Effects of alkali and alkaline earth metals on the formation of light aromatic hydrocarbons during coal pyrolysis

- The effect of AAEMs in coal on light arenes formation is investigated during coal pyrolysis.
- The distribution of coal tar composition will be changed under the catalytic effect of AAEMs.
- AAEMs can crack phenols and condensed aromatics into light aromatic hydrocarbons.

Light aromatic hydrocarbons from coal pyrolysis such as benzene, toluene, xylene, and naphthalene have been found wide applications as industrial raw materials. The alkali and alkaline earth metals (AAEMs) are of considerable effect on the yield and distribution of coal tar during pyrolysis. In this study, the yield and distribution of the pyrolysis products of three raw coals with different ranks, demineralized coals prepared by acid washing, and metal-loaded coals were investigated using pyrolysis-gas chromatograph/mass spectrometer (Py-GC/MS). The results show that the yields of benzene, xylene, toluene, and naphthalene are significantly different before and after acid washing, and the generation of light aromatic hydrocarbons has an obvious dependency on AAEMs in coal. AAEMs have good catalytic activity on the decomposition of phenols and condensed aromatics to light aromatic hydrocarbons.