Effects of the reaction conditions on the distribution of sulphur among the products of the catalytic dissolution of Turkish lignites

Effects of the process parameter on the distribution of the inherent sulphur among the products of the catalytic liquefaction of two Turkish lignites have been investigated. The dissolution reactions were carried out in tetralin at 350–425 °C under nitrogen atmosphere. Fe2O3, Mo(CO)6, MoO3 or Al2O3 were used as the added catalysts. The starting nitrogen pressure ranged from atmospheric to 5 MPa, the isothermal extraction periods ranged from 0 to 120 min, solvent/lignite ratio ranged from 1/1 to 6/1. After drying in vacuum, the char and the soluble products were analyzed for their sulphur contents. The results indicate that the sulphur content of the soluble products were generally lower than 1% and only a small portion (≈0.5–7%) of the initial total sulphur passed to the soluble product. Most of the sulphur was remained in the char or passed into the gaseous products. Besides the process conditions, the structures of sulphur in the original lignites strongly affect the partitioning of the sulphur among the products.