Much has been made of "Tar Sand", or "Oil Sand", such as in Canada's massive and much-touted Athabasca deposit, as a resource that could help us overcome our liquid fuel shortfalls.
It could do that, but the public doesn't seem to understand, really, the true nature of such deposits and what the implications are of extraction and usage.
First, the "tar", in tar sands, is more appropriately referred to as "bitumen". It is a nearly-solid substance highly contaminated with inorganic, non-combustible waste which is directly analagous to the "ash" in coal.
It has been postulated, in fact, that tar sands are just organic deposits that got interrupted during the process of being turned into coal.
Nevertheless, tar sands do represent significant, exploitable deposits of organic material that can be employed to help us satisfy our liquid fuel needs.
What isn't too well-known, except in certain circles, is that coal, and especially some fuel-type liquids extracted from coal, are very beneficial agents needed to "upgrade" tar sand bitumen so that it can be further refined into a liquid petroleum substitutes.
The enclosed report, from Japan, is just one of many available attesting to the enhancement of oil sand refining attained through the employment of coal or, better, as explained following the excerpt, liquids derived from coal, in the processing of tar or oil sand bitumen.
As follows:
"Document title
Addition effects of coal-derived oil and coal on upgrading of oil sand bitumenAuthors
YOSHIDA T. ; NAGAISHI H. ; SASAKI M. ; YAMAMOTO M. ; KOTANIGAWA T. ; SASAKI A. ; IDOGAWA K. ; FUKUDA T. ; YOSHIDA R. ; MAEKAWA Y. ;Authors Affiliation
Hokkaido national industrial res. inst., MITI, Toyohira, Sapporo 062, JAPONAbstract
The mechanism of synergistic interaction between bitumen and coal in coprocessing was investigated in conjunction with hydrogen transfer between them. Two types of reaction systems were used in this work: the upgrading of bitumen and coal-derived oil, and the coprocessing of bitumen with either coal-derived oil or coal. Considerable retrogressive reaction was observed in the upgrading of bitumen alone at 450 °C but was effectively suppressed by the addition of either coal-derived oil or coal. These results strongly suggest that both coal-derived oil and coal act as good hydrogen donors or shuttlers in the coprocessing. Furthermore, their addition resulted in more production of light oil from bitumen. The conversion of coal into toluene solubles was influenced by the concentration of coal itself in the slurry feed, but the formation of distillable oil from coal seemed to be negligibly small."There is, obviously, much not fully-explained in the Abstract. But, "coal-derived oil" "suppressed" retrograde reaction of the oil sand bitumen. The implications are that coal-derived liquids are preferable to the use of coal itself, since, in the tar sand bitumen upgrading process, "the formation of distillable oil from coal (itself) seemed to be negligibly small". But, already-synthesized "coal-derived oil" acts as a "good hydrogen" donor for the tar sand bitumen, with resultant synergies for both.
It is noted that raw coal was not appreciably transformed into "distillable oil" during the bitumen processing; but, liquids derived from coal and tar sand bitumen can be co-processed together more efficiently, than the bitumen can be alone, into liquid fuel raw materials.