ScienceDirect - Fuel : Comparison of the effect of catalysts in coal liquefaction with tetralin and coal tar distillates
In further support of our earlier documentation that coal processing by-products, such as coal tars, can be beneficial additives that enhance the efficiency of some direct coal liquefaction processes, we submit this research from Spain, where, as we've elsewhere documented, coal was converted into liquid fuels in at least one facility, using WWII-era German indirect coal liquefaction technology, until the 1960's.
As follows:
"Comparison of the effect of catalysts in coal liquefaction with tetralin and coal tar distillates
J. Andres Legarreta, Blanca M. Caballero, Isabel de Marco, M. Jesus Chomón and Pedro M. Uría
Departamento de Ingeniería Química y del Medio Ambiente, Escuela de Ingenieros de Bilbao, Universidad del País Vasco, Alda, Urquijo s/n, 48013, Bilbao, Spain; 1996
Abstract
Special CoMo/Al2O3 catalysts were prepared for testing in coal liquefaction: a conventional CoMo/Al2O3 catalyst, one containing Zn as a second promoter and one having the alumina acidified with fluorine. Their activities were compared with that of red mud. The experiments were conducted in a stirred autoclave with a subbituminous coal and solvent (tetralin, anthracene oil or creosote oil) at 425°C and 17 MPa. The liquefaction products were fractioned into oils, asphaltenes and preasphaltenes with pentane, toluene and THF. The Co(Zn)Mo/Al2O3 catalysts have far higher activities than red mud. Zn and fluorine have beneficial effects on the catalyst activity. Coal tar distillates give higher conversions and oil + gas yields than tetralin when the prepared catalysts are used."
"Tetralin" is the hydrogen-donor solvent we have documented many times, from many sources, as being extremely useful in some direct coal liquefaction technologies, most especially WVU's "West Virginia Process".
But, note: "Coal tar distillates (which would include "anthracene oil or creosote oil") give higher conversions and oil + gas yields than tetralin when the prepared catalysts are used." As we've elsewhere documented, coal products and by-products, the various coal tars and coal tar chemicals, can be beneficial, productive additives for a direct coal conversion process, perhaps by contributing more hydrogen.
Further, "Co(Zn)Mo/Al2O3 catalysts", though formulaically vague, might indicate these Spanish researchers were also working with zeolite catalysts, like the one specified by ExxonMobil in their "MTG"(r), methanol-to-gasoline, Process; wherein the methanol is posited to be made from coal. However, other research we've documented for you also indicates that Iron Group metals, i.e., "Co", Cobalt, as above, are useful coal conversion catalysts. And, both Zinc (Zn) and Molybdenum (Mo), as coal conversion catalysts, have also been elsewhere noted.
As we've earlier explained, the "red mud", named in the Abstract, is an iron-rich waste product of at least one commercial process for refining aluminum from bauxite ore. It is not an exotic material, but the mention of it again emphasizes the value of Iron-group metals in some coal-to-liquid conversion processes.
