Soot elimination

Some of these residual-fuel additives also contain rust inhibitors and soot eliminators (16). 

SIMULTANEOUS NOx REDUCTION AND SOOT ELIMINATION FROM DIESEL EXHAUST ON PEROVSKITE-TYPE OXIDE CATALYSTS... 

Higashi. M. IJchida. S. Suzuki, N. and Fuji), K. Soot elimination and NOx and SOx reduction in dicscl-cngine exhaust by a combination fo discharge plasma and oil dynamics IEEE Trans. Plasma Sci, 1992. 20, 1-12... 

As catalytic supports, lanthana has been used in the synthesis of methanol from syngas [32], in the ethane hydrogenolysis and cyclopropane hydrogenation [5], in the n-heptane dehydrocyclization [33] and in the oxidative coupling of methane [34], as well as in diesel soot elimination [35] and diy reforming of methane [36],... 

Miro, E. E., Ravelli, F., Ulla, M. A., Comaglia, L. M. Querini, C. A. (2000). Catalytic diesel soot elimination on Co-K/La203 catalysts Reaction mechanism and the effect of NO addition. Stud. Surf. Sci. Catal, 130, 731-736. 

For environmental reasons, burning should be smokeless. Long-chain and unsaturated hydrocarbons crack in the flame producing soot. Steam injection helps to produce clean burning by eliminating carbon through the water gas reaction. The quantity of steam required can be as high as 0.05—0.3 kg steam per kg of gas burned. A multijet flare can also be used in which the gas bums from a number of small nozzles parallel to radiant refractory rods which provide a hot surface catalytic effect to aid combustion. 

Fig. 11. The loss of carbon rapidly increases with the increase of temperature. Heating of the catalysts in open air for 30 minutes at 973 K leads to the total elimination of carbon from the surface. The gasification of amorphous carbon proceeds more rapidly than that of filaments. The tubules obtained after oxidation of carbon-deposited catalysts during 30 minutes at 873 K are almost free from amorphous carbon. The process of gasification of nanotubules on the surface of the catalyst is easier in comparison with the oxidation of nanotubes containing soot obtained by the arc-discharge method[28, 29]. This can be easily explained, in agreement with Ref [30], by the surface activation of oxygen of the gaseous phase on Co-Si02 catalyst.

A "mild reformer" is assumedto eliminate of the higher hydrocarbons prior to entering the fuel cell to prevent sooting. This reformer is called a "mild reformer" to indicate that the reforming reactions are not pushed to completion, for it is desired that the methane be reformed in the fuel cell for better temperature management. Some of the methane, however, will be reformed with the higher hydrocarbons in the mild reformer. 

The combustion efficiency of the benzene was beyond 99.999% even at an overall equivalence ratio of 1.0 (including the entrainment air which was 30% of the total air flow). With the controller off, the flame was extremely sooty and, in fact, sooting as the quartz tube would be blackened and the mass spectrometer sampling probe clogged in a matter of seconds, and soot was sucked into the scrubber system. This comparison between controller off and controller on conditions with benzene fuel is extremely dramatic and shows the efficacy of active combustion control in vortices to eliminating soot from diffusion flames. 

Photographs of diffusion and partially premixed flames in the present study and many of the references cited here have shown that this strategy can be applied to soot reduction and possibly smoke elimination. Further work is needed to establish the window of opportunity to utilize partial premixing for smoke elimination, without affecting stability, ignition, and re-light capabilities. 

In this process (Figure 10-7), a controlled mixture of preheated feedstock and oxygen is fed to the top of the generator where carbon monoxide and hydrogen emerge as the products. Soot, produced in this part of the operation, is removed in a water scrubber from the product gas stream and is then extracted from the resulting carbon-water slurry with naphtha and transferred to a fuel oil fraction. The oil-soot mixture is burned in a boiler or recycled to the generator to extinction to eliminate carbon production as part of the process. 

The physical and chemical properties of synthetic crudes are different from those of petroleum. Increased NO and soot production are the principal problems of the combustion of synthetic fuels, and control concepts for these two problems are in conflict. Fuel-rich combustion decreases NO but augments soot production, while fuel-lean combustion decreases (and can eliminate) soot production but augments NO emissions. Moreover, control procedures can affect combustion efficiency and heat-transfer distribution to the chamber surfaces. Table I, taken from Grumer (6), illustrates some specific relevant properties of synthetic liquid fuels and petroleum-based fuels. The principal differences between these fuels as related to their combustion behavior are summarized in Table II. 

The highly exothermic reaction for the formation of MgF2 heats up the carbon soot formed to approx. 2200 K, which then emits the IR radiation. Moreover, in Mg rich formulations (m > 2), the evaporating Mg is oxidized in the gas phase (3100 K). In addition, the carbon which is formed from the reductive elimination of fluorine from Teflon can be oxidized further to CO or C02 by atmospheric oxygen ... 

There are several ways in which to adjust the composition of the solution. For one, different elemental precursor chemicals can be used. The choice of precursors depends on their solubility in a given solvent or solvent system. Similarly, the choice of solvent is primarily dictated by the requirement to fully dissolve the precursor. Furthermore, carbon-free solvents, such as water, and low carbon residue (soot) solvents, such as methanol, may be used to control the amount of elemental carbon in the flame. The elimination of impurities can also be extremely significant in certain applications. For example, sulfur and sodium can be detrimental to many coatings in such cases solvents and precursors must be free of these and other common impurities. 

Extracts of different organic solvents normally contain the same soluble species empty fullerenes such as Ceo, C70, and Cs4 are dominant, whereas M Cs2 is always the most abundant EMF species and M2 Cso is normally the most abundant di-metallofullerene. Extraction of TNT cluster metallofullerenes is easier because of both the high production yield and the high solubility in common solvents. The general extraction process for TNT EMFs is the following the soot is first washed by acetone to eliminate hydrocarbon byproducts then the residue is subjected to solvent extraction with CS2 or xylene [68, 69]. 

The goal of the symposium is to provide a forum for chemists, chemical engineers, and combustion scientists to discuss the most recent advances in combustion research of fuel sprays in order to improve the eflBciency in energy conversion, to eliminate soot and pollution by-products, and to improve the fuel quality by chemical means. It is also befitting the occasion of our Nations Bicentennial Celebration and of our Society s Centennial Meeting to address ourselves to one of the most urgent problems of our nation—conservation of energy and environmental resources. 

Diesel exhaust usually demands special aftertreatment technologies. In the following two subsections, removal of hydrocarbons and carbon monoxide and a novel approach to the elimination of soot particles are discussed. The effective removal of NOx under the lean conditions prevailing in diesel exhaust has not yet been commercialized, and some... 

Since ATRs combine some of the best features of steam reforming and partial or full oxidation, some groups have developed compact catalyst systems to eliminate the need for a robust burner and mixer design. The catalyst system also reduces the formation of carbon and soot. Farrauto et al.6 and Giroux et al.7 discussed ATR-based systems for fuel cell applications in detail. 

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