Effect of fuel sulfur

Engine lubricant formulators are aware of the problems associated with fuel sulfur and develop products to help combat its corrosive effect. Lubricants containing overbased calcium sulfonates and phenates are utilized to chemically neutralize the acids which form as a result of burning fuel sulfur. These oils can be effective at preventing the corrosive effects of fuel sulfur. However, the oils must be frequently changed to ensure that the acid-neutralizing effect is maintained. 

Fuel sulfur can decompose alkyl lead compounds and can diminish the effectiveness of lead compounds at inhibiting combustion knock. The effect of fuel sulfur at degrading alkyl lead compounds can be rated as follows ... 

Ford Position on the Effects of Fuel Sulfur on Advanced Emission Control Technology , Ford Motor Company, March 25 1996. 

Effects of Fuel Sulfur Levels on Mass Exhaust Emissions", Auto/Oil Air Quality Improvement Research Program, Technical Bulletin No. 2,... 

The concentration of NO required to form the NO2 must be high enough to oxidize the trapped soot. In addition, CO and HC were also oxidized in this same catalyst however, any SO2 was oxidized by the precious metals to SO3. Because of the complex effects of fuel sulfur in this technology (deactivation of NO oxidation catalyst and formation of SO3), this technology is limited to low... 

Benson, J.D. et al. (1991), Effects of gasoline sulfur level on mass exhaust emissions . SAE paper No. 91-2323, International fuels and lubricants meeting, Toronto, Ontario. 

Products of Combustion For lean mixtures, the products of combustion (POC) of a sulfur-free fuel consist of carbon dioxide, water vapor, nitrogen, oxygen, and possible small amounts of carbon monoxide and unburned hydrocarbon species. Figure 27-12 shows the effect of fuel-air ratio on the flue gas composition resulting from the combustion of natural gas. In the case of solid and liquid fuels, the... 

Matsuzaki Y and Yasuda I. Effect of a sulfur-containing impurity on electrochemical properties of a Ni-YSZ cermet electrode. In Yokokawa H, Singhal SC, editors. Proceedings of the Seventh International Symposium on Solid Oxide Fuel Cells (SOFC-VII), Pennington, NJ The Electrochemical Society, 2001 2001(16) 769-779. 

The catalytic reduction of the radicals, particularly the O atom, by sulfur compounds will generally reduce the rates of reactions converting atmospheric nitrogen to NO by the thermal mechanism. However, experiments do not permit explicit conclusions [21], For example, Wendt and Ekmann [46] showed that high concentrations of S02 and H2S have an inhibiting effect on thermal NO in premixed methene-air flames, while deSoete [47] showed the opposite effect. To resolve this conflict, Wendt el al. [48] studied the influence of fuel-sulfur on fuel-NO in rich flames, whereupon they found both enhancement and inhibition. 

Lewis, A., Graham, R., Aviation Kerosine Effect of High Sulfur-Content Fuels upon... 

Sulfur species are found in ambient air in most parts of North America and in most industrial countries. Their sources include natural emissions (biogenic and volcanic), smelting of ores and other industrial refining processes, and combustion of sulfurbearing fuels. This paper will focus on the combustion sources in the United States and some of the effects of their sulfur emissions. The environmental effects of sulfur in the environment have been of interest for many years and much of the information presented here has been drawn from the various conference proceedings and assessment documents that have been published in recent years (1-11). When specific references are not listed in the text, the information represents a consensus from these various sources. 

A major challenge in the ultradeep desulfurization of hydrocarbon fuels is the inhibiting effects of fuel components (e.g., nitrogen compounds) and reaction products (e.g., hydrogen sulfide). While this area has been studied in catalysis literature, it is expected to gain increased attention because of the severity of the new sulfur specifications. ... 

Corrosion of heating equipment can occur if the sulfur oxides formed on combustion of fuel oil are allowed to condense in the presence of moisture on the cooler parts of the flue system. Corrosion of metal parts of the fuel system may also reflect the presence of corrosive sulfur components in the fuel. The corrosive tendencies of the fuel may be detected by the copper strip test (ASTM D-130, ASTM D-849, IP 154), the effect of these sulfur compounds being indicated by discoloration of the copper strip. 

Maynard D, Coull BA, Gryparis A et al (2007) Mortality risk associated with short-term exposure to traffic particles and sulfates. Environ Health Perspect 115 751-755 McDonald JD, Harrod KS, Seagrave J et al (2004) Effects of low sulfur fuel and a catalyzed particle trap on the composition and toxicity of diesel emissions. Environ Health Perspect 112 1307-1312... 

Garcfa-Labiano, E., de Diego, L.F., Gayan, P. et al. (2009) Effect of fuel gas composition in chemical-looping combustion with Ni-based oxygen carriers. 1. fate of sulfur. Industrial Engineering Chemistry Research, 48,2499-2508. 

It is noteworthy, however, that traces of sulfur can have beneficial effects on the anti-wear resistance of fuel injection pumps. It is thus undesirable to reduce the sulfur content to extremely low values unless additives having lubricating qualities are added. Independently from total sulfur content, the presence of mercaptans that are particularly aggressive towards certain metal or synthetic parts is strictly controlled. The mercaptan content is thereby limited to 0.002% (20 ppm) maximum. The analysis is performed chemically in accordance to the NF M 07-022 or ASTM D 3227 procedures. 

The main justification for diesel fuel desulfurization is related to particulate emissions which are subject to very strict rules. Part of the sulfur is transformed first into SO3, then into hydrated sulfuric acid on the filter designed to collect the particulates. Figure 5.21 gives an estimate of the variation of the particulate weights as a function of sulfur content of diesel fuel for heavy vehicles. The effect is greater when the test cycle contains more high temperature operating phases which favor the transformation of SO2 to SO3. This is particularly noticeable in the standard cycle used in Europe (ECE R49). 

Steps such as the substitution of low sulfur fuels or nonvolatile solvents, change of taw materials, lowering of operation temperatures to reduce NO formation or vo1ati1i2ation of process material, and instaHion of weU-designed hoods (31—37) at emission points to effectively reduce the air quantity needed for pollutant capture are illustrations of the above principles. 

There has been extensive recent rethinking of the role of fees and fines as means of influencing industrial decision making with regard to investment in pollution control equipment and pollution-free processes. In their new roles, fees and fines take the form of tax write-offs and credits for polluhon control investment taxes on the sulfur and lead content of fuels continuing fines based on the pollution emission rate and effluent fees on the same basis. Tax write-offs and credits tend to be resisted by treasury officials because they diminish tax income. Air pollution control agencies tend to look with favor on such write-offs and credits because they result in air pollution control with minimal effort on the part of their staffs and with minimal effect on their budget. 

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