Pyrolysis Chamber Design

The pyrolysis chamber is generally heated with a high velocity gas burner. In order to avoid hot-spots, an impingement plate is used such that there is no flame impingement on the vessel itself. In newer designs however the chamber is heated indirectly with a hot air burner so that hot spots and flame impingement problems are eliminated. 

Various laser pyrolyser designs have been reported [351-355]. A relatively cheap (non-commercial) low-power system has been designed that simplifies and improves access to laser pyrolysis (LPy). This system uses a Nd-Cr-GGG laser that delivers 600 mJ pulses of 500 /as with a slow repeat rate of 40 s [355]. The laser energy is delivered to the pyrolysis chamber via an optical fibre. 

The pyrolysis chamber consists of a glass tube designed to contain the microreactor system during a pyrolysis experiment. The upper part of the chamber is connected with a hammer assembly through a kolvar tube sealed to the glass. The lower part is designed to hold the... 

Old polyurethane on rims may be removed either on a lathe, by solvent attack, or by freezing in liquid nitrogen. For more complex shapes, the reinforcing may be recovered by the above methods as well as by pyrolysis in a specially designed chamber, where the material is heated in the absence of air to above the decomposition temperature of the polyurethane. The fumes are then burned using special after-burners. 

Once the sample has been pyrolyzed, volatile fragments are swept from the heated pyrolysis/injection port by carrier gas into the GC or GC/MS system. In Py-MS, it is likewise desired to transfer pyrolysis products to the ionization source of the MS without appreciable degradation, condensation loss, or recombination. Designs of Curie-point Py-MS systems have incorporated glass reaction tubes, expansion chambers, heated walls, and positioning of the pyrolysis reactor directly in front of the ion source."... 

PyMS is a mass spectrometric technique in which a flash pyrolysis device is coupled directly or indirectly to a mass spectrometer. Total PyMS experiments can be performed in a few minutes. Off-line PyMS of polymers was first reported in 1948 [671, 672] and on-line PyMS of polymers in 1953 [673]. In the ideal experimental design the pyrolytic fragments of macromolecules are generated under non-isothermal conditions, escape sufficiently fast from the dissociating matrix so that overheating and further rearrangement of the pyrolysis products are prevented, and are analysed without further wall contact by soft ionisation MS techniques. The ideal conditions are most closely met when pyrolysis takes place inside the ionisation chamber, but in practice the analytical PyMS conditions are often quite different. 

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