Laboratory-scale pyrolysers

Laboratory-scale pyrolysers can be used for producing oils for analytical purposes. Many scientific and technical publications report on the pyrolysis of well-characterized polymers in open or closed reaction vessels, furnace-heated tubes, fixed-bed and fluidized-bed reactors. The pyrolysis products are generally analysed off-line, being condensed in cooled traps. 

Polyfluoroparafins, fluorocarbons, and other perfluoro denvatives show remarkable heat stability They are usually stable at temperatures below 300 C Thermal decomposition at 500-800 °C, however, causes all possible splits in the molecules and produces complex mixtures that are difficult to separate For preparative purposes, only pyrolyses that do not yield complicated mixtures of products are of interest [7] The pyrolytic reacpons of polyfluoro and perfluoro derivatives, when carried out at 500-11 Ofl °C, represent the most useful route to preparative generation of perfluoroolefins on the laboratory scale [7]... 

Li et al. [16] also stndied the influence of pyrolysis temperature on the pyrolysis products derived from solid waste in a rotary kiln reactor. They used an externally heated laboratory-scale rotary kiln pyrolyser (Figure 19.8). The length of the rotary kiln was 0.45 m with an internal diameter of 0.205 m. Kiln rotation speed can be adjusted from 0.5 to 10 rpm. The raw materials used in this study were polyethylene (PE), wood and waste tyres. The results obtained by Li et al. [16] reiterated that as the reaction temperature profile changes so does the product yield (Figure 19.9). 

Thermal decompositions (pyrolyses) and catalysed reactions in the vapour phase are widely used large-scale industrial techniques. These vapour phase reactions often lead to more economic conversions than the smaller batchwise laboratory methods, because relatively inexpensive catalyst preparations (compared to the often expensive reagents required in laboratory procedures) may be used, and because the technique lends itself to automated continuous production. In undergraduate laboratory courses the technique has not achieved widespread use. The discussion below of the various apparatus designs, to meet a range of experimental conditions, may be regarded as an introduction to this topic. 

INDUSTRIAL AND LABORATORY PYROLYSES (REACTOR DETAIL NOT TO SCALE)... 

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