Kentucky Liquefies Coal and Plastic

Direct liquefaction of waste plastics and coliquefaction of coal-plastic mixtures

 

In our earlier dispatch concerning the achievements of Northwestern University, who demonstrated the synergistic co-conversion of coal and plastic wastes into liquid fuel raw materials, we made note of their collaboration with the University of Kentucky in that effort.

 

Herein is some confirmation of UK's own work, confirming that coal can be synergistically combined with "oils", created by the thermal degradation of some waste plastics, to increase the yields of petroleum-type products from coal liquefaction processes.

 

Comment follows: 

Direct liquefaction of waste plastics and coliquefaction of coal−plastic mixtures

FENG Z.; ZHAO J.; ROCKWELL J.; BAILEY D.; HUFFMAN G.

CFFLS, 533 South Limestone St., Room 111 University of Kentucky, Lexington, KY 40506-0043

 

(Note: "CFFLS" stands for "Consortium for Fossil Fuel Liquefaction Science", which at some time, for some reason, in the subsequent decade, became abbreviated to the, perhaps, in light of a Big Oil presidential regime, more discreet, but less informative, "CFFS", the "Consortium For Fossil Fuel ... Science" - JtM)

Journal

Abstract

We have conducted further investigations of the direct liquefaction reactions of waste plastics, medium and high density polyethylene, polypropylene; and coal−plastic mixtures, varying the catalyst, temperature, gas, pressure, time and solvent. The experiments used four types of catalysts: a commercial HZSM-5 zeolite catalyst, and three catalysts synthesized in our laboratory, ferrihydrite treated with citric acid, coprecipitated Al2O3−SiO2, and a ternary ferrihydrite−Al2O3−SiO2. For direct liquefaction of plastics alone, a solid acid catalyst such as HZSM-5 or Al2O3−SiO2 markedly improves oil and total liquid yields, as determined by pentane and THF solubility, respectively. Yields are higher when using either a waste oil solvent or no solvent than using tetralin as the solvent. For PE, temperatures of 430 °C or higher are required for good yields, while PPE gives excellent yields at 420 °C. A commingled plastic provided by the American Plastics Council exhibited peak oil and total liquid yields at 445−460 °C. The oil yields and total liquid from PE ... and the APC commingled waste plastic decreased only slightly with decreasing hydrogen pressure (from 800 to 100 psig H2 ... . Furthermore, yields were as high under nitrogen (200−600 psig) as under hydrogen. Coliquefaction experiments were conducted on 50−50 mixtures of PE, PPE and the APC plastic with Black Thunder coal. For these experiments, the best results were obtained when the solvent was tetralin or a mixture of tetralin and waste oil. Lower yields were observed with only waste oil or with no solvent. Either HZSM-5 or Al2O3−SiO2−ferrihydrite increased oil and total yields by approximately 10% at 460 °C. Under the same conditions, yields from a PPE−coal mixture were substantially higher than those from a PE−coal mixture."

 

First, note that both WVU's coal liquefaction solvent, tetralin, specified in their "West Virginia Process" for direct coal liquefaction, and Exxon-Mobil's "HZSM-5", the zeolite  catalyst specified in their "MTG"(r), "methanol-to-gasoline" Process, wherein the methanol is posited to be made from coal, both of which we have previously documented, were utilized in these University of Kentucky developments.

 

Also note, somewhat importantly we think, that the use of hydrogen-rich plastics, in the liquefaction of Black Thunder Coal, enabled the liquefaction, the hydrogenation, to proceed just as effectively under an inert atmosphere as under one that might have been expected to increase liquid hydrogenation yields, but would have been far more difficult, and far more expensive, to use industrially, as in: "yields were as high under nitrogen (200−600 psig) as under hydrogen". 

 

It's all just more evidence that the technology does exist which would enable us to effectively combine our abundant coal with some of our, unfortunately, abundant and persistent wastes to manufacture the liquid fuels we grow increasingly short of, and increasingly dependent on other nations, many of whom we can't really call our friends, for the supply of.