Range Fuels

Over the years, a variety of fuel types were employed. Originally, natural uranium slugs canned in aluminum were the source of plutonium, while lithium—aluminum alloy target rods provided control and a source of tritium. Later, to permit increased production of tritium, reactivity was recovered by the use of enriched uranium fuel, ranging from 5—93%. 

There are several important Hquid fuels, ranging from volatile fuels for internal combustion engines to heavy hydrocarbon fractions, sold commercially as fuel oils. The technology for the combustion of Hquid fuels for spark-ignition and compression-ignition internal combustion engines is not described here. 

Gas turbines are capable of burning a wide variety of fuels, both gaseous and liquid. Typical liquid fuels range from kerosene and diesel to light crudes. They are also capable of running on natural gas and industrial gases... 

A number of such processes were established before the second World War in Germany, Japan, and France for the production of hydrocarbon mixtures in the liquid fuel range (P2). This way of manufacturing automotive fuels is now uneconomical in most areas, but related processes may be utilized for the production of various chemicals, such as paraffinic waxes or oxygenated compounds. (The manufacture of methanol from carbon monoxide and hydrogen, usually by catalytic reaction in fixed-bed gas-particle operation, is an important process of this type.)... 

Current EPA analytical methods do not allow for the complete speciation of the various hydrocarbon compounds. EPA Methods 418.1 and 8015 provide the total amount of petroleum hydrocarbons present. However, only concentrations within a limited hydrocarbon range are applicable to those particular methods. Volatile compounds are usually lost, and samples are typically quantitated against a known hydrocarbon mixture and not the specific hydrocarbon compounds of concern or the petroleum product released. By conducting EPA Method 8015 (Modified) using a gas chromatograph fitted with a capillary column instead of the standard, hand-packed column, additional separation of various fuel-ranged hydrocarbons can be achieved. 

Source Concentrations in 8 diesel fuels ranged from 0.026 to 40 mg/L with a mean value of 6.275 mg/L (Westerholm and Li, 1994). Lee et al. (1992) reported concentration ranges of 100-300 mg/L and 0.04-2 pg/L in diesel fuel and corresponding aqueous phase (distilled water), respectively. Schauer et al. (1999) reported anthracene in diesel fuel at a concentration of 5 pg/g and in a diesel-powered medium-duty truck exhaust at an emission rate of 12.5 pg/km. Anthracene was detected in a distilled water-soluble fraction of used motor oil at concentrations ranging from 1.1 to 1.3 pg/L (Chen et al., 1994). 

Source Concentrations in 8 diesel fuels ranged from 0.018 to 5.9 mg/L with a mean value of 0.93 mg/L (Westerholm and Li, 1994). Identified in Kuwait and South Louisiana crude oils at concentrations of 2.3 and 1.7 ppm, respectively (Pancirov and Brown, 1975). 

To avoid excessive fragmentation of the feed, which could result in the formation of unsaturated hydrocarbons and carbon deposits on the catalyst, feed preheat temperatures for liquid fuels range from ambient to just above their boiling point. Reaction temperatures are typically in the range of 700 to 900°C. If organic sulfur is present in the feed, then the reactor is typically operated at higher temperatures, where metal sulfides are less stable. The O2 in... 

The spent fuel matrix is a ceramic material with a fascinating chemical composition and a large degree of phase heterogeneity. The physical state and chemical composition of spent fuel largely depends on the bum-up of the fuel once it is taken out of the reactor. In Fig. 6 we indicate the dependence of the chemical composition on the bum-up for a series of PWR fuels. However, the fact that remains constant is that U02 constitutes the major component of spent fuel, ranging within a total of 95-98% in weight (see Fig. 7). 

These H-Coal and SRC-II syncrudes are low boiling and do not contain residuum. As shown in Figure 1, much of each syncrude boils in the jet fuel range. Only about 25 vol % boils below the start of the jet fuel range (250°F), and about 5 vol % boils above the end of the jet fuel range (600°F). 

This volume provides an overview of current fundamental and applied combustion research studies that address the use of synthetic fuels. The main emphasis in these studies is on the combustion of liquid fuels, ranging from research on spray atomization to pilot-scale testing of the combustion of synthetic fuels. 

N0X Emissions. The nitrogen content in the distillate fuels ranged from 0.0 to 0.75 wt%. The influence of this range on N0X emissions is displayed in Figure 11. The values plotted correspond to the minimal N0X level for each fuel. Since the minima occurred over a small range of primary combustor equivalence ratio (1.5 << >p <1.57) these data also represent operation at constant combustor conditions. As can be observed, the N0X emissions were independent of fuel nitrogen. An... 

In 1980 additional regulations imposed by the U.S. Environmental Protection Agency (EPA) required control of NOx (NO, N02, N20) emissions. Its removal coupled with the continuing need to remove CO and CyHn proved to be quite challenging because the latter had to be oxidized and the former reduced. Thus it appeared two separate environments were needed. This problem was solved by the development of the three-way catalyst or TWC capable of catalyzing the conversion of all three pollutants simultaneously provided the exhaust environment could be held within a narrow air-to-fuel range. This is shown in Fig. 7.10. 

Economics Typical consumption figures (feed + fuel) range from 6.7 to 7.2 Gcal per metric ton of ammonia and will depend on the individual plant concept as well as local conditions. 

Economics Typical consumption figures (feed+fuel) range from 7 to 8 Gcal per metric ton of methanol and will vary on individual plant concept. 

Four unleaded fuels were selected for the octane evaluation program. The fuels ranged from a regular grade of leaded gasoline without the tetraethyl lead to Indolene high octane, the unleaded fuel used for emissions certification. Indolene is the trade name for the test fuel manufactured by Standard Oil Co. to meet the specification called out in Ref. 7. Some of the base fuel properties are given in Table I. 

---