Furnace Pyrolyser

Pyrrole, alkyl pyrroles, benzeneacetonitrile and benzenepropanenitrile. Pyrolyser continuous mode micro furnace pyrolysing injection system Pyrojector (SGE, Austin, Texas, USA) furnace pressure 14 psi purge flow 0.5 ml min 1 [28],... 

Figure 11.9 Pyrogram of a paint sample collected from sixteenth century wall paintings in the Messer Filippo cell of the tower in Spilamberto, Italy. Pyrolysis was performed with a micro furnace pyrolyser, at 600°C, in the presence of HMDS. 1, Carbohydrate pyrolysis products 2, lauric acid 3, suberic acid 4, levoglucosane 5, azelaic acid 6, miristic acid 7, hexadecanenitrile 8, palmitic acid 9, octadecanenitrile 10, oleic acid 11, stearic acid. TMS derivative [74]...

Continuous mode (furnace) pyrolyser A pyrolyser in which the sample is introduced into a pyrolyser preheated to the final temperature. 

A six tube furnace (Pyrolyser-6 Trio ) supplied by Raddec Ltd. (www.raddec.com) was used for the study (Fig. 1). The furnace consists of three independent heated regions comprising a sample zone, a middle zone and a catalyst zone. The sample zone, where samples are... 

In principle, equation (10) allows the calibration of any pyrolyser for a series of given temperatures with corresponding temperatures acquired by the sample. It is interesting, however, that a study regarding the pyrolysis of Kraton 1107 in a furnace pyrolyser [7] found linearity between T and R only at temperatures between 450° C and 625° C. 

A factor that must be considered with furnace pyrolysers as well as with the other types of pyrolysers is the achieving of short TRT values. A slow sample introduction in the hot zone of the furnace will end in a long TRT. A poor contact between the sample and the hot source may also lead to long TRT, most of the heat being transferred by radiation and convection and not by conduction. However, fairly short TRTs in furnace pyrolysers were reported in literature [16,17]. 

Another problem with the furnace pyrolysers can be the difference in the temperature between the furnace and the sample. Again, due to the poor contact between the sample and the hot source, the sample may reach a lower actual temperature than the temperature of the furnace wall. It is interesting that in microfurnace systems there were reported variations in the pyrolysis products as compared to the results obtained in inductively or filament heated pyrolysers [7,18]. As an example, a study done on Kraton 1107 [7] decomposition found linearity between the oven temperature and the ratio of two decomposition monomers (styrene and dipentene) only in a narrow temperature range, namely from 450° C to 625° C. Kraton 1107 was found to decompose in filament or Curie point pyrolysers such that linearity can be noticed between temperature and styrene/dipentene ratio from 500° C to 850° C. The reproducibility of pyrolysis in a furnace was also found lower than for other pyrolysers [7]. 

The mechanical problems related to the rapid solid sample introduction or related to the introduction of solid samples with no air leak makes this type of pyrolyser more appropriate for liquid or even gas sample pyrolysis. Also, it being possible to build large furnace pyrolysers, this type is successfully used when larger amounts of sample are necessary to be pyrolysed. This is a common case for the pyrolysis of non-homogeneous samples when a few mg of sample do not represent well the average sample composition. 

Other different models of furnace pyrolysers were also reported in literature [18b]. As an example, a two-temperature zone furnace was made, and it was utilized to provide information about more volatile compounds trapped (adsorbed) in a sample as well as for performing true pyrolysis. In this system, the sample is heated first at 300° C where the volatile compounds are eliminated, and then the sample is pyrolysed at 550° C. 

The study of the matrix on pyrolysis result has an additional use besides the understanding of the origin of pyrolysate components. This is related to the influence of the matrix on the generation of specific hydrocarbons from a certain starting organic substrate under the infiuence of heat and of catalysis [46,47]. However, most of these studies are not directly related to analytical pyrolysis. In these studies, furnace pyrolysers were commonly preferred to small sample and flash pyrolysis [46]. These and other pyrolysis appiications for the study of kerogens and also of oil related components such as asphaltenes [47] have been proven extremely useful in practice [19]. 

Various ways of introducing a sample into a pyrolyser of the tubular reactor (furnace) type have been described. The sample can be introduced into the pyrolysis zone with the aid of a magnet [73], directly by means of a special injector for solid samples [74] and by gravity (free fall) [75]. The latter type of furnace pyrolysers includes a simple vertical device developed by Japanese investigators [75]. It meets the general requirements imposed on pyrolysers of this type, namely (1) it is made of an inert material (quartz) ... 

Micro)furnace pyrolysers, which are preheated to the desired final pyrolysis temperature before introduction of the sample, are categorised as continuousmode pyrolysers. In such devices, the sample is either moved into a preheated pyrolysis chamber (isothermal mode) or heated rapidly from ambient to pyrolysis temperature (programmable mode). However, furnace pyrolysers are generally held isother-maUy at the desired pyrolysis temperature, and the samples are introduced into the hot volume. 

From the above, some important features of pyrolysis GC-MS emerge, as given in Table 2.33. On-line flash pyrolysis GC-MS, with Curie-point, resistively-heated filament or furnace pyrolysers, is very widely utilised for identification of pyrolysis products from synthetic polymers. The main characteristics of PyGC-MS of polymers, as given by Schulten et al. [692], are shown in Table 2.34. PyGC-MS is an excellent tool for fast product quality control for R D purposes fiiU control of the (many) experimental parameters is needed. Polymer standards e.g. SEC standards) can be used to determine sensitivity and precision of PyGC-MS. 

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