Fuels solid, typical composition

Some of the unusual properties of a solid propellant results from its basic composition. The two general categories of double-base and composite rubber binder propellants have many subcategories, but no exhaustive compilation will be attempted here. Most modem propellants consist of a deformable binder phase and a crystalline salt filler, such as ammonium perchlorate and usually a powdered metallic fuel such as aluminum. Table I gives some typical compositions for both composite rubber-based and composite double-base systems. 

Table 5.1.32 Typical composition of solid fuels (Falbe, 1977).

It is useful to examine the combustion process applied to solid wastes as fuels and sources of energy. All solid wastes are quite variable in composition, moisture content, and heating value. Consequently, they typically are burned in systems such as grate-fired furnaces or fluidized-bed boilers where significant fuel variability can be tolerated. 

Solid propellants may be classified as monopropellants or composite propellants. Monopropellants are substances in which the fuel and oxidizer are both contained within the same molecule or at least in a single phase. These materials may either burn slowly at subsonic rates or may decompose rapidly in detonation. Depending on the use to which this type of material is put, it may be classified either as propellant or high explosive. In general, useful monopropellants are difficult to detonate. The typical example of a monopropellant is the so-called double-base propellant. This substance consists of nitrocellulose which has been colloidized by nitroglycerine along with various minor constituents which have been added to... 

C2H40, which is taken as typical in per cent compositions lor many solid proplnt fuels 1)K perchlorate 50-80 C2H40 50-20% 2)Amm perchlorate 50-85 C2H40 50-15% and 3)Amm nitrate 80 C2HaO 20% with catalyst added 2%... 

Explosives in which the oxidizer and fuel portions come from different molecules are called composite explosives because they are a mixture of two or more chemicals. A classic industrial example is a mixture of solid ammonium nitrate (AN) and liquid fuel oil (FO). The common designation for this explosive is the acronym, ANFO. The oil used (typically 2 diesel fuel) is added in sufficient quantity to react with the available oxygen from the nitrate portion of AN. The redox reaction of ANFO is as follows ... 

The composition of the exhaust depends on the type and composition of the fuel and on combustion conditions. The main components are O2 (0-15%), CO2 (3-12%), H2O (6-18%) and N2. Typical ranges of air pollutants from the combustion of natural gas, oil and coal are shown in Table I. In addition to NOx, commonly encountered pollutants include carbon monoxide (CO), hydrocarbons or Volatile Organic Compounds (VOCs), sulfur oxides (SOx) and particulates. Municipal Solid Waste (MSW) incinerator or waste-to-energy plant exhausts may also contain acid gases (e.g., HCl, HF), dioxins, furans and trace amounts of toxic metals such as mercury, cadmium and lead. 

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