Ash residue

Incinerator ash Residue from direct Most dumped As fill and for covering... 

XRD analysis on sulfated ash residue of new additive packages in lubricating oils has indicated the presence of nonstoichiometric mixed salts of the elements Mg, Ca, Zn, P and B [60],... 

RDF source Calorific value (MJ/kg) Ash residue (wt.%) Chlorine content (wt.%) Sulfur content (wt.%) Water content (wt.%)... 

The thermal treatment of some wastes (e.g. industrial, medical, and military) through their incineration results in the formation of relatively highly toxic residues. The ash residue being a secondaiy waste is sometimes more toxic than the primary solid feed. 

Waste incineration leads to a decrease of the waste mass only. From 15 to 30 % of feed mass is still the ash residue. 

A filter paper is ashless if it is completely volatilized when burned, leaving no ash residue. In Experiments 6 and 7, if the filter paper were not ashless, a residue would remain in the crucible and add weight to the precipitate. This in turn would increase the calculated percent, and the results reported would be high. 

Gasification is the conversion by partial oxidation at elevated temperature of a carbonaceous feedstock into a gaseous energy carrier consisting of permanent, noncondensable gases. Ideally, the process produces only a non-condensable gas and an ash residue. However, since gasification processes are carried out far from equilibrium, tars (condensable organic material) are produced and the ash resi-... 

This transition produces an isomorphous phase and the resulting y-alumina has the same morphology and texture as its boehmite precursor. With increasing temperature and time the mean pore diameter increases gradually and other phases appear (S-, 6-alumina). Due to the broad XRD lines, the distinction between y- and S-alumina cannot be made 6-alumina occurs at about 900°C while the conversion to the chemically very stable a-alumina phase takes place at T> 1000°C. Some typical results for alumina membranes synthesized without binders are given in Table 2.4. When PVA was used as a binder, thermogravimetric analysis showed that, provided the appropriate binder type was used, the binder could be effectively removed at T > 400°C. The ash residue is of the order of 0.01 wt.%. Mean pore size and... 

Incineration. A "pesticide Incinerator" Is defined as "any Installation capable of the controlled combustion of pesticides, at a temperature of 1000 C (1832 F) for two seconds dwell time In the combustion zone, or lower temperatures and related dwell times that will assure complete conversion of the specific pesticide to Inorganic gases and solid ash residues" ( 2). In addition, an Incinerator must meet the performance standards promulgated under RCRA (40 CFR 264 Subpart 0) If pesticides regulated under RCRA are to be burned. This means that an Incinerator must be capable of destroying or removing 99.99% of the pesticide put Into It. Test burns that are fully monitored are normally required to determine whether this performance standard Is achieved. 

Sample Sample ID Sample wt. Sample DM Fractional sample DM S dry wt. Sample ash %. Fractional ash Sample OM Residual wt. Residual ash Residual OM OMD g/kg DOMD g/kg DM DMD g/kg Average... 

In combustion of solids such as coal, wood, and charcoal the reaction of O2 occurs with solid carbon, sometimes leaving a solid ash residue. Fuel oil drops react with O2 in a similar process in boilers and in diesel engines. Since the exothermicity of these processes creates very large temperature differences, we will describe them in the next chapter. 

The vendor also prepared economic projections for facilities treating asbestos ash residues at varying input rates. These facilities would require higher labor costs, with power requirements being the second highest component of treatment costs. Treatment costs varied from 130 to 175 per ton. Details of these estimates are given in D17167P, pp. 22-24. 

Particle size distributions of smaller particles have been made using electrical mobility analyzers and diffusion batteries, (9-11) instruments which are not suited to chemical characterization of the aerosol. Nonetheless, these data have made major contributions to our understanding of particle formation mechanisms (1, 1 ). At least two distinct mechanisms make major contributions to the aerosols produced by pulverized coal combustors. The vast majority of the aerosol mass consists of the ash residue which is left after the coal is burned. At the high temperatures in these furnaces, the ash melts and coalesces to form large spherical particles. Their mean diameter is typically in the range 10-20 pm. The smallest particles produced by this process are expected to be the size of the mineral inclusions in the parent coal. Thus, we expect few residual ash particles smaller than a few tenths of a micrometer in diameter (12). 

Only a small fraction of these particles is included in the impactor sample because the cyclone separator removed most particles larger than about 2 urn. The composition of those large particles which were collected by the impactor is that expected for the ash residue. The major species are the oxides of Si,... 

Modem coal combustion employs two principal techniques combustion in a fluidized bed or pulverization, followed by combustion of fine particles suspended in moving air. Figure 1 shows a schematic of pulverized coal combustion, a process much used in steam-raising plants. Each process produces a characteristic residue fluidized bed combustion gives rise mainly to a clinker-like or granular product, whereas pulverization, followed by combustion, produces mainly a much finer, micrometre-sized ash residue. Pulverization also yields a coarser fraction, the so called bottom ash , which is periodically removed without difficulty. However, the finer fly ash has to be recovered by filtration and electrostatic precipitation. Commercially, fly ash has... 

The chemical composition of CCPs varies with coal origin and rank however, the major elemental constituents of all coal ash residues are O, Si, Al, Fe, and Ca, along with lesser amounts of Mg, S, and C. The relative abundance of constituents that typically make up more than 1 % of the total mass of fly ash and bottom ash are summarized in Table 4. These elements are found in the ash because of their lower volatility and the short time the particles actually remain in the furnace during combustion (Helmuth 1987). Both crystalline and non-crystalline compounds form on the surface of fly ash particles when elements react with oxygen in the flue gases, and through... 

Semi-coke, or coke ash residue. This waste material accumulates when oil shale is retorted. The residues and their leachates contain organic contaminants, most importantly phenolic species, for example, phenol, cresols, xylenols, and resorcinols (Raidma 1994 Kahru et al. 1999). 

Table 9. Physical properties and chemical composition of ash residues from combustion of Estonian kukersites in power plants ...

During MSW combustion in a modern mass burn combustor with reciprocating grates, 11 of MSW is converted to heat gases such as C02, NOx, SOx, and H20 and about 350 kg of ash residuals partitioned into the various ash streams. For every tonne of MSW combusted, about 5 kg of grate siftings, 295 kg of grate ash, 5 kg of boiler/economizer ash, 20 kg of ESP ash, and 12 kg of dry scrubber solids are produced (Chandler et al. 1997). 

Ash. Ash residue shall be determined by measuring 50 ml of the sample in a graduate and transferring to a 125 ml platinum dish which has been ignited to constant weight, cooled in a desiccator, and cared to the nearest 0.1 mg. The dish shall be heated until the vapors continue to... 

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