Characteristics of in situ coal gasification liquids from a cretaceous coal
The concept of harnessing energy from fossil fuel by gasification of coal in the ground has been revived with the aim to increase usuable coal reserves and to minimize the environmental impacts of mining and other problems. We report here the characteristics of liquids formed as a by-product of an underground gasification pilot test burn of a Cretaceous coal seam at a central Alberta location. The simplicity of the composition of liquids produced suggests that in situ coal gasification may be an economically viable source of refinery feeds or fuel.
The smaller molecules obtainable from coal and their significance: Part 6. Hydrocarbons from coal heated in thin layers
Abstract Heating the same weakly-caking coal as was used in previous work in thin layers in nitrogen resulted in an evolution of hydrocarbons in two distinct stages. Only small amounts were obtained up to 250 °C, the boiling ranges of which corresponded to those within which the coal was heated for their liberation. Above 250 °C, the boiling ranges were wide; a tendency was discernible, though not as clearly as in solvent extraction, for molecules to emerge in an order of diminishing molecular size. The manner of retention of the hydrocarbons in the coal is thought to explain this.
Time and Heritage
As a historian studying what can be considered a form of intellectual history, I have slowly come to adopt Michel de Certeau’s observation made at the end of the 1980s that ‘objectifying the past, for the last three centuries, has undoubtedly left unconsidered time within a discipline that has continued to use it as a taxonomic instrument’. To a certain degree, time has become commonplace for the historian who has preserved or instrumentalized it. It is not considered because it is inconceivable, but because we do not think of it or, more simply, we do not think about it. As a historian attempting to pay attention to the time I’m living in, I have thus, like many others, noticed the swift development of the category of the present until it has become obvious that the present is omnipresent. This is what I refer to here as ‘presentism’.