Effect of dehydrogenation on the pyrolysis of two coals

AbstractThe series of dehydrogenated coals previously prepared1 by treating a 902 rank and a 401 rank coal with sulphur have been pyrolysed in a Gray‐King furnace to 600°. The variations in the yields of products have been compared as functions of the changes in the structure of the coals produced by the previous chemical dehydrogenation. The results obtained confirm the ‘hydroaromaticities’ previously deduced for the two coals and support the interpretation of the manner in which the coals reacted with sulphur. Furthermore, it is shown that when the two original coals were pyrolysed: All the acetylatable hydroxyl groups in the coals formed water, Both the ethane and the ethylene evolved derived from the ‘hydroaromatic’ parts of the coals, Tar was evolved by the disruption of the ‘hydroaromatic’ material which linked the aromatic nuclei in the coals, On the other hand, much of the ‘hydroaromatic’ material dehydrogenated to give an extended aromatic network which remained in the char, The hydrogen liberated by the dehydrogenation of the ‘hydroaromatic’ material was essential to many of those reactions which formed gas.