Solid combustion products

Several studies investigating the environmental effects of controlled tyre combustion have been conducted. It is evident that atmospheric emissions can be greatly reduced if proper air pollution control systems are installed. Laboratory and field data provide evidence indicating that concentrations of some environmental pollutants, especially NOx, may decrease due to tyre combustion, whereas others increase compared to pure coal combustion. Zinc is an example of an element that increases in both solid combustion products and atmospheric emissions. The geochemical impact of higher Zn contents in fly and bottom ash on leaching processes in disposal sites remains to be tested. 

As discussed in the previous section, trace elements are essentially retained in the solid combustion products and, because many are present on the surfaces of the particles, they are potentially leachable. Our data show the elements Mo, As, Cu, Zn, Pb, U, Tl, and Se will be readily accessible for leaching. A significant fraction of the V, Cr, and Ni, and a minor proportion of the Ba and Sr will also be potentially leachable because of the surface association, but most of these elements appear to be located in particles and will be released more slowly as the dissolution of the glass and other phases takes place. Rubidium, Y, Zr, Mn, and Nb are contained almost entirely within the particles and dissolution is potentially slower. The extent to which elements are leached also depends on their speciation and solubility in the porewaters, and the pH exerts a major control. In oxidizing solutions, elements such as, Cd, Cu, Mn, Ni, Pb, and Zn form hydrated cations that adsorb onto mineral surfaces at higher pH values and desorb at lower pH values. In contrast, the elements As, U, Mo, Se, and V, under similar Eh conditions, form oxyanions that adsorb onto mineral surfaces at low pH values and desorb at higher values (Jones 1995). 

I96I) (A delay mixt for use in ordnance missiles or app which forms solid combustion products consists of Mn 1/3, PbCr04 1/3 BaCr04 1/3 parrs)... 

The combustion of an energetic material is an irreversible process in which mainly gaseous and to a lesser extent solid combustion products are formed. One can differentiate between two borderline cases of combustion ... 

Mah ( ) measured the enthalpy of combustion of vanadium mononitride at 303.15 K. which corresponds to the nitrogen-rich boundary of the mononitride phase (see Phase Data section). Chemical analysis also showed that the sample contained 0.07 weight percent of unreacted vanadium. The composition of the combustion products ranged from 2 231 2 296 diffraction patterns showed the solid combustion products to be a mixture of and JANAF... 

Figure 25.5. Image of the thermal ignition of an aerogel iron (III) oxide/nanometiic aluminum energetic composite that shows the production of high-temperature solid combustion products.

Davies et al. 37) studied the combustion of tin tetraalkyls by static bomb calorimetry, and found that virtually complete combustion can be attained. Analysis of the bomb gases after combustion showed that combustion of the carbon content was from 99.8-100% complete, and the solid combustion product was shown to be Sn02, only small amounts of unburned tin remaining admixed with it. Davies et al. obtained the results given in the table. 

An electrostatic precipitator consists of two parallel plates separated by a distance of 0.06 m. The flow of gas through the system at 121°C and 207 X 10 N/m2 pressure has a Reynolds number of lO. Combustion products are anticipated to have log normal distribution with the average log normal length diameter of 6.0 Mm. The solid combustion product has a density of 1282 kg/m3. The electric field is 10,000 N/C with a particle charge of 10" ih c. What is the drift velocity of the average particle, the length of the precipitator needed for capture of this particle, and the efficiency of the precipitator ... 

In gas-solid extractions the sample is passed through a container packed with a solid adsorbent. One example of the application of gas-solid extraction is in the analysis of organic compounds for carbon and hydrogen. The sample is combusted in a flowing stream of O2, and the gaseous combustion products are passed through a series of solid-phase adsorbents that remove the CO2 and 1T20. 

Fig. 2. Overall schematic of solid fuel combustion (1). Reaction sequence is A, heating and drying B, solid particle pyrolysis C, oxidation and D, post-combustion. In the oxidation sequence, left and center comprise the gas-phase region, tight is the gas—solids region. Noncondensible volatiles include CO, CO2, CH4, NH, H2O condensible volatiles are C-6—C-20 compounds oxidation products are CO2, H2O, O2, N2, NO, gaseous organic compounds are CO, hydrocarbons, and polyaromatic hydrocarbons (PAHs) and particulates are inerts, condensation products, and solid carbon products.

Exposures to chemicals may involve solids, liquids, or airborne matter as mists, aerosols, dusts, fumes (i.e. pm-sized particulates), vapours or gases in any combination. Many situations, e.g. exposure to welding fumes or to combustion products from fossil fuels, include mixtures both of chemicals and of physical forms. Quantification of exposure is then difficult. 

Fire Hazards - Flash Point Not pertinent (combustible solid) Flammable Limits in Air (%) Not pertinent Fire Extinguishing Agents Water, foam Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Toxic oxides of nitrogen may be formed in a fire Behavior in Fire Not pertinent Ignition Temperature Not pertinent Electrical Hazard Not pertinent Burning Rate Not pertinent. 

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