Effects of Fatty Acids Composition on Fuel Properties of Jatropha Curcas Biodiesel

In the efforts to reduce effects of climate change, biodiesel fuels from plant oils such as Jatropha curcas have been proposed as alternative fuels which can be used in the transportation sector in diesel engines. The current study investigates the effects of fatty acids composition on fuel properties of biodiesel derived from Jatropha curcas seeds obtained from selected regions of Botswana. The physicochemical fuel properties investigated include kinematic viscosity, flash point, energy content, density, pour point and cloud point from derived Jatropha curcas biodiesel. Results of the study showed that Jatropha curcas biodiesel samples for all regions under review are dominated by unsaturated fatty acids which are desirable for cold flow properties and kinematic viscosity of the biodiesel fuel. The major fatty acids in Jatropha curcas biodiesel fuels from all the regions range from 69.00% to 77.81% of unsaturated fatty acids. The overall results conclude that fatty acids composition has influence on the fuel properties of the biodiesel under investigated.

A review and evaluation of nonroad diesel mobile machinery emission control in China

China’s emission control for nonroad diesel mobile machinery(NDMM)must deal with a fast increase in stock as well as regulations that are two decades behind those for on-road vehicles.This study provides the first large-scale review and evaluation of China’s NDMM policies,along with emission measurements and an investigation on diesel fuel quality.The sulfur contents of the investigated diesel declined from 430 ppm(median value)in 2011 to6-8 ppm during the 2017-2018 period.The emission control of NO_(x)and PM greatly improved with the shift from the China II to China IV standards,as demonstrated by engine tests and field NO_(x)measurements.However,the NO_(x)emission factors for non-type-approved engines were approximately twice the limits of the China II standards.Emission compliance based on bench tests was not sufficient to control actual emissions because the field-measured NO_(x)emission factors of all machinery ranged from 24%to 225%greater than the respective emission limits for the engines.These circumstances adversely affected the effectiveness of the regulations and policies for China’s emission control of NDMM.Nevertheless,the policies on new and in-use NDMM,as well as diesel fuel quality,prevented NO_(x)and PM emissions amounting to 4.4 Tg and 297.8 Gg during the period 2008-2017,respectively.The emission management strategy contributed to enhancing the international competitiveness of China’s NDMM industries by promoting advanced technologies.For effective NDMM emission control in the future,portable testing and noncontact remote supervision should be strengthened;also,the issue of noncompliant diesel should be addressed through rigorous control measures and financial penalties.

Impact of gasoline engine deposits on light duty vehicle emissions： in-use case study in Beijing, China

Tailpipe emissions from light-duty gasoline vehicles usually deteriorate over time. The accumulation of engine deposits due to inadequate gasoline detergency is considered to be one of the major causes of such emission deterioration. Six in-use light-duty gasoline vehicles in Beijing were tested to investigate the impact of engine deposits on emissions of hydrocarbons （HC）, carbon monoxide （CO） and nitrogen oxides （NOx）. Emissions under cold start and hot running test conditions from the six light duty vehicles were measured before and after engine deposits were removed. Results show that although individual vehicles reacted differently for each of the pollutants, elimination of engine deposits on average reduced HC emissions under hot running conditions by 29.4%, CO emissions under cold start conditions by 23.0% and CO emissions under hot running conditions by 35.5% （t 〈 0.05 in all cases）. No pollutant emissions increased with statistical significance （t 〈 0.05） after the removal of engine deposits. Variations of emission changes upon removal of engine deposits were observed. Such variations are in line with previous studies, implying that the impact patterns of engine deposits on vehicle emissions may be subject to many influencing factors that are not fully understood and difficult to control under all conditions. A statistical view of the impact of engine deposits on vehicle emissions may be appropriate for evaluation of emissions reductions across a city or a country. It is necessary to maintain sufficient and effective gasoline fuel detergency in practice to keep the engines clean and in tum reduce vehicle emissions.

In vitro toxicity of particulate matter emissions from residential pellet combustion

Particulate matter emissions(PM10)from the combustion,in a residential stove,of two com-mercial brands of certified(ENplus A1)pellets,a non-certified brand and laboratory made pellets of acacia were tested for their ability to induce ecotoxic,cytotoxic,and mutagenic re-sponses in unicellular organisms and a human cell line.Ecotoxicity was evaluated through the Vibrio fischeri bioluminescence inhibition assay.Moreover,cytotoxicity was assessed at two time points(24-and 48-hr)through two complementary techniques in order to evaluate the cellular metabolic activity and membrane integrity of human lung epithelial cells A549.The Ames test using two Salmonella typhimurium strains(TA100 and TA98)was employed to assess the mutagenic potential of the polycyclic aromatic hydrocarbon fraction extracted from the PM10 samples.Results obtained with the bioluminescent bacteria indicated that only particles from the combustion of acacia pellets were toxic.All samples induced im-pairment on the A549 cells metabolic activity,while no significant release of lactate dehy-drogenase was recorded.PM10 emissions from acacia pellets were the most cytotoxic,while samples from both certified pellets evoked significant cytotoxicity at lower doses.Cytotox-icity time-dependency was only observed for PM10 from the combustion of acacia pellets and one of the brands of certified pellets.Mutagenic activity was not detected in both S.typhi murium strains.This study emphasises the role of the raw material for pellet manu-facturing on the toxicological profile of PM emissions.Alternative raw materials should be deeply investigated before their use in pelletisation and combustion in residential appli-ances.