Sulfur content fuel oils

Table V. Economic Summary (Capacity 100,000 bbl/day of Fuel Oil) Sulfur content, Parameter 0,60 wt % OM...

Low sulfur fuel oils were prepared from a high volatile bituminous coal by hydrogenation under high temperatures and pressures. At a coal conversion of 80%, the ratio of oiU to-gas yields was about three, and 23% of the coal sulfur was contained in the oil. Sulfur content of the oil, however, remained the same at different coal conversion levels. The data obtained in the semi-continuous, dilute phase hydrogenation system showed that the whole oil can be directly used as a fuel oil where 1% sulfur is tolerated. Fuel oils containing 0,5 and 0,25% sulfur were produced by desulfurization of the whole oil, A preliminary economic evaluation indicated that low sulfur fuel oils can be produced from coal by hydrogenation at a manufacturing cost of about 5-6 per barrel. 

Following 1 October 1996, diesel fuel should be desulfurized to a level of 0.05% while the maximum sulfur content of home-heating oils will stay provisionally at 0.2 %. 

In France there are four categories of heavy fuels whose specifications are given in Table 5.19 the different product qualities are distinguished essentially by the viscosity, equal to or less than 110 mm /s at SOT for No. 1 fuel oil, equal to or greater than 110 mm /s for No. 2 fuel oil, and by the sulfur content varying from 4 wt. % (No. 2 fuel oil) to 1 wt. % (No. 2 TBTS - very low sulfur content fuel oil). 

In the past, reducing the sulfur content was mainly concerned with the heaviest products, most particularly the fuel oils. This development is explained by a legitimate concern to reduce SO2 emissions, notably in areas around large population centers. This is how low sulfur heavy fuels —having a maximum of 2% sulfur— and very low sulfur ( % sulfur) came into being. Currently the whole range of petroleum products, particularly motor fuels, should be strongly desulfurized for reasons we will explain hereafter. 

For example, in the case of light Arabian crude (Table 8.16), the sulfur content of the heavy gasoline, a potential feedstock for a catalytic reforming unit, is of 0.036 weight per cent while the maximum permissible sulfur content for maintaining catalyst service life is 1 ppm. It is therefore necessary to plan for a desulfurization pretreatment unit. Likewise, the sulfur content of the gas oil cut is 1.39% while the finished diesel motor fuel specification has been set for a maximum limit of 0.2% and 0.05% in 1996 (French specifications). 

Residual fuel-oil represented more than 20 to 25% of the crude and the content in pollutants (sulfur, nitrogen, metals) increased. 

Heavy residue conversion is linked to the demand for high quality diesel motor fuel (aromatics content 10%, cetane number 55) as well as to the demand for production of light fuel-oil having very low sulfur, nitrogen and metal contents. 

Furthermore, 60—100 L (14—24 gal) oil, having sulfur content below 0.4 wt %, could be recovered per metric ton coal from pyrolysis at 427—517°C. The recovered oil was suitable as low sulfur fuel. Figure 15 is a flow sheet of the Rocky Flats pilot plant. Coal is fed from hoppers to a dilute-phase, fluid-bed preheater and transported to a pyrolysis dmm, where it is contacted by hot ceramic balls. Pyrolysis dmm effluent is passed over a trommel screen that permits char product to fall through. Product char is thereafter cooled and sent to storage. The ceramic balls are recycled and pyrolysis vapors are condensed and fractionated. 

Over the years, larger quantities of sulfur have been recovered for a number of reasons. These iaclude iacreased petroleum refining and natural-gas processiag, more stringent limitations on sulfur dioxide emissions, and higher sulfur contents of the cmde oil refined. Another contributiag factor is the lower sulfur content limits set on petroleum-based fuels. 

The Council of the European Economic Community, established under the 1957 Treaty of Rome, in 1973 issued a declaration on the environment (4), which the European Commission in Brussels has interpreted as giving it authority to issue directives on matters related to the emission of air pollutants, such as one limiting the sulfur content of fuel oil (5). 

Give preference to natural gas over heavy fuel oil for use as fuel and to coke with lower sulfur content. 

The high-chromium casting alloys (50% nickel, 50% chromium and 40% nickel, 60% chromium) are designated for use at temperatures up to 900 C in furnaces and boilers Ared by fuels containing vanadium, sulfur and sodium compounds (e.g., residual petroleum products). Alloys with lower chromium contents cannot be used with residual fuel oils at temperature above 6S0 C because the nickel reacts with the vanadium, sulfur and sodium -impurities to form compounds that are molten above 650 C [27]. 

Mercaptan extraction is used to reduce the total sulfur content of the fuel. When potassium isobutyrate and sodium cresylate are added to caustic soda, the solubility of the higher mercaptans is increased and they can be extracted from the oil. To remove traces of hydrogen sulfide and alkyl phenols, the oil is pretreated with caustic soda in a packed column or other mixing device. The mixture is allowed to settle and the product water washed before storage. 

The reduction of SO, is best achieved by reducing the sulfur content of the fuel oil. Ship engineers arc required to replace high-sulfur fuel with expensive higher-grade oil fuel as their ships approach coastlines where strict pollution restrictions apply. 

Ultradeep desulfurization of fuel oils is used for producing not only clean fuels but also sulfur-free hydrogen used in fuel-cell systems, in which the hydrogen can be produced potentially through the reforming of fuel oils. Fuel-cell systems must be run with little-to-no sulfur content, because sulfur can irreversibly poison the precious metal catalysts and electrodes used [12]. 

There is a need to seek an environmentally benign, technically feasible and economical alternative fuel because of the limited crude oil reserves and serious pollution all over the world. Recently, dimethyl ether (DME) is proved to be used as an alternative clean fuel in transportation, power generation and household use for its excellent behavior in compression ignition for combustion, cetane number of over 55 and zero sulfur content, and is praised as a super-clean fuel in the 21 century. It has a promising foreground of application. Therefore, the efficient synthesis of DME from syngas derived from natural gas, coal or biomass has drawn much attention. 

Brunnock et al. [67] have also determined beach pollutants. They showed that weathered crude oil, crude oil sludge, and fuel oil can be differentiated by the n-paraffin profile as shown by gas chromatography, wax content, wax melting point, and asphaltene content. The effects of weathering at sea on crude oil were studied parameters unaffected by evaporation and exposure are the contents of vanadium, nickel, and n-paraffins. The scheme developed for the identification of certain weathered crude oils includes the determination of these constituents, together with the sulfur content of the sample. 

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