Characteristics of pyrolysis

The fuel oils coming out of olefin plants are also characterized by an abundance of polynuclear aromatic molecules, (Same definition as for Figure 2—1). They are sometimes inaccurately referred to as having a high aromatics content. Nomenclature aside, because of this, the burning characteristics of pyrolysis gas oil and pyrolysis pitch are poor. They are smoky, sooty, and gum formers they rend to be more viscous, and because of their polynuclear aromatic concent, they are suspected carcinogens. They are basically a witchs brew of unsavory hydrocarbons.. ... 

The thermod> naniic and kinetic characteristics of pyrolysis examined above therefore impose a number of requirements concerning industrial operating conditions ... 

Different grades of pyrolysis oil were burned at 4 MW nominal power output in a test furnace of Oilon Oy s R D Centre. Operation, dimensions, adjustment parameters, and characteristics of pyrolysis oils were tested and compared, and ertussions in different cases were measured. 

In addition to the characteristics of pyrolysis oils and burner settings, different furnace constructions were compared in the test runs. By insulating the forepart of the furnace the mean tenqierature levels of flame were increased and hence combustion inqiroved. 

As seen from several examples, the main characteristic of pyrolysis of poly(acrylic acid esters) is the formation of monomer, dimer, trimer, etc. The specific yield of monomer, dimer, trimer, etc. is temperature dependent, higher temperatures favoring the formation of lower molecular weight compounds. 

One of the most important characteristics of pyrolysis is the temperature pattern of sample heating. Therefore, the changes of the filament temperature with time is an essential characteristic of pyrolysers. The most significant parameters are as follows (1) filament (sample) heating time (2) reproducibility of the kinetic heating curve and (3) constancy and stability of the maintained temperature. 

Characteristics of pyrolysis lubes ihc operation is conducted at a feedstock flow rate set for constant tube outlet pressure and dilution rate in tubes 0.103 m in diameter. Tbe rise in the tube skin temperature is offset by a decrease in their length and hence in contact time, to ensure operation at constant severity in the neighborhood of the maximum ethylene yield. 

Table 3.25 Characteristics of pyrolysis gasoline from different levels of cracking...

Pyrolysis mass spectrometry, which does not require a volatile derivative, has been applied to various penicillins (78MI51100). These spectra contained fragments arising from the bicyclic ring system (4,5-dihydro-5,5-dimethylthiazole at mje 115, 1- and 2-methylpyrrole at mje 81 and unidentified peaks at m/e 100 and 125) as well as a series of fragments characteristic of the C(6) side chain. 

Thermogravimetry may be used to determine the composition of binary mixtures. If each component possesses a characteristic unique pyrolysis curve, then a resultant curve for the mixture will afford a basis for the determination of its composition. In such an automatic gravimetric determination the initial weight of the sample need not be known. A simple example is given by the automatic determination of a mixture of calcium and strontium as their carbonates. 

The quality and quantity of sites which are capable of reversible lithium accommodation depend in a complex manner on the crystallinity, the texture, the (mi-cro)structure, and the (micro)morphology of the carbonaceous host material [7, 19, 22, 40-57]. The type of carbon determines the current/potential characteristics of the electrochemical intercalation reaction and also potential side-reactions. Carbonaceous materials suitable for lithium intercalation are commercially available in many types and qualities [19, 43, 58-61], Many exotic carbons have been specially synthesized on a laboratory scale by pyrolysis of various precursors, e.g., carbons with a remarkably high lithium storage capacity (see Secs. 

Pyrolysis characteristics of polyethylene using waste catalysts... 

Pyrolysis gas chromatography is an indirect method of analysis in which heat is used to transform a sample into a series of volatile products characteristic of sample and the... 

The MAB ion source offers several advantages over El for PyMS. By eliminating excessive fragmentation, characteristic of electron ionisation, and by producing highly reproducible mass spectra MAB (Kr) greatly simplifies the analysis of pyrolysis data. Furthermore, MAB ionisation, when combined to MS/MS, provides a useful tool for structural elucidation of pyrolysis products. The ability for selective ionisation can be very useful to reduce the background combination in techniques such as GC-MS, LC-MS or SFC-MS. 

The material balance is consistent with the results obtained by OSA (S2+S4 in g/100 g). For oil A, the coke zone is very narrow and the coke content is very low (Table III). On the contrary, for all the other oils, the coke content reaches higher values such as 4.3 g/ 100 g (oil B), 2.3 g/ioo g (oil C), 2.5 g/ioo g (oil D), 2.4/100 g (oil E). These organic residues have been studied by infrared spectroscopy and elemental analysis to compare their compositions. The areas of the bands characteristic of C-H bands (3000-2720 cm-1), C=C bands (1820-1500 cm j have been measured. Examples of results are given in Fig. 4 and 5 for oils A and B. An increase of the temperature in the porous medium induces a decrease in the atomic H/C ratio, which is always lower than 1.1, whatever the oil (Table III). Similar values have been obtained in pyrolysis studies (4) Simultaneously to the H/C ratio decrease, the bands characteristics of CH and CH- groups progressively disappear. The absorbance of the aromatic C-n bands also decreases. This reflects the transformation by pyrolysis of the heavy residue into an aromatic product which becomes more and more condensed. Depending on the oxygen consumption at the combustion front, the atomic 0/C ratio may be comprised between 0.1 and 0.3 ... 

The first part of this paper has shown that Australian black and brown coals differ significantly in a number of respects from coals of similar ranks from North America and elsewhere in the northern hemisphere. The rest of the paper than proceeded to indicate the progress being made to determine how the characteristics of Australian coals influence their conversion to volatile and liquid products during pyrolysis and hydrogenation. 

Non volatile organic compounds are not amenable for gas chromatography. However, some types of non volatile compounds, upon pyrolysis, yield volatile products which are characteristic of the original substance and can be used as a basis of a method for estimating these substances. 

Biomass pyrolysis in the presence of a catalyst, in situ, is considered as one of the options to overcome the problem characteristics of bio-oil mentioned above. Selective removal, by decarboxylation, of carboxylic acids (formic, acetic acids)... 

The influence of pyrolysis conditions on the structure, morphology, electrical properties, and electrochemical behavior has been investigated. Raman spectroscopy shows that characteristic sp carbon bands form from the pyrolysis treatments. The electrochemical properties for a few of the electrode systems have been reported and, for the most part. 

EPR has been observed and studied in porous carbons by numerous authors 178-182). The carbons studied have been prepared by pyrolysis of organic material such as dextrose 180), coal 181), and natural gas or oils 181,182). Porous carbons are of considerable technological importance and show catalytic activity for the ortho-parahydrogen conversion, the hydrogen-deuterium reaction, and many reactions of inorganic complex ions 156). Relationships between the characteristics of the EPR absorption and the catalytic activity of porous carbons for the o-p Hj and Hj-D reactions have been demonstrated by Turkevich and Laroche 183). 

The analysis of lignitic woods by analytical pyrolysis has shown that lignin structural units can be preserved as biomaikers in samples as old as Carboniferous age, or approximately 300 million years. At least half or more of the pyrolysis products in lignitic wood of Cretaceous age are methoxyphenols characteristic of lignin. The pn uct distributions in these Cretaceous samples indicate that the lignin is mainly altered in the 3-carbon side chains. Phenols, cresols, catechols, and other methylated phenols account for most of the remaining pyrolysis products. It is likely diat these products are also derived frx>m li in, especially lignin that has been altered by coalification reactions. 

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