for compression ignition engines

Over the past years, there were dramatic improvements in identifying and assessing various feedstocks for the production of biodiesel fuels. To promote a particular feedstock as a renewable source of energy, it is important to analyze their energy, economic, and engine performance characteristics. The current work attempts to evaluate the net energy and economic indices for both fossil diesel and coconut-blended diesel (B20) considering the diesel consumption by the Indian railways. Further, we present the experimental results of a multi-cylinder diesel engine operated with neat coconut biodiesel (B100) and fossil diesel at various load and speed conditions. The engine experiments reveal that the coconut biodiesel exhibits leaner combustion and shorter ignition delay than fossil diesel. Lower amount of carbon monoxide, hydrocarbon, and smoke emission is observed in the case of coconut biodiesel, with higher levels of nitric oxide (14%) and fuel consumption than diesel. The coefficient of variation in indicated mean effective pressure is within the range of better driveability zone for both the fuels at all test conditions. Overall the engine performance, emission and combustion results with neat coconut biodiesel are favorable with a penalty in NO emission at high load conditions. The techno-economical study highlights higher production cost per liter of B20 than the cost of fossil diesel. However, the net energy ratio (NER) for B20 is 1.021, favoring higher output than diesel and thus lowers the dependency on crude oil.

     

The influence of a NAPL on the loss and biodegradation of 14C-phenanthrene residues in two dissimilar soils

This study was carried out to assess the influence of diesel, applied over a log concentration range, on the loss and extractability of phenanthrene (measured as putative 14C-phenanthrene residues) in two different soils. The influence of diesel on the ability of a cyclodextrin based extraction method to predict the microbial bioavailability of 14C-residues was also assessed. An increase in loss of 14C-residues with increasing diesel concentration from 0 to 2000 mg kg-1 was generally observed with time in both soils. It is suggested that this trend is attributable to competitive sorption for soil sorption sites and to a lesser extent to displacement of 14C-residues from soil sorption sites by diesel resulting in greater compound availability and therefore greater loss by degradation via the actions of indigenous microorganisms. However, in the 20000 mg kg-1 diesel treatments of both soils, results indicated a delayed loss. It is suggested that this retarded loss was due to the formation of a discrete NAPL-phase into which 14C-phenanthrene residues partitioned, thereby decreasing their availability and as a consequence their degradation. Furthermore, it is suggested that nutrient limitation may have slowed down degradation rates as diesel concentrations increased. Comparison between cyclodextrin-extractability and microbial mineralisation supported the use of cyclodextrin to assess microbial bioavailability of 14C-residues after 50 d or more ageing up to diesel concentrations of 2000 mg kg-1. However, results suggested that at high diesel concentrations (specifically 20000 mg kg-1) co-extraction of 14C-phenanthrene residues may have occurred as a result of the combined solvation powers of both the cyclodextrin and the diesel. Furthermore, mineralisation of 14C-phenanthrene residues may have been affected by extreme nutrient limitation in this treatment.     

An experimental investigation on waste fishing net as an alternate fuel source for diesel engine

In this experimental study, the feasibility of using the oil obtained from waste fishing net as a substitute for diesel fuel was investigated. Waste fishing net oil (WFNO) was obtained through pyrolysis process on a laboratory scale setup and used as a fuel in diesel engine. The properties of oil obtained from waste fishing net were examined and compared with conventional diesel fuel. Results indicated that the WFNO possesses excellent fuel properties. The calorific value of WFNO is 44,450 kJ/kg, which is higher than diesel by 1.48%. In order to study the possibility of using WFNO and its blends (WFNO 25%, WFNO 50%, WFNO 75% and WFNO 100%) with diesel as a fuel, an experimental investigation was carried out on a single-cylinder, four-stroke diesel engine. Experimental results proved that WFNO works satisfactorily on a diesel engine without any engine modifications. Brake thermal efficiency was decreased and brake-specific fuel consumption was increased while using WFNO and its blends. Moreover, there was a slight increase in engine emissions like CO, UHC, NO with WFNO and its blends.

     

Review of light-duty diesel and heavy-duty diesel gasoline inspection programs

Emissions from diesel vehicles and gas-powered heavy-duty vehicles are becoming a new focus of many inspection and maintenance (I/M) programs. Diesel particulate matter (PM) is increasingly becoming more recognized as an important health concern, while at the same time, the public awareness of diesel PM emissions because of their visibility have combined to increase the focus on diesel emissions in the United States. This has resulted in an increased interest by some states in including heavy-duty vehicle testing in their I/M program. This paper provides an overview of existing I/M programs focused on testing light-duty diesel vehicles, heavy-duty diesel vehicles, and heavy-duty gasoline vehicles (HDGVs). Information on 39 I/M programs in 27 different states in the United States plus 9 international inspection programs is included. Information on the status of diesel emissions technology and current test procedures is also presented. The goal is to provide useful information for air quality managers as they work to decide whether such I/M programs would be worth pursuing in their respective areas and in evaluating the emissions measurement technology to be used in the program. Testing of HDGVs is generally limited to idle testing, because dynamometer testing of these vehicles is not practical, and most were not certified on a chassis basis. Testing of diesel vehicles has mostly been limited to SAE J1667 "snap-idle" opacity testing. Cost-effective technology for measuring diesel emissions currently does not exist, and, therefore, opacity-type measurements, although not effective at reducing the pollutants of most significant health concern, will continue to be used.     

Visual modflow在模拟实验室含水砂槽中柴油运移特征中的应用

Visual modflow是一个可以对三维地下水水流和溶质运移进行数值模拟评价的标准可视化专业软件.建立了砂箱物理实验模型来研究柴油在含水砂槽中的迁移特征.通过模型检验,各个监测时期观测值和预测值相关系数r值在0.564 ～0.669之间,证明这种建模方法是合理的和有效的.利用校正的模型对实验室含水砂槽中柴油运移特征进行模拟,发现所建模型可以较为准确地反映出含水砂槽中柴油污染物的分布特征,拟合、验证和预测结果显示该模型可作为地下水管理的有效工具,这为深入研究柴油污染地下水提供理论依据.     

An evaluation of the tapered element oscillating microbalance method for measuring diesel particulate emissions

We determined the usefulness of tapered element oscillating microbalances (TEOMs) for researchers and engineers involved with measuring diesel particulate mass. Two different test facilities were used for generating diesel particulates and comparing the TEOM to the commonly used U.S. Environmental Protection Agency (EPA) manual filter method. The EPA method is very labor-intensive and requires long periods of time to complete. The TEOM is an attractive approach because it has the potential to reduce the amount of time and labor required in diesel testing, as well as to provide real-time particulate-mass data that are not obtainable with the EPA method. It was found that the TEOM was a precise and easy-to-operate instrument that could measure the mass concentration (MC) of diesel particulate emissions in real time. Although the TEOM diesel particulate MC measurements were highly correlated with the manual filter measurements, the two techniques were not equivalent because the TEOM consistently reported MC results that were 20-25% lower than those obtained using the manual filter technique. In conclusion, the TEOM can be used to increase test-cell throughput and to measure transient values of diesel particulate emissions at sites performing diesel-engine testing. However, unless EPA is able to certify the TEOM as an equivalent method, it cannot replace the manual filter method for diesel certification work.     

Particulate matter in new technology diesel exhaust (NTDE) is quantitatively and qualitatively very different from that found in traditional diesel exhaust (TDE)

Diesel exhaust (DE) characteristic of pre-1988 engines is classified as a "probable" human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency has classified DE as "likely to be carcinogenic to humans." These classifications were based on the large body of health effect studies conducted on DE over the past 30 or so years. However, increasingly stringent U.S. emissions standards (1988-2010) for particulate matter (PM) and nitrogen oxides (NOx) in diesel exhaust have helped stimulate major technological advances in diesel engine technology and diesel fuel/lubricant composition, resulting in the emergence of what has been termed New Technology Diesel Exhaust, or NTDE. NTDE is defined as DE from post-2006 and older retrofit diesel engines that incorporate a variety of technological advancements, including electronic controls, ultra-low-sulfur diesel fuel, oxidation catalysts, and wall-flow diesel particulate filters (DPFs). As discussed in a prior review (T. W. Hesterberg et al.; Environ. Sci. Technol. 2008, 42, 6437-6445), numerous emissions characterization studies have demonstrated marked differences in regulated and unregulated emissions between NTDE and "traditional diesel exhaust" (TDE) from pre-1988 diesel engines. Now there exist even more data demonstrating significant chemical and physical distinctions between the diesel exhaust particulate (DEP) in NTDE versus DEP from pre-2007 diesel technology, and its greater resemblance to particulate emissions from compressed natural gas (CNG) or gasoline engines. Furthermore, preliminary toxicological data suggest that the changes to the physical and chemical composition of NTDE lead to differences in biological responses between NTDE versus TDE exposure. Ongoing studies are expected to address some of the remaining data gaps in the understanding of possible NTDE health effects, but there is now sufficient evidence to conclude that health effects studies of pre-2007 DE likely have little relevance in assessing the potential health risks of NTDE exposures.     

水中柴油污染物的微生物降解及其动力学

以混合柴油为靶污染物,通过对比实验研究了油污染物在模拟水环境中的降解效果。研究表明,模拟自然条件下混合柴油污染物总体降解较慢,油质去除率低;生物强化降解条件下,向混合柴油污染水样中添加驯化培养的微生物混合菌群,生物降解速率明显提高,油质去除率达到98%以上。研究还发现,各污染水样中油的降解速率与降解效果随柴油的配比而不同,混合柴油样本中生物柴油的比例越高,样本的降解率越高,表明生物柴油作为碳源有效改善了水中有机营养配比,促进了柴油的去除效果。进一步分析表明,混合柴油在水中的降解过程符合一级反应动力学,生物强化降解条件下,生物柴油比例越高,混合柴油降解速率越快,除油微生物以菌胶团、球菌和丝状菌为主。     

Emission characteristics of PCDD/Fs in diesel engine with variable load rate

Emission characteristics of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in diesel engine were studied with variable load rate of the diesel engine with the emission test cycles, US D-13 mode. The load rate is changed from 25% to 50% and 75% at constant speed of 2400 rpm. PCDD/Fs concentration and phase distribution of PCDD/Fs with the isokinetic sampling of exhaust gas is obtained in this study. The average PCDD/Fs concentrations per unit of exhaust gas with 25%, 50% and 75% load rate are 14.5, 6.9 and 6.4 pg-TEQ/N m3, respectively. In all diesel engine runs, PCDFs are more prevalent than PCDDs. As a load rate is increased, the ratio of PCDDs is gradually decreased. The amount of high-chlorinated PCDDs emitted in diesel engine is larger than that of low-chlorinated PCDDs. The significant emission form of PCDD/Fs produced from diesel engines exhaust is a gas phase.     

土壤柴油污染修复的抽气提取去除实验研究

为得到土壤气相抽提(SVE)去除柴油的优化条件,进行了一维土柱抽气提取去除柴油污染物的实验研究,研究不同初始含水率、不同抽气量对污染土壤中柴油去除率的影响及不同深度残留柴油的变化规律。结果表明：在本实验模拟的范围内,抽气量越大,SVE处理效果越好;初始含水率越低,处理效果越好;此外,不同深度去除率变化的规律基本上是随深度的增大而减小。实验结果可为土壤轻油污染实际治理提供实验数据基础。