Gustavo Adolfo Castillo Quintero

The effects of morphological changes and mineral matter on h2s evolution during coal pyrolysis

The H2S release profiles of five important Colombian coals have been monitored using temperature programmed pyrolysis. It was found that there was no correlation between the amount of H2S and the sulphur content of the original coals. Coals which had been treated to remove all of the mineral matter and inorganic sulphur showed a good correlation with the free swelling index of the coals. This was explained by the physical trapping of H2S in closed porosity formed during pyrolysis. A similar result was found for demineralised coals with pyrite present. The H2S for untreated coals showed no systematic variation with rank, the coal sulphur content or free swelling index. This was because certain coals were rich in finely dispersed calcium which could chemically prevent H2S release.

The catalytic liquefaction of coal in the presence of ethanol

Liquefaction experiments have been performed on two Colombian coals under high pressure nitrogen atmospheres in the presence of ethanol and a catalyst of ZnCl2. It was observed that the production of products soluble in toluene and THF increased with reaction temperature and nitrogen pressure. The addition of a partial pressure of 10% hydrogen also increased yields although further increases in hydrogen pressure had no effect. It was observed that ethanol swelled both coals significantly and it was believed that the swelling increased the accessibility of the ethanol and catalyst to the macromolecular structure thus creating a very efficient hydrogenation system. The efficiency of the system was attributed to dissolution of the catalyst in the ethanol and swelling of the coal macromolecular structure.

Liquefaction characteristics of some Colombian coals: 1. Reactivity in catalytic hydrogenation

Abstract The liquefaction characteristics of two Colombian coal have been investigated using catalysis. Cerrejon coal 81% C (the biggest coal mine in Colombia) and Amaga coal 75% C were treated at different reaction temperatures (380–450 °C) and different reaction times (15–60min). At 425 °C and 60min reaction time the products obtained from both coals using a Ni catalyst were almost 100% soluble in THF. At temperatures lower than 425 °C, the Cerrejon coal is more reactive than the Amaga coal.