Energy Citations Database (ECD) - - Document #7150506
We confess that this submission, originating from Pittsburgh's USDOE Coal research center, takes a lot of study to glean much useful from it - at least to our less-than-able eyes.
Several points can be gotten, however, and this effort might relate to additional Coal conversion work that was done at another USDOE lab, in New Mexico, about which we will report in coming days.
We attempt summary following excerpts from the initial and following links to:
1 Mb View Document or Access Individual Pages - DOI: 10.2172/7150506
"OSTI ID: 7150506; Report Nos: DOE/PC/91041-T4; BCRNL-L--1668; DOE Contract AC22-91PC91041
Title: Preconversion processing of bituminous coals: New directions to improved direct catalytic coal liquefaction. [High temperature soaking (of) coal in coal liquids prior to liquefaction]; October, 1992.
Research Organization: BCR National Lab, Pittsburgh, PA; Sponsor: USDOE
Abstract: Soaking coal in coal liquids ... has been studied for coal dissolution prior to liquefaction.
Two high-volatile bituminous coals, Illinois No. 6 and Pittsburgh No. 8, were examined in three different coal liquids. The high-temperature soaking was effective to solubilize more than 70 wt% of these coals.
The mechanism of disintegration of coal by the high-temperature soaking was investigated under various soaking conditions. The products was also analyzed with solvent swelling. These results were rationalized that coal is solubilized primarily by physical disintegration. The derived mechanism was consistent with the new concept of coal structure: A significant portion of coal is physically associated, not three-dimensionally cross-linked.
Therefore, free-radical initiators may, under some circumstances, provide a positive effect on conversion.
Coal is mixed with a recycle oil and fed to a reactor in many coal liquefaction processes.
(Note: Scientists at Pittsburgh, PA's, Bituminous Coal Research National Lab could write knowledgeably about there being "many coal liquefaction processes". Who, among the general US Coal Country Public, really knew there was even just one?)
lt is desirable that coal be largely solubilized or disintegrated before liquefaction (but) preconversion has not been fully utilized. However, high volatile bituminous coal can be solubilized to a large extent by soaking in a
coal liquid (or recycle oil).
The disintegrated coal generated by the high-temperature soaking is still high-molecular-mass material, and extractability with poorer solvents such as toluene and cyclohexane is still low. Therefore, an alternative simple pretreatment to approach the breakdown of the high-molecular-mass material is further desired before liquefaction. The ... effect of radicals on preconversion of a high volatile bituminous coal is studied to develop chemical breakdown after or during physical dissolution.
In principle, the coal is soaked in tetralin and a coal liquid ... the effect ... is examined by extractability with three different solvents."
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Note that the "tetralin", as above, is an hydrogenated Coal, or Coke oven, tar derivative; and is, we believe, specified by WVU, in their "West Virginia Process" for the direct liquefaction of Coal.
Aside from that, the "pre-treatment" was studied as to it's effect on the subsequent conversion - and hydrogenation and liquefaction - of Coal in different solvents and "initiators".
In point of fact, the experimental focus seems to us to have been somewhat diffuse, and the results are presented mostly in charts and graphs that are nearly impenetrable.
However, one fact that can be gleaned from the DOE's tabulations is, that, after some types of pre-treatment, with use of specified reactants, a total Coal liquefaction/hydrogenation rate in excess of 90% can be achieved under either a Hydrogen, or - importantly, we think, because of economics - Nitrogen atmosphere, after the initial soaking in a Coal-derived oil resulted in a "more than 70 wt%" dissolution of the raw Coal.
Again, this work might, in part, relate to the additional hydrogenation and refining of Coal liquids which was conducted at the USDOE's Sandia National Lab, in New Mexico, and about which we will later make report.
But, one plain fact that can be sorted out of the graphics tangle is, that:
More than 90% of raw Coal, by weight, can, after specific pre-treatment with Coal-derived tars and oils, be converted into hydrocarbon liquids.