Pyrolysis of peat

The release of nitrogen and sulphur compounds in peat pyrolysis was investigated between 300 and 700 °C. Seven peats with different nitrogen and sulphur contents (N:0.8729 %. S: 0.08—0.24 %) were studied. The pyrolysis was studied indirectly by following the elemental composition and the structure of the char residue. The tars of one peat sample were trapped.

The greatest portion of the sulphur-containing compounds pyrolysed below 500 °C, Nitrogenrcontaining compounds pyrolysed in a larger temperature range. One group of peats contained easily pyrolysable and the other group weakly pyrolysable nitrogen compounds. This suggests that the behaviour of fuel nitrogen in combustion will be difficult to predict because pyrolysis compounds may react further to corresponding oxides. The nitrogen content may be high in the tar in which case the tarry intermediates may also increase the amount of NO in flue gases. Infrared spectroscopy provided information about the decomposition of the main compounds in peat, like carbohydrates and long chained hydrocarbons during charring complementary to the information provided by elemental analyses.