%0 Research Notes %T The usability of the thermogravimetry in fuel research. Part IV. The effect of the reduced pressure on the pyrolysis %A Tummavuori, Jouni %A Venäläinen, Hannu %A Nyrönen, Timo %D 1979 %J Suo - Mires and peat %V 30 %N 1 %U http://suo.fi/article/9486 %X In this article we survey the pyrolysis of some solid domestic fuels in the lowered pressure, which completes the picture of the pyrolysis. Also, the possible comparison between the pyrolysis of the domestic fuels and the research methods have been rendered. The lowered pressure has a significant effect on the pyrolysis, because part of the polymerization and the coking are hindered. Up to the 650 K the pyrolysis seems to occur as in the nitrogen gas but thereafter no coking appears but the thermal decomposition proceeds. The remaining part of the reaction equals to the ash amount obtained after the reaction in the mixed gas. It is also obvious, that the particle size plays an important role in the pyrolysis in the lowered pressure. This can be seen from the inconsistent results presented in the literature. The substances under investigation are mixtures of several organic compounds whose composition or even an average molecular mass is unknown. The calculation methods employed here are based on the approximations which are valid for the simple reactions of the compounds with known structures. Their application to the unknown reactions is strongly criticized. If we perform the measurements in equal conditions and interprete the results as pseudo constants, they have, however, significance if the average properties of the pyrolysis of different substances are compared. Finally, since the pyrolysis of the organic matter completely occurs in the lowered pressure, this may have meaning when the refining processes are developed.