Soot emissions

Additives for Improving Combustion and for Reducing Smoke and Soot Emissions... 

Combined Soot W2O, and CO2 Radiation The spectral overlap of H9O and CO9 radiation has been taken into account by the constants for obtaining Ec- Additional overlap occurs when soot emissivity , is added. If the emission bands of water vapor and CO9 were randomly placed in the spectrum and soot radiation were gray, the combined emissivity would be Eg phis , minus an overlap correction g s- But monochromatic soot emissivity is higher the shorter the wavelength, and in a highly sooted flame at 1500 K half the soot emission hes below 2.5 [Lm where H9O and CO9 emission is negligible. Then the correction g s must be reduced, and the following is recommended ... 

Where stack temperatures are low and sulfur gases are present, problems of dry soot emissions give way to wet acid smutting. 

Unlike the known approaches we develop the use of water- fuel emulsions with the soluble in water catalytic non- corroding additions and ultrasonic mixing by the sharp superheated steam for reduction of the oxides of nitrogen and soot emission in the combustion engines. Our know how is also the use of the electro-activated water for emulgation. The first results testily the technical and economic expedience of the chosen direction. 

For the prediction of NOx formation, the extended Zeldovich mechanism described by Heywood[603] was implemented. The soot emission modelis a modified version of previously published models for soot formation and oxidation. Details of the soot emission model have been discussed by Han et al.[604]... 

Soot emission from hydrocarbon flames is an important snbject since it plays an important role in relation to both heat transfer by radiation and air pollution (Sha-had and Mohanuned, 2000). The use of CNG in internal combnstion (1C) engines permits operation with decreased advances and decreases NO without increasing soot formation. 

Figure 6.3 Comparison of uncontrolled and controlled soot emissions for different fuel forcing levels between propane (1 — minimum and 2 — maximum soot level) and ethylene (3 — minimum and 4 — maximum soot level)...

The initial-unforced emission level is nearly five times larger for the ethylene flame. The drop in soot emission occurred at a certain threshold level of the fuel forcing level. This level is lower in the propane flame relative to the ethylene flame. Following this rapid drop, the slope of all the curves is similar. The... 

The lack of a complete data base on soot concentrations in Los Angeles is of particular importance. As noted by Pierson (12). Los Angeles air quality is likely to be heavily affected by increased soot emissions if large numbers of diesel passenger cars are introduced into the vehicle fleet. It is important to characterize existing air quality before this occurs. 

Especially the application of particulate filter systems is broadly considered to be the most efficient way for a significant reduction of the soot emission for diesel engines. Consequently, these systems also make high demands on the measurement systems, especially in sensitivity. 

Diesel soot emissions can be reduced by two different end-of-pipe technologies ... 

The reduction of diesel soot emissions measured as a soot deposit on a filter paper was achieved more easily by improved fuel injection and engine control technique. 

The European regulations did not require lower soot emission levels. 

By using improved fuel injection and engine control techniques, the concentration of soot particles in the exhaust gas was reduced (less gray filter paper), but the number of soot particles was increased and their average size was reduced, which made the diesel engine emissions even more harmful. So, everyone was back to square one - and the unfavored end-of-pipe technology for the reduction of diesel soot emissions came back to life again ... 

Koylii, U.O. and Feath, G.M. Carbon monoxide and soot emissions from liquid-fueled buoyant turbulent diffusion flames. Combustion and Flame, 1991. 87, 61-76. 

Figure 5. Soot Emissions From Toluene/Iso-Octane Blends...

Farmer, R. C. Edelman, R. B. Wong, E. "Modeling Soot Emissions in Combustion Systems" Particulate Carbon Formation During Combustion, 1980, GM Research Symposium. 

Emissions of soot on the other hand represent a smaller fraction of the overall emission, but are probably of greater concern from the standpoint of visibility and health effects. It has been suggested that soot emissions from fuel oil flames result from processes occurring in the vicinity of individual droplets (droplet soot) before macroscale mixing of vaporized material, and from reactions in the bulk gas stream (bulk soot) remote from individual droplets. Droplet soot appears to dominate under local fuel lean conditions (1, 2), while bulk soot formation occurs in fuel rich zones. Factors which are known to affect soot formation from liquid fuel flames include local stoichiometry, droplet size, gas-droplet relative velocity and fuel properties (primarily C H ratio). 

Finally, charge transfer reactions have been advanced also to explain the eflFect of metalhc additives on soot emission from flames. The ability of metallic additives either to diminish or to enhance the soot formation in flames has been well known for many years (3). Their role is usually linked either to modification of the production rate of hydrocarbon ions (4) or to alteration of the concentration of OH radicals (3). Although there is still some disagreement about experimental results as well as their interpretation, it now appears (29) that the soot-promoting effect is linked to ions resulting from metallic additives through reactions such as ... 

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