Pyrolysis, flash properties

Table 17. Properties and Analysis of Liquid Fuel and No. 6 Fuel Oil Liquid fuel produced by flash pyrolysis using char recycle (Fig. 10).

Most nitrile oxides are unstable, some of them are explosive. This fact hinders the study of their physical properties. Nevertheless, there are a number of publications concerning not only stable but also unstable nitrile oxides. In particular, mass spectral data for nitrile oxides among other unstable compounds containing an N+-X bond are summarized in a review (9). In such studies, the molecular ions must be generated using indirect procedures, including dissociative electron ionization, online flash-vacuum pyrolysis mass spectrometry, or ion-molecular reactions. Their characterization is mainly based on collisional activation and ion-molecular reactions. 

Silacyclopentan-2-ol properties, 1, 612 Silacyclopentan-3-ol properties, 1, 612 Silacyclopent-3-ene, 1,1 -dichloro-NMR, 1, 614 Silacyclopentenes flash vacuum pyrolysis, 1, 615 synthesis, 1, 610-612 Silacyclopent-2-enes synthesis, 1, 610 Silacyclopent-3-enes properties, 1, 612 reactions... 

The different properties of sulfur-rich kerogen and asphaltenes, on the one hand, and sulfur-rich resins on the other hand (flash pyrolysis behaviour) may be explained only by differences in degree of (sulfur) cross-linking and thus by differences in molecular size and in degree of condensation. 

The chemical properties of 2,3-dihydro-1,4-diazepines are dominated by the presence of the diene portion of the molecules, either by electrophilic attack at the 1, 4 or 6 positions, or nucleophilic attack at positions 5 or 7. There have previously been no observations of the involvement of the saturated part of the molecule. It has now been demonstrated, however, that in vacuum flash pyrolysis there is a suprafacial 1,5 hydrogen shift of a proton from position 7 to position 3 . This has been confirmed by deutero-labelling studies when 7-deutero-2,3-dihydro-methyl-1,4-diazepine is converted into the 3-deutero-isomer. When the study is repeated with the bicyclic t/.s-2,3-cyclohexano derivative the /ram-isomer is isolated, confirminf a suprafacial shift mechanism... 

The liquids require a hydrorefining step to stabilize their reactive properties, to reduce the asphaltenes and preasphaltenes, to reduce sulfur, nitrogen, and oxygen, and to make the liquids more distillable. The extent of hydrorefining depends on the end use of liquids—fuel oil or chemical feedstocks. The objective of this work is to evaluate the hydrorefining processibility of ORC flash pyrolysis coal tar as a part of the tar characterization task. Results of the initial phase of catalyst screening tests are reported in this chapter. 

The quality of the product is of primary importance in developing a recycling technology converting plastics into fuels by pyrolysis. Today the characterization of a liquid fuel from any sources is obviously based on the qualification methods and standards of fuels from mineral oil. The properties of the pyrolysis-derived fuels from plastics are expected to be similar to conventional fuels (energy content, viscosity, density, octane and cetane number, flash-point, etc.). However, in addition to the familiar ranking values it is necessary to know more about the chemical composition of the plastic pyrolysis oil, because of the peculiarities as follows ... 

The composition of the plastic feedstock for pyrolysis processes has a direct bearing on the quality of the resultant fuel products, especially flash point, cetane index, low-temperature properties and heteroatom content (e.g. sulphur, chlorine and nitrogen). 

The yield and properties of the char depend also on the rate of heating. Flash pyrolysis by intense, thermal radiation leaves little char (see Section III,2b, p. 456), in contrast to heating at slowly rising temperatures, which results in carbonization of cellulose. 

TABLE 8.11 Typical Properties of No. 6 Fuel Oil and Liquid Fuel from Flash Pyrolysis of Refuse-Derived Fuel ... 

A few properties of the liquid oils produced by selected flash pyrolysis and the PERC and LBL processes are listed in Table 8.13. It as apparent that there are some basic differences between the two classes of oils. The oils from the flash pyrolysis processes are quite similar, as are the oils from the PERC and LBL processes. But there are major differences in their elemental analyses and... 

The complexity arises from the degradation of lignin, cellulose, hetnicellulose and any other organics in the feed material, giving a broad spectrum of phenolic and many other classes of compounds that result from uncontrolled degradation as described below. The liquid from fast or flash pyrolysis has significantly different physical and chemical properties compared to the liquid from slow pyrolysis processes, which is more like a tar. 

In general, there are two possible means of creating a solid with the desired properties, the so-called matrix. The molecules of interest can be generated from suitable precursors by reactions in the gas phase. The routine method is the high-vacuum flash pyrolysis of thermally labile compounds followed by direct condensation of the reaction products and co-deposition with an excess of host material on the cold matrix holder. The second way is to produce the... 

Physical Properties of Tars Due to the differences in chemical composition of the tars, the physical properties also vary significantly The pyrolytic oxygenates exhibit considerable water solubility In addition to water, other lightweight polar compounds such as acetic acid, hydroxyacetaldehyde, methanol, and hydroxypro-panone are present which also act as solvents As a result, the conventional flash pyrolysis oil can be thought of as a solution of polar organics in a water, acid, ketone solvent This solution has a high density (>1 2 g/ml) and a relatively low viscosity (60 cps at 40 O ... 

All these theoretical quantities are very useful for studies on the chemical and physical properties of copolymers. And methods which allow identification of particular structures (e.g. isolated units, some types of sequences or linkages. ..) might then either confirm or not the correctness of the envisioned kinetical schemes. From this point of view, NMR is a very efficient tool. Nevertheless, IR spectroscopy and flash pyrolysis gave us some interesting results [79, 20]. 

Azete 6 crystallizes as reddish needles of mp 37°C. In its chemical properties, 6 shows analogies to cyclobutadienes. Its flash pyrolysis at 700°C gives di-tert-butyl acetylene and tBu-CN AG for this decomposition is very high, since a concerted (2 + 2)-cycloreversion is not allowed according to the Woodward-Hoffman rules ... 

Recent examples featuring acenaphthylene moieties are included in this section. In general, Pd-catalyzed methods of constructing the CPPAs have overtaken traditional annulations and the harsh conditions of flash vacuum pyrolysis. Readily available haloarenes and reliable synthetic procedures have allowed the preparation of these planar fullerene fragments. Study of the compounds has brought to light some of the defining properties of CPPAs and how the desirable traits of fullerenes can be expressed in small molecules. 

---