Fuel characteristics

Diesel Fuel Characteristics Imposed by its Combustion Behavior... 

Fuel Characteristics. Historically, chemical reprocessing of irradiated fuel was developed specifically to handle the U.S. government s defense-related fuels. These were of two types. There were the very low enrichments and bum-ups, eg, 0.9% U and 2000 MW-d/t, as was used for... 

Boiler Design Issues Boiler design involves the interaction of many variables water-steam circulation, fuel characteristics, firing systems and heat input, and heat transfer. The furnace enclosure is one of the most critical components of a steam generator and must be conservatively designed to assure high boiler availability. The furnace... 

Fuel Characteristics Fuel choice has a major impact on boiler design and sizing. Because of the heat transfer resistance offered by ash deposits in the furnace chamber in a coal-fired boiler, the mean absorbed heat flux is lower than in gas- or oil-fired boilers, so a greater surface area must be provided. Figure 27-42 shows a size comparison between a coal-fired and an oil-fired boiler for the same duty. 

C(psi) — venting equation constant, fuel characteristic constant for explosion venting equation. Table 7-27 (constant characterizes the fuel and clears the dim.ensional units (gases and vapors))... 

To its advantage, the fluid bed may utilize fuels with high ash contents, which affect the availability of other systems. It is also possible to control the acid emissions by additions to the bed during combustion. They are also less selective in fuels and can cope with a wide range of solid-fuel characteristics. 

The role of plastics in municipal solid waste combustion is discussed, and in particular, their fuel characteristics. Details are given of a state-of-art municipal solid waste combustor and the effects of plastics on the different combustion stages. In addition, the contribution of plastics to the total output spread over the various emission paths of solids, liquids and gases, is also assessed. 

Different technology suppliers worldwide have developed gasifiers. The choice of the type of the gasifier is purely a factor of the coal/fuel characteristics. Various technology suppliers for the gasification process are listed in Table 2.2. 

Sulfur fuels characteristically bum with flames that are pale blue, sometimes very intensely so. This color comes about from emissions as a result of the reaction... 

Propylene, like ethylene, is a colorless gas at room temperature. It is as flammable as LPG (liquefied petroleum gas or propane). In fact, propylene can be used as a. substitute or supplement to LPG. The fuel characteristics are nearly indistinguishable. However, the petrochemicals industry bids propylene away from the fuels market and gives it a much higher price than LPG. 

The input requirements for post-flashover types of models can be quite broad. Besides the compartment and vent dimensions, detailed fuel combustion characteristics are often needed. The fuel characteristics include the fraction of carbon, hydrogen, nitrogen, and oxygen that make up the fuel, the burning efficiency, and the quantity of fuel available for burning. Mechanical ventilation flow rates and the material properties of the compartment boundaries may be necessary. Some models can account for the heat transfer through the boundaries in detail, and may even allow the user to supply time-dependent material properties. An example of a post-flashover fire model is COMPF (Babrauskas, 1979). 

Some of the important fuel characteristics associated with high paraffin content in fuel are described as follows ... 

Jet Fuels (Grades JP-3, JP-4, JP-S JP-6). Specifications for early aircraft jet fuels were based primarily on manufg considerations, since it was believed that aircraft could burn almost anything of the nature of kerosene fuels (Ref 1). Later improvements in aircraft, particularly in high-speed jets, made it necessary to pay more attention to fuel characteristics and less attn to ease of manuf. The most important of these fuel characteristics is fuel stability at high temps. Other problems associated with jet aviation fuels, both for military civilian use, are minor compared to stability at high temps. Such problems include availability, handling physical property specifications... 

Data from Polasek Jervis (1994), for pure tyre ash. Major elemeni oxides add up to only 71 wt% no further details available. Data from Lemieux (1994), collected after co-firing natural gas and TDF crumbs. Major element oxides add up to 85 and 87 wt%, respectively. Ash represents fly ash from combustion of TDF crumbs, whose fuel characteristics are listed in Tables 4 and 5. Lemieux (1994) suspected that some elements (Al, Si, Zr) may have originated from the rotary kiln insulation. 

In contrast, very little is known of the mechanism of the combustion process in the gas turbine engine or of the fuel characteristics which would improve combustion performance. Despite the classified nature of much of the work in this field, it is apparent that very extensive research investigations—both fundamental and applied—are in progress. A substantial portion of this effort is in connection with the mechanics of combustion itself and, because of the necessarily fundamental approaches in this field, it is reasonable to expect that the results to be obtained will apply to all fuels, whether or not derived from petroleum, and may even be extended into the field of lubrication. 

Kittredge, G. D., Evaluation of Fuel Characteristics in Thermojet Combustion Proc-... 

Barnett, H. C., Hibbard, R. R., Fuel Characteristics Pertinent to Design of Aircraft... 

Biomass differs from conventional fossil fuels in the variability of fuel characteristics, higher moisture contents, and low nitrogen and sulfur contents of biomass fuels. The moisture content of biomass has a large influence on the combustion process and on the resulting efficiencies due to the lower combustion temperatures. It has been estimated that the adiabatic flame temperature of green wood is approximately 1000°C, while it is 1350°C for dry wood [41]. The chemical exergies for wood depend heavily on the type of wood used, but certain estimates can be obtained in the literature [42]. The thermodynamic efficiency of wood combustors can then be computed using the methods described in Chapter 9. 

The distilled alcohol product mixture was also esterified by refluxing with glacial acetic acid in the presence of a catalytic amount of sulfuric acid. The product was extracted with water followed by extraction with saturated sodium bicarbonate solution. It was further washed with water and dried over anhydrous sodium sulfate. The crude ester was distilled, and the distillate was stored for further use. The percent yield of esters was 86%. The mixed ester was determined by GC to be composed of (1.3%) methyl acetate, (1.3%) ethyl acetate, (11.5%) n-propyl acetate, (81.7%) isobutyl acetate, (1.2%) 2-methy 1-1-butyl acetate, and (1.9%) other components. The composition corresponded closely to that of the parent alcohol mixture. The fuel characteristics of the alcohol mixture and the ester mixture prepared from it were reported earlier (24). 

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