Pyrolytic processing

With respect to the formation of unwanted polyaromatic hydrocarbons in the pyrolytic process, it has been shown that conditions can be maintained where such fonuation is negligible according to EPA and OSHA standards. As production rates are increased, it will be incumbent on any manufacturer to maintain a set of operating parameters which produce an environmentally-benign product however, current information regarding the process for fiber formation reveals no barriers to accomplishing this. 

SBA-Kellogg A pyrolytic process for making ethylene and acetylene from saturated hydrocarbon gases, similar to the Hoechst HTP process but with the addition of steam which increases the yield of C2 gases. 

Visbreaking A thermal cracking process which reduces the viscosity of the residues from petroleum distillation, so that they may be handled at lower temperatures. It is essentially a high-temperature, noncatalytic pyrolytic process conducted in the presence of steam. See also HSC. 

Figure 3 shows the relationships between the temperatures and molecular weight distributions for 6 successive regions of the Til profile in Figure 1. Interestingly, regions a, b and c, primarily representing the low temperature components, show relatively narrow MW distributions around M values which markedly increase with temperature. This is consistent with the proposed interpretation of the low temperature hump as a vacuum desorption and distillation process rather than as a pyrolytic process. By contrast, regions d, e and f, representing the major Til maximum in Figure 1, exhibit much broader MW...

In Curie-point Py-LVMS studies of maceral concentrates (22). vitrinitic moieties were shown to be the main source of the hydroxy aromatic components. Thus, the hydroxy aromatic signals observed in Figure 2d appear to be primarily derived from vitrinite-like components by means of pyrolytic processes. Presumably, therefore, the "nonmobile phase", rather than the "mobile phase , is the main source of the phenols observed in TG/MS and Py-MS studies of Pittsburgh 8 coal (9,16). Further support for this conjecture comes from the observation that phenolic products are also observed in Py-MS analysis of pyridine extracts of Pittsburgh 8 coal known to contain colloidal matter whereas the corresponding tetrahydrofuran extracts, free of colloidal material, produced no phenols (21). 

On the other hand, forty years ago a lot of properties of carbon based materials coming from pyrolytic processes were well known [10-14] but it was in the last years where new kinds of CMS, fullerenes and carbon nanotubes [15-17] were discovered and studied These materials have the limitation of their small open pore size, which in general is near 10 A diameter, and then, diffusional and esteric problems may be present when they must interact with molecules of equal or bigger size within the mentioned pore diameter. 

Carbon films and graphite films have been prepared by vacuum evaporation [28,42,76,77], pyrolysis [29,36,78-83], screen printing [46,62,63,65,66,84], and laser photoactivation of sites on a graphite or glassy carbon substrate [85]. Various pyrolytic processes have been successful, most based on the deposition of volatile precursor compounds. For example, methane can be pyrolyzed while... 

The characteristic pyrolytic process for acid chlorides is loss of HC1 and this occurs for the bicyclic example 235 on FVP at 800 °C to give cyclohexa-1,2-diene 238 by way of the ketene 236 and carbene 237 as shown113. The product can be directly observed by low-temperature IR and forms a [2 + 2] dimer on warming up. FVP of >-toluoyl chloride 239 at 630 °C also results in loss of HC1 to provide a dependable large-scale synthesis of benzocyclobutenone 240 in excellent yield114. Pyrolysis of trichloroacetyl chloride, CI3C—COC1, over a bed of zinc at 420 °C results in dechlorination... 

PAHs are released to the environment from a number of sources pyrogenic sources including fossil fuel combustion and pyrolytic processes of organic matter such as incineration and petrogenic sources such as oils spills. Direct oil spilled from stationary sources and accidents cause contamination of land. Oil spills at US Army bases in South Korea is reported as a source of soil and groundwater contamination to nearby area... 

It should be noted that the latter reaction is complicated a deeper phenylation also forms methyldiphenyldichlorosilane, whereas pyrolytic processes form diphenyl, diphenylbenzene and other substances. 

Haloclean A pyrolytic process for destroying scrap plastics, especially those derived from scrap electronic equipment. The material is passed through a horizontal rotary kiln containing metal spheres that aid the heat transfer. Developed in Karlsruhe, Germany, and piloted from 2006. 

Hitachi Zosen A pyrolytic process for converting waste plastics into liquid fuels. Developed in the 1990s by Hitachi Zosen Corporation. 

Noell (1) A pyrolytic process for treating solid wastes. Developed in Germany by Preussag Noell Wassertechnik. 

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