Ageing of diesel

The age of diesel oil in the subsurface soil environment can be determined by utilizing the fact that the composition of the diesel oil (the ratio between -alkanes and isoprenoids) changes due to biodegradation. In one study, the ratio of C , to pristane was highly correlated with the residence time of diesel fuel at 12 test locations (Christensen et al 1993). 

Christensen LB, Larsen TH. 1993. Method for determining the age of diesel oil spills in the soil. Ground Water Monitor Remediation 13(4) 142. 

The procedure most commonly employed (NF M 07-047 or ASTM D 2274) Is to age the diesel fuel for 16 hours while bubbling oxygen into it at 95°C. The gums and sediment obtained are recovered by filtration and weighed. There is no official French specification regarding oxidation stability however, in their own specifications, manufacturers have set a maximum value of 1.5 mg/100 ml. 

Konstandopoulos, A. G., Kostoglou, M., Skaperdas, E., Papaioannou, E., Zarvalis, D., and Kladopoulou, E., Fundamental studies of diesel particulate filters Transient loading, regeneration and aging. SAE Technical Paper No. 2000-01-1016 (SP-1497) (2000). 

As diesel ages a fine sediment and gum forms in the fuel brought about by the reaction of diesel components with oxygen from the air. The fine sediment and gum will block fuel filters, leading to fuel starvation and engine failure. Frequent filter changes are then... 

The first results on the durability of the diesel NO i reduction catalyst show that engine aging decreases the maximum NO.v conversion and shifts the onset of the conversion to higher temperatures. This deactivation was found to be caused by phenomena similar to those identified for the deactivation of diesel oxidation catalysts. 

The test matrix that will be carried out in the EUPHORE chamber is shown in Tables 1 and 2. These series of tests provide experiments that will examine the effects of aging, photolysis, HO, O3 and the NO3 radieal (in the dark) on the eomposition of diesel exhaust. The experiments are divided into dark (Table 1) and light (Table 2) exposures test matrixes. The dark experiments D-1, D-2, and D-5 provide baselines for other experiments. Experiment D-3 investigates the effeets of O3 on diesel exhaust in the dark and experiment D-4 allows the effect of the NO3 radical on diesel exhaust to be studied. Dinitrogen pentoxide is used as a source of NO3 radicals. N2O5 is prepared by reacting ozone with NO2 direetly in the chamber. 

Reduction of diesel exhaust emissions has, in some cases, led to engines producing more soot within the lubricant, exacerbated by extended oil drain intervals leading to more soot-related wear. Some low-emission engines have also experienced increased fuel dilution, causing premature ageing of the lubricant. These issues have presented the lubricant formulator with an array of problems that must be addressed. 

Many catalysts exhibit a catalytic activity for NO reduction, under conditions of Diesel exhausts, not very inferior to that of ZSM-5, especially copper-MCM-22, copper-EMT, copper FAU-type zeolites and copper-Beta. EMT-catalysts which present a good potential for Diesel exhaust after-treatment suffer from deactivation in the presence of water as it is the case for ZSM-5 catalysts. Dealumination was a significant cause of this loss of activity when the catalysts were aged. It was not possible to avoid dealumination while keeping the catalyst... 

The next important parameter of diesel fuel is stability or storage stability. As fuel ages, it can become unstable and form insoluble particulates that accumulate and eventually end up on the fuel filter. For the most part, instability involves the chemical conversion of precursors to compounds of higher molecular weight with limited fuel solubility. The precursors are certain nitrogen and/or sulfur containing compounds, organic acids, and reactive olefins. The conversion process often involves oxidation of the precursors. Certain dissolved metals, especially... 

GC/MSD instrument detection limit is typically 1 to 5 ig/mL (ppm) operated in scan mode. For a 1-g sample extracted into 10 mL, the method detection limit is about 10 /ig/g (ppm) which is sufficient for screening purposes. Table 16.1 summarizes typical recovery figures using this simplified extraction procedure. For soils fortified with 100 ppm of diesel with matrix ranging from sand to peat moss, recovery varies from 68 to 83%. To test the rapid extraction further, an actual sample contaminated with well-aged diesel was analyzed and showed a value of 54% of that obtained by more vigorous extraction (2,254 ppm versus 4,200 ppm). 

Konstandopoulos AG, Skaperdas E, Papaioannou E, Zarvalis D, Kladopoulou E (2000) Fundamental Studies of Diesel Partieulate Filters Transient Loading, Regeneration and Aging. SAE paper 2000-01-1016... 

Anthropogenic sources of NgO include adipic and nitric acid production, fossil fuel and biomass combustion, land cultivation, and vehicle emissions. " NgO emissions from gasoline-powered engines have been related to the aging of three-way catalysts (TWCs) and NgO is also emitted as a by-product of Pt-based prototypic catalysts for the selective catalytic reduction (SCR) of NO with hydrocarbons in diesel engine exhausts. ... 

Long-chain esters of pentaerythritol have been used as pour-point depressants for lubricant products, ranging from fuel oils or diesel fuels to the high performance lubricating oils requited for demanding outiets such as aviation, power turbines, and automobiles. These materials requite superior temperature, viscosity, and aging resistance, and must be compatible with the wide variety of metallic surfaces commonly used in the outiets (79—81). 

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